Christine M Walko

Julphar School of Pharmacy, North Carolina, United States

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Publications (33)120.96 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This pilot study examined the feasibility of outpatient screening and clopidogrel dose adjustment for patients with previous percutaneous coronary intervention and at least one CYP2C19 loss-of-function allele. After screening a total of 211 outpatients, 50 patients were enrolled in a crossover study comparing 30 days of standard dose (75 mg) to 30 days of high-dose clopidogrel (150 mg). Platelet function was assessed with the VerifyNow P2Y12 assay. In patients with CYP2C19*2, 150 mg daily of clopidogrel was associated with improved ADP-specific platelet inhibition (217 vs 258 P2Y12 reaction units, p = 0.01). Outpatient screening for CYP2C19 loss-of-function polymorphisms is feasible, and a strategy of clopidogrel dose escalation may improve platelet inhibition in appropriately selected patients.
    Pharmacogenomics 05/2014; 15(7):915-923. · 3.86 Impact Factor
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    ABSTRACT: Cisplatin is a widely used antineoplastic. One of the major complications of cisplatin use is dose-limiting nephrotoxicity. There are many strategies to prevent this toxicity, including the use of mannitol as a nephroprotectant in combination with hydration. We aimed to evaluate the rates of cisplatin-induced nephrotoxicity in cancer patients receiving single-agent cisplatin with and without mannitol. This single-center retrospective analysis was a quasi experiment created by the national mannitol shortage. Data were collected on adult cancer patients receiving single-agent cisplatin as an outpatient from January 2011 to September 2012. The primary outcome was acute kidney injury (AKI). We evaluated 143 patients who received single-agent cisplatin; 97.2% of patients had head and neck cancer as their primary malignancy. Patients who did not receive mannitol were more likely to develop nephrotoxicity: odds ratio [OR] = 2.646 (95% CI = 1.008, 6.944; P = 0.048). Patients who received the 100 mg/m(2) dosing and patients who had a history of hypertension also had a higher likelihood of developing nephrotoxicity: OR = 11.494 (95% CI = 4.149, 32.258; P < 0.0001) and OR = 3.219 (95% CI = 1.228, 8.439; P = 0.017), respectively. When limited quantities of mannitol are available, it should preferentially be given to patients at particularly high risk of nephrotoxicity. Our analysis suggests that those patients receiving the dosing schedule of 100 mg/m(2) cisplatin every 3 weeks and those with hypertension are at the greatest risk of nephrotoxicity and would benefit from the addition of mannitol.
    Annals of Pharmacotherapy 04/2014; · 2.57 Impact Factor
  • Christine M Walko, Carolyn Grande
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    ABSTRACT: Sorafenib, a tyrosine kinase inhibitor, is indicated for the treatment of patients with unresectable hepatocellular carcinoma (HCC) and advanced renal cell carcinoma (RCC). Sorafenib is currently being evaluated in phase II and III trials in various malignancies as a single agent (locally advanced/metastatic radioactive iodine-refractory differentiated thyroid cancer [DTC]), as part of multimodality care (HCC), and in combination with chemotherapies (metastatic breast cancer). Grade 1 and 2 adverse events (AEs) that commonly occur during treatment (ie, dermatologic manifestations, diarrhea, fatigue, and hypertension) should be proactively managed. The goal is to allow patients to remain on their full dose of sorafenib for as long as their treatment is indicated. A combination of early recognition of and intervention for AEs, patient education, and an open dialogue between patients and their multidisciplinary healthcare team, with timely reporting of AEs, will allow for effective management of AEs and minimize the need for sorafenib dose reduction or discontinuation.
    Seminars in Oncology 02/2014; 41S2:S17-S28. · 4.33 Impact Factor
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    ABSTRACT: Background: CYP2D6 is a critical enzyme in the metabolism of tamoxifen and potentially a key determinant in breast cancer outcomes. Our study examined patients' beliefs about how the CYP2D6 genotype would affect their prognoses. Methods: Women enrolled in a pharmacogenomic clinical trial and on tamoxifen for prevention or treatment of breast cancer underwent CYP2D6 genotyping (EM = extensive, IM = intermediate, PM = poor metabolizing alleles). The informed consent said that the purpose of the trial was to examine effects of dose adjustment based on genotype, but that clinical benefits were uncertain. Our embedded sub-study surveyed 320 patients prior to receiving their genotypes. We experimentally manipulated 6 vignettes to describe hypothetical tamoxifen treatment (no or yes) and hypothetical genotype (EM, IM or PM). For each vignette, women gave their perceived recurrence risk (RR; 0-100%). Results: Women believed that genotype would not affect their RR if they did not take tamoxifen (p = 0.06). However, women believed that if prescribed tamoxifen, genotype would affect their RR (22% if EM, 30% if IM and 40% if PM, p < 0.001). Conclusion: Women believed that extensive tamoxifen metabolizers had better prognoses, despite study materials stating uncertainty about any benefit. The rapidly changing nature of genomic science calls for caution when communicating clinical utility. © 2014 S. Karger AG, Basel.
    Public Health Genomics 01/2014; · 2.57 Impact Factor
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    ABSTRACT: PurposeThe primary purpose of this study was to determine the rate of infusion reactions to cetuximab in oncology patients treated at the University of North Carolina Cancer Hospital. Secondarily, we sought to evaluate predictors of grade 3-4 hypersensitivity, including geography. /st>Data were collected by retrospective chart review for patients treated with cetuximab at the University of North Carolina Cancer Hospital between 15 November 2006 and 31 December 2010. Data were analyzed for occurrence of hypersensitivity reaction in 125 patients with various cancer types. /st>Of the 125 subjects, 31 (24.8%) experienced an infusion reaction of any grade. Of 125, 18 (14.4%) experienced a grade 3 or 4 reaction. The odds ratio for patients with an allergy history having a grade 3 or 4 reaction was 2.57 (95% CI 0.93 to 7.09, p = 0.07). Pretreatment with steroids was associated with absence of grade 3 or 4 reaction with an odds ratio of 0.21 (95% CI 0.05 to 0.83, p = 0.04). Mapping of reaction rates by county revealed higher rates in some of the more rural counties of North Carolina, however, statistical power was lacking. /st>Rates of hypersensitivity reaction at UNC are similar to rates seen in other areas of the southeastern United States and higher than in other regions of the United States and Europe. Rates of both hypersensitivity reactions and grade 3 to 4 hypersensitivity reactions have not substantially changed over time. Geography, allergy history, and perhaps smoking or cancer type may help predict who will react to cetuximab. Steroids should be strongly considered as premedication in addition to diphenhydramine.
    Journal of Oncology Pharmacy Practice 11/2013;
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    ABSTRACT: A pediatric study has established a maximum tolerated dose (MTD) for temsirolimus (Tem) of more than 150 mg/m intravenously/week. A phase I trial was conducted to establish the MTD for Tem in combination with valproic acid (VPA) in children and adolescents with refractory solid tumors. The secondary aims included expression of mammalian target of rapamycin (mTOR) markers on archival tumor tissue; Tem pharmacokinetics; assessment of histone acetylation (HA); and tumor response. Patients were treated with VPA (5 mg/kg orally three times daily) with a target serum level of 75-100 mcg/ml. Tem was started at an initial dose of 60 mg/m/week. Pharmacokinetics and HA measurements were performed during weeks 1 and 5. Two of the first three patients experienced dose-limiting toxicity (grade 3 mucositis). Tem at 35 mg/m/week was found to be tolerable. Peak Tem concentrations were higher in all patients compared with those in previously published reports of single agent Tem. Increases in HA are correlated with VPA levels. All tumor samples expressed mTORC1 and mTORC2. An objective response was observed in one patient (melanoma), whereas transient stable disease was observed in four other patients (spinal cord ependymoma, alveolar soft part sarcoma, medullary thyroid carcinoma, and hepatocellular carcinoma). The MTD of Tem when administered with VPA is considerably lower than when used as a single agent, with mucositis the major dose-limiting toxicity. The combination merits further study and may have activity in melanoma. Attention to drug-drug interactions will be important in future multiagent trials including Tem.
    Anti-cancer drugs 01/2013; · 2.23 Impact Factor
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    Christine M Walko, Ogechi Ikediobi
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    ABSTRACT: Oncology chemotherapeutics frequently exhibit a narrow therapeutic index, further complicated by the serious nature of dosing either too high (dangerous toxicities) or too low (loss of antitumor benefits). This underscores the need for optimal individualized drug selection and dosing, especially with agents that have wide interpatient variability. Pharmacogenomic assessment of drug metabolizing enzymes can improve the ability to optimally dose patients being treated with certain agents such as 6-mercaptopurine, irinotecan, tamoxifen, and flurouracil. Two of these agents (6-mercaptopurine and irinotecan) already have mention of pharmacogenomic testing in their FDA approved package inserts. Ongoing retrospective and prospective trials will help to further optimize the place in clinical practice for not only performing these pharmacogenomic assessments but, more importantly, how the results should be incorporated into therapy dosing decisions for patients.
    Journal of Pharmacy Practice 08/2012; 25(4):439-46.
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    ABSTRACT: • Paclitaxel and rosiglitazone are primarily metabolized by CYP2C8 and their in vitro metabolism by human liver microsomes is correlated. Probe assays that quantify the in vivo activity of CYP enzymes which are important in drug metabolism have been developed for use in clinical pharmacology research. A probe of CYP2C8 that is easy to administer and interpret may be valuable for individualized dosing of paclitaxel. • This pilot study demonstrates for the first time that there is an in vivo correlation between paclitaxel and rosiglitazone exposure. The finding, that a single rosiglitazone plasma concentration after oral dosing may explain significant variance in paclitaxel exposure, suggests that rosiglitazone may satisfy the requirements of a clinically useful in vivo probe. However, it is acknowledged that there is a need for further studies evaluating the use of rosiglitazone as a CYP2C8 probe and quantifying the relationship, in order to guide dosing of narrow therapeutic index drugs metabolized primarily by CYP2C8, such as paclitaxel. To evaluate the use of rosiglitazone and the erythromycin breath test (ERMBT), as probes of CYP2C8 and CYP3A4, respectively, to explain inter-individual variability in paclitaxel exposure. The concentration of rosiglitazone at 3 h and ERMBT results were included in a regression model to explain the variability in paclitaxel exposure in 14 subjects. Rosiglitazone concentration was significantly correlated with paclitaxel exposure (P= 0.018) while ERMBT had no predictive value (P= 0.47). The correlation between the exposure of rosiglitazone and paclitaxel likely reflects mutual dependence on the activity of CYP2C8. Rosiglitazone or similar agents may have value as in vivo probes of CYP2C8 activity.
    British Journal of Clinical Pharmacology 07/2012; 74(1):197-200. · 3.58 Impact Factor
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    Jai N Patel, Christine M Walko
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    ABSTRACT: To review the currently available literature on peginterferon alfa-2b (pegIFN [Sylatron]), including its role in therapy and toxicity for adjuvant treatment of locally advanced melanoma. A literature search was performed of PubMed and the American Society of Clinical Oncology abstracts from 1976 to February 2012, using the primary search terms peginterferon alfa-2b, interferon, Sylatron, and melanoma. All available English-language articles and trials that described the pharmacology, pharmacokinetics, pharmacodynamics, clinical activity, or safety profile of pegIFN were reviewed. PegIFN was approved in March 2011 for the adjuvant treatment of node-positive melanoma. Interferon (IFN) is commonly used in patients with melanoma who remain at high risk for relapse following surgery; however, the optimal scheduling and dose are not agreed upon. Pegylation of IFN involves conjugation with polyethylene glycol. Following subcutaneous injection of pegIFN, the rate of absorption, renal and cellular clearance, and immunogenicity are reduced. As a result of the extended serum half-life, once-weekly administration is feasible, compared with the daily and/or thrice weekly dosing of IFN. When compared with observation alone in patients with resected stage III melanoma, pegIFN demonstrated a significant increase in relapse-free survival, with a marginal impact on overall survival. The most common adverse events were as expected with IFN and included fatigue, increased liver enzymes, pyrexia, headache, anorexia, myalgia, nausea, chills, depression, and injection site reactions. A large Phase 3 study is underway to further assess outcome and toxicity differences between pegIFN weekly and low-dose IFN thrice weekly. PegIFN is a modified version of the previously approved interferon indicated for the adjuvant treatment of melanoma. Although the safety profile remains similar between the pegylated and non-pegylated forms, once-weekly administration is feasible secondary to an extended serum half-life and may have improved convenience for the patient.
    Annals of Pharmacotherapy 05/2012; 46(6):830-8. · 2.57 Impact Factor
  • Christine M Walko, Howard McLeod
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    ABSTRACT: Tamoxifen is a selective estrogen-receptor modulator that is commonly utilized in the treatment and prevention of endocrine receptor-positive breast cancer. Ultimate conversion of the parent drug by the enzyme CYP2D6 to the active metabolite, endoxifen, is required for tamoxifen to exert its anticancer effects. CYP2D6 exists in varying concentrations across individuals due, in part, to genetic variation. Lower concentrations of endoxifen have been associated with inferior breast cancer outcomes in numerous retrospective trials. In an effort to increase the endoxifen concentrations, three prospective trials have assessed different methods of increasing tamoxifen dose based on patient CYP2D6 genotypes. All three demonstrated the ability to increase endoxifen concentrations using tamoxifen at a dose of 30 or 40 mg daily. These positive findings support future investigations to determine, not only the clinical benefit of genotype-guided therapy, but also the optimal dose needed for individual patients.
    Pharmacogenomics 04/2012; 13(6):691-7. · 3.86 Impact Factor
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    ABSTRACT: The prodrug cyclophosphamide is metabolized by cytochrome P450(CYP)2B6 to the active metabolite, 4-hydroxycyclophosphamide (4-OH), and by CYP3A4/5 to toxic chloracetaldehyde and 2-dechloroethylcyclophosphamide (DCE). Since aprepitant is a moderate inhibitor of CYP3A4, the study was designed to determine whether its concurrent use alters the pharmacokinetics (PK) of cyclophosphamide. In addition, we sought to determine the effect of race and pharmacogenomics on cyclophosphamide PK. Eighteen patients with localized breast cancer were randomized in this double-blinded cross-over study to receive aprepitant or placebo in addition to cyclophosphamide 600 mg/m(2) and doxorubicin 60 mg/m(2). Blood samples were collected for both PK analysis of cyclophosphamide and metabolites and pharmacogenomic analysis. Single nucleotide polymorphisms genotyped were CYP3A4*1B, CYP3A5*3, and CYP2B6*6. The geometric mean area under concentration-time curve (AUC(0-t) μg/mL h) for cyclophosphamide was 282 following aprepitant and 230 following placebo (ratio 1.23; 90% CI 1.13, 1.33). 4-OH AUC(0-t) (μg/mL h) was 6.80 following aprepitant and 6.96 following placebo (ratio 0.98; 90% CI 0.88, 1.08). DCE AUC(0-t) (μg/mL h) was 6.76 following aprepitant and 9.37 following placebo (ratio 0.72; 90% CI 0.64, 0.81). Genotype analysis was confounded by race. Race was a significant predictor of DCE lnAUC(0-t) (P = 0.0169) as African Americans had approximately a 2-fold higher DCE AUC than Caucasians. Aprepitant altered the exposure of cyclophosphamide and DCE but not the active 4-OH metabolite, making it unlikely that aprepitant would change the clinical efficacy of cyclophosphamide. African Americans were also found to have altered PK compared with Caucasian patients.
    Cancer Chemotherapy and Pharmacology 01/2012; 69(5):1189-96. · 2.80 Impact Factor
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    ABSTRACT: What this adds: What is already known about this subject Paclitaxel and rosiglitazone are primarily metabolized by CYP2C8 and their in vitro metabolism by human liver microsomes is correlated. Probe assays that quantify the in vivo activity of CYP enzymes which are important in drug metabolism have been developed for use in clinical pharmacology research. A probe of CYP2C8 that is easy to administer and interpret may be valuable for individualized dosing of paclitaxel. What this study adds This pilot study demonstrates for the first time that there is an in vivo correlation between paclitaxel and rosiglitazone exposure. The finding, that a single rosiglitazone plasma concentration after oral dosing may explain significant variance in paclitaxel exposure, suggests that rosiglitazone may satisfy the requirements of a clinically useful in vivo probe. However, it is acknowledged that there is a need for further studies evaluating the use of rosiglitazone as a CYP2C8 probe and quantifying the relationship, in order to guide dosing of narrow therapeutic index drugs metabolized primarily by CYP2C8, such as paclitaxel. ABSTRACT: Aims: Evaluate the use of rosiglitazone and the Erythromycin Breath Test (ERMBT), as probes of CYP2C8 and CYP3A4, respectively, to explain inter-individual variability in paclitaxel exposure. Methods: 3-hour rosiglitazone concentration and ERMBT results were included in a regression model to explain the variability in paclitaxel exposure in 14 subjects. Results: Rosiglitazone concentration was significantly correlated with paclitaxel exposure (p = 0.018) while ERMBT had no predictive value (p = 0.47). Conclusions: The correlation between the exposure of rosiglitazone and paclitaxel likely reflects mutual dependence on the activity of CYP2C8. Rosiglitazone or similar agents may have value as in vivo probes of CYP2C8 activity.
    British Journal of Clinical Pharmacology 12/2011; · 3.58 Impact Factor
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    ABSTRACT: We examined the feasibility of using CYP2D6 genotyping to determine optimal tamoxifen dose and investigated whether the key active tamoxifen metabolite, endoxifen, could be increased by genotype-guided tamoxifen dosing in patients with intermediate CYP2D6 metabolism. One hundred nineteen patients on tamoxifen 20 mg daily ≥ 4 months and not on any strong CYP2D6 inhibiting medications were assayed for CYP2D6 genotype and plasma tamoxifen metabolite concentrations. Patients found to be CYP2D6 extensive metabolizers (EM) remained on 20 mg and those found to be intermediate (IM) or poor (PM) metabolizers were increased to 40 mg daily. Eighty-nine evaluable patients had tamoxifen metabolite measurements repeated 4 months later. As expected, the median baseline endoxifen concentration was higher in EM (34.3 ng/mL) compared with either IM (18.5 ng/mL; P = .0045) or PM (4.2 ng/mL; P < .001). When the dose was increased from 20 mg to 40 mg in IM and PM patients, the endoxifen concentration rose significantly; in IM there was a median intrapatient change from baseline of +7.6 ng/mL (-0.6 to 23.9; P < .001), and in PM there was a change of +6.1 ng/mL (2.6 to 12.5; P = .020). After the dose increase, there was no longer a significant difference in endoxifen concentrations between EM and IM patients (P = .84); however, the PM endoxifen concentration was still significantly lower. This study demonstrates the feasibility of genotype-driven tamoxifen dosing and demonstrates that doubling the tamoxifen dose can increase endoxifen concentrations in IM and PM patients.
    Journal of Clinical Oncology 08/2011; 29(24):3232-9. · 18.04 Impact Factor
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    ABSTRACT: The development, implementation, and early experience with a program providing clinical pharmacist services at the hematology-oncology clinics of a university teaching hospital are described. With funding from a university research grant and other sources, a pharmacist was hired to launch a new program addressing four goals identified in a needs assessment: (1) improved management of supportive care, (2) enhanced education of patients receiving complicated chemotherapy regimens, (3) improved efficiency in the chemotherapy infusion unit, and (4) development of an experiential learning opportunity for pharmacy students and residents. The pharmacist hired to lead the ongoing program was a state-approved clinical pharmacist practitioner (CPP) who had authority to prescribe with physician oversight under established protocols. An oncology supportive care consultation service implemented by the CPP in collaboration with a nurse and a physician served 89 new patients in its first 18 months of operation; during that period the CPP made 186 interventions and wrote 136 prescriptions. The CPP also established a chemotherapy counseling service that provided more than 900 bill-able patient education sessions over 18 months. In addition, the CPP launched an effort to increase use of a rituximab rapid-infusion protocol among eligible patients. The creation of the new oncology pharmacist position has given dozens of pharmacy students and residents a new opportunity for interaction with oncology clinic patients and other health care team members. Integration of the services of a CPP into the hematology-oncology clinics has helped achieve goals set by physician, nursing, and pharmacy leaders.
    American journal of health-system pharmacy: AJHP: official journal of the American Society of Health-System Pharmacists 04/2011; 68(7):613-9. · 2.10 Impact Factor
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    ABSTRACT: The objectives of this study were to determine whether the midazolam clearance predicted docetaxel pharmacokinetics, CA-125 change, and response and to assess the impact of cytochrome P450 (CYP) 3A5 and ATP-binding cassette, subfamily B, member 1 (ABCB1) genotypes on docetaxel pharmacokinetics and pharmacodynamics in ovarian or primary peritoneal cancer patients. Thirty-four patients with advanced ovarian and primary peritoneal cancer were administered docetaxel at 75 mg/m(2) as a 1-h infusion in combination with carboplatin IV over 30 min at a target AUC of 5 mg/ml min. Cycles were repeated every 21 days for 6 cycles. Midazolam was administered at 2 mg as a 30-min IV infusion the day prior to cycle one of docetaxel administration. Pharmacokinetic studies of docetaxel and CYP3A5 and ABCB1 genotype studies were performed. There was an inverse relationship between midazolam clearance (CL) and CA-125 level after cycle 6 where a higher midazolam CL was associated with a CA-125 <10 U/ml (P = 0.007) and CA-125 <15 U/ml (P = 0.048). The CA-125 categories were associated with response achieved (complete response/partial response) (CR/PR), stable disease (SD), and progressive disease (PD) at the end of therapy (P = 0.0173). Docetaxel CL was not related to midazolam CL or genotype. Docetaxel exposure and genotypes were not related to toxicity or response (P > 0.05). The midazolam CL predicted CA-125 levels and response that was independent of other factors including docetaxel pharmacokinetics. Future studies need to evaluate the mechanism for the relationship between midazolam CL and response in patients with ovarian cancer.
    Cancer Chemotherapy and Pharmacology 03/2011; 68(5):1255-62. · 2.80 Impact Factor
  • Ryan S Raddin, Christine M Walko, Young E Whang
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    ABSTRACT: Androgen deprivation with a luteinizing hormone-releasing hormone (LH-RH) agonist is the standard treatment for patients with metastatic prostate cancer who prefer nonsurgical options. Therapy with these agents is usually successful in achieving and maintaining castrate levels (< 50 ng/dl) of serum testosterone, but failures have been reported in up to 10% of patients. Traditionally, these patients are offered surgical castration with bilateral orchiectomy. However, the novel LH-RH antagonists may offer a nonsurgical alternative. We describe two patients with advanced prostate cancer who failed to achieve castrate levels of testosterone while on an LH-RH agonist, but subsequently responded to the LH-RH antagonist, degarelix. The first patient is a 63-year-old man who was treated with leuprolide for metastatic prostate cancer. He initially responded with prostate-specific antigen (PSA) that fell to 0.6 ng/ml. However, after 15 months of therapy, his PSA rose to 18.3 ng/ml and his testosterone was noted to be 208 ng/dl. He was switched to degarelix, and 4 weeks later his testosterone was adequately suppressed at 16 ng/dl. The second patient is a 41-year-old man with metastatic prostate cancer who was started on leuprolide, but after 3 months of therapy, was found to have a rising PSA and a testosterone of 96 ng/dl. Four weeks after switching to degarelix, his testosterone was 18 ng/dl and his PSA decreased concordantly. With continued monthly injections of degarelix, his testosterone has consistently remained to be at less than 20 ng/dl over 7 months of follow-up.
    Anti-cancer drugs 03/2011; 22(3):299-302. · 2.23 Impact Factor
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    ABSTRACT: Sorafenib has demonstrated single agent activity in non-small cell (NSCLC) and small cell lung cancer (SCLC). Carboplatin/pemetrexed (CbP) and cisplatin/etoposide (PE) are commonly used in the treatment of these diseases. A phase I trial escalating doses of sorafenib in combination with fixed doses of PE (Arm A) or CbP (Arm B) was performed using a 3-patient cohort design to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT); DLT were assessed in the first cycle. The trial was subsequently amended with closure of Arm B and to include Arm C with a reduced dose of carboplatin. Between 9/2007 and 9/2008, 20 pts were treated on the trial; median age 62 (range 42-73), male/female ratio 12/8, PS 0/1 ratio 6/14, and median number of prior therapies 2 (range 1-4). The most common tumor types were NSCLC and SCLC. On Arm A at dose level 0 (sorafenib 200 mg BID), 2 of 4 patients experienced DLT; 2 patients were enrolled at dose level -1 (sorafenib 200 mg QD) without DLT, but this arm was closed due to slow accrual. On Arm B, 2 of 3 patients experienced DLT at dose level 0 (sorafenib 200 mg BID). On Arm C at dose level 0 (sorafenib 200 mg BID), 1 of 6 patients experienced DLT, and at dose level +1 (sorafenib 400 mg BID) 2 of 5 patients experienced a DLT. The MTD of sorafenib was 200 mg BID continuously in combination with carboplatin (AUC of 5) and pemetrexed 500 mg/m² every 3 weeks. However, only 6 patients were treated at this dose level, and the results should be interpreted cautiously.
    Lung cancer (Amsterdam, Netherlands) 02/2011; 71(2):151-5. · 3.14 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2011; 57(14).
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2011; 57(14).
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    ABSTRACT: Resistance to 5-fluorouracil (5-FU) represents a major contributor to cancer-related mortality in advanced colorectal cancer patients. Genetic variations and expression alterations in genes involved in 5-FU metabolism and effect have been shown to modulate 5-FU sensitivity in vitro, however these alterations do not fully explain clinical resistance to 5-FU-based chemotherapy. To determine if alterations of DNA copy number in genes involved in 5-FU metabolism-impacted clinical resistance to 5-FU-based chemotherapy, we assessed thymidylate synthetase (TYMS) and thymidine phosphorylase (TYMP) copy number in colorectal liver metastases. DNA copy number of TYMS and TYMP was evaluated using real time quantitative PCR in frozen colorectal liver metastases procured from 62 patients who were pretreated with 5-FU-based chemotherapy prior to surgical resection (5-FU exposed) and from 51 patients who received no pretreatment (unexposed). Gain of TYMS DNA copy number was observed in 18% of the 5-FU exposed metastases, while only 4% of the unexposed metastases exhibited TYMS copy gain (p = 0.036). No significant differences were noted in TYMP copy number alterations between 5-FU-exposed and -unexposed metastases. Median survival time was similar in 5-FU-exposed patients with metastases containing TYMS amplification and those with no amplification. However, TYMS amplification was associated with shorter median survival in patients receiving post-resection chemotherapy (hazard ratio = 2.7, 95% confidence interval = 1.1-6.6; p = 0.027). These results suggest amplification of TYMS amplification as a putative mechanism for clinical resistance to 5-FU-based chemotherapy and may have important ramifications for the post-resection chemotherapy choices for metastatic colorectal cancer.
    European journal of cancer (Oxford, England: 1990) 12/2010; 46(18):3358-64. · 4.12 Impact Factor

Publication Stats

325 Citations
120.96 Total Impact Points

Institutions

  • 2012–2014
    • Julphar School of Pharmacy
      North Carolina, United States
  • 2005–2012
    • University of North Carolina at Chapel Hill
      • • Department of Medicine
      • • Division of Pharmacotherapy and Experimental Therapeutics
      Chapel Hill, NC, United States
  • 2010
    • Institut Multidisciplinaire d'Oncologie - Clinique de Genolier
      Vaud, Switzerland