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Niraparib for the treatment of ovarian cancer

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Abstract

Introduction Poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors are being developed in maintenance and recurrence treatment settings in ovarian cancer. They inhibit single-stranded DNA repair, inducing synthetic lethality in cells with underlying homologous recombination deficiency (HRD). Marked responses are seen in ovarian cancers with breast cancer gene 1 (BRCA1) or 2 (BRCA2) mutation, although up to 50% of high-grade serous ovarian cancers (HGSOC) have HRD may also benefit. Areas covered This review focuses on niraparib (oral PARP I and II inhibitor), its clinical testing in ovarian cancer, including the Myriad MyChoice HRD test as a potential companion diagnostic. Future directions plus ongoing trials, including novel combinations are highlighted. Expert opinion There is now level 1 evidence of efficacy from the first randomized placebo-controlled phase III trial using niraparib maintenance in women with platinum-sensitive recurrent HGSOC with complete or partial response post platinum-based chemotherapy. Niraparib improved progression free survival over placebo in all groups of women. The benefit was greatest in patients with germline BRCA1/2 mutant, followed by HRD positive tumors; however, absence of either does not exclude the possibility of benefit from niraparib maintenance. Additiona2l studies are underway with niraparib in the first line maintenance, and 4th/5th line recurrence treatment settings.

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... 6 BRCA1/2 loss of function, either through mutation or promoter methylation, compromises the double-strand DNA repair mechanism of homologous recombination, forcing more error-prone mechanisms such as nonhomologous end joining (NHEJ). 7 Poly (ADP-ribose) polymerase (PARP) family proteins are known to function through a wide array of DNA repair mechanisms, including base excision, single-strand break DNA repair, NHEJ regulation, transcriptional regulation, chromatin modification, telomere length, and genomic stability. [8][9][10] Consequently, PARP inhibition (PARPi), mainly through PARP1, also compromises cellular DNA repair capacity and genome integrity. ...
... Genomic mutational signatures of HRD, such as Myriad Genetics MyChoice HRD test, are also being used to correlate PARPi sensitivity to cancer's genetic background in hopes of generating predictive markers of response. 7 Ongoing clinical trials have been underway to combine PARPi with DNA damaging chemotherapies that induce DNA damage in complementary DNA repair pathways, including pairing niraparib with carboplatin (NCT03209401). Platinum-based chemotherapy in combination with PARPi has illustrated objective responses as high as 70% in patients with deleterious BRCA mutations, 6 with previous preclinical work demonstrating effective IC penetration and response. ...
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Background Despite the poor prognosis of triple negative breast cancer (TNBC) brain metastases, there are no approved systemic therapies. We explored the DNA-damaging Poly(ADP-ribose) polymerase (PARP) inhibitor (PARPi) niraparib in intracranial mouse models of BRCA-mutant TNBC. Methods Mice bearing intracranial human-derived TNBC cell lines (SUM149, MDA-MB-231Br, or MDA-MB-436) were treated with niraparib and monitored for survival; intracranial tissues were analyzed for PAR levels and niraparib concentration by mass spectrometry. RNASeq data of primary breast cancers using The Cancer Genome Atlas was analyzed for DNA damage signatures. Combined RAD51 and PARP inhibition in TNBC cell lines were assessed in vitro by colony forming assays. Results Daily niraparib increased median survival and decreased tumor burden in the BRCA-mutant MDA-MB-436 model, but not in the BRCA-mutant SUM149 or BRCA-wild-type MDA-MB-231Br models despite high concentrations in intracranial tumors. RAD51 inhibitor B02 was shown to sensitize all cell lines to PARP inhibition. In analysis of BRCA-mutant primary human TNBCs, gene expression predictors of PARPi sensitivity and DNA repair signatures demonstrate widespread heterogeneity, which may explain the differential response to PARPi. Interestingly, these signatures are significantly correlated to RAD51 expression including PARPi sensitivity (R2 = 0.602, R2= 0.758). Conclusions Niraparib penetrates intracranial tumor tissues in mouse models of TNBC with impressive single-agent efficacy in BRCA-mutant MDA-MB-436. Clinical evaluation of niraparib to treat TNBC brain metastases, an unmet clinical need desperate for improved therapies, is warranted. Further compromising DNA repair through RAD51 inhibition may further augment TNBC’s response to PARPi.
... By accounting for somatic mutations that have accumulated as a consequence of the mentioned processes, large-scale consortia [6][7][8][9] have attributed and revealed the many mutational signatures associated with human cancer types and etiology. This approach also presents mutational signatures with the ability to serve as biomarkers, enabling benefiting opportunities for diagnosis [10] and treatment guidance [11][12][13][14]. ...
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Background: Aristolochic acids (AAs) are potent mutagens commonly found in herbal plant-based remedies widely used throughout Asian countries. Patients and methods: To understand whether AA is involved in the tumorigenesis of the oro-gastrointestinal tract, we used whole-exome sequencing to profile 54 cases of four distinct types of oro-gastrointestinal tract cancer (OGITC) from Taiwan. Results: A diverse landscape of mutational signatures including those from DNA mismatch repair and reactive oxygen species was observed. APOBEC mutational signatures were observed in 60% of oral squamous cell carcinomas. Only one sample harbored AA mutational signatures, contradictory to prior reports of cancers from Taiwan. The metabolism of AA in the liver and urinary tract, transient exposure time, and high cell turnover rates at OGITC sites may explain our findings. Conclusion: AA signatures in OGITCs are rare and unlikely to be a major contributing factor in oro-gastrointestinal tract tumorigenesis.
... Smallmolecule Bax agonists (SMBA1, SMBA2, and SMBA3) have been reported to dephosphorylate Bax at the S184 site to restore the proapoptotic function in lung cancer (Xin et al., 2014). Moreover, these small molecule activators can bind to pyruvate kinase 2 (PKM2) to Epithelial ovarian, fallopian tube, or primary peritoneal cancer (Kanjanapan et al., 2017) *EGFR, epidermal growth factor receptor; ERBB, VEGFR, endothelial growth factor receptor; PDGFR, platelet-derived growth factor receptors; SCF, stem-cell factor receptor; ALK, anaplastic lymphoma kinase; FGFR, Fibroblast growth factor receptors; Itk, Interleukin-2 receptor-inducible T-cell kinase; Lck, Leukocyte-specific protein tyrosine kinase; BTK, Bruton's tyrosine kinase; BRCA, breast cancer gene; CDK, Cyclin-dependent kinases; PARP, Poly (ADP-ribose) polymerase. induce serine auxotrophy, leading to cytostasis in human adenocarcinomic alveolar basal epithelial (A459) cancer cells (Kung et al., 2012). ...
... As they inhibit SSB repair, inducing synthetic lethality in cells with underlying HRD as seen in BRCA1/2 mutant tumors (Fig. 3). Marked responses have been observed in ovarian cancers with BRCA1/2 mutation, even if up to 50% of HGSOC having HRD may also be better treated compared to cancers with HRD negative (HR proficient) genotypes [19,20]. ...
Article
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Poly (ADP-ribose) polymerases (PARPs) are an important family of nucleoproteins highly implicated in DNA damage repair. Among the PARP families, the most studied are PARP1, PARP2 and PARP 3. PARP1 is found to be the most abundant nuclear enzyme under the PARP series. These enzymes are primarily involved in base excision repair as one of the major single strand break (SSB) repair mechanisms. Being double stranded, DNA engages itself in reparation of a sub-lethal SSB with the aid of PARP. Moreover, by having a sister chromatid, DNA can also repair double strand breaks with either error-free homologous recombination or error-prone non-homologous end-joining. For effective homologous recombination repair, DNA requires functional heterozygous breast cancer genes (BRCA) which encode BRCA1/2. Currently, the development of PARP inhibitors has been one of the promising breakthroughs for cancer chemotherapy. In March 2017, the United States Food and Drug Administration (FDA) approved niraparib for maintenance therapy of recurrent gynecologic cancers (epithelial ovarian, primary peritoneal and fallopian tube carcinomas) which are sensitive to previous platinum based chemotherapy irrespective of BRCA mutation and homologous recombination deficiency status. It is the third drug in this class to receive FDA approval, following olaparib and rucaparib and is the first global approval for maintenance therapy of the aforementioned cancers. Niraparib preferentially blocks both PARP1 and PARP2 enzymes. The daily tolerated dose of niraparib is 300 mg, above which dose limiting grade 3 and 4 toxicities were observed. In combination with humanized antibody, pembrolizumab, it is also under investigation for those patients who have triple negative breast cancer. By and large, there are several clinical trials that are underway investigating clinical efficacy and safety, as well as other pharmacokinetic and pharmacodynamic profiles of this drug for various malignancies.
... PARP inhibitors are currently being tested in clinical trials with approval from the Food and Drug Administration (FDA) and European Medicines Agency (EMA) (Parkes et al., 2016). A Phase III trial with the PARP1 and PARP2 inhibitor Niraparib (MK-4827) for ovarian cancer showed that Niraparib inhibited PARP-triggered DNA damage and cell death, and the ultimate oncogenic progression (Lin et al., 2017;Kanjanapan et al., 2017). Another oral PARP inhibitor ...
Article
Poly ADP ribose polymerase (PARP) is a NAD-consuming enzyme and its specific role in the pathogenesis of alcoholic fatty liver disease (AFLD) is still elusive. In current study, we applied PJ34 to inhibit hepatic PARP activity to examine the corresponding pathological alteration in AFLD in mice and the underlying molecular mechanism. We found that PJ34 decreased the intracellular TG content in hepatocyte. Moreover, PJ34 suppressed the gene expression of DGAT1 and DGAT2 and elevated the intracellular NAD+ level in hepatocyte. These mechanistic observations were validated in alcohol-fed mice injected with PJ34 intraperitoneally. Results indicate that the PJ34 injection attenuated hepatic TG accumulation in alcohol-fed mice. Furthermore, the gene expression of hepatic SERBP-1c, DGAT1 and DGAT2 were lowered by PJ34 injection, while the hepatic NAD+ level was augmented by PJ34 injection in alcohol-fed mice. Finally, the nicotinamide riboside supplementation alleviated hepatic TG accumulation in alcohol-fed mice. These data indicate that applying PARP specific inhibitor PJ34 by intraperitoneal injection attenuated hepatic NAD+ depletion and TG accumulation in alcohol-fed mice, which may be a potential candidate for AFLD therapy.
... There is presently an ongoing phase II trial QUADRA single-arm test of niraparib treatment in relapsed HGSOC, fallopian tube cancer or primary peritoneal cancer patients who had received previously 3 or 4 regimens of chemotherapy. Patients enrolled in the trial must have experienced a platinum-based first-line therapy response lasting over 6 months (NCT02354586) [257,279]. The development process of niraparib bases also on extensive phase III doubleblind, placebo-controlled trial NOVA which has been recently completed. ...
Article
Cancer is a heterogeneous disease with a high degree of diversity between and within tumors. Our limited knowledge of their biology results in ineffective treatment. However, personalized approach may represent a milestone in the field of anticancer therapy. It can increase specificity of treatment against tumor initiating cancer stem cells (CSCs) and cancer progenitor cells (CPCs) with minimal effect on normal cells and tissues. Cancerous cells carry multiple genetic and epigenetic aberrations which may disrupt pathways essential for cell survival. Discovery of synthetic lethality has led a new hope of creating effective, personalized anti-tumor treatment. Synthetic lethality occurs when simultaneous inactivation of two genes or their products causes cell death whereas individual inactivation of either gene is not lethal. The effectiveness of numerous anti-tumor therapies depend on induction of DNA damage therefore tumor cells expressing abnormalities in genes whose products are crucial for DNA repair pathways are promising targets for synthetic lethality. Here, we discuss mechanistic aspects of synthetic lethality in the context of deficiencies in DNA double strand break repair pathways. In addition, we review clinical trials utilizing synthetic lethality interactions and discuss the mechanisms of resistance.
... A significant benefit in PFS in BRCA mutated patients receiving Olaparib was later confirmed with data from the SOLO2 trial [26]. In the United States, Olaparib monotherapy was approved by the Food and Drug Administration (FDA) as fourth or later line of treatment in advanced OC with deleterious germ-line BRCA1/2 mutation, based on results from a phase II study (NCT01078662), demonstrating a response rate of 31% and a median overall survival (OS) of 16.6 months in a population of 193 ovarian cancer patients treated with Olaparib [27,28]. Even more recently, on March 2017, Niraparib (ZEJULA, Tesaro) was approved as maintenance treatment of patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete (CR) or partial response (PR) to platinumbased chemotherapy. ...
... Although niraparib exhibits modest suppression to PARP catalytic activity, it showed stronger PARP trapping effects, as compared to olaparib and veliparib (Murai et al., 2012). Additional studies have demonstrated niraparib sensitized other solid tumors, such as ovarian cancer and colorectal cancer, to chemo-and radio-therapies (Genther Williams et al., 2015;Kanjanapan, Lheureux, & Oza, 2017). However, in some patientderived xenograft (PDX) models, niraparib failed to augment the effect of carboplatin/paclitaxel regimen in either homologous recombination (HR) deficient or proficient ovarian carcinoma (AlHilli et al., 2016), indicating more assays are essential to guide the performance of PARP inhibitor, except HR status. ...
Article
DNA repair pathways are evolutionarily conserved molecular mechanisms that maintain the integrity of genomic DNA. In cancer therapies, the integrity and activity of DNA repair pathways predict therapy resistance and disease outcome. Members of the poly (ADP-ribose) polymerase (PARP) family initiate and organize the biologic process of DNA repair, which counteracts many types of chemotherapies. Since the first development in approximately 3 decades ago, PARP inhibitors have greatly changed the concept of cancer therapy, leading to encouraging improvements in tumor suppression and disease outcomes. Here we summaries both pre-clinical and clinical findings of PARP inhibitors applications, particularly for combination therapies.
... Both of these tests are approved for ovarian cancer only and used primarily for the consideration of PARPi therapy. 46,47 FoundationOne CDX was recently approved as an NGS gene panel test for all solid tumors and includes genomic signatures for tumor mutation burden and MSI assessments. However, this panel is relatively unique in that it is also approved as a companion diagnostic for FDA-approved therapies in five tumor types: ovarian cancer, non-small cell lung cancer, melanoma, breast cancer, and colorectal cancer. ...
Article
The diffusion of high-throughput next-generation sequencing technologies has sustained massive parallel sequencing of tumor tissue providing a deep insight into tumor biology and advancement of personalized medicine. A substantial number of targeted agents have been investigated in gynecologic cancer and some have received U.S. Food and Drug Administration approval, like PARP inhibitors in ovarian cancer, bevacizumab in ovarian and cervical cancers, and pembrolizumab in microsatellite-unstable or mismatch repair-deficient endometrial cancer. To improve effectiveness of targeted therapy, identification of predictive biomarkers able to guide the selection of the correct drug for the correct patient is crucial. Different limitations must be addressed to favor a more rapid implementation of a genotyping approach in treatment selection, such as the possibility to easily assess tumor heterogeneity and clonal evolution along the disease trajectory and the need for innovative trial designs like adaptive or basket trials incorporating molecular features as selection criteria. A deep dive into the genomic features of exceptional responders may also favor better understanding of tumor biology, mechanism of action of a specific target agent, and identification or predictive biomarkers for subsequent tailored studies.
... 10 In contrast to olaparib, niraparib is approved for use in all patients with recurrent ovarian, fallopian tube or peritoneal cancers, as well as in patients who have previously received carboplatin. 11 The C max for niraparib in a patient ingesting 100 mg of the drug is approximately 2.5 μM; dosing is 100 mg TID in patients. Multiple groups have demonstrated that compounds that inhibit PARP1 can synergize with conventional genotoxic chemotherapies, including topoisomerase I inhibitors, ionizing radiation and DNA alkylating agents to kill a wide variety of tumor cell types. ...
Article
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Inhibitors of PARP1 are approved therapeutic agents in ovarian carcinomas. We determined whether the novel clinically relevant CHK1 inhibitor SRA737 interacted with PARP1 inhibitors to kill carcinoma cells. In multiple mammary and ovarian cancer lines SRA737 synergized with the PARP1 inhibitors olaparib and niraparib to cause cell death. The [SRA737 + niraparib] drug combination activated an ATM-AMPK-ULK1-mTOR pathway which resulted in the formation of autophagosomes, temporally followed by autolysosome formation. Phosphorylation of ULK1 S317 was essential for kinase activation against ATG13. The drug combination elevated eIF2α phosphorylation which was causal at increasing Beclin1 and ATG5 expression, reducing MCL-1 and BCL-XL levels, and causing CD95 activation. Knock down of CD95, eIF2α, ATM, AMPKα, ULK1, Beclin1 or ATG5 reduced drug combination lethality. Blockade of either caspase 9 function or that of AIF each partially prevented cell death. Expression of activated mTOR or of c-FLIP-s or of BCL-XL reduced cell killing. In vivo, SRA737 and niraparib interacted in an additive fashion to suppress the growth of mammary tumors. Multiplex analyses revealed that drug combination treated tumors had reduced their plasma levels of sERBB1, sERBB2, sVEGFR1, sVEGFR2, sIL-6R, HGF, PDGFAB/BB and CXCL16 and enhanced the levels of CCL26, IL-8 and MIF. Surviving tumors had activated ERK1/2 and AKT. This finding argues that IL-8/ERK/AKT signaling may be an evolutionary survival response to [SRA737 + niraparib].
... However, this assay did not have sufficient precision to deselect patients who would not benefit from niraparib, since a statistically significant PFS rate increase was demonstrated also in the HRD-negative group. 12,84 The phase II ARIEL2 trial was aimed to assess the ability of tumour genomic LOH to predict the response to rucaparib in the treatment setting. Tumours scoring above the LOH cut-off of 14% (LOH-high) with the Founda-tionFocus assay were deemed HRD-positive. ...
Article
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Poly (ADP‐ribose) polymerase (PARP) inhibitors have provided great clinical benefits to ovarian cancer patients. To date, three PARP inhibitors, namely, olaparib, rucaparib and niraparib have been approved for the treatment of ovarian cancer in the United States. Homologous recombination deficiency (HRD) and platinum sensitivity are prospective biomarkers for predicting the response to PARP inhibitors in ovarian cancers. Preclinical data have focused on identifying the gene aberrations that might generate HRD and induce sensitivity to PARP inhibitors in vitro in cancer cell lines or in vivo in patient‐derived xenografts. Clinical trials have focused on genomic scar analysis to identify biomarkers for predicting the response to PARP inhibitors. Additionally, researchers have aimed to investigate mechanisms of resistance to PARP inhibitors and strategies to overcome this resistance. Combining PARP inhibitors with HR pathway inhibitors to extend the utility of PARP inhibitors to BRCA‐proficient tumours is increasingly foreseeable. Identifying the population of patients with the greatest potential benefit from PARP inhibitor therapy and the circumstances under which patients are no longer suited for PARP inhibitor therapy are important. Further studies are required in order to propose better strategies for overcoming resistance to PARP inhibitor therapy in ovarian cancers.
... In the second subtype, nine drugs were obtained by the community (enriched by the "DNA metabolic process") and six drugs could be used to treat ovarian cancer, and the p-values of the community were 2.73 × 10 −5 . Specially, the drug Niraparib could target to the PARP2 in this community and it was one of the most familiar drug for recurrent ovarian cancer (Kanjanapan et al., 2017;Scott, 2017). Using the community enriched by the "response to endogenous stimulus, " 183 drugs were screened and 115 drugs could be used for cancer patients, (p-value of 4.08 × 10 −7 ). ...
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Due to the high heterogeneity and complexity of cancer, it is still a challenge to predict the prognosis of cancer patients. In this work, we used a clustering algorithm to divide patients into different subtypes in order to reduce the heterogeneity of the cancer patients in each subtype. Based on the hypothesis that the gene co-expression network may reveal relationships among genes, some communities in the network could influence the prognosis of cancer patients and all the prognosis-related communities could fully reveal the prognosis of cancer patients. To predict the prognosis for cancer patients in each subtype, we adopted an ensemble classifier based on the gene co-expression network of the corresponding subtype. Using the gene expression data of ovarian cancer patients in TCGA (The Cancer Genome Atlas), three subtypes were identified. Survival analysis showed that patients in different subtypes had different survival risks. Three ensemble classifiers were constructed for each subtype. Leave-one-out and independent validation showed that our method outperformed control and literature methods. Furthermore, the function annotation of the communities in each subtype showed that some communities were cancer-related. Finally, we found that the current drug targets can partially support our method.
... Tumors with mutations in BRCA1/2 are defective in the HRR process. These tumors show promising responses to treatment with a PARP inhibitor (olaparib), a drug that decreases the DDR in cancer cells to a fatally low level [31][32][33]. DNA-damaging agents that directly induce double strand breaks, such as chemotherapy based on platinum salts, prove therapeutically efficient in these cancers as well [34][35][36]. Recently, a model that can accurately predict HRR deficiency (HRDetect) was developed for breast cancers [11]. ...
Article
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Background In the past decade, systematic and comprehensive analyses of cancer genomes have identified cancer driver genes and revealed unprecedented insight into the molecular mechanisms underlying the initiation and progression of cancer. These studies illustrate that although every cancer has a unique genetic make-up, there are only a limited number of mechanisms that shape the mutational landscapes of cancer genomes, as reflected by characteristic computationally-derived mutational signatures. Importantly, the molecular mechanisms underlying specific signatures can now be dissected and coupled to treatment strategies. Systematic characterization of mutational signatures in a cancer patient’s genome may thus be a promising new tool for molecular tumor diagnosis and classification. Results In this review, we describe the status of mutational signature analysis in cancer genomes and discuss the opportunities and relevance, as well as future challenges, for further implementation of mutational signatures in clinical tumor diagnostics and therapy guidance. Conclusions Scientific studies have illustrated the potential of mutational signature analysis in cancer research. As such, we believe that the implementation of mutational signature analysis within the diagnostic workflow will improve cancer diagnosis in the future.
... The clinical trial of the drug combination of olaparib and taxol for terminal gastric cancer treatment finally failed in 2018. Niraparib, a PARP inhibitor derived from the indazole carboxamide lead developed by Merck, was approved by the FDA in 2017 for treatment of Pt-sensitive recurring (PSR) ovarian and peritoneal cancers without the limitation of BRCA mutations [10][11][12]. Besides competitively inhibiting catalytic active site of PARP-1, niraparib has the strongest ability to capture PARP-1 on DNA chains [13]. ...
Article
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A series of benzimidazole carboxamide derivatives have been synthesized and characterized by 1H-NMR, 13C-NMR and HRMS. PARP inhibition assays and cellular proliferation assays have also been carried out. Compounds 5cj and 5cp exhibited potential anticancer activities with IC50 values of about 4 nM against both PARP-1 and PARP-2, similar to the reference drug veliparib. The two compounds also displayed slightly better in vitro cytotoxicities against MDA-MB-436 and CAPAN-1 cell lines than veliparib and olaparib, with values of 17.4 µM and 11.4 µM, 19.8 µM and 15.5 µM, respectively. The structure-activity relationship based on molecular docking was discussed as well.
... The combination of niraparib with temozolomide was synergistic in the MTT cells, although not in human primary cultures. PARP inhibition by niraparib suppresses DNA repair, and sensitizes tumors to alkylating DNA-damaging agents (14,79,80) thus synergizing with temozolomide in the murine PCC cell lines. Consistent with this, in an allograft PCC mouse model, a PARP inhibitor sensitized PCCs to temozolomide (15). ...
Article
There are no officially approved therapies for metastatic pheochromocytomas apart from ultratrace 131I-MIBG therapy approved only in the United States. We have, therefore, investigated the anti-tumor potential of novel molecular-targeted approaches in murine pheochromocytoma cell lines (MPC/MTT), immortalized mouse chromaffin Sdhb-/- cells, 3D-pheochromocytoma tumor models (MPC/MTT spheroids) and human pheochromocytoma primary cultures. We identified the specific PI3Kα inhibitor BYL719 and the mTORC1 inhibitor everolimus as the most effective combination in all models. Single treatment with clinically relevant doses of BYL719 and everolimus significantly decreased MPC/MTT and Sdhb-/- cell viability. A targeted combination of both inhibitors synergistically reduced MPC and Sdhb-/- cell viability and showed an additive effect on MTT cells. In MPC/MTT spheroids, treatment with clinically relevant doses of BYL719 alone or in combination with everolimus was highly effective, leading to a significant shrinkage or even a complete collapse of the spheroids. We confirmed the synergism of clinically relevant doses of BYL719 plus everolimus in human pheochromocytoma primary cultures of individual patient tumors with BYL719 attenuating everolimus-induced AKT activation. We have thus established a method to assess molecular-targeted therapies in human pheochromocytoma cultures and identified a highly effective combination therapy. Our data pave the way to customized combination therapy to target individual patient tumors.
... 5 Niraparib was studied in a whole-cell assay that measured the number of PAR chains formed as a result of exposure to hydrogen peroxide, which resulted in DNA damage. 15 Cell lines that were used included the following: BRCA wild-type cervical cancer, HeLa cells and OC A2780 cells, and the BRCA2-deficient pancreatic cancer CAPAN-1 cells. Niraparib inhibited intracellular PARylation with 50% inhibitory concentration and 90% inhibitory concentration of about 4 nM and 50 nM, respectively. ...
Article
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Objective: To review the efficacy and safety of niraparib for the treatment of recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancer (OC, FTC, and PPC). Data sources: A literature search via MEDLINE through PubMed from August 2013 to January 2020 was performed using the key terms niraparib, PARP inhibitors, ovarian cancer, fallopian tube cancer, and primary peritoneal cancer. Study selection and data extraction: Completed and ongoing trials were identified through a review of the website trial registry https://www.clinicaltrials.gov. Data synthesis: In a phase III, double-blind clinical trial, progression-free survival improved in patients treated with niraparib compared with placebo as maintenance treatment for patients with platinum-sensitive, recurrent OC: 21 versus 5.5 months in the germline breast cancer susceptibility gene (gBRCA) cohort (hazard ratio [HR] = 0.27; 95% CI = 0.17 to 0.41; P < 0.001) and 9.3 versus 3.9 months in the overall nongermline breast cancer susceptibility gene (non-gBRCA) cohort (HR = 0.45; 95% CI = 0.34 to 0.61; P < 0.001). Adverse events included thrombocytopenia and anemia. Relevance to patient care and clinical practice: Poly (ADP-ribose) polymerase (PARP) inhibitors have gained a place in the therapeutic management of OC, FTC, and PPC because of their ability to suppress growth of homologous recombination deficiency-positive tumors, including those with BRCA1/2 mutations. Niraparib inhibits the DNA repair mechanism vital to the survival of cancer cells, poly-ADP ribose polymerase. Conclusions: PARP inhibitors can be used as a single agent for maintenance therapy for platinum-sensitive recurrent disease in patients with partial or complete response following 2 or more rounds of platinum-based therapy.
... Niraparib tosylate monohydrate (compound 19) Compound 19 (AEJULA ® ) is an excellent poly (ADP)ribose polymerase (PARP)-1 and PARP-2 inhibitor marketed in 2017 and approved by the FDA and EMA for the treatment of primary and secondary peritoneal cancer, fallopian tube cancer, and epithelial ovarian cancer [88][89][90][91][92][93][94][95]. It was developed by Merck Tesaro Zaiding Pharmaceutical Janssen Takeda and GSK It has high selectivity for PARP-1 and PARP-2 is characterized by controlled tolerance and more importantly allows patients to maintain their quality of life during the treatment [96,97]. ...
Article
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More and more attention has been paid to the structurally diverse indazole analogs in recent years which are widely present in numerous commercially available drugs. Indazole-containing derivatives are endowed with a broad range of biological properties, such as anti-inflammatory, antibacterial, anti-HIV, antiarrhythmics, antifungal and antitumor activities. This review is a guide for pharmacologists who are in search of valid preclinical/clinical drug compounds where the progress, from 1966 to the present day, of approved marketed drugs containing indazole scaffold is examined.
... In such context, the combinatorial presence of two-gene mutation, deletion or suppression, as by chemical compounds or small interfering RNAs, constitutes a vital mode of potential control of double-strand break repair in activating tumor cell death pathways. PARP inhibitors inhibit single-stranded DNA repair and induce synthetic lethality in cells with deficient homologous recombination, as in ovarian cancers showing mutation of BRCA1 or 2 [5]. Cell-cycle checkpoints and DNA repair pathways function to maintain genome stability and RAD54B constitutes an ideal target for synthetic lethality with targeting specific genes associated with carcinogenesis [6]. ...
Article
Ovarian cancer is a deadly malignancy with a growing therapeutic armamentarium, though achieving sustained benefit in the clinic remains largely elusive. Through biomarker and genetic analysis, several pathways of resistance and sensitivity to commonly used therapeutics have been identified, expanding the potential of identifying unique drug combinations and indicating new directions for improving clinical outcomes. Here, we review the mechanisms of angiogenic response and antiangiogenic therapy in ovarian cancer, as well as the interactions it exhibits with the immune and DNA damage response pathways. We discuss results from clinical trials examining the combinations of antiangiogenics, PARP inhibitors, and immune checkpoint inhibitors are also discussed, as well as several ongoing trials.
Article
Background Maintenance therapy induces remission and prolongs disease free interval in primary and recurrent ovarian disease. For the treatment decision making process, aspects of quality of life and patients′ preferences are crucial, despite the fact that scientific data are lacking. Therefore, we conducted this European-wide study in patients with ovarian cancer. Methods A 25 item questionnaire was provided to ovarian cancer patients via the internet or as a paper version in 10 European countries (Austria, Belgium, France, Germany, Italy, Romania, Slovenia, Finland, Turkey, and Spain). Data recorded were demographics, tumor stage, therapy after firstline and recurrent disease, preferences for administration, and expectations concerning maintenance therapy. Results Overall, 1954 patients participated from September 2013 to March 2016; 42% had recurrent disease. Most patients (98%) with primary epithelial ovarian cancer underwent surgery followed by chemotherapy (91%). Almost one-third of participants (29%) were receiving maintenance therapy whereas 45% had only heard of it. For 70% of patients with primary epithelial ovarian cancer, they heard about maintenance therapy from their doctor, 10% heard about maintenance therapy from other patients, and 8% from the internet. The main source of information about maintenance therapy in patients with epithelial ovarian cancer relapse was from the treating physician (72%), from other patients (8%), and from the internet (7%). For patients undergoing maintenance therapy, the four most disturbing adverse effects were polyneuropathy (37%), nausea (36%), hair loss (34%), and vomiting (34%). The main objective of maintenance treatment, as perceived by patients, was to increase the chances of cure (73%), improvement in quality of life (47%), and delay in tumor growth (37%). Many patients were willing to undergo maintenance therapy until tumor progression (38%) and 39% would prefer oral administration. No significant differences were detected in the cross country subanalysis regarding expectations of maintenance therapy and patients with primary or relapsed ovarian cancer. Conclusion Patients with ovarian cancer were willing to accept maintenance therapy of prolonged duration and preferred oral administration. There is still a gap between the efficacy of maintenance therapy and patient expectations. Patients need more information on the adverse effects and treatment goals of maintenance therapy to avoid misunderstandings.
Background Heterocyclic compounds, also called heterocycles, are a major class of organic chemicalcompound that plays a vital role in the metabolism of all living cells. The heterocyclic compound, indazole, has attracted more attention in recent years and is widely present in numerous commercially available drugs. Indazole-containing derivatives, representing one of the most important heterocycles in drug molecules, are endowed with a broad range of biological properties. Methods A literature search was conducted in PubMed, Google Scholar and Web of Science regarding articles related to indazole and its therapeutic application. Results The mechanism and structure-activity relationship of indazole and its derivatives were described. Based on their versatile biological activities, the compounds were divided into six groups: anti-inflammatory, antibacterial, anti-HIV, antiarrhythmic, antifungal and antitumour. At least 43 indazole-based therapeutic agents were found to be used in clinical application or clinical trials. Conclusion This review is a guide for pharmacologists who are in search of valid preclinical/clinical drug compoundswhere the progress of approved marketed drugs containing indazole scaffold is examined from 1966 to the present day. Future direction involves more diverse bioactive moieties with indazole scaffold and greater insights into its mechanism.
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The anti-apoptotic BCL2 family of proteins elicits a broad cell survival program mainly by promoting cell migration, invasion, and metastasis. High expression level of BCL2 family proteins is a characteristic feature of cancer cells, especially in cisplatin-resistant cancer cells. Recent studies have shown that BCL2 family proteins play a housekeeping role in modulating mitochondrial dynamics. However, it is not clear whether BCL2 family proteins are relevant to mitochondrial fission and fusion in cisplatin-resistant ovarian cancer cells. Here, we report that the BCL2/BCLXL inhibitor ABT737 induced apoptosis more potently in cisplatin-resistant SKOV3/DDP ovarian cancer cells than in cisplatin-sensitive SKOV3 ovarian cancer cells. ABT737 significantly increased levels of DRP1 in mitochondria and increased rates of mitochondrial fission, and then induced cytochrome C release from mitochondria and mitophagy in SKOV3/DDP cells. Mdivi-1, a selective inhibitor of DRP1, weakened ABT737-induced mitochondrial fission, intrinsic apoptotic pathways, and mitophagy in SKOV3/DDP cells. Taken together, these results demonstrate a novel function of ABT737 in inducing DRP1-dependent apoptotic mitochondrial fission and highlight that targeting anti-apoptotic BCL2 family proteins may be an emerging therapeutic strategy for patients with cisplatin-resistant ovarian cancer.
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Purpose: BRCA1/2 mutated and some sporadic triple negative breast cancers (TNBCs) have DNA repair defects and are sensitive to DNA-damaging therapeutics. Recently, three independent DNA-based measures of genomic instability were developed based on loss of heterozygosity (LOH), telomeric allelic imbalance (TAI), and large-scale state transitions (LST). Experimental design: We assessed a combined homologous recombination deficiency (HRD) score, an unweighted sum of LOH, TAI, and LST scores, in three neoadjuvant TNBC trials of platinum-containing therapy. We then tested the association of HR deficiency, defined as HRD score {greater than or equal to}42 or BRCA1/2 mutation, with response to platinum-based therapy. Results: In a trial of neoadjuvant platinum, gemcitabine, and iniparib, HR deficiency predicted Residual Cancer Burden score of 0 or 1 (RCB 0/1) and pathologic complete response (pCR) (OR=4.96, p=0.0036; OR=6.52, p=0.0058). HR deficiency remained a significant predictor of RCB 0/1 when adjusted for clinical variables (OR=5.86, p=0.012). In two other trials of neoadjuvant cisplatin therapy, HR deficiency predicted RCB 0/1 and pCR (OR=10.18, p=0.0011; OR=17.00, p=0.0066). In a multivariable model of RCB 0/1, HR deficiency retained significance when clinical variables were included (OR=12.08, p=0.0017). When restricted to BRCA1/2 non-mutated tumors, response was higher in patients with high HRD scores: RCB 0/1 p=0.062, pCR p=0.063 in the neoadjuvant platinum, gemcitabine, and iniparib trial; RCB 0/1 p=0.0039, pCR p=0.018 in the neoadjuvant cisplatin trials. Conclusions: HR deficiency identifies TNBC tumors, including BRCA1/2 non-mutated tumors more likely to respond to platinum-containing therapy.
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Ovarian cancer is burdened by the highest mortality rate among gynecological cancers. Gold standard is represented by the association of platinum— taxane —based chemotherapy and radical surgery. Despite several adjustments occurred in cytotoxic drug in last decades, most patients continue to relapse, and no significant enhancement has been reached in the overall survival. The development of drug resistance and the recurrence of disease have prompted the investigations of other targets that can be used in the treatment of ovarian cancers. Among such targets, polyadenosine diphosphate—ribose polymerase (PARP) represents a novel way to target specific patways involved in tumor growth. PARP accelerates the reaction of the polyADP—ribosylation of proteins implicated in DNA repair. PARP inhibitors have shown activity in cancers with BRCA mutations, with other deficient DNA repair genes or signaling pathways that modulate DNA repair, or in association with DNA damaging agents not involved in DNA repair dysfunction. A number of inhibitors for PARP has been developed, and such drugs are under investigation in clinical trials to identify their impact in the treatment of ovarian cancers. This review aims to summarize the recent researches and clinical progress on PARP inhibitors as novel target agents in ovarian cancer.
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Patients with high-grade serous ovarian cancer (HGSC) have experienced little improvement in overall survival, and standard treatment has not advanced beyond platinum-based combination chemotherapy, during the past 30 years. To understand the drivers of clinical phenotypes better, here we use whole-genome sequencing of tumour and germline DNA samples from 92 patients with primary refractory, resistant, sensitive and matched acquired resistant disease. We show that gene breakage commonly inactivates the tumour suppressors RB1, NF1, RAD51B and PTEN in HGSC, and contributes to acquired chemotherapy resistance. CCNE1 amplification was common in primary resistant and refractory disease. We observed several molecular events associated with acquired resistance, including multiple independent reversions of germline BRCA1 or BRCA2 mutations in individual patients, loss of BRCA1 promoter methylation, an alteration in molecular subtype, and recurrent promoter fusion associated with overexpression of the drug efflux pump MDR1.
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Platinum and PARP inhibitor (PARPi) sensitivity commonly coexist in epithelial ovarian cancer (EOC) due to the high prevalence of alterations in the homologous recombination (HR) DNA repair pathway that confer sensitivity to both drugs. In this report, we describe a unique subset of EOC with alterations in another DNA repair pathway, the nucleotide excision repair (NER) pathway, which may exhibit a discordance in sensitivities to these drugs. Specifically, 8% of high-grade serous EOC from The Cancer Genome Atlas dataset exhibited NER alterations, including nonsynonymous or splice site mutations and homozygous deletions of NER genes. Tumors with NER alterations were associated with improved overall survival (OS) and progression-free survival (PFS), compared with patients without NER alterations or BRCA1/2 mutations. Furthermore, patients with tumors with NER alterations had similar OS and PFS as BRCA1/2-mutated patients, suggesting that NER pathway inactivation in EOC conferred enhanced platinum sensitivity, similar to BRCA1/2-mutated tumors. Moreover, two NER mutations (ERCC6-Q524* and ERCC4-A583T), identified in the two most platinum-sensitive tumors, were functionally associated with platinum sensitivity in vitro. Importantly, neither NER alteration affected HR or conferred sensitivity to PARPi or other double-strand break-inducing agents. Overall, our findings reveal a new mechanism of platinum sensitivity in EOC that, unlike defective HR, may lead to a discordance in sensitivity to platinum and PARPi, with potential implications for previously reported and ongoing PARPi trials in this disease. Cancer Res; 75(4); 1-7. ©2014 AACR. ©2014 American Association for Cancer Research.
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Purpose: Olaparib is an oral poly (ADP-ribose) polymerase inhibitor with activity in germline BRCA1 and BRCA2 (BRCA1/2) -associated breast and ovarian cancers. We evaluated the efficacy and safety of olaparib in a spectrum of BRCA1/2-associated cancers. Patients and methods: This multicenter phase II study enrolled individuals with a germline BRCA1/2 mutation and recurrent cancer. Eligibility included ovarian cancer resistant to prior platinum; breast cancer with ≥ three chemotherapy regimens for metastatic disease; pancreatic cancer with prior gemcitabine treatment; or prostate cancer with progression on hormonal and one systemic therapy. Olaparib was administered at 400 mg twice per day. The primary efficacy end point was tumor response rate. Results: A total of 298 patients received treatment and were evaluable. The tumor response rate was 26.2% (78 of 298; 95% CI, 21.3 to 31.6) overall and 31.1% (60 of 193; 95% CI, 24.6 to 38.1), 12.9% (eight of 62; 95% CI, 5.7 to 23.9), 21.7% (five of 23; 95% CI, 7.5 to 43.7), and 50.0% (four of eight; 95% CI, 15.7 to 84.3) in ovarian, breast, pancreatic, and prostate cancers, respectively. Stable disease ≥ 8 weeks was observed in 42% of patients (95% CI, 36.0 to 47.4), including 40% (95% CI, 33.4 to 47.7), 47% (95% CI, 34.0 to 59.9), 35% (95% CI, 16.4 to 57.3), and 25% (95% CI, 3.2 to 65.1) of those with ovarian, breast, pancreatic, or prostate cancer, respectively. The most common adverse events (AEs) were fatigue, nausea, and vomiting. Grade ≥ 3 AEs were reported for 54% of patients; anemia was the most common (17%). Conclusion: Responses to olaparib were observed across different tumor types associated with germline BRCA1/2 mutations. Olaparib warrants further investigation in confirmatory studies.
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Anti-poly(ADP-ribose)polymerase (PARP) drugs were initially developed as catalytic inhibitors to block the repair of DNA single-strand breaks. We recently reported that several PARP inhibitors have an additional cytotoxic mechanism by trapping PARP-DNA complexes, and that both olaparib and niraparib act as PARP poisons at pharmacological concentrations. Therefore, we have proposed that PARP inhibitors should be evaluated based both on catalytic PARP inhibition and PARP-DNA trapping. Here, we evaluated the novel PARP inhibitor, BMN 673, and compared its effects on PARP1 and PARP2 with two other clinical PARP inhibitors, olaparib and rucaparib, using biochemical and cellular assays in genetically-modified chicken DT40 and human cancer cell lines. Although BMN 673, olaparib and rucaparib are comparable at inhibiting PARP catalytic activity, BMN 673 is ~100-fold more potent at trapping PARP-DNA complexes and more cytotoxic as single agent than olaparib, while olaparib and rucaparib show similar potencies in trapping PARP-DNA complexes. The high level of resistance of PARP1/2 knockout cells to BMN 673 demonstrates the selectivity of BMN 673 for PARP1/2. Moreover, we show that BMN 673 acts by stereospecific binding to PARP1 as its enantiomer, LT674, is several orders of magnitude less efficient. BMN 673 is also ~100-fold more cytotoxic than olaparib and rucaparib in combination with the DNA alkylating agents methyl methane sufonate (MMS) and temozolomide. Our study demonstrates that BMN 673 is the most potent clinical PARP inhibitor tested to date with the highest efficiency at trapping PARP-DNA complexes.
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Small-molecule inhibitors of PARP are thought to mediate their antitumor effects as catalytic inhibitors that block repair of DNA single-strand breaks (SSB). However, the mechanism of action of PARP inhibitors with regard to their effects in cancer cells is not fully understood. In this study, we show that PARP inhibitors trap the PARP1 and PARP2 enzymes at damaged DNA. Trapped PARP-DNA complexes were more cytotoxic than unrepaired SSBs caused by PARP inactivation, arguing that PARP inhibitors act in part as poisons that trap PARP enzyme on DNA. Moreover, the potency in trapping PARP differed markedly among inhibitors with niraparib (MK-4827) > olaparib (AZD-2281) > veliparib (ABT-888), a pattern not correlated with the catalytic inhibitory properties for each drug. We also analyzed repair pathways for PARP-DNA complexes using 30 genetically altered avian DT40 cell lines with preestablished deletions in specific DNA repair genes. This analysis revealed that, in addition to homologous recombination, postreplication repair, the Fanconi anemia pathway, polymerase β, and FEN1 are critical for repairing trapped PARP-DNA complexes. In summary, our study provides a new mechanistic foundation for the rational application of PARP inhibitors in cancer therapy. Cancer Res; 72(21); 5588-99. ©2012 AACR.
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BACKGROUND: Defects in BRCA1, BRCA2, and other members of the homologous recombination pathway have potential therapeutic relevance when used to support agents that introduce or exploit double-stranded DNA breaks. This study examines the association between homologous recombination defects and genomic patterns of loss of heterozygosity (LOH). METHODS: Ovarian tumours from two independent data sets were characterised for defects in BRCA1, BRCA2, and RAD51C, and LOH profiles were generated. Publically available data were downloaded for a third independent data set. The same analyses were performed on 57 cancer cell lines. RESULTS: Loss of heterozygosity regions of intermediate size were observed more frequently in tumours with defective BRCA1 or BRCA2 (P=10�-11). The homologous recombination deficiency (HRD) score was defined as the number of these regions observed in a tumour sample. The association between HRD score and BRCA deficiency was validated in two independent ovarian cancer data sets (P=10-�5 and 10�-29), and identified breast and pancreatic cell lines with BRCA defects. CONCLUSION: The HRD score appears capable of detecting homologous recombination defects regardless of aetiology or mechanism. This score could facilitate the use of PARP inhibitors and platinum in breast, ovarian, and other cancers.
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BRCA1 inactivation is a frequent event in basal-like breast carcinomas (BLC). However, BRCA1 can be inactivated by multiple mechanisms and determining its status is not a trivial issue. As an alternate approach, we profiled 65 BLC cases using single-nucleotide polymorphism arrays to define a signature of BRCA1-associated genomic instability. Large-scale state transitions (LST), defined as chromosomal break between adjacent regions of at least 10 Mb, were found to be a robust indicator of BRCA1 status in this setting. Two major ploidy-specific cutoffs in LST distributions were sufficient to distinguish highly rearranged BLCs with 85% of proven BRCA1-inactivated cases from less rearranged BLCs devoid of proven BRCA1-inactivated cases. The genomic signature we defined was validated in a second independent series of 55 primary BLC cases and 17 BLC-derived tumor cell lines. High numbers of LSTs resembling BRCA1-inactivated BLC were observed in 4 primary BLC cases and 2 BLC cell lines that harbored BRCA2 mutations. Overall, the genomic signature we defined predicted BRCA1/2 inactivation in BLCs with 100% sensitivity and 90% specificity (97% accuracy). This assay may ease the challenge of selecting patients for genetic testing or recruitment to clinical trials of novel emerging therapies that target DNA repair deficiencies in cancer. Cancer Res; 72(21); 1-9. ©2012 AACR.
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Olaparib (AZD2281) is an oral poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitor that has shown antitumor activity in patients with high-grade serous ovarian cancer with or without BRCA1 or BRCA2 germline mutations. We conducted a randomized, double-blind, placebo-controlled, phase 2 study to evaluate maintenance treatment with olaparib in patients with platinum-sensitive, relapsed, high-grade serous ovarian cancer who had received two or more platinum-based regimens and had had a partial or complete response to their most recent platinum-based regimen. Patients were randomly assigned to receive olaparib, at a dose of 400 mg twice daily, or placebo. The primary end point was progression-free survival according to the Response Evaluation Criteria in Solid Tumors guidelines. Of 265 patients who underwent randomization, 136 were assigned to the olaparib group and 129 to the placebo group. Progression-free survival was significantly longer with olaparib than with placebo (median, 8.4 months vs. 4.8 months from randomization on completion of chemotherapy; hazard ratio for progression or death, 0.35; 95% confidence interval [CI], 0.25 to 0.49; P<0.001). Subgroup analyses of progression-free survival showed that, regardless of subgroup, patients in the olaparib group had a lower risk of progression. Adverse events more commonly reported in the olaparib group than in the placebo group (by more than 10% of patients) were nausea (68% vs. 35%), fatigue (49% vs. 38%), vomiting (32% vs. 14%), and anemia (17% vs. 5%); the majority of adverse events were grade 1 or 2. An interim analysis of overall survival (38% maturity, meaning that 38% of the patients had died) showed no significant difference between groups (hazard ratio with olaparib, 0.94; 95% CI, 0.63 to 1.39; P=0.75). Olaparib as maintenance treatment significantly improved progression-free survival among patients with platinum-sensitive, relapsed, high-grade serous ovarian cancer. Interim analysis showed no overall survival benefit. The toxicity profile of olaparib in this population was consistent with that in previous studies. (Funded by AstraZeneca; ClinicalTrials.gov number, NCT00753545.).
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A catalogue of molecular aberrations that cause ovarian cancer is critical for developing and deploying therapies that will improve patients' lives. The Cancer Genome Atlas project has analysed messenger RNA expression, microRNA expression, promoter methylation and DNA copy number in 489 high-grade serous ovarian adenocarcinomas and the DNA sequences of exons from coding genes in 316 of these tumours. Here we report that high-grade serous ovarian cancer is characterized by TP53 mutations in almost all tumours (96%); low prevalence but statistically recurrent somatic mutations in nine further genes including NF1, BRCA1, BRCA2, RB1 and CDK12; 113 significant focal DNA copy number aberrations; and promoter methylation events involving 168 genes. Analyses delineated four ovarian cancer transcriptional subtypes, three microRNA subtypes, four promoter methylation subtypes and a transcriptional signature associated with survival duration, and shed new light on the impact that tumours with BRCA1/2 (BRCA1 or BRCA2) and CCNE1 aberrations have on survival. Pathway analyses suggested that homologous recombination is defective in about half of the tumours analysed, and that NOTCH and FOXM1 signalling are involved in serous ovarian cancer pathophysiology.
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Secondary somatic BRCA1/2 mutations may restore BRCA1/2 protein in hereditary ovarian carcinomas. In cell lines, BRCA2 restoration mediates resistance to platinum chemotherapy and poly (ADP-ribose) polymerase (PARP) inhibitors. We assessed primary and recurrent BRCA1/2-mutated ovarian carcinomas to define the frequency of secondary mutations and correlate these changes with clinical outcomes. Neoplastic cells were isolated with laser capture microdissection, and DNA was sequenced at the site of the known germline BRCA1/2 mutation. When secondary mutations were found that restored wild-type sequence, haplotyping was performed using single nucleotide polymorphisms in tumor and paired lymphocyte DNA to rule out retention of the wild-type allele. There were 64 primary and 46 recurrent ovarian carcinomas assessed. Thirteen (28.3%) of 46 (95% CI, 17.3% to 42.6%) recurrent carcinomas had a secondary mutation compared with two (3.1%) of 64 (95% CI, 1.0% to 10.7%) primary carcinomas (P = .0003, Fisher's exact test). Twelve (46.2%) of 26 (95% CI, 28.7% to 64.7%) platinum-resistant recurrences had secondary mutations restoring BRCA1/2, compared with one (5.3%) of 19 (95% CI, 1.2% to 24.8%) platinum-sensitive recurrences (P = .003, Fisher's exact test). Six (66.7%) of nine (95% CI, 34.8% to 87.8%) women with prior breast carcinoma had a recurrent carcinoma with a secondary mutation, compared with six (17.1%) of 35 (95% CI, 8.2% to 32.8%) with no history of breast carcinoma (P = .007, Fisher's exact test). Secondary somatic mutations that restore BRCA1/2 in carcinomas from women with germline BRCA1/2 mutations predict resistance to platinum chemotherapy and may also predict resistance to PARP inhibitors. These mutations were detectable only in ovarian carcinomas of women whom have had previous chemotherapy, either for ovarian or breast carcinoma.
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Selective tumor cell cytotoxicity can be achieved through a synthetic lethal strategy using poly(ADP)-ribose polymerase (PARP) inhibitor therapy in BRCA1/2 mutation carriers in whom tumor cells have defective homologous recombination (HR) DNA repair. Platinum-based chemotherapy responses correlate with HR DNA repair capacity. Olaparib is a potent, oral PARP inhibitor that is well tolerated, with antitumor activity in BRCA1/2 mutation carriers. Patients with BRCA1/2-mutated ovarian cancer were treated with olaparib within a dose-escalation and single-stage expansion of a phase I trial. Antitumor activity was subsequently correlated with platinum sensitivity. Fifty patients were treated: 48 had germline BRCA1/2 mutations; one had a BRCA2 germline sequence change of unknown significance, and another had a strong family history of BRCA1/2-associated cancers who declined mutation testing. Of the 50 patients, 13 had platinum-sensitive disease, 24 had platinum-resistant disease, and 13 had platinum-refractory disease (according to platinum-free interval). Twenty (40%; 95% CI, 26% to 55%) achieved Response Evaluation Criteria in Solid Tumors (RECIST) complete or partial responses and/or tumor marker (CA125) responses, and three (6.0%) maintained RECIST disease stabilization for more than 4 months, giving an overall clinical benefit rate of 46% (95% CI, 32% to 61%). Median response duration was 28 weeks. There was a significant association between the clinical benefit rate and platinum-free interval across the platinum-sensitive, resistant, and refractory subgroups (69%, 45%, and 23%, respectively). Post hoc analyses indicated associations between platinum sensitivity and extent of olaparib response (radiologic change, P = .001; CA125 change, P = .002). Olaparib has antitumor activity in BRCA1/2 mutation ovarian cancer, which is associated with platinum sensitivity.
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Whereas target-specific drugs are available for treating ERBB2-overexpressing and hormone receptor-positive breast cancers, no tailored therapy exists for hormone receptor- and ERBB2-negative (“triple-negative”) mammary carcinomas. Triple-negative tumors account for 15% of all breast cancers and frequently harbor defects in DNA double-strand break repair through homologous recombination (HR), such as BRCA1 dysfunction. The DNA-repair defects characteristic of BRCA1-deficient cells confer sensitivity to poly(ADP-ribose) polymerase 1 (PARP1) inhibition, which could be relevant to treatment of triple-negative tumors. To evaluate PARP1 inhibition in a realistic in vivo setting, we tested the PARP inhibitor AZD2281 in a genetically engineered mouse model (GEMM) for BRCA1-associated breast cancer. Treatment of tumor-bearing mice with AZD2281 inhibited tumor growth without signs of toxicity, resulting in strongly increased survival. Long-term treatment with AZD2281 in this model did result in the development of drug resistance, caused by up-regulation of Abcb1a/b genes encoding P-glycoprotein efflux pumps. This resistance to AZD2281 could be reversed by coadministration of the P-glycoprotein inhibitor tariquidar. Combination of AZD2281 with cisplatin or carboplatin increased the recurrence-free and overall survival, suggesting that AZD2281 potentiates the effect of these DNA-damaging agents. Our results demonstrate in vivo efficacy of AZD2281 against BRCA1-deficient breast cancer and illustrate how GEMMs of cancer can be used for preclinical evaluation of novel therapeutics and for testing ways to overcome or circumvent therapy resistance. • breast cancer • drug resistance • P-glycoprotein • GEMM • DNA repair
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Although the value of primary cytoreductive surgery for epithelial ovarian cancer is beyond doubt, the value of debulking surgery after induction chemotherapy has not yet been defined. In this randomized study we investigated the effect on survival of debulking surgery. Eligible patients had residual lesions measuring more than 1 cm in diameter after primary surgery. After three cycles of cyclophosphamide and cisplatin, these patients were randomly assigned to undergo either debulking surgery or no surgery, followed by further cycles of cyclophosphamide and cisplatin. The study end points were progression-free and overall survival. At surgery 65 percent of the patients had lesions measuring more than 1 cm. In 45 percent of this group, the lesions were reduced surgically to less than 1 cm. Of the 319 patients who underwent randomization, 278 could be evaluated (140 patients who underwent surgery and 138 patients who did not). Progression-free and overall survival were both significantly longer in the group that underwent surgery (P = 0.01). The difference in median survival was six months. The survival rate at two years was 56 percent for the group that underwent surgery and 46 percent for the group that did not. In the multivariate analysis, debulking surgery was an independent prognostic factor (P = 0.012). Overall, after adjustment for all other prognostic factors, surgery reduced the risk of death by 33 percent (95 percent confidence interval, 10 to 50 percent; P = 0.008). Surgery was not associated with death or severe morbidity. Debulking surgery significantly lengthened progression-free and overall survival. The risk of death was reduced by one third, after adjustment for a variety of prognostic factors.
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Ovarian carcinomas with mutations in the tumour suppressor BRCA2 are particularly sensitive to platinum compounds. However, such carcinomas ultimately develop cisplatin resistance. The mechanism of that resistance is largely unknown. Here we show that acquired resistance to cisplatin can be mediated by secondary intragenic mutations in BRCA2 that restore the wild-type BRCA2 reading frame. First, in a cisplatin-resistant BRCA2-mutated breast-cancer cell line, HCC1428, a secondary genetic change in BRCA2 rescued BRCA2 function. Second, cisplatin selection of a BRCA2-mutated pancreatic cancer cell line, Capan-1 (refs 3, 4), led to five different secondary mutations that restored the wild-type BRCA2 reading frame. All clones with secondary mutations were resistant both to cisplatin and to a poly(ADP-ribose) polymerase (PARP) inhibitor (AG14361). Finally, we evaluated recurrent cancers from patients whose primary BRCA2-mutated ovarian carcinomas were treated with cisplatin. The recurrent tumour that acquired cisplatin resistance had undergone reversion of its BRCA2 mutation. Our results suggest that secondary mutations that restore the wild-type BRCA2 reading frame may be a major clinical mediator of acquired resistance to platinum-based chemotherapy.
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To assess efficacy of the novel, selective poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor AZD2281 against newly established BRCA2-deficient mouse mammary tumor cell lines and to determine potential synergy between AZD2281 and cisplatin. We established and thoroughly characterized a panel of clonal cell lines from independent BRCA2-deficient mouse mammary tumors and BRCA2-proficient control tumors. Subsequently, we assessed sensitivity of these lines to conventional cytotoxic drugs and the novel PARP inhibitor AZD2281. Finally, in vitro combination studies were done to investigate interaction between AZD2281 and cisplatin. Genetic, transcriptional, and functional analyses confirmed the successful isolation of BRCA2-deficient and BRCA2-proficient mouse mammary tumor cell lines. Treatment of these cell lines with 11 different anticancer drugs or with gamma-irradiation showed that AZD2281, a novel and specific PARP inhibitor, caused the strongest differential growth inhibition of BRCA2-deficient versus BRCA2-proficient mammary tumor cells. Finally, drug combination studies showed synergistic cytotoxicity of AZD2281 and cisplatin against BRCA2-deficient cells but not against BRCA2-proficient control cells. We have successfully established the first set of BRCA2-deficient mammary tumor cell lines, which form an important addition to the existing preclinical models for BRCA-mutated breast cancer. The exquisite sensitivity of these cells to the PARP inhibitor AZD2281, alone or in combination with cisplatin, provides strong support for AZD2281 as a novel targeted therapeutic against BRCA-deficient cancers.
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Background: Poly(ADP-ribose) polymerase (PARP) inhibitors have activity in ovarian carcinomas with homologous recombination deficiency. Along with BRCA1 and BRCA2 (BRCA) mutations genomic loss of heterozygosity (LOH) might also represent homologous recombination deficiency. In ARIEL2, we assessed the ability of tumour genomic LOH, quantified with a next-generation sequencing assay, to predict response to rucaparib, an oral PARP inhibitor. Methods: ARIEL2 is an international, multicentre, two-part, phase 2, open-label study done at 49 hospitals and cancer centres in Australia, Canada, France, Spain, the UK, and the USA. In ARIEL2 Part 1, patients with recurrent, platinum-sensitive, high-grade ovarian carcinoma were classified into one of three predefined homologous recombination deficiency subgroups on the basis of tumour mutational analysis: BRCA mutant (deleterious germline or somatic), BRCA wild-type and LOH high (LOH high group), or BRCA wild-type and LOH low (LOH low group). We prespecified a cutoff of 14% or more genomic LOH for LOH high. Patients began treatment with oral rucaparib at 600 mg twice per day for continuous 28 day cycles until disease progression or any other reason for discontinuation. The primary endpoint was progression-free survival. All patients treated with at least one dose of rucaparib were included in the safety analyses and all treated patients who were classified were included in the primary endpoint analysis. This trial is registered with ClinicalTrials.gov, number NCT01891344. Enrolment into ARIEL2 Part 1 is complete, although an extension (Part 2) is ongoing. Findings: 256 patients were screened and 206 were enrolled between Oct 30, 2013, and Dec 19, 2014. At the data cutoff date (Jan 18, 2016), 204 patients had received rucaparib, with 28 patients remaining in the study. 192 patients could be classified into one of the three predefined homologous recombination deficiency subgroups: BRCA mutant (n=40), LOH high (n=82), or LOH low (n=70). Tumours from 12 patients were established as BRCA wild-type, but could not be classified for LOH, because of insufficient neoplastic nuclei in the sample. The median duration of treatment for the 204 patients was 5·7 months (IQR 2·8-10·1). 24 patients in the BRCA mutant subgroup, 56 patients in the LOH high subgroup, and 59 patients in the LOH low subgroup had disease progression or died. Median progression-free survival after rucaparib treatment was 12·8 months (95% CI 9·0-14·7) in the BRCA mutant subgroup, 5·7 months (5·3-7·6) in the LOH high subgroup, and 5·2 months (3·6-5·5) in the LOH low subgroup. Progression-free survival was significantly longer in the BRCA mutant (hazard ratio 0·27, 95% CI 0·16-0·44, p<0·0001) and LOH high (0·62, 0·42-0·90, p=0·011) subgroups compared with the LOH low subgroup. The most common grade 3 or worse treatment-emergent adverse events were anaemia or decreased haemoglobin (45 [22%] patients), and elevations in alanine aminotransferase or aspartate aminotransferase (25 [12%]). Common serious adverse events included small intestinal obstruction (10 [5%] of 204 patients), malignant neoplasm progression (10 [5%]), and anaemia (nine [4%]). Three patients died during the study (two because of disease progression and one because of sepsis and disease progression). No treatment-related deaths occurred. Interpretation: In patients with BRCA mutant or BRCA wild-type and LOH high platinum-sensitive ovarian carcinomas treated with rucaparib, progression-free survival was longer than in patients with BRCA wild-type LOH low carcinomas. Our results suggest that assessment of tumour LOH can be used to identify patients with BRCA wild-type platinum-sensitive ovarian cancers who might benefit from rucaparib. These results extend the potential usefulness of PARP inhibitors in the treatment setting beyond BRCA mutant tumours. Funding: Clovis Oncology, US Department of Defense Ovarian Cancer Research Program, Stand Up To Cancer-Ovarian Cancer Research Fund Alliance-National Ovarian Cancer Coalition Dream Team Translational Research Grant, and V Foundation Translational Award.
Article
Background Niraparib is an oral poly(adenosine diphosphate [ADP]–ribose) polymerase (PARP) 1/2 inhibitor that has shown clinical activity in patients with ovarian cancer. We sought to evaluate the efficacy of niraparib versus placebo as maintenance treatment for patients with platinum-sensitive, recurrent ovarian cancer. Methods In this randomized, double-blind, phase 3 trial, patients were categorized according to the presence or absence of a germline BRCA mutation (gBRCA cohort and non-gBRCA cohort) and the type of non-gBRCA mutation and were randomly assigned in a 2:1 ratio to receive niraparib (300 mg) or placebo once daily. The primary end point was progression-free survival. Results Of 553 enrolled patients, 203 were in the gBRCA cohort (with 138 assigned to niraparib and 65 to placebo), and 350 patients were in the non-gBRCA cohort (with 234 assigned to niraparib and 116 to placebo). Patients in the niraparib group had a significantly longer median duration of progression-free survival than did those in the placebo group, including 21.0 vs. 5.5 months in the gBRCA cohort (hazard ratio, 0.27; 95% confidence interval [CI], 0.17 to 0.41), as compared with 12.9 months vs. 3.8 months in the non-gBRCA cohort for patients who had tumors with homologous recombination deficiency (HRD) (hazard ratio, 0.38; 95% CI, 0.24 to 0.59) and 9.3 months vs. 3.9 months in the overall non-gBRCA cohort (hazard ratio, 0.45; 95% CI, 0.34 to 0.61; P<0.001 for all three comparisons). The most common grade 3 or 4 adverse events that were reported in the niraparib group were thrombocytopenia (in 33.8%), anemia (in 25.3%), and neutropenia (in 19.6%), which were managed with dose modifications. Conclusions Among patients with platinum-sensitive, recurrent ovarian cancer, the median duration of progression-free survival was significantly longer among those receiving niraparib than among those receiving placebo, regardless of the presence or absence of gBRCA mutations or HRD status, with moderate bone marrow toxicity. (Funded by Tesaro; ClinicalTrials.gov number, NCT01847274.)
Article
Objective: Poly(ADP-ribose) polymerase (PARP) inhibitors have yielded encouraging responses in high-grade serous ovarian carcinomas (HGSOCs), but the optimal treatment setting remains unknown. We assessed the effect of niraparib on HGSOC patient-derived xenograft (PDX) models as well as the relationship between certain markers of homologous recombination (HR) status, including BRCA1/2 mutations and formation of RAD51 foci after DNA damage, and response of these PDXs to niraparib in vivo. Methods: Massively parallel sequencing was performed on HGSOCs to identify mutations contributing to HR deficiency. HR pathway integrity was assessed using fluorescence microscopy-based RAD51 focus formation assays. Effects of niraparib (MK-4827) on treatment-naïve PDX tumor growth as monotherapy, in combination with carboplatin/paclitaxel, and as maintenance therapy were assessed by transabdominal ultrasound. Niraparib responses were correlated with changes in levels of poly(ADP-ribose), PARP1, and repair proteins by western blotting. Results: Five PDX models were evaluated in vivo. Tumor regressions were induced by single-agent niraparib in one of two PDX models with deleterious BRCA2 mutations and in a PDX with RAD51C promoter methylation. Diminished formation of RAD51 foci failed to predict response, but Artemis loss was associated with resistance. Niraparib generally failed to enhance responses to carboplatin/paclitaxel chemotherapy, but maintenance niraparib therapy delayed progression in a BRCA2-deficient PDX. Conclusions: Mutations in HR genes are neither necessary nor sufficient to predict response to niraparib. Assessment of repair status through multiple complementary assays is needed to guide PARP inhibitor therapy, design future clinical trials and identify ovarian cancer patients most likely to benefit from PARP inhibition.
Article
Each year, the American Cancer Society estimates the numbers of new cancer cases and deaths that will occur in the United States in the current year and compiles the most recent data on cancer incidence, mortality, and survival. Incidence data were collected by the National Cancer Institute (Surveillance, Epidemiology, and End Results [SEER] Program), the Centers for Disease Control and Prevention (National Program of Cancer Registries), and the North American Association of Central Cancer Registries. Mortality data were collected by the National Center for Health Statistics. In 2016, 1,685,210 new cancer cases and 595,690 cancer deaths are projected to occur in the United States. Overall cancer incidence trends (13 oldest SEER registries) are stable in women, but declining by 3.1% per year in men (from 2009-2012), much of which is because of recent rapid declines in prostate cancer diagnoses. The cancer death rate has dropped by 23% since 1991, translating to more than 1.7 million deaths averted through 2012. Despite this progress, death rates are increasing for cancers of the liver, pancreas, and uterine corpus, and cancer is now the leading cause of death in 21 states, primarily due to exceptionally large reductions in death from heart disease. Among children and adolescents (aged birth-19 years), brain cancer has surpassed leukemia as the leading cause of cancer death because of the dramatic therapeutic advances against leukemia. Accelerating progress against cancer requires both increased national investment in cancer research and the application of existing cancer control knowledge across all segments of the population. CA Cancer J Clin 2016. © 2016 American Cancer Society.
Article
Unlabelled: Approximately 50% of epithelial ovarian cancers (EOC) exhibit defective DNA repair via homologous recombination (HR) due to genetic and epigenetic alterations of HR pathway genes. Defective HR is an important therapeutic target in EOC as exemplified by the efficacy of platinum analogues in this disease, as well as the advent of PARP inhibitors, which exhibit synthetic lethality when applied to HR-deficient cells. Here, we describe the genotypic and phenotypic characteristics of HR-deficient EOCs, discuss current and emerging approaches for targeting these tumors, and present challenges associated with these approaches, focusing on development and overcoming resistance. Significance: Defective DNA repair via HR is a pivotal vulnerability of EOC, particularly of the high-grade serous histologic subtype. Targeting defective HR offers the unique opportunity of exploiting molecular differences between tumor and normal cells, thereby inducing cancer-specific synthetic lethality; the promise and challenges of these approaches in ovarian cancer are discussed in this review.
Article
A catalogue of molecular aberrations that cause ovarian cancer is critical for developing and deploying therapies that will improve patients’ lives. The Cancer Genome Atlas project has analysed messenger RNA expression, microRNA expression, promoter methylation and DNA copy number in 489 high-grade serous ovarian adenocarcinomas and the DNA sequences of exons from coding genes in 316 of these tumours. Here we report that high-grade serous ovarian cancer is characterized by TP53 mutations in almost all tumours (96%); low prevalence but statistically recurrent somatic mutations in nine further genes including NF1, BRCA1, BRCA2, RB1 and CDK12; 113 significant focal DNA copy number aberrations; and promoter methylation events involving 168 genes. Analyses delineated four ovarian cancer transcriptional subtypes, three microRNA subtypes, four promoter methylation subtypes and a transcriptional signature associated with survival duration, and shed new light on the impact that tumours with BRCA1/2 (BRCA1 or BRCA2) and CCNE1 aberrations have on survival. Pathway analyses suggested that homologous recombination is defective in about half of the tumours analysed, and that NOTCH and FOXM1 signalling are involved in serous ovarian cancer pathophysiology.
Article
Background: Inherited mutations in the BRCA1 gene may be responsible for almost half of inherited breast carcinomas. However, somatic (acquired) mutations in BRCA1 have not been reported, despite frequent loss of heterozygosity (LOH or loss of one copy of the gene) at the BRCA1 locus and loss of BRCA1 protein in tumors. To address whether BRCA1 may be inactivated by pathways other than mutations in sporadic tumors, we analyzed the role of hypermethylation of the gene's promoter region. Methods: Methylation patterns in the BRCA1 promoter were assessed in breast cancer cell lines, xenografts, and 215 primary breast and ovarian carcinomas by methylation-specific polymerase chain reaction (PCR). BRCA1 RNA expression was determined in cell lines and seven xenografts by reverse transcription–PCR. P values are two-sided. Results: The BRCA1 promoter was found to be unmethylated in all normal tissues and cancer cell lines tested. However, BRCA1 promoter hypermethylation was present in two breast cancer xenografts, both of which had loss of the BRCA1 transcript. BRCA1 promoter hypermethylation was present in 11 (13%) of 84 unselected primary breast carcinomas. BRCA1 methylation was strikingly associated with the medullary (67% methylated; P = .0002 versus ductal) and mucinous (55% methylated; P = .0033 versus ductal) subtypes, which are overrepresented in BRCA1 families. In a second series of 66 ductal breast tumors informative for LOH, nine (20%) of 45 tumors with LOH had BRCA1 hypermethylation, while one (5%) of 21 without LOH was methylated (P = .15). In ovarian neoplasms, BRCA1 methylation was found only in tumors with LOH, four (31%) of 13 versus none of 18 without LOH (P = .02). The BRCA1 promoter was unmethylated in other tumor types. Conclusion: Silencing of the BRCA1 gene by promoter hypermethylation occurs in primary breast and ovarian carcinomas, especially in the presence of LOH and in specific histopathologic subgroups. These findings support a role for this tumor suppressor gene in sporadic breast and ovarian tumorigenesis.
Article
Poly (ADP-ribose) polymerase (PARP) inhibitors have shown promising activity in epithelial ovarian cancers, especially relapsed platinum-sensitive high-grade serous disease. Consistent with preclinical studies, ovarian cancers and a number of other solid tumor types occurring in patients with deleterious germline mutations in BRCA1 or BRCA2 seem to be particularly sensitive. However, it is also becoming clear that germline BRCA1/2 mutations are neither necessary nor sufficient for patients to derive benefit from PARP inhibitors. We provide an update on PARP inhibitor clinical development, describe recent advances in our understanding of PARP inhibitor mechanism of action, and discuss current issues in the development of these agents. © 2015 by American Society of Clinical Oncology.
Article
The poly(ADP-ribose) polymerase inhibitor olaparib has shown antitumour activity in patients with platinum-sensitive, recurrent, high-grade serous ovarian cancer with or without BRCA1 or BRCA2 mutations. The aim of this study was to assess the efficacy and tolerability of olaparib in combination with chemotherapy, followed by olaparib maintenance monotherapy, versus chemotherapy alone in patients with platinum-sensitive, recurrent, high-grade serous ovarian cancer. In this randomised, open-label, phase 2 study, adult patients with platinum-sensitive, recurrent, high-grade serous ovarian cancer who had received up to three previous courses of platinum-based chemotherapy and who were progression free for at least 6 months before randomisation received either olaparib (200 mg capsules twice daily, administered orally on days 1-10 of each 21-day cycle) plus paclitaxel (175 mg/m(2), administered intravenously on day 1) and carboplatin (area under the curve [AUC] 4 mg/mL per min, according to the Calvert formula, administered intravenously on day 1), then olaparib monotherapy (400 mg capsules twice daily, given continuously) until progression (the olaparib plus chemotherapy group), or paclitaxel (175 mg/m(2) on day 1) and carboplatin (AUC 6 mg/mL per min on day 1) then no further treatment (the chemotherapy alone group). Randomisation was done by an interactive voice response system, stratified by number of previous platinum-containing regimens received and time to disease progression after the previous platinum regimen. The primary endpoint was progression-free survival according to Response Evaluation Criteria in Solid Tumors version 1.1, analysed by intention to treat. Prespecified exploratory analyses included efficacy by BRCA mutation status, assessed retrospectively. This study is registered with ClinicalTrials.gov, number NCT01081951, and has been completed. Between Feb 12 and July 30, 2010, 173 patients at 43 investigational sites in 12 countries were enrolled into the study, of whom 162 were eligible and were randomly assigned to the two treatment groups (81 to the olaparib plus chemotherapy group and 81 to the chemotherapy alone group). Of these randomised patients, 156 were treated in the combination phase (81 in the olaparib plus chemotherapy group and 75 in the chemotherapy alone group) and 121 continued to the maintenance or no further treatment phase (66 in the olaparib plus chemotherapy group and 55 in the chemotherapy alone group). BRCA mutation status was known for 107 patients (either at baseline or determined retrospectively): 41 (38%) of 107 had a BRCA mutation (20 in the olaparib plus chemotherapy group and 21 in the chemotherapy alone group). Progression-free survival was significantly longer in the olaparib plus chemotherapy group (median 12·2 months [95% CI 9·7-15·0]) than in the chemotherapy alone group (median 9·6 months [95% CI 9·1-9·7) (HR 0·51 [95% CI 0·34-0·77]; p=0·0012), especially in patients with BRCA mutations (HR 0·21 [0·08-0·55]; p=0·0015). In the combination phase, adverse events that were reported at least 10% more frequently with olaparib plus chemotherapy than with chemotherapy alone were alopecia (60 [74%] of 81 vs 44 [59%] of 75), nausea (56 [69%] vs 43 [57%]), neutropenia (40 [49%] vs 29 [39%]), diarrhoea (34 [42%] vs 20 [27%]), headache (27 [33%] vs seven [9%]), peripheral neuropathy (25 [31%] vs 14 [19%]), and dyspepsia (21 [26%] vs 9 [12%]); most were of mild-to-moderate intensity. The most common grade 3 or higher adverse events during the combination phase were neutropenia (in 35 [43%] of 81 patients in the olaparib plus chemotherapy group vs 26 [35%] of 75 in the chemotherapy alone group) and anaemia (seven [9%] vs five [7%]). Serious adverse events were reported in 12 (15%) of 81 patients in the olaparib plus chemotherapy group and 16 of 75 (21%) patients in the chemotherapy alone group. Olaparib plus paclitaxel or carboplatin followed by maintenance monotherapy significantly improved progression-free survival versus paclitaxel plus carboplatin alone, with the greatest clinical benefit in BRCA-mutated patients, and had an acceptable and manageable tolerability profile. AstraZeneca. Copyright © 2014 Elsevier Ltd. All rights reserved.
Article
Background: Olaparib is a poly(ADP-ribose) polymerase inhibitor and cediranib is an anti-angiogenic agent with activity against VEGF receptor (VEGFR) 1, VEGFR2, and VEGFR3. Both oral agents have antitumour activity in women with recurrent ovarian cancer, and their combination was active and had manageable toxicities in a phase 1 trial. We investigated whether this combination could improve progression-free survival (PFS) compared with olaparib monotherapy in women with recurrent platinum-sensitive ovarian cancer. Methods: In our randomised, open-label, phase 2 study, we recruited women (aged ≥18 years) who had measurable platinum-sensitive, relapsed, high-grade serous or endometrioid ovarian, fallopian tube, or primary peritoneal cancer, or those with deleterious germline BRCA1/2 mutations from nine participating US academic medical centres. We randomly allocated participants (1:1) according to permuted blocks, stratified by germline BRCA status and previous anti-angiogenic therapy, to receive olaparib capsules 400 mg twice daily or the combination at the recommended phase 2 dose of cediranib 30 mg daily and olaparib capsules 200 mg twice daily. The primary endpoint was progression-free survival analysed in the intention-to-treat population. The phase 2 trial is no longer accruing patients. An interim analysis was conducted in November, 2013, after 50% of expected events had occurred and efficacy results were unmasked. The primary analysis was performed on March 31, 2014, after 47 events (66% of those expected). The trial is registered with ClinicalTrials.gov, number NCT01116648. Findings: Between Oct 26, 2011, and June 3, 2013, we randomly allocated 46 women to receive olaparib alone and 44 to receive the combination of olaparib and cediranib. Median PFS was 17·7 months (95% CI 14·7-not reached) for the women treated with cediranib plus olaparib compared with 9·0 months (95% CI 5·7-16·5) for those treated with olaparib monotherapy (hazard ratio 0·42, 95% CI 0·23-0·76; p=0·005). Grade 3 and 4 adverse events were more common with combination therapy than with monotherapy, including fatigue (12 patients in the cediranib plus olaparib group vs five patients in the olaparib monotherapy group), diarrhoea (ten vs none), and hypertension (18 vs none). Interpretation: Cediranib plus olaparib seems to improve PFS in women with recurrent platinum-sensitive high-grade serous or endometrioid ovarian cancer, and warrants study in a phase 3 trial. The side-effect profile suggests such investigations should include assessments of quality of life and patient-reported outcomes to understand the effects of a continuing oral regimen with that of intermittent chemotherapy. Funding: American Recovery and Reinvestment Act grant from the National Institutes of Health (NIH) (3 U01 CA062490-16S2); Intramural Program of the Center for Cancer Research; and the Division of Cancer Treatment and Diagnosis, National Cancer Institute, NIH.
Article
Poly(ADP-ribose) polymerase (PARP) is implicated in DNA repair and transcription regulation. Niraparib (MK4827) is an oral potent, selective PARP-1 and PARP-2 inhibitor that induces synthetic lethality in preclinical tumour models with loss of BRCA and PTEN function. We investigated the safety, tolerability, maximum tolerated dose, pharmacokinetic and pharmacodynamic profiles, and preliminary antitumour activity of niraparib. In a phase 1 dose-escalation study, we enrolled patients with advanced solid tumours at one site in the UK and two sites in the USA. Eligible patients were aged at least 18 years; had a life expectancy of at least 12 weeks; had an Eastern Cooperative Oncology Group performance status of 2 or less; had assessable disease; were not suitable to receive any established treatments; had adequate organ function; and had discontinued any previous anticancer treatments at least 4 weeks previously. In part A, cohorts of three to six patients, enriched for BRCA1 and BRCA2 mutation carriers, received niraparib daily at ten escalating doses from 30 mg to 400 mg in a 21-day cycle to establish the maximum tolerated dose. Dose expansion at the maximum tolerated dose was pursued in 15 patients to confirm tolerability. In part B, we further investigated the maximum tolerated dose in patients with sporadic platinum-resistant high-grade serous ovarian cancer and sporadic prostate cancer. We obtained blood, circulating tumour cells, and optional paired tumour biopsies for pharmacokinetic and pharmacodynamic assessments. Toxic effects were assessed by common toxicity criteria and tumour responses ascribed by Response Evaluation Criteria in Solid Tumors (RECIST). Circulating tumour cells and archival tumour tissue in prostate patients were analysed for exploratory putative predictive biomarkers, such as loss of PTEN expression and ETS rearrangements. This trial is registered with ClinicalTrials.gov, NCT00749502. Between Sept 15, 2008, and Jan 14, 2011, we enrolled 100 patients: 60 in part A and 40 in part B. 300 mg/day was established as the maximum tolerated dose. Dose-limiting toxic effects reported in the first cycle were grade 3 fatigue (one patient given 30 mg/day), grade 3 pneumonitis (one given 60 mg/day), and grade 4 thrombocytopenia (two given 400 mg/day). Common treatment-related toxic effects were anaemia (48 patients [48%]), nausea (42 [42%]), fatigue (42 [42%]), thrombocytopenia (35 [35%]), anorexia (26 [26%]), neutropenia (24 [24%]), constipation (23 [23%]), and vomiting (20 [20%]), and were predominantly grade 1 or 2. Pharmacokinetics were dose proportional and the mean terminal elimination half-life was 36·4 h (range 32·8-46·0). Pharmacodynamic analyses confirmed PARP inhibition exceeded 50% at doses greater than 80 mg/day and antitumour activity was documented beyond doses of 60 mg/day. Eight (40% [95% CI 19-64]) of 20 BRCA1 or BRCA2 mutation carriers with ovarian cancer had RECIST partial responses, as did two (50% [7-93]) of four mutation carriers with breast cancer. Antitumour activity was also reported in sporadic high-grade serous ovarian cancer, non-small-cell lung cancer, and prostate cancer. We recorded no correlation between loss of PTEN expression or ETS rearrangements and measures of antitumour activity in patients with prostate cancer. A recommended phase 2 dose of 300 mg/day niraparib is well tolerated. Niraparib should be further assessed in inherited and sporadic cancers with homologous recombination DNA repair defects and to target PARP-mediated transcription in cancer. Merck Sharp and Dohme.
Article
Poly(ADP-ribose) polymerase (PARP)-inhibitors and anti-angiogenics have activity in recurrent ovarian and breast cancer; however, the effect of combined therapy against PARP and angiogenesis in this population has not been reported. We investigated the toxicities and recommended phase 2 dosing (RP2D) of the combination of cediranib, a multitargeted inhibitor of vascular endothelial growth factor receptor (VEGFR)-1/2/3 and olaparib, a PARP-inhibitor (NCT01116648). Cediranib tablets once daily and olaparib capsules twice daily were administered orally in a standard 3+3 dose escalation design. Patients with recurrent ovarian or metastatic triple-negative breast cancer were eligible. Patients had measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 or met Gynecologic Cancer InterGroup (GCIG) CA125 criteria. No prior PARP-inhibitors or anti-angiogenics in the recurrent setting were allowed. 28 patients (20 ovarian, 8 breast) enrolled to 4 dose levels. 2 dose limiting toxicities (DLTs) (1 grade 4 neutropenia ⩾4days; 1 grade 4 thrombocytopenia) occurred at the highest dose level (cediranib 30mg daily; olaparib 400mg twice daily [BID]). The RP2D was cediranib 30mg daily and olaparib 200mg BID. Grade 3 or higher toxicities occurred in 75% of patients, and included grade 3 hypertension (25%) and grade 3 fatigue (18%). One grade 3 bowel obstruction occurred. The overall response rate (ORR) in the 18 RECIST-evaluable ovarian cancer patients was 44%, with a clinical benefit rate (ORR plus stable disease (SD) >24weeks) of 61%. None of the seven evaluable breast cancer patients achieved clinical response; two patients had stable disease for >24weeks. The combination of cediranib and olaparib has haematologic DLTs and anticipated class toxicities, with promising evidence of activity in ovarian cancer patients.
Article
Unlabelled: DNA repair competency is one determinant of sensitivity to certain chemotherapy drugs, such as cisplatin. Cancer cells with intact DNA repair can avoid the accumulation of genome damage during growth and also can repair platinum-induced DNA damage. We sought genomic signatures indicative of defective DNA repair in cell lines and tumors and correlated these signatures to platinum sensitivity. The number of subchromosomal regions with allelic imbalance extending to the telomere (N(tAI)) predicted cisplatin sensitivity in vitro and pathologic response to preoperative cisplatin treatment in patients with triple-negative breast cancer (TNBC). In serous ovarian cancer treated with platinum-based chemotherapy, higher levels of N(tAI) forecast a better initial response. We found an inverse relationship between BRCA1 expression and N(tAI) in sporadic TNBC and serous ovarian cancers without BRCA1 or BRCA2 mutation. Thus, accumulation of telomeric allelic imbalance is a marker of platinum sensitivity and suggests impaired DNA repair. Significance: Mutations in BRCA genes cause defects in DNA repair that predict sensitivity to DNA damaging agents, including platinum; however, some patients without BRCA mutations also benefit from these agents. NtAI, a genomic measure of unfaithfully repaired DNA, may identify cancer patients likely to benefit from treatments targeting defective DNA repair.
Article
This randomized, multicenter, blinded, placebo-controlled phase III trial tested the efficacy and safety of bevacizumab (BV) with gemcitabine and carboplatin (GC) compared with GC in platinum-sensitive recurrent ovarian, primary peritoneal, or fallopian tube cancer (ROC). Patients with platinum-sensitive ROC (recurrence ≥ 6 months after front-line platinum-based therapy) and measurable disease were randomly assigned to GC plus either BV or placebo (PL) for six to 10 cycles. BV or PL, respectively, was then continued until disease progression. The primary end point was progression-free survival (PFS) by RECIST; secondary end points were objective response rate, duration of response (DOR), overall survival, and safety. Overall, 484 patients were randomly assigned. PFS for the BV arm was superior to that for the PL arm (hazard ratio [HR], 0.484; 95% CI, 0.388 to 0.605; log-rank P < .0001); median PFS was 12.4 v 8.4 months, respectively. The objective response rate (78.5% v 57.4%; P < .0001) and DOR (10.4 v 7.4 months; HR, 0.534; 95% CI, 0.408 to 0.698) were significantly improved with the addition of BV. No new safety concerns were noted. Grade 3 or higher hypertension (17.4% v < 1%) and proteinuria (8.5% v < 1%) occurred more frequently in the BV arm. The rates of neutropenia and febrile neutropenia were similar in both arms. Two patients in the BV arm experienced GI perforation after study treatment discontinuation. GC plus BV followed by BV until progression resulted in a statistically significant improvement in PFS compared with GC plus PL in platinum-sensitive ROC.
Article
Poly(ADP-ribose) polymerase (PARP) catalyzed poly(ADP-ribosyl)ation is one of the earliest post-translational modification of proteins detectable at sites of DNA strand interruptions. The considerable recent progress in the science of PARP in the last decade and the discovery of a PARP superfamily (17 members) has introduced this modification as a key mechanism regulating a wide variety of cellular processes including among others transcription, regulation of chromatin dynamics, telomere homeostasis, differentiation and cell death. However, the most extensive studied and probably the best characterized role is in DNA repair where it plays pivotal roles in the processing and resolution of the damaged DNA. Although much of the focus has been on PARP1 in DNA repair, recent advances highlight the emergence of other DNA-dependent PARPs (i.e. PARP2, PARP3 and possibly Tankyrase) in this process. Here we will summarize the recent insights into the molecular functions of these PARPs in different DNA repair pathways in which they emerge as specific actors. Furthermore, the DNA repair functions of PARP1 have stimulated another area of intense research in the field with the development of potent and selective PARP1 inhibitors to promote genome instability and cell death in tumor cells. Their current use in clinical trials have demonstrated potentiation of antitumoral drugs and cytotoxicity in repair deficient tumor cells.
Article
This study examined the impact of secondary cytoreductive surgery on survival of patients with recurrent epithelial ovarian carcinoma. One hundred six patients with a disease free interval (DFI) > 6 months after primary treatment underwent secondary cytoreductive surgery. Multivariate analysis determined which variables influenced the cytoreductive outcome and survival. Eighty-seven patients (82.1%) underwent removal of all visible tumor. The median and estimated 5-year survival for the entire cohort after recurrence was 35.9 months and 28%, respectively. The probability of complete cytoreduction was influenced by the largest size of recurrent tumor (< 10 cm ¿90.0% vs. > 10 cm ¿66.7%; P = 0.003), use of salvage chemotherapy before secondary surgery (chemotherapy given ¿64.3% vs. chemotherapy not given ¿93.8%; P = 0.001), and preoperative Gynecologic Oncology Group performance status (0 ¿100%, 1 ¿91.4%, 2 ¿82.4%, and 3 ¿47.4%; P = 0.001). Survival was influenced by the DFI after primary treatment (6-12 months ¿median, 25.0 months vs. 13-36 months ¿median, 44.4 months vs. > 36 months ¿median, 56.8 months; P = 0.005), the completeness of cytoreduction (visibly disease free ¿median, 44.4 months vs. any residual disease ¿median, 19.3 months; P = 0.007), the use of salvage chemotherapy before secondary surgery (chemotherapy given ¿median, 24.9 months vs. chemotherapy not given ¿median, 48.4 months; P = 0.005), and the largest size of recurrent tumor (< 10 cm ¿median, 37.3 months vs. > 10 cm ¿median, 35.6 months; P = 0.04). Complete cytoreduction is possible for the majority of patients with recurrent epithelial ovarian carcinoma and maximizes survival if undertaken before salvage chemotherapy. The authors believe a randomized trial should be initiated to confirm these findings.
Article
We disclose the development of a novel series of 2-phenyl-2H-indazole-7-carboxamides as poly(ADP-ribose)polymerase (PARP) 1 and 2 inhibitors. This series was optimized to improve enzyme and cellular activity, and the resulting PARP inhibitors display antiproliferation activities against BRCA-1 and BRCA-2 deficient cancer cells, with high selectivity over BRCA proficient cells. Extrahepatic oxidation by CYP450 1A1 and 1A2 was identified as a metabolic concern, and strategies to improve pharmacokinetic properties are reported. These efforts culminated in the identification of 2-{4-[(3S)-piperidin-3-yl]phenyl}-2H-indazole-7-carboxamide 56 (MK-4827), which displays good pharmacokinetic properties and is currently in phase I clinical trials. This compound displays excellent PARP 1 and 2 inhibition with IC(50) = 3.8 and 2.1 nM, respectively, and in a whole cell assay, it inhibited PARP activity with EC(50) = 4 nM and inhibited proliferation of cancer cells with mutant BRCA-1 and BRCA-2 with CC(50) in the 10-100 nM range. Compound 56 was well tolerated in vivo and demonstrated efficacy as a single agent in a xenograft model of BRCA-1 deficient cancer.
Article
This study was undertaken to evaluate the efficacy of secondary surgical cytoreduction in the management of ovarian cancer. The cases of 100 patients with recurrent or progressive epithelial ovarian cancer whose initial treatment had been cytoreduction followed by cytotoxic therapy with a cisplatin-based regimen were reviewed. All 100 patients underwent surgery, after recurrence or progression was documented preoperatively, by gynecologic oncologists at the Mount Sinai Medical Center, New York, NY, between 1980 and 1991 with the intention of performing radical tumor reduction. Sixty-one patients had a secondary cytoreduction that left residual disease less than 2 cm in diameter. The median survival, determined from the date of the secondary cytoreduction to the date of death or last follow-up, is 27.1 months in the optimally treated group and 9.0 months for the 39 patients whose surgery was suboptimal (P = .0001). Other variables associated with statistically significant longer survival, and a significantly higher probability of achieving a successful secondary cytoreduction, included age < or = 55 years at the time of secondary cytoreduction, interval from initial diagnosis to secondary cytoreduction of more than 12 months, residual disease at initial staging laparotomy of less than 2 cm, and a complete clinical response to a cisplatin-based front-line regimen. Multivariate analysis confirms the survival benefit provided by a successful secondary cytoreduction when adjusted for the above variables. There was one postoperative mortality. Ten percent of the successfully cytoreduced patients and 18% of the unsuccessfully cytoreduced patients experienced some degree of postoperative morbidity. These data justify the performance of secondary cytoreductive surgery for patients who develop gross recurrent or progressive ovarian cancer following cisplatin therapy.
Article
The aim of this prospective study was to evaluate the influence of secondary cytoreductive surgery on survival of patients with recurrent epithelial ovarian cancer. Between June 1993 and June 1999, 149 patients after primary treatment underwent secondary cytoreductive surgery: 69 (46.3%) had recurrence-free interval (RFI) 7-12 months, 59 (39.6%) RFI 13-24 months, and 21 (14.1%) RFI >24 months. Exclusion criteria included secondary cytoreduction during second-look laparotomy, interval cytoreduction, and palliative surgery in patients with intestinal obstruction or progressive disease. The median follow-up was 27 months. According to multivariate analysis, RFI groups, prior chemotherapy combination, and residual tumor after secondary surgery were associated independently with overall survival. Residual tumor after secondary surgery was by far the most strongly predictive factor for patient's survival (hazard ratio (HR) 2.65; 95% confidence interval (CI) 1.43-4.92). The 2-year survival rates were 22.3, 62.9, and 22.7%, respectively, for patients with RFI 7-12, 13-24, and >24 months. The 5-year survival was 29% for patients with RFI 13-24 months. No patients with RFI 7-12 and >24 months outlived the 4-year estimate. Unexpectedly, RFI >24 months was not correlated significantly with overall survival. However, 17 patients (81%) with RFI >24 months were heavily treated with chemotherapy before secondary surgery. Patients who have documented gross disease preoperatively should be selected for a secondary debulking operation; the entity of surgical effort would be modulated in relation to previous treatment.
Article
It is believed that BRCA1 and BRCA2 germline mutations account for the majority of hereditary ovarian carcinomas; however, to the authors' knowledge, there are scant data on the prevalence and spectrum of mutations, genotype/phenotype correlations, tumor histology, and family history characteristics. To address this gap, the authors conducted a population-based study of 232 incident epithelial ovarian carcinomas in the Tampa Bay area. Genetic testing for the BRCA1 and BRCA2 genes was performed through full sequencing and BRCA1 rearrangement testing. Of 209 women with invasive ovarian carcinoma, 32 women (15.3%) had mutations in BRCA1 or BRCA2, including 20 BRCA1 mutations and 12 BRCA2 mutations. Of the BRCA2 mutations, 58% were outside the "ovarian cancer cluster region" (OCCR). Variants of uncertain significance were detected in 8.2% of women with invasive ovarian carcinoma. No mutations were identified in women with borderline or invasive mucinous tumors. Among the BRCA mutation-positive women, 63% had serous tumors. A family history of breast and/or ovarian carcinoma was reported in 65%, 75%, and 43.5% of relatives of BRCA1 carriers, BRCA2 carriers, and non-BRCA1/BRCA2 carriers, respectively. The data from this study suggested that 1) previous studies may have underestimated the frequency of BRCA1 and BRCA2 mutations in ovarian carcinomas, especially outside the OCCR; 2) it may be reasonable to offer genetic counseling to any woman with an invasive, nonmucinous epithelial ovarian tumor; and 3) among patients with invasive ovarian carcinoma, family history is not sufficiently accurate to predict mutation status.
Article
The benefit of cytoreductive surgery for patients with recurrent epithelial ovarian cancer has not been defined clearly. The objective of this study was to identify prognostic factors for survival in patients who underwent secondary cytoreduction for recurrent, platinum-sensitive epithelial ovarian cancer and to establish generally applicable guidelines and selection criteria. The authors reviewed all patients who underwent secondary cytoreduction for recurrent epithelial ovarian cancer from 1987 to 2001. Potential prognostic factors were evaluated in univariate and multivariate analyses. In total, 157 patients underwent secondary cytoreduction, and 153 of those patients were evaluable. After secondary cytoreduction, the median follow-up was 36.9 months (range, 0.2-125.6 months), and the median survival was 41.7 months (95% confidence interval, 36.0-47.2 months). For patients who had a disease-free interval prior to recurrence of between 6 months and 12 months, the median survival was 30 months compared with 39 months for patients who had a disease-free interval between 13 months and 30 months and 51 months for patients who had a disease-free interval >30 months (P = .005). For patients who had a single site of recurrence, the median survival was 60 months compared with 42 months for patients who had multiple sites of recurrence and 28 months for patients who had carcinomatosis (P <.001). The median survival for patients who had residual disease that measured < or =0.5 cm was 56 months compared with 27 months for patients who had residual disease that measured >0.5 cm (P <.001). On multivariate analysis, disease-free interval (P = .004), the number of recurrence sites (P = .01), and residual disease (P <.001) were significant prognostic factors. In the authors' analysis of secondary cytoreduction for recurrent epithelial ovarian cancer, a significant survival benefit was demonstrated for residual disease that measured < or = 0.5 cm. The disease-free interval and the number of recurrence sites should be used as selection criteria for offering secondary cytoreduction.
Article
BRCA1 and BRCA2 mutations in general populations and in various types of cancers have not been well characterized. We investigated the presence of these mutations in unselected patients with newly diagnosed incident ovarian cancer in Ontario, Canada, with respect to cancers reported among their relatives. A population series of 1171 unselected patients with incident ovarian cancer diagnosed between January 1, 1995, and December 31, 1999, in Ontario, Canada, was screened for germline mutations throughout the BRCA1 and BRCA2 genes. Screening involved testing for common variants, then protein truncation testing of long exons, and then denaturing gradient gel electrophoresis or denaturing high-performance liquid chromatography for the remainder of BRCA1 and BRCA2, respectively. Cox regression analysis was used to examine cancer outcomes reported by the case probands for their 8680 first-degree relatives. Population allele frequencies and relative risks (RRs) were derived from the regression results by an extension of Saunders-Begg methods. Age-specific Ontario cancer incidence rates were used to estimate cumulative incidence of cancer to age 80 years by mutation status. Among 977 patients with invasive ovarian cancer, 75 had BRCA1 mutations and 54 had BRCA2 mutations, for a total mutation frequency of 13.2% (95% confidence interval [CI] = 11.2% to 15.5%). Higher risks for various cancer types in the general Ontario population were associated with BRCA1 mutation carriage than with noncarriage, including ovarian (RR = 21, 95% CI = 12 to 36), female breast (RR = 11, 95% CI = 7.5 to 15), and testis (RR = 17, 95% CI = 1.3 to 230) cancers. Higher risks were also associated with BRCA2 mutation carriage than with noncarriage, particularly for ovarian (RR = 7.0, 95% CI = 3.1 to 16), female and male breast (RR = 4.6, 95% CI = 2.7 to 7.8, and RR = 102, 95% CI = 9.9 to 1050, respectively), and pancreatic (RR = 6.6, 95% CI = 1.9 to 23) cancers. Cancer risks differed according to the mutation's position in the gene. Estimated cumulative incidence to age 80 years among women carrying BRCA1 mutations was 24% for ovarian cancer and 90% for breast cancer and among women carrying BRCA2 mutations was 8.4% for ovarian cancer and 41% for breast cancer. For the general Ontario population, estimated carrier frequencies of BRCA1 and BRCA2 mutations, respectively, were 0.32% (95% CI = 0.23% to 0.45%) and 0.69% (95% CI = 0.43% to 1.10%). BRCA1 and BRCA2 mutations may be more frequent in general populations than previously thought and may be associated with various types of cancers.
Secondary mutations as a mechanism of cisplatin resistance in BRCA2-mutated cancers
  • W Sakai
  • Em Swisher
  • By Karlan
Cancer Genome Atlas Research N. Integrated genomic analyses of ovarian carcinoma