Global population pharmacokinetics of the investigational Aurora A kinase inhibitor alisertib in cancer patients: rationale for lower dosage in Asia.

AIMS: This population pharmacokinetic analysis was conducted to describe quantitatively the regional differences and sources of interpatient variability on the apparent oral clearance of alisertib. METHODS: A population pharmacokinetic analysis was performed on data from 671 cancer patients in Western countries and in Japan/East Asia to whom alisertib 5-150 mg once or twice daily (b.i.d.) was administered in multiple dosing schedules. The final model was used to simulate alisertib pharmacokinetics in patients in the West and East Asian regions in the single-agent schedule of 7 days of dosing in a 21-day cycle. Exposure-safety relationships for mechanism-related antiproliferative toxicities (neutropenia, mucositis and diarrhoea) were estimated by logistic regression. RESULTS: Alisertib pharmacokinetics were described by a two-compartment model with four-transit compartment absorption and linear elimination. The final model included a covariate effect of region on relative bioavailability, with patients in the East Asian region estimated to have a 52% higher bioavailability compared with Western patients. Population simulated exposure at 30 mg b.i.d. in patients in Asia was similar to that at 50 mg b.i.d. in Western patients [geometric mean (coefficient of variation) steady state area under the concentration-time curve over the dosing interval (AUC(0-τ) ): 21.4 µM.h (52.3%) and 24.1 µM.h (53.6%), respectively]. Exposure-AE relationships could be described for neutropenia, stomatitis and diarrhoea, supporting the lower dosage of alisertib in Asia for global clinical development. CONCLUSIONS: Model-based simulations support the achievement of similar alisertib exposures in patients in Asia who are administered a 40% lower dose compared with the Western population, thereby providing a quantitative clinical pharmacology bridging and regional dosing rationale for global drug development.

Phase 1 study of ixazomib alone or combined with lenalidomide-dexamethasone in Japanese patients with relapsed/refractory multiple myeloma.

We report the first clinical investigation conducted in Japan to confirm the safety, tolerability, and pharmacokinetics of ixazomib alone and combined with lenalidomide-dexamethasone (Rd) in Japanese patients with relapsed/refractory multiple myeloma. Adult patients with measurable disease and ≥2 prior lines of therapy received oral ixazomib 4.0 mg on days 1, 8, 15 alone or combined with lenalidomide 25 mg on days 1-21 and dexamethasone 40 mg on days 1, 8, 15, 22 in 28-day cycles. Fourteen patients who had received a median of seven prior therapies were enrolled (seven per cohort). One of six evaluable patients in each cohort experienced dose-limiting toxicities [diarrhea, nausea, hypokalemia, hypertension, thrombocytopenia, hyponatremia (ixazomib cohort); thrombocytopenia, and neutropenia (ixazomib + Rd cohort)]. The most common drug-related adverse events were neutropenia, thrombocytopenia, leukopenia, and lymphopenia. Drug-related grade ≥3 adverse events occurring in ≥3 patients per cohort were (ixazomib/ixazomib + Rd cohort, n): neutropenia (4/2), thrombocytopenia (3/2), and lymphopenia (5/2). Ixazomib was rapidly absorbed with a median T max of approximately 1-2-h post-dose, and had a geometric mean terminal half-life of 5-6 days. Of 13 response-evaluable patients, one achieved a partial response (duration ∼38 weeks; ixazomib cohort) and seven had stable disease.

A phase 1 multiple-dose study of orteronel in Japanese patients with castration-resistant prostate cancer.

PURPOSE: Orteronel (TAK-700) is a non-steroidal, selective, reversible inhibitor of 17,20-lyase. We evaluated the safety, tolerability, pharmacokinetics, pharmacodynamics, and antitumor effect of orteronel with or without prednisolone in Japanese patients with castration-resistant prostate cancer (CRPC). METHODS: We conducted a phase 1 study in men with progressive and chemotherapy-naïve CRPC. Patients received orteronel orally at doses of 200-400 mg twice daily (BID) with or without oral prednisolone (5 mg BID). Dose-limiting toxicity (DLT) was assessed during Cycle 1 (28 days). Patients could continue study treatment until any of criteria for treatment discontinuation were met. Gonadotropin-releasing hormone therapy was continued in patients without prior orchidectomy. RESULTS: Fifteen patients were enrolled and administered at least one dose of orteronel. No DLTs were reported during Cycle 1 in this study. Adverse events (AEs) were reported in all 15 patients. Most common AEs (>30%) were hyperlipasemia (47%), hyperamylasemia (40%), and constipation (33%). Acute pancreatitis (Grades 2 and 3) and pancreatitis (Grade 1) were complicated in three patients during the study. Dose-dependent increase in plasma orteronel concentrations was indicated over the 200-400 mg BID dose range. Prednisolone coadministered did not alter PK of orteronel. Serum testosterone was rapidly suppressed below the lower limit of quantification across all doses. Of 15 subjects, 13 achieved at least a 50% reduction from baseline in prostate-specific antigen. CONCLUSIONS: Orteronel at doses up to 400 mg BID was tolerable in Japanese CRPC patients. The present results support further evaluation of orteronel with or without prednisolone.

Phase I / II study of brentuximab vedotin in Japanese patients with relapsed or refractory CD30-positive Hodgkin's lymphoma or systemic anaplastic large-cell lymphoma.

Brentuximab vedotin is an antibody-drug conjugate that selectively delivers the antimicrotubule agent monomethyl auristatin E into CD30-expressing cells. To assess its safety, pharmacokinetics, and efficacy in Japanese patients with refractory or relapsed CD30-positive Hodgkin's lymphoma or systemic anaplastic large-cell lymphoma, we carried out a phase I/II study. Brentuximab vedotin was given i.v. on day 1 of each 21-day cycle up to 16 cycles. In the phase I part of a dose-escalation design, three patients per cohort were treated at doses of 1.2 and 1.8 mg/kg. In the phase II part, a dose of 1.8 mg/kg was given to 14 patients (nine with Hodgkin's lymphoma and five with systemic anaplastic large-cell lymphoma). The median number of treatment cycles was 16 (range, 4-16). In the phase I part, no dose-limiting toxicity event was observed. In the total population, common adverse events included lymphopenia (80%), neutropenia (65%), leukopenia (65%), and peripheral sensory neuropathy (60%). Grade 3/4 adverse events in more than two patients were lymphopenia (50%) and neutropenia (15%). The pharmacokinetic profile was similar to that observed in the previous studies in the USA. In the phase II part, six patients (67%) with Hodgkin's lymphoma achieved an objective response with 56% of complete response rate, and five patients (100%) with systemic anaplastic large-cell lymphoma achieved an objective response with 80% of complete response rate. These results show that brentuximab vedotin has an acceptable safety profile and promising antitumor activity in the Japanese population. This trial was registered in JAPIC Clinical Trials Information (JapicCTI-111650).

Safety, tolerability, pharmacokinetics and antitumor activity of ganitumab, an investigational fully human monoclonal antibody to insulin-like growth factor type 1 receptor, combined with gemcitabine as first-line therapy in patients with metastatic pancreatic cancer: a phase 1b study.

OBJECTIVE: Previous Phase 1 studies have shown the acceptable safety profile of ganitumab-a fully human monoclonal antibody to insulin-like growth factor Type 1 receptor-in patients with advanced solid tumors. However, ganitumab 20 mg/kg in combination with gemcitabine had not been administered to patients with metastatic pancreatic cancer. To evaluate the safety, tolerability, pharmacokinetics and antitumor activity of ganitumab 20 mg/kg combined with gemcitabine 1000 mg/m(2) as first-line therapy in patients with metastatic pancreatic cancer, we conducted a Phase 1b study. METHODS: Eligible patients were adults with previously untreated metastatic adenocarcinoma of the pancreas. Patients received gemcitabine 1000 mg/m(2) on Days 1, 8 and 15 plus ganitumab 20 mg/kg on Days 1 and 15 of each 28-day cycle. Gemcitabine was administered intravenously over 30-60 min. Ganitumab was administered intravenously over 60 min after completing gemcitabine infusion. RESULTS: Six patients were enrolled and received the study treatment. All patients had thrombocytopenia and leukopenia. Other most common adverse events were neutropenia and nausea. One patient had a dose-limiting toxicity defined as Grade 3 neutropenia with fever. Exposure to ganitumab 20 mg/kg was not affected by the administration of gemcitabine. No apparent pharmacokinetic drug-drug interaction was observed. No anti-ganitumab antibodies were detected. Five patients had a measurable tumor region at baseline. Of these, four patients had a best response of stable disease. CONCLUSIONS: Ganitumab 20 mg/kg combined with gemcitabine 1000 mg/m(2) was tolerable and showed an acceptable safety profile in patients with untreated metastatic pancreatic cancer.

Phase 1 study of trebananib (AMG 386), an angiogenesis targeting angiopoietin-1/2 antagonist, in Japanese patients with advanced solid tumors.

PURPOSE: To evaluate the safety, tolerability, pharmacokinetics, and antitumor activity of trebananib (AMG 386)--a first-in-class angiopoietin-1/2 antagonist peptide-Fc fusion protein--in Japanese patients, we conducted a phase 1, dose escalation study. METHODS: Eligible patients were men or women, aged between 20 and 74 years, who had histologically or cytologically confirmed advanced solid tumors refractory to standard treatment. Trebananib (3, 10, and 30 mg/kg) was administered intravenously over 60 min in weekly cycles. RESULTS: From June 2009 to April 2010, a total of 18 patients (6 for each dose cohort) were enrolled into the study. Trebananib was tolerated at all dose levels. No dose-limiting toxicities were observed. The most common adverse events were peripheral edema, constipation, fatigue, and pyrexia. Exposure to trebananib appeared to increase according to the dose administered. Serum clearance appeared to be similar across the dose range with the mean terminal-phase half-life ranging from 93.9 to 95.9 h. No neutralizing antibodies were detected. Tumor response was assessed in 18 patients. Of these, one patient with colon cancer in the 3-mg/kg cohort and one with bladder cancer in the 30-mg/kg cohort had partial responses as their best responses. These 2 patients were on treatment at the time of data cutoff (January 17, 2012). CONCLUSION: Trebananib was tolerated and showed acceptable safety profile in Japanese patients with advanced solid tumors. The pharmacokinetic profiles were similar to those in the previous studies in the United States. Trebananib also showed evidence of durable antitumor activity in some patients.

Phase 1 study of ganitumab (AMG 479), a fully human monoclonal antibody against the insulin-like growth factor receptor type I (IGF1R), in Japanese patients with advanced solid tumors.

PURPOSE: This study was to investigate the safety and tolerability of ganitumab in Japanese patients with advanced solid tumors. METHODS: Patients were enrolled into 1 of 3 dose cohorts (6, 12, or 20 mg/kg) of single-agent ganitumab administered intravenously every 2 weeks. Dose-limiting toxicity (DLT) was assessed for the first 28 days. The primary objectives were to assess the safety, tolerability, and pharmacokinetics (PK) of ganitumab in Japanese patients with advanced solid tumors. An exploratory pharmacodynamic analysis was done to investigate the relationship between exposure and changes in the level of circulating factors in IGF1R pathway (IGFBP-3 and total IGF-1). RESULTS: Nineteen patients with ECOG performance status 0-1 (6 in cohort 1 and 3, 7 in cohort 2) received at least 1 dose of ganitumab. Median age was 58.0 years. Tumor types included: breast (4), gastric (3), rectal (2), NSCLC (2), thymic (2), and other cancers (6). No DLTs were observed. The most common grade ≥3 adverse events were neutropenia (21 %), leukopenia (16 %) and lymphopenia (11 %). There was a trend of dose-dependency on severity of thrombocytopenia, but not on that of neutropenia. No neutralizing anti-ganitumab antibodies were detected during this study. Dose-linearity on PK of ganitumab was indicated in the dose range. Tumor response was assessed for 19 patients. Stable disease as best response was reported in 7 patients. CONCLUSIONS: Ganitumab up to 20 mg/kg was tolerable in Japanese patients with advanced solid tumors. The safety and PK profiles were similar to those previously observed in non-Japanese patients.

Sensitive and selective liquid chromatography-electrospray ionization tandem mass spectrometry analysis of hydrochlorothiazide in rat plasma.

A sensitive and selective method for the determination of hydrochlorothiazide (HCTZ) concentrations in rat plasma was developed using high performance liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS). An aliquot of plasma (50 microl) was mixed with the solution of internal standard, hydrofluorothiazide (HFTZ), and extracted with tert-butyl methyl ether. The reconstituted extract was applied to the LC-MS/MS system with a reversed phase C8 column and eluted with distilled water/acetonitrile (85/15, v/v). To enhance negative ionization of HCTZ and HFTZ in the multiple reaction monitor (MRM), the solution consisting of acetonitlile/1% (v/v) ammonia solution (95/5, v/v) was delivered after column separation. This additional technique, so-called the post-column addition, increased sensitivity of HCTZ and HFTZ about 500- and 200-fold, respectively. The calibration curve showed good linearity (r = 0.999) over the range of 4-1000 ng/ml. Acceptable accuracy (100.8-113.1%) and precision (0.28-16.4%) were confirmed in the intra- and the inter-day analyses. It is indicated that this LC-MS/MS method is useful for pharmacokinetic studies of HCTZ in small animals, because it enabled the serial determination of plasma level of HCTZ in rats.

Uptake of lamivudine by rat renal brush border membrane vesicles.

Uptake of lamivudine, a nucleoside analogue antiviral agent, by brush border membrane vesicles (BBMV) prepared from rat renal cortex was investigated. Initial uptake of lamivudine by BBMV was stimulated in the presence of an outward pH gradient. Determination of the kinetic parameters of the initial uptake yielded apparent Km and Vmax values of 2.28 mm and 1.56 nmol (mg protein)(-1) (20 s)(-1), respectively. The pH-driven uptake of lamivudine was inhibited by organic cations such as trimethoprim and cimetidine. The inhibitory effect of trimethoprim on lamivudine uptake was competitive, with an apparent Ki of 27.6 microM. The uptake of lamivudine was also inhibited by nitrobenzylthioinosine, a representative inhibitor of nucleoside transport, and by other nucleoside analogues, such as azidothymidine and dideoxycytidine, that are excreted by renal tubular secretion. These findings suggest that efflux of lamivudine at the brush border membrane of renal tubular epithelium is mediated by an H+/lamivudine antiport system, which may correspond to the H+/organic cation antiport system, and that this system is also involved in the renal secretion of other nucleoside analogues.