Ramucirumab for the treatment of metastatic gastric or gastroesophageal junction adenocarcinoma following disease progression on first-line platinum- or fluoropyrimidine-containing combination therapy in Japanese patients: a phase 2, open-label study.

BACKGROUND: Ramucirumab, a monoclonal antibody vascular endothelial growth factor receptor-2 antagonist, given as monotherapy improved survival in a global phase 3 study (REGARD) of patients with gastric cancer. However, REGARD did not include Japanese patients. This study evaluated the efficacy and safety of ramucirumab monotherapy in Japanese patients with advanced gastric cancer. METHODS: This multicenter, open-label, nonrandomized phase 2 study (Clinicaltrials.gov: NCT01983878) was performed at 16 Japanese sites. Patients with advanced gastric or gastroesophageal junction cancer after disease progression following first-line chemotherapy received intravenous ramucirumab 8 mg/kg every 2 weeks. Primary efficacy outcome: 12-week progression-free survival rate (PFS). RESULTS: Thirty-six patients were enrolled. The 12-week PFS rate was 23.8% [90% confidence interval (CI) 12.4-37.2); the primary outcome was not met as the lower limit of the CI was outside the threshold of 16%. Median PFS was 6.6 weeks (90% CI 6.1-7.1). No patients achieved an objective response, and 11 (31%) patients achieved disease control. Median overall survival was 8.6 months (90% CI 5.7-10.7). The most frequent treatment-emergent adverse events (TEAEs) were diarrhea (9/36; 25%) and decreased appetite (8/36; 22%). Three patients reported Grade ≥ 3 ileus; all other Grade ≥ 3 TEAEs were reported by ≤ 2 patients. The most frequent adverse events of special interest (AESIs) were hypertension (10/36; 28%), bleeding/hemorrhage (7/36; 19%), and proteinuria (7/36; 19%). All Grade ≥ 3 AESIs were reported by ≤ 2 patients. CONCLUSIONS: These findings suggest that ramucirumab monotherapy has clinical activity and a manageable safety profile in Japanese patients with gastric cancer after disease progression following first-line chemotherapy.

A randomized, double-blind, phase II study of ramucirumab plus docetaxel vs placebo plus docetaxel in Japanese patients with stage IV non-small cell lung cancer after disease progression on platinum-based therapy.

OBJECTIVES: Ramucirumab plus docetaxel prolongs survival in patients with non-small cell lung cancer (NSCLC) with disease progression after platinum-based therapy. This phase II, double-blind, randomized, placebo-controlled study assessed efficacy and safety of second-line ramucirumab-docetaxel in Japanese patients with NSCLC. MATERIALS AND METHODS: Patients with NSCLC with progression after platinum-based therapy (28 Japanese sites; 19 December, 2012 to 22 May, 2015) were randomized (computer-generated sequence) to ramucirumab 10mg/kg or placebo, followed by docetaxel 60mg/m(2) (Day 1, 21-day cycle). Prior epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) monotherapy was prohibited in the primary population, but EGFR mutation-positive NSCLC patients who were treated with EGFR-TKI were enrolled as a separate exploratory population. Primary endpoint was progression-free survival (PFS); secondary outcomes included overall survival, tumor response rates, and safety. Investigator tumor assessments were used for the efficacy endpoints. RESULTS: In the primary population (N=160 randomized, n=157 treated), median (95% CI) PFS was longer with ramucirumab-docetaxel (5.22 [3.52-6.97] months; n=76) than with placebo-docetaxel (4.21 [2.83-5.62] months; n=81); hazard ratio 0.83 (95% CI 0.59-1.16). Median (95% CI) overall survival was 15.15 (12.45-26.55) months with ramucirumab-docetaxel and 14.65 (11.93-24.44) months with placebo-docetaxel (hazard ratio [95% CI] 0.86 [0.56-1.32]). Objective response rate (28.9% vs 18.5%) and disease control rate (78.9% vs 70.4%) were numerically greater with ramucirumab-docetaxel than with placebo-docetaxel. Incidence and severity of most adverse events were similar, but febrile neutropenia was more common with ramucirumab-docetaxel (34.2%) than with placebo-docetaxel (19.8%). CONCLUSION: Second-line ramucirumab-docetaxel improved PFS similar to that seen in the REVEL trial with a manageable safety profile in Japanese patients with NSCLC.

The relationship between clinical pharmacokinetics of aripiprazole and CYP2D6 genetic polymorphism: effects of CYP enzyme inhibition by coadministration of paroxetine or fluvoxamine.

PURPOSE: To investigate the effects of coadministration of paroxetine or fluvoxamine on the pharmacokinetics of aripiprazole in healthy adult Japanese with different CYP2D6 genotypes. METHODS: Fourteen CYP2D6 extensive metabolizer (EM) and 14 CYP2D6 intermediate metabolizer (IM) subjects were coadministered a single oral dose of aripiprazole 3 mg after steady-state plasma concentrations of the SSRIs paroxetine (20 mg/day) or fluvoxamine (100 mg/day) were reached by repeated oral doses for 6-7 days. The pharmacokinetics of aripiprazole with and without coadministration of SSRIs were compared according to CYP2D6 genotypes. RESULTS: Coadministration of paroxetine, a potent CYP2D6 inhibitor, decreased systemic clearance (CL/F) of aripiprazole by 58 and 23% in CYP2D6 EMs and IMs, respectively, demonstrating that the percentage inhibition of CYP2D6 activity by coadministration of paroxetine was apparently greater in CYP2D6 EMs than in IMs. Coadministration of fluvoxamine, a less potent CYP3A4 inhibitor, decreased the CL/F of aripiprazole by 39% in CYP2D6 EMs and 40% in IMs, indicating the same inhibitory effect on CYP enzymes, regardless of the CYP2D6 genotype. Percent contribution of CYP2D6 to total CL/F (CYP2D6 plus CYP3A4) of aripiprazole estimated as a reduced percentage of CL/F by CYP enzyme inhibition was 62% for CYP2D6 EMs and 24% for IMs in paroxetine coadministration, and 40% for CYP2D6 EMs and 18% for IMs in fluvoxamine coadministration. CONCLUSIONS: There were marked differences in the degree of influence of paroxetine coadministration on the pharmacokinetics of aripiprazole between CYP2D6 EMs and IMs, but no apparent differences were found between two CYP2D6 genotypes in fluvoxamine coadministration. Aripiprazole can be used safely in combination with SSRIs that have a CYP enzyme-inhibitory action.

Prediction of interindividual variability in pharmacokinetics for CYP3A4 substrates in humans.

A method for predicting the interindividual variability of human exposure for CYP3A4 substrates using Monte Carlo simulation was developed based on relevant factors. The coefficient of variation (CV) values for CYP3A4 content in human liver microsomes, hepatic blood flow, liver volume and body weight, and the unbound blood fraction were collected from the published literature. The parallel tube and dispersion models were found to be appropriate mathematical models to describe the pharmacokinetics (PK). Simulation results using 33% as the CV for CYP3A4 content reflected reported CV values of the area under the curve (AUC) for 40 CYP3A4 substrates for both intravenous and oral administration. We also successfully predicted the clearance of midazolam in Japanese and in European American subjects. In all cases, the simulated mean and SD values reflected the reported values. Thus, the interindividual variability of the AUC of CYP3A4 substrates was predictable for both intravenous and oral administration.

Nonlinear mixed effects model analysis of the pharmacokinetics of aripiprazole in healthy Japanese males.

The population pharmacokinetic parameters of aripiprazole in healthy Japanese males were estimated using a nonlinear mixed effects model (NONMEM) program. Pharmacokinetic data for population analysis were obtained from the single-dose (24 subjects), multiple-dose (15 subjects), and itraconazole-coadministration (27 subjects) trials. The time course of plasma aripiprazole concentration following oral administration was well described by a two-compartment model with first-order input. The mean values of the absorption lag time (ALAG) and absorption rate constant (KA) were estimated to be 0.805 h and 2.65 h(-1), respectively. The mean volume of the central (V(1)/F) and peripheral (V(2)/F) compartment was 3.84 and 1.54 l/kg, respectively, and the mean value of inter-compartment clearance (Q/F) was 0.168 l/h/kg. Oral clearance (CL/F) was estimated to be 0.0645 l/h/kg in the group with CYP2D6*1/*1, *1/*2 and *2/*2. The decrease in CL/F was estimated to be 0.0135 l/h/kg in the group with CYP2D6*1/*5, *1/*10, *2/*5, *2/*10, and *2/*41, and 0.0293 l/h/kg in the group with CYP2D6*5/*10, *10/*10, and *41/*41. The plasma concentration of aripiprazole was increased by coadministration of itraconazole, and the decrease in CL/F was estimated to be 0.0181 l/h/kg.

Pharmacokinetics of aripiprazole, a new antipsychotic, following oral dosing in healthy adult Japanese volunteers: influence of CYP2D6 polymorphism.

We investigated the pharmacokinetics (PK) of aripiprazole, a newly developed antipsychotic, and its active metabolite in healthy Japanese, and the influence of CYP2D6 polymorphism on the PK of aripiprazole. Following a single oral 6 mg dose, the mean C(max), t(max), and t(1/2, z) (terminal phase half life) of aripiprazole were 31.0 ng/mL, 3.6 hr, and 61.0 hr, respectively. The t(1/2, z) in CYP2D6 IM subjects (75.2 hr) was significantly (p<0.01) longer than that in CYP2D6 EM subjects (45.8 hr), and the systemic clearance of IM subjects was approximately 60% that of EM subjects. The PK in one subject with the CYP2D6*41 homozygote was similar to that of IM subjects. In repeated oral administration, plasma concentrations of aripiprazole and active metabolite both reached a steady state by Day 14. The half-life of aripiprazole following repeated administration was similar to that following single administration, suggesting that pharmacokinetics was constant during 14-day administration. Our investigations revealed that there is no clear ethnic difference between Japanese and Western subjects in terms of mean plasma PK, while the CYP2D6*10 allele distinctive to Asian populations influences the PK of aripiprazole. Moreover, our observations suggest that the CYP2D6*41 allele significantly affects drug-metabolizing activity.

Influence of itraconazole co-administration and CYP2D6 genotype on the pharmacokinetics of the new antipsychotic ARIPIPRAZOLE.

The results of in vitro studies indicated that ARIPIPRAZOLE, a newly developed antipsychotic, is mainly metabolized by the human cytochrome P450 isozymes CYP3A4 and CYP2D6. The objective of the present study was to investigate the influence of itraconazole (hereafter referred to as ITZ) co-administration (CYP3A4 inhibition) on the pharmacokinetics of ARIPIPRAZOLE administered to 24 healthy adult male volunteers in a fasting condition. The influence of CYP3A4 inhibition was also examined by CYP2D6 genotype. All subjects were administered a single oral dose of ARIPIPRAZOLE alone in Period I and a single oral dose of ARIPIPRAZOLE following administration of ITZ at 100 mg/day for 7 consecutive days in Period II. The pharmacokinetic parameters of ARIPIPRAZOLE and its main metabolite OPC-14857 were determined. Co-administration of ITZ increased the Cmax, AUC336 hr, and t1/2,z of ARIPIPRAZOLE and OPC-14857 by 19.4%, 48.0%, and 18.6% and by 18.6%, 38.8%, and 53.4%, respectively. By co-administration of ITZ, the CL/F of ARIPIPRAZOLE in extensive metabolizers was decreased by 26.6%, with an even greater decrease (47.3%) in intermediate metabolizers. For the co-administration period, the CL/F of ARIPIPRAZOLE in intermediate metabolizers was about half of that in extensive metabolizers. For Cmax, there was no significant difference between extensive metabolizers and intermediate metabolizers, and the percent change by co-administration of ITZ was less than 20% in both extensive metabolizers and intermediate metabolizers. For OPC-14857, the t(max) in intermediate metabolizers was longer than that in extensive metabolizers, with the difference being amplified by co-administration of ITZ. The AUC336 hr showed similar increases by co-administration of ITZ in all genotypes. The urinary 6beta-hydroxycortisol/cortisol concentration ratio following ITZ administration for 7 consecutive days was about half of that before the start of ITZ administration, indicating that CYP3A4 metabolic activity was inhibited by administration of ITZ. The influence of CYP3A4 inhibition on the pharmacokinetics of ARIPIPRAZOLE was not considered to be clinically significant. On the other hand, definite differences in pharmacokinetics were observed between CYP2D6 genotypes.