Suresh Ramalingam

University of Colorado Denver, Denver, CO, USA

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Publications (39)145.52 Total impact

  • Source
    Article: Population pharmacokinetic analysis of 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) in adult patients with solid tumors.
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    ABSTRACT: To identify sources of exposure variability for the tumor growth inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) using a population pharmacokinetic analysis. A total 67 solid tumor patients at 2 centers were given 1 h infusions of 17-DMAG either as a single dose, daily for 3 days, or daily for 5 days. Blood samples were extensively collected and 17-DMAG plasma concentrations were measured by liquid chromatography/mass spectrometry. Population pharmacokinetic analysis of the 17-DMAG plasma concentration with time was performed using nonlinear mixed effect modeling to evaluate the effects of covariates, inter-individual variability, and between-occasion variability on model parameters using a stepwise forward addition then backward elimination modeling approach. The inter-individual exposure variability and the effects of between-occasion variability on exposure were assessed by simulating the 95 % prediction interval of the AUC per dose, AUC(0-24 h), using the final model and a model with no between-occasion variability, respectively, subject to the five day 17-DMAG infusion protocol with administrations of the median observed dose. A 3-compartment model with first order elimination (ADVAN11, TRANS4) and a proportional residual error, exponentiated inter-individual variability and between occasion variability on Q2 and V1 best described the 17-DMAG concentration data. No covariates were statistically significant. The simulated 95% prediction interval of the AUC(0-24 h) for the median dose of 36 mg/m(2) was 1,059-9,007 mg/L h and the simulated 95 % prediction interval of the AUC(0-24 h) considering the impact of between-occasion variability alone was 2,910-4,077 mg/L h. Population pharmacokinetic analysis of 17-DMAG found no significant covariate effects and considerable inter-individual variability; this implies a wide range of exposures in the population and which may affect treatment outcome. Patients treated with 17-DMAG may require therapeutic drug monitoring which could help achieve more uniform exposure leading to safer and more effective therapy.
    Cancer Chemotherapy and Pharmacology 03/2012; 70(1):201-5. · 2.83 Impact Factor
  • Article: Adenoid cystic carcinoma of the head and neck: Incidence and survival trends based on 1973-2007 Surveillance, Epidemiology, and End Results data.
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    ABSTRACT: Adenoid cystic carcinoma (ACC) of the head and neck (ACCHN) is a rare tumor of minor salivary, parotid, and submandibular glands. The biologic behavior of the disease is poorly understood, and nonsurgical treatment strategies have yet to be standardized. The long-term prognosis continues to be guarded, with an estimated 10-year survival of <60%. Population-based studies examining ACC are scarce. The authors aimed to analyze incidence rates and survival outcomes for patients diagnosed with ACCHN using national population-based data. Data were obtained from the US National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program. Newly diagnosed ACCHN cases reported to SEER from 1973 through 2007 were categorized according to their sex, race, age, year of diagnosis, marital status, treatment interventions, primary tumor site, and disease stage. Incidence of ACCHN and postdiagnosis survival were examined over time and compared across different demographic and disease-related categories. The authors identified 3026 patients with ACCHN. The mean age at diagnosis among those cases was 57.4 years (range, 11-99 years). Analyses of incidence data demonstrated a decline in ACCHN rates between 1973 and 2007, noted across all sexes and races with no detectable inflexion points. The overall 5-year, 10-year, and 15-year survival outcomes for ACCHN patients were 90.3%, 79.9%, and 69.2%, respectively. Females, patients with localized disease, and younger patients were found to have significantly better survival across all time periods (all comparison-specific log-rank P values <0.001). Multivariate analyses revealed better prognosis among women compared with men (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.65-0.82), among married compared with unmarried individuals (HR, 0.81; 95% CI, 0.71-0.91), with certain sites of origin and stage of disease (HR, 2.788; 95% CI, 2.36-3.29), and in those who had surgery of the primary tumor site (HR, 0.45; 95% CI, 0.37-0.54). The overall incidence of ACC is declining. The noted differences in survival based on sex, marital status, site of origin, and treatment intervention require further investigation. Cancer 2012. © 2012 American Cancer Society.
    Cancer 01/2012; 118(18):4444-51. · 4.77 Impact Factor
  • Article: Mechanism-based model characterizing bidirectional interaction between PEGylated liposomal CKD-602 (S-CKD602) and monocytes in cancer patients.
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    ABSTRACT: S-CKD602 is a PEGylated liposomal formulation of CKD-602, a potent topoisomerase I inhibitor. The objective of this study was to characterize the bidirectional pharmacokinetic-pharmacodynamic (PK-PD) interaction between S-CKD602 and monocytes. Plasma concentrations of encapsulated CKD-602 and monocytes counts from 45 patients with solid tumors were collected following intravenous administration of S-CKD602 in the phase I study. The PK-PD models were developed and fit simultaneously to the PK-PD data, using NONMEM(®). The monocytopenia after administration of S-CKD602 was described by direct toxicity to monocytes in a mechanism-based model, and by direct toxicity to progenitor cells in bone marrow in a myelosuppression-based model. The nonlinear PK disposition of S-CKD602 was described by linear degradation and irreversible binding to monocytes in the mechanism-based model, and Michaelis-Menten kinetics in the myelosuppression-based model. The mechanism-based PK-PD model characterized the nonlinear PK disposition, and the bidirectional PK-PD interaction between S-CKD602 and monocytes.
    International Journal of Nanomedicine 01/2012; 7:5555-64. · 3.13 Impact Factor
  • Article: A phase II study of halichondrin B analog eribulin mesylate (E7389) in patients with advanced non-small cell lung cancer previously treated with a taxane: a California cancer consortium trial.
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    ABSTRACT: Eribulin mesylate (E7389) is an analog of halichondrin B with a unique mechanism of microtubule binding. The activity and toxicity of eribulin were assessed in patients with advanced non-small cell lung cancer (NSCLC) previously treated with a taxane. An open-label phase II study included patients with NSCLC previously treated with platinum and taxane-based therapy, with up to two prior cytotoxic regimens, given for metastatic disease or as adjuvant therapy. Patients were stratified by taxane-sensitivity: taxane-sensitive (TS, progression >90 days after taxane) or taxane-resistant (TR, progression ≤90 days after taxane). Patients received an intravenous infusion of eribulin at 1.4 mg/m on days 1 and 8 every 21 days. The primary end point was objective response rate and secondary end points included progression-free survival and overall survival. Sixty-six patients were accrued. The objective response rate was 5% with a median duration of response of 7.8 months. In the TS arm, 3 of 45 patients (7%) achieved a partial response and another 11 of 45 (24%) achieved stable disease for at least 3 months, whereas in the TR arm, no patients achieved a partial response and 4 of 21 (19%) achieved stable disease for at least 3 months. Median progression-free survival was 2.9 months in the TS subgroup and 1.2 months in the TR subgroup. The median overall survival was 12.6 months in the TS subgroup and 8.9 months in the TR subgroup. Toxicities were primarily hematologic; only two patients developed grade 3 neuropathy. Eribulin mesylate is well tolerated and demonstrates activity in pretreated, TS NSCLC.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 12/2011; 7(3):574-8. · 4.55 Impact Factor
  • Article: An open-label study to describe pharmacokinetic parameters of erlotinib in patients with advanced solid tumors with adequate and moderately impaired hepatic function.
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    ABSTRACT: To compare the pharmacokinetic (PK) parameters of a single dose of erlotinib in cancer patients with moderate hepatic impairment (MHI) to those of cancer patients with adequate hepatic function (AHF). Cancer patients with either AHF or MHI were treated with a single 150 mg dose of erlotinib on day 1 only followed by 96 h of plasma sampling for PK assessment. From day 5, patients were allowed to continue daily erlotinib in a maintenance phase. Non-smoking patients were stratified into an AHF cohort (total bilirubin ≤ upper limit of normal [ULN] and ALT/AST ≤ 1.5 X ULN) or a MHI cohort (Child-Pugh score of 7-9). The frequency of adverse events and laboratory changes were assessed. Thirty-six patients, 21 with AHF and 15 with MHI, received at least one dose of erlotinib. The PK of erlotinib was similar between the two cohorts with a median C (max) of 1.09 versus 0.828 μg/mL and corresponding median AUC(0-t ) 29.3 versus 30.5 μg h/mL for the AHF and MHI cohorts, respectively. Adverse events from erlotinib in cancer patients with MHI were consistent with the known safety profile. The PK and safety profiles of erlotinib in patients with MHI were similar to those with AHF. As a result, a reduced starting dose of erlotinib in patients with MHI is not required and treatment should be guided by patients' tolerability.
    Cancer Chemotherapy and Pharmacology 09/2011; 69(3):605-12. · 2.83 Impact Factor
  • Article: Gender and ethnic disparities in incidence and survival of squamous cell carcinoma of the oral tongue, base of tongue, and tonsils: a surveillance, epidemiology and end results program-based analysis.
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    ABSTRACT: Squamous cell carcinomas (SCC) of the oral tongue (OT) and of the base of the tongue and tonsils (BTT) differ with respect to etiology, treatment and prognosis. Human papillomavirus has been linked to the increased incidence of BTT, yet, the trends in incidence of BTT and OT tumors among gender and ethnic origin groups have not been well examined. We sought to examine the trend in gender-, ethnic origin- and age-specific incidence of these tumors over time. Data were obtained from the Surveillance, Epidemiology and End Results Program of the US National Cancer Institute. We examined temporal trends in sex- and ethnic origin-specific incidence of SCC by calculating the annual percent changes followed by joinpoint analyses evaluating changes in trend. While BTT increased in age-adjusted rates among white males with a more pronounced increase observed in the mid-1990s, white females experienced a significant increase in incidence of OT tumors. Patients with advanced OT carcinoma had a significantly lower survival compared to those with advanced BTT disease; however, patients with early-stage OT tumors had a better survival compared to patients with BTT. While the increase in incidence of BTT tumors in white men is likely human papillomavirus driven, more studies are needed to elucidate the increasing incidence of OT tumors in white women. The differences in outcomes across ethnic origin groups are also described and discussed.
    Oncology 09/2011; 81(1):12-20. · 2.27 Impact Factor
  • Article: Bidirectional pharmacodynamic interaction between pegylated liposomal CKD-602 (S-CKD602) and monocytes in patients with refractory solid tumors.
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    ABSTRACT:  STEALTH(®) liposomal CKD-602 (S-CKD602), a camptothecin analog, is eliminated by the reticuloendothelial system (RES), which consists of cells, including monocytes. We evaluated the relationship between monocyte and absolute neutrophil counts (ANCs) in the blood and pharmacokinetic disposition of S-CKD602 and nonliposomal CKD-602 (NL-CKD602) in patients.  As part of a phase I study of S-CKD602 and phase I and II studies of NL-CKD602, the percent decreases in ANC and monocytes at their nadir were calculated. After S-CKD602, the amount of CKD-602 recovered in urine was measured.  For S-CKD602 in patients <60 years, the percent decrease in ANC and monocytes were 43  ±  31 and 58  ±  26%, respectively (P = 0.001). For S-CKD602 in patients ≥60, the percent decrease in ANC and monocytes were 41  ±  31 and 45  ±  36%, respectively (P =  0.50). For NL-CKD602 (n = 42), the percent decrease in ANC and monocytes were similar (P >  0.05). For S-CKD602, the relationship between the percent decrease in monocytes and CKD-602 recovered in urine was stronger in patients <60 (R(2) =  0.82), compared with patients ≥60 (R(2) =  0.30).  Monocytes are more sensitive to S-CKD602, compared with neutrophils, and the increased sensitivity is related to the liposomal formulation, not CKD-602. These results suggest that monocytes engulf S-CKD602, which causes the release of CKD-602 from the liposome and toxicity to the monocytes, and that the effects are more prominent in patients <60.
    Journal of Liposome Research 06/2011; 21(2):158-65. · 1.71 Impact Factor
  • Article: Population Pharmacokinetics of Pegylated Liposomal CKD-602 (S-CKD602) in Patients With Advanced Malignancies.
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    ABSTRACT: S-CKD602 is a pegylated long-circulating liposomal formulation of CKD-602, a potent topoisomerase I inhibitor. A population pharmacokinetic (PK) model for encapsulated and released CKD-602 following administration of S-CKD602 was developed to assess factors that may influence S-CKD602 PK. Plasma samples from 45 patients with solid tumors were collected in a phase 1 study. S-CKD602 was administered as a 1-hour intravenous infusion with doses ranging from 0.1 to 2.5 mg/m(2). Plasma concentrations of encapsulated and released CKD-602 were used to develop a population PK model using NONMEM. PK of encapsulated CKD-602 was described by a 1-compartment model with nonlinear clearance, and PK of released CKD-602 was described by a 2-compartment model with linear clearance for all patients. Covariate analysis revealed that tumor in the liver was a significant covariate for clearance of encapsulated CKD-602 and that age significantly influenced the release rate of CKD-602 from S-CKD602. Maximum elimination rate in patients with liver tumor is 1.5-fold higher compared with patients without liver tumor. Release rate of CKD-602 from S-CKD602 in patients less than 60 years old was 2.7-fold higher compared with patients 60 years old or older. These observations have potential implications in the optimal dosing of liposomal agents.
    The Journal of Clinical Pharmacology 01/2011; · 2.91 Impact Factor
  • Article: Randomized phase II trial of concurrent versus sequential bortezomib plus docetaxel in advanced non-small-cell lung cancer: a California cancer consortium trial.
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    ABSTRACT: The proteasome inhibitor bortezomib sensitizes tumor cells to chemotherapy-induced apoptosis. In preclinical non-small-cell lung cancer (NSCLC) models, p53-dependent growth arrest after bortezomib treatment resulted in reduced cytotoxicity if bortezomib preceded docetaxel. The reverse sequence of docetaxel before bortezomib was associated with increased apoptosis, cleavage of caspase-3 and PARP (poly [ADP-ribose] polymerase), and reduction in Bcl-2. A prospective randomized phase II trial of concurrent versus sequential docetaxel and bortezomib was conducted to assess whether administration sequence resulted in measurable clinical differences. Previously treated patients with advanced NSCLC were randomized to concurrent (CON) or sequential (SEQ) docetaxel (75 mg/m² intravenous [I.V.]) followed by bortezomib, every 3 weeks. In the CON arm, bortezomib (1.6 mg/m² I.V.) was given on days 1 and 8, and in the SEQ arm, it was given on days 2 and 8. Previous erlotinib as well as treated or controlled brain metastases were allowed. The primary endpoint was objective response rate (RR); progression-free (PFS) and overall survival (OS) were secondary endpoints. Eighty-one patients were randomized (40 CON and 41 SEQ). Grade 3+ toxicities were mostly due to myelosuppression. One patient each had grade 4 hyponatremia and syncope. Toxicities were similar between the arms. There was 1 treatment-related death in the SEQ arm. There were 8 partial responders, 4 in each arm, for an overall RR of 10%. Disease control rate was similar in both arms (50% vs. 49%). Median PFS was 12 weeks in the CON arm and 11 weeks in the SEQ arm. Median OS times in the CON and SEQ arms were 13.3 and 10.5 months, respectively. Docetaxel plus bortezomib given sequentially or concurrently has similar RR and PFS. Median survival in the SEQ arm exceeds published survival estimates for either agent alone or in combination. Any further studies in this population would require molecular characterization of a phenotype most likely to benefit from proteasome inhibitor therapy.
    Clinical Lung Cancer 01/2011; 12(1):33-7. · 2.94 Impact Factor
  • Article: A first in human study of SB-743921, a kinesin spindle protein inhibitor, to determine pharmacokinetics, biologic effects and establish a recommended phase II dose.
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    ABSTRACT: To determine the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), safety, pharmacokinetics, and pharmacodynamics of SB-743921 when administered as a 1-h infusion every 21 days to patients with advanced solid tumors or relapsed/refractory lymphoma. Patients who failed prior standard therapy or those without any standard options were eligible. Forty-four patients were enrolled using an initial accelerated dose-escalation phase followed by a standard dose-escalation phase. An additional 20 patients were enrolled at the recommended phase II dose to obtain additional safety and pharmacokinetic data. The doses evaluated ranged from 2 to 8 mg/m(2). The pharmacokinetics of SB-743921 was evaluated at 19 time-points over 48 h following during administration during cycle 1. Toxicity was assessed by the NCI Common Terminology Criteria version 3.0. Response evaluation was performed every 6 weeks. The most common and consistent DLT was neutropenia. Other DLTs observed included hypophosphatemia, pulmonary emboli, SVC syndrome, transaminitis, hyponatremia, and hyperbilirubinemia. The MTD of SB-743921 as a 1-h infusion every 21 days was established as 4 mg/m(2). The maximum plasma concentration and area under the plasma concentration time curve appeared to increase proportionally to dose. One durable objective response was seen in a patient with metastatic cholangiocarcinoma who was on treatment 11 months and 6 patients had stable disease for over four cycles. The recommended phase II dose of SB-743921 on this specific schedule of a 1-h infusion every 3 weeks is 4 mg/m(2). The promising efficacy and lack of severe toxicities in this study warrant the continued development of SB-743921.
    Cancer Chemotherapy and Pharmacology 05/2010; 67(2):447-54. · 2.83 Impact Factor
  • Article: Summary of selected presentations from the 8th annual targeted therapy in lung cancer symposium.
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    ABSTRACT: Lung cancer is the leading cause of cancer-related death in the United States. Outcomes for patients with lung cancer have reached a plateau with cytotoxic chemotherapy. Lung cancer remains very much at the vanguard of the new revolution in cancer therapy using molecular targets. Although striking improvements in survival have been observed in the treatment of chronic myeloid leukemia, gastrointestinal stromal tumors, and in a subset of breast cancer using this approach, the impact of targeted therapies in lung cancer is quite modest. Along with advances in imaging and cancer genomics, there is now considerable optimism that the pace of progress in the treatment of lung cancer will accelerate in the next 10 years. As has been the custom for the past 8 years, leading experts in the biology, diagnosis and treatment of lung cancer met for three days to discuss current areas of research and future directions. This summary provides a brief snapshot of the discussions held at the 8th Annual Meeting on Targeted Therapies for Lung Cancer sponsored by the International Association for the Study of Lung Cancer in Santa Monica in early February 2008.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 08/2009; 4(7):930-5. · 4.55 Impact Factor
  • Article: Phosphorylated eukaryotic translation initiation factor 4 (eIF4E) is elevated in human cancer tissues.
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    ABSTRACT: Eukaryotic translation initiation factor 4E (eIF4E) is a rate-limiting factor for cap-dependent protein synthesis and is regulated by PI3 kinase/mTOR and mitogen-activated protein kinase (MAPK)/Mnk signaling pathways. Recent studies have shown that Mnk-mediated eIF4E phosphorylation is absolutely required for eIF4E's oncogenic function. Overexpression of eIF4E has been reported in many types of cancers; however, the expression of phosphorylated eIF4E (p-eIF4E) in human cancer tissues, particularly solid tumor tissues, has not been reported. The current study focused on evaluating p-eIF4E expression patterns in the tumor tissues obtained from patients with a variety of malignancies. Using three different tissue microarrays consisting of a total of 380 cases of human cancers and 146 cases of adjacent normal tissues, we detected p-eIF4E positive staining in 63.4% (241/380) of cancers, but only in 30.1% (44/146) of adjacent normal tissues. Thus, p-eIF4E expression is significantly higher in cancers than in adjacent normal tissues (p < 0.001). In general, there was no major difference in p-eIF4E staining between cancers with and without lymph node metastasis. In certain types of maligancies such as lung, gastric and colorectal cancers, p-eIF4E staining was significantly higher in the early stage (T1) than in the late stage (T3) disease (p < 0.05). Collectively, these findings suggest that p-eIF4E may play a critical role in cancer development, particularly early stages of tumorigenesis and support p-eIF4E as a good cancer therapeutic target.
    Cancer biology & therapy 08/2009; 8(15):1463-9. · 2.64 Impact Factor
  • Article: Phase I and pharmacokinetic study of pegylated liposomal CKD-602 in patients with advanced malignancies.
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    ABSTRACT: S-CKD602 is a pegylated liposomal formulation of CKD602, a semisynthetic camptothecin analogue. Pegylated (STEALTH) liposomes can achieve extended drug exposure in plasma and tumor. Based on promising preclinical data, the first phase I study of S-CKD602 was done in patients with refractory solid tumors. S-CKD602 was administered i.v. every 3 weeks. Modified Fibonacci escalation was used (three to six patients/cohort), and dose levels ranged from 0.1 to 2.5 mg/m2. Serial plasma samples were obtained over 2 weeks and total (lactone+hydroxyl acid) concentrations of encapsulated, released, and sum total (encapsulated+released) CKD602 measured by liquid chromatography-tandem mass spectrometry. Forty-five patients (21 males) were treated. Median age, 62 years (range, 33-79 years) and Eastern Cooperative Oncology Group status, 0 to 1 (43 patients) and 2 (2 patients). Dose-limiting toxicities of grade 3 mucositis occurred in one of six patients at 0.3 mg/m2, grade 3 and 4 bone marrow suppression in two of three patients at 2.5 mg/m2, and grade 3 febrile neutropenia and anemia in one of six patients at 2.1 mg/m2. The maximum tolerated dose was 2.1 mg/m2. Partial responses occurred in two patients with refractory ovarian cancer (1.7 and 2.1 mg/m2). High interpatient variability occurred in the pharmacokinetic disposition of encapsulated and released CKD602. S-CKD602 represents a promising new liposomal camptothecin analogue with manageable toxicity and promising antitumor activity. Phase II studies of S-CKD602 at 2.1 mg/m2 i.v. once every 3 weeks are planned. Prolonged plasma exposure over 1 to 2 weeks is consistent with STEALTH liposomes and provides extended exposure compared with single doses of nonliposomal camptothecins.
    Clinical Cancer Research 03/2009; 15(4):1466-72. · 7.74 Impact Factor
  • Article: Phase II study of belinostat (PXD101), a histone deacetylase inhibitor, for second line therapy of advanced malignant pleural mesothelioma.
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    ABSTRACT: Belinostat (PXD 101) is a novel inhibitor of class I and II histone deacetylases. This class of compounds has demonstrated anticancer activity in malignant mesothelioma. We conducted a phase II study of belinostat in patients with relapsed malignant pleural mesothelioma. Patients with advanced mesothelioma, progression with one prior chemotherapy regimen and Eastern Cooperative Oncology Group performance status 0-2 were eligible. Belinostat was administered at 1000 mg/m intravenously over 30 minutes on days 1-5 of every 3 week cycle. The primary end point was response rate. The Simon two-stage design was used. Disease assessments were performed every two cycles. Thirteen patients were enrolled. Baseline characteristics were: median age of 73 years; Eastern Cooperative Oncology Group performance status 0 (n = 4), 1 (8) and 2 (1). A median of two cycles of therapy were administered. Disease stabilization was seen in two patients. No objective responses were noted and the study did not meet criteria to proceed to the second stage of accrual. Median survival was 5 months with a median progression-free survival of 1 month. Salient toxicities included nausea, emesis, fatigue, and constipation. One patient died as a consequence of cardiac arrhythmia which was deemed 'possibly' related to therapy. Belinostat is not active as monotherapy against recurrent malignant pleural mesothelioma. Evaluation of combination strategies or alternate dosing schedules may be necessary for further development of this novel agent in mesothelioma.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 02/2009; 4(1):97-101. · 4.55 Impact Factor
  • Article: Effect of the CYP3A inhibitor ketoconazole on the pharmacokinetics and pharmacodynamics of bortezomib in patients with advanced solid tumors: a prospective, multicenter, open-label, randomized, two-way crossover drug-drug interaction study.
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    ABSTRACT: The proteasome inhibitor bortezomib undergoes oxidative biotransformation via multiple cytochrome P450 (CYP) enzymes, with CYP3A4 identified as a partial, yet potentially important, contributor based on in vitro drug metabolism studies. The aim of this study was to assess the effect of concomitant administration of ketoconazole on the pharmacokinetics (PK) and pharmacodynamics (PD) of bortezomib. This was a prospective, multicenter, open-label, randomized, multiple-dose, 2-way crossover study in patients with advanced solid tumors. All patients received bortezomib 1.0 mg/m(2) IV (on days 1, 4, 8, and 11 of two 21-day cycles) and were randomized to receive concomitant ketoconazole 400 mg on days 6, 7, 8, and 9 of cycle 1 or 2. Serial blood samples were collected over the day-8 dosing interval (immediately prior to bortezomib administration, and from 5 minutes to 72 hours after administration) in cycles 1 and 2 for measurement of plasma bortezomib concentrations for noncompartmental PK analysis and blood 20S proteasome inhibition for PD analysis. All adverse events (AEs) were recorded during each cycle including serious AEs and all neurotoxicity events for up to 30 days after the last dose of bortezomib. Twenty-one patients (median age, 57 years; sex, 67% male; race, 86% white; median body surface area, 2.01 m(2)) were randomized to treatment. Twelve patients completed the protocol-specified dosing and PK sampling in both cycles 1 and 2. Assessment of the effect of ketoconazole on bortezomib PK and PD was based on data in these 12 PK-evaluable patients. The ratio of geometric mean bortezomib AUC(0-tlast)(AUC from time 0 to last quantifiable concentration) for bortezomib plus ketoconazole versus bortezomib alone was 1.352 (90% CI, 1.032-1.772). Consistent with this observed mean increase in bortezomib exposure, concomitant administration of ketoconazole was associated with a corresponding increase (24%-46%) in the blood proteasome inhibitory effect. Concomitant administration of the CYP3A inhibitor ketoconazole with bortezomib resulted in a mean increase of 35% in bortezomib exposure. ClinicalTrials.gov identifier: NCT00129207.
    Clinical Therapeutics 01/2009; 31 Pt 2:2444-58. · 2.32 Impact Factor
  • Article: Overcoming mTOR inhibition-induced paradoxical activation of survival signaling pathways enhances mTOR inhibitors' anticancer efficacy.
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    ABSTRACT: The mammalian target of rapamycin (mTOR) has emerged as an important cancer therapeutic target. Several mTOR inhibitors are currently being tested in cancer clinical trials. Both PI3K/Akt and MEK/ERK signaling regulate mTOR axis. However, inhibition of mTOR activates Akt survival signaling, which in turn attenuates mTOR inhibitors' anticancer efficacy. We are interested in developing strategies for enhancing mTOR-targeted cancer therapy. In this study, we report that mTOR inhibition also induced activations of the MEK/ERK signaling pathway in some cancer cell lines after a prolonged treatment. The combination of rapamycin with the MEK inhibitor U0126 significantly enhanced growth inhibitory effects of cancer cells, suggesting that MEK/ERK activation may counteract mTOR inhibitors' anticancer efficacy. Similarly, the combination of an mTOR inhibitor with the EGF receptor inhibitor erlotinib synergistically inhibited the growth of both human cancer cells in cell cultures and xenografts in nude mice. Moreover, the presence of erlotinib suppressed rapamycin-induced phosphorylation of Akt, ERK and eIF4E as well, implying that erlotinib can suppress mTOR inhibition-induced feedback activation of several survival signaling pathways including Akt, ERK and eIF4E. Thus, we suggest a therapeutic strategy for enhancing mTOR-targeted cancer therapy by preventing mTOR inhibition-induced feedback activation of several survival mechanisms.
    Cancer biology & therapy 01/2009; 7(12):1952-8. · 2.64 Impact Factor
  • Article: Minimal progress, potential promise in small-cell lung cancer.
    Taofeek Owonikoko, Suresh Ramalingam
    Oncology (Williston Park, N.Y.) 12/2008; 22(13):1495-6. · 1.03 Impact Factor
  • Article: The role of targeted agents in the treatment of elderly patients with non-small cell lung cancer (NSCLC).
    Taofeek K Owonikoko, Suresh Ramalingam
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    ABSTRACT: The introduction of targeted biological agents represents the most promising approach to improve the disease control and outcome for patients with non-small cell lung cancer. The epidermal growth factor and the vascular endothelial growth factor signaling pathways have been successfully targeted using both orally administered small molecule tyrosine kinase inhibitors and monoclonal antibodies, with associated improvement in overall survival. Although the trials that established the efficacy of these agents allowed the enrollment of patients older than 70 years, the elderly patients constituted the minority. Given the stringent enrolment criteria in terms of organ function and performance status for most clinical trials, the elderly patients on clinical trials are not entirely representative of the overall elderly patient population. Therefore, the applicability of these data to the overall patient population deserves critical appraisal in the absence of trials dedicated specifically to the elderly. Preplanned and unplanned subset analysis of registration trial data is becoming increasingly common as a substitute measure to provide valuable information to guide the use of targeted agents in the elderly. Using this approach, it has been demonstrated that elderly patients are able to tolerate targeted biological therapies but suffer increased rate of toxicities. However, they derive benefit from such agents when they are carefully selected and have their drug doses adjusted appropriately to minimize potential toxicities. This article reviews the use of targeted agents for the treatment of NSCLC in elderly patients.
    Current Treatment Options in Oncology 12/2008; 9(4-6):313-25. · 2.68 Impact Factor
  • Article: Diallyl trisulfide selectively causes Bax- and Bak-mediated apoptosis in human lung cancer cells.
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    ABSTRACT: Garlic-derived organosulfur compounds (OSCs) are highly effective in affording protection against chemically induced pulmonary carcinogenesis in animal models. We now demonstrate that garlic constituent diallyl trisulfide (DATS) suppresses viability of cultured human lung cancer cell lines H358 (anon-small cell lung cancer cell line) and H460 (a large cell lung cancer cell line) by causing G2-M phase cell cycle arrest and apoptotic cell death. On the other hand, a normal human bronchial epithelial cell line BEAS-2B was significantly more resistant to growth inhibition and apoptosis induction by DATS compared with lung cancer cells. We also found that even a subtle change in the OSC structure could have a significant impact on its biological activity. For example, DATS was significantly more effective than either diallyl sulfide or diallyl disulfide against proliferation of lung cancer cells. The DATS-mediated G2-M phase cell cycle arrest was explained by down-regulation of cyclin-dependent kinase 1 (Cdk1) and cell division cycle 25C protein expression leading to accumulation of Tyr15 phosphorylated (inactive) Cdk1. The DATS-induced apoptosis correlated with induction of pro-apoptotic proteins Bax, Bak and BID, and a decrease in the expression of anti-apoptotic proteins Bcl-2 and Bcl-xL in lung cancer cells but not in BEAS-2B. Knockdown of Bax and Bak proteins conferred significant protection against DATS-induced apoptotic cytoplasmic histone-associated DNA fragmentation. On the other hand, BID protein was dispensable for DATS-induced apoptosis. In conclusion, the present study indicates that Bax and Bak proteins are critical targets of DATS-induced apoptosis in human lung cancer cells.
    Environmental and Molecular Mutagenesis 10/2008; 50(3):201-12. · 3.71 Impact Factor
  • Article: Gene expression profiling of non-small cell lung cancer.
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    ABSTRACT: Functional genomics has emerged over the past 10 years as a novel technology to study genetic alterations. Gene expression arrays are one genomic technique employed to discover changes in the DNA expression that occur in neoplastic transformation. Microarrays have been applied to investigating lung cancer. Specific applications include discovering novel genetic changes that occur in lung tumors. Microarrays can also be applied to improve diagnosis, staging and discover prognostic markers. The eventual goal of this technology is to discover new markers for therapy and to customize therapy based on an individual tumor genetic composition. In this review, we present the current state of gene expression array technology in its application to lung cancer.
    Lung Cancer 07/2008; 60(3):313-24. · 3.43 Impact Factor