Regorafenib in Japanese patients with solid tumors: phase I study of safety, efficacy, and pharmacokinetics.

The safety, pharmacokinetics, and antitumor activity of the multikinase inhibitor regorafenib in Japanese patients was assessed in this multicenter, single-arm, phase I trial. Fifteen patients with treatment-refractory advanced solid tumors received regorafenib 160 mg once daily for the first 3 weeks of each 4-week cycle until disease progression, unacceptable toxicity, or investigator or patient decision to stop. The median duration of treatment was 2.1 months (range, 0.9-20.1 months). At data cutoff, one patient was still receiving regorafenib in cycle 21. Reasons for treatment discontinuation were disease progression (n = 12) and adverse events (liver enzyme elevation n = 1; anemia n = 1). Adverse events necessitated dose reduction in six patients, interruption of daily treatment in seven patients, and cycle delay in four patients. All patients experienced at least one drug-related adverse event, particularly gastrointestinal (87 %), dermatologic (73 %), or hematologic (67 %) events. There was no significant change in time to maximum concentration or terminal half-life of regorafenib and its active metabolites M2 and M5 between single dosing and 21-day continuous dosing. The area under the concentration-time curve was 2.1-fold higher for regorafenib, 5.2-fold higher for M2, and 37.3-fold higher for M5, and the maximum concentration was 2.0-fold, 4.8-fold, and 36.0-fold higher, respectively, after continuous dosing than after single dosing. One patient had a partial response (duration 10.5 months) and seven patients had stable disease. This study indicates that regorafenib 160 mg orally once daily (21 days on/7 days off treatment) can be given to Japanese patients who have solid tumors, without undue toxicity.

A phase I study of sorafenib in combination with S-1 plus cisplatin in patients with advanced gastric cancer.

BACKGROUND: Sorafenib inhibits several receptor tyrosine kinases involved in tumor progression and angiogenesis. S-1, an oral fluorouracil antitumor drug, plus cisplatin (CDDP) is the standard regimen for advanced gastric adenocarcinoma (AGC) in Japan. The purpose of this phase I study was to evaluate the safety, pharmacokinetics, and preliminary efficacy of sorafenib in combination with S-1 plus CDDP. METHODS: Patients with histologically confirmed previously untreated AGC were evaluated for eligibility and treated with sorafenib (400 mg bid, days 1-35), S-1 (40 mg/m(2) bid, days 1-21), and CDDP (60 mg/m(2), day 8). Treatment was continued until disease progression or unacceptable toxicity. Pharmacokinetics for sorafenib, 5-FU, and CDDP were investigated in cycle 1. RESULTS: Thirteen patients were enrolled and received at least one dose of the study treatment. No specific or serious adverse event was newly reported in this study. Five patients had partial response and 8 had stable disease as the best response. Pharmacokinetic analysis showed no significant differences in the exposures of sorafenib when administered alone or in combination with S-1 and CDDP. CONCLUSIONS: The present phase I study demonstrates the acceptable toxicity and preliminary efficacy of combined treatment with S-1, CDDP, and sorafenib.

Pharmacokinetics, pharmacodynamics, and safety of asundexian in healthy Chinese and Japanese volunteers, and comparison with Caucasian data.

There is an unmet clinical need for effective anticoagulant therapies for the management of thromboembolic diseases that are not associated with a relevant risk of bleeding. Asundexian (BAY 2433334) is an oral, direct, small-molecule inhibitor of activated factor XI (FXIa). Phase I data from healthy Caucasian male participants indicated predictable pharmacokinetic (PK) and pharmacodynamic (PD) profiles and no clinically relevant bleeding-related adverse events (AEs). Reported here are data from two phase I, randomized, placebo-controlled, single- and multiple-dose escalation studies of asundexian conducted in 60 healthy men: 24 Japanese and 36 Chinese. Baseline characteristics were comparable between the treatment groups. All treatment-emergent AEs were mild, with no serious AEs or AEs of special interest reported. Systemic exposure to asundexian increased dose proportionally after single or multiple dosing, with relatively low accumulation following multiple once-daily dosing in both Chinese and Japanese volunteers. Asundexian induced dose-dependent prolongation of activated partial thromboplastin time and inhibition of FXIa activity, with no effects on prothrombin time or FXI concentration in Japanese participants. There were no clinically relevant interethnic differences in PK profile across the Japanese, Chinese, and Caucasian (data from the previous phase I study) participants and no clinically relevant difference in PD response between Japanese and Caucasian participants.

Pharmacokinetics, pharmacodynamics, and safety of fesomersen, a novel antisense inhibitor of factor XI, in healthy Chinese, Japanese, and Caucasian volunteers.

The inhibition of coagulation factor XI (FXI) presents an attractive approach for anticoagulation as it is not expected to increase the risk of clinically relevant bleeding and is anticipated to be at least as effective as currently available anticoagulants. Fesomersen is a conjugated antisense oligonucleotide that selectively inhibits the expression of FXI. The article describes three clinical studies that investigated the safety, pharmacokinetic (PK), and pharmacodynamic (PD) profiles of fesomersen after subcutaneous (s.c.) injection to healthy participants. The studies included participants from diverse ethnic backgrounds (Caucasian, Japanese, and Chinese). Fesomersen demonstrated good safety and tolerability in all three studies. No major bleeding events were observed. After single-dose s.c. injection, fesomersen was rapidly absorbed into the systemic circulation, with maximum fesomersen-equivalent (fesomersen-eq) concentrations (Cmax) in plasma observed within a few hours. After reaching Cmax, plasma fesomersen-eq concentrations declined in a biphasic fashion. The PD analyses showed that the injection of fesomersen led to dose-dependent reductions in FXI activity and increases in activated partial thromboplastin time (aPTT). The maximum observed PD effects were reached between Day 15 and 30, and FXI activity and aPTT returned to near-baseline levels by Day 90 after a single dose. The PK/PD profiles after a single injection were similar among the various ethnic groups. Collectively, the study results suggest that fesomersen has a favorable safety profile and predictable and similar PK and PD profiles across Chinese, Japanese, and Caucasian participants.

Phase 1 study of darolutamide (ODM-201): a new-generation androgen receptor antagonist, in Japanese patients with metastatic castration-resistant prostate cancer.

PURPOSE: This trial assessed the safety, pharmacokinetics, and efficacy of darolutamide (ODM-201), a new-generation nonsteroidal androgen receptor antagonist, in Japanese patients with metastatic castration-resistant prostate cancer (mCRPC). METHODS: In this open-label, nonrandomized, two-cohort, dose-escalating phase 1 study, Japanese patients with mCRPC were enrolled after a screening period. In the single-dose period (≈1 week), darolutamide was administered at 300 mg (Cohort 1) or 600 mg (Cohort 2) on day -5 (fasting state) and day -2 (fed condition). In the subsequent multiple-dose period (fed condition), patients received darolutamide 300 mg twice daily (Cohort 1) or 600 mg twice daily (Cohort 2) for 12 weeks. Primary endpoints: evaluate safety and pharmacokinetics of darolutamide. RESULTS: Of 12 patients enrolled, 9 received darolutamide (Cohort 1, n = 3; Cohort 2, n = 6). All 9 patients experienced ≥1 treatment-emergent adverse event (TEAE; majority Grade 1/2). Incidence of drug-related TEAEs (DR-TEAEs) was 44% (all grades; n = 4); most common DR-TEAE was decreased appetite (22%), and 1 serious DR-TEAE (Grade 3 nausea) was observed. No Grade ≥4 DR-TEAEs or new safety signals were observed. C max and AUC (0-t last) were dose-dependent; pharmacokinetics of each dose appeared to be linear over time. Prostate-specific antigen response was observed in 11% (1/9) of patients. Compared with fasting status, geometric mean C max increased 2.5-fold after 300 mg and 2.8-fold after 600 mg; geometric mean AUC (0-t last) increased 2.5-fold after both doses under fed conditions. CONCLUSIONS: Darolutamide was well tolerated at the examined doses in Japanese patients with mCRPC, without differences in safety and pharmacokinetics relative to Western patients.

Confirmation of model-based dose selection for a Japanese phase III study of rivaroxaban in non-valvular atrial fibrillation patients.

This study was designed to confirm the appropriateness of the dose setting for a Japanese phase III study of rivaroxaban in patients with non-valvular atrial fibrillation (NVAF), which had been based on model simulation employing phase II study data. The previously developed mixed-effects pharmacokinetic/pharmacodynamic (PK-PD) model, which consisted of an oral one-compartment model parameterized in terms of clearance, volume and a first-order absorption rate, was rebuilt and optimized using the data for 597 subjects from the Japanese phase III study, J-ROCKET AF. A mixed-effects modeling technique in NONMEM was used to quantify both unexplained inter-individual variability and inter-occasion variability, which are random effect parameters. The final PK and PK-PD models were evaluated to identify influential covariates. The empirical Bayes estimates of AUC and C(max) from the final PK model were consistent with the simulated results from the Japanese phase II study. There was no clear relationship between individual estimated exposures and safety-related events, and the estimated exposure levels were consistent with the global phase III data. Therefore, it was concluded that the dose selected for the phase III study with Japanese NVAF patients by means of model simulation employing phase II study data had been appropriate from the PK-PD perspective.

Model-based dose selection for phase III rivaroxaban study in Japanese patients with non-valvular atrial fibrillation.

The global ROCKET AF phase III trial evaluated rivaroxaban 20 mg once daily (o.d.) for stroke prevention in atrial fibrillation (AF). Based on rivaroxaban pharmacokinetics in Japanese subjects and lower anticoagulation preferences in Japan, particularly in elderly patients, the optimal dose regimen for Japanese AF patients was considered. The aim of this analysis was dose selection for Japanese patients from a pharmacokinetic aspect by comparison of simulated exposure in Japanese patients with those in Caucasian patients. As a result of population pharmacokinetics-pharmacodynamics analyses, a one-compartment pharmacokinetic model with first-order absorption and direct link pharmacokinetic-pharmacodynamic models optimally described the plasma concentration and pharmacodynamic models (Factor Xa activity, prothrombin time, activated partial thromboplastin time, and HepTest), which were also consistent with previous works. Steady-state simulations indicated 15 mg rivaroxaban o.d. doses in Japanese patients with AF would yield exposures comparable to the 20 mg o.d. dose in Caucasian patients with AF. In conclusion, in the context of the lower anticoagulation targets in Japanese practice, the population pharmacokinetic and pharmacodynamic modeling supports 15 mg o.d. as the principal rivaroxaban dose in J-ROCKET AF.