No abstract

UMIN000001396.

The effect of the C3435T mutation at exon 26 of the MDR1 gene on the expression levels of MDR1 messenger ribonucleic acid (mRNA) was evaluated by means of real-time polymerase chain reaction in 51 biopsy specimens of duodenum obtained from 13 healthy Japanese subjects. The mRNA levels of MDR1 were 0.38 +/- 0.15, 0.56 +/- 0.14, and 1.13 +/- 0.42 (mean value +/- SE) in the subjects with the homozygote of wild-type allele (C/C), compound heterozygote with mutant T allele (C/T), and the homozygote of the mutant allele (T/T), respectively, reasonably explaining the lower digoxin serum concentration after administration of a single oral dose to subjects harboring a mutant T allele. Good correlation (r =.797; P <.01) was observed between the mRNA concentrations of MDR1 and CYP3A4 in the individual biopsy specimens. This finding suggested a lower plasma concentration of the substrates for CYP3A4 in subjects harboring the C3435T mutation of the MDR1 gene.

Background Nivolumab showed improvement in overall survival (OS) in ATT RAC TION-2, the first phase 3 study in patients with gastric/gastroesophageal junction (G/GEJ) cancer treated with ≥ 2 chemotherapy regimens. The 2-year follow-up results of ATT RAC TION-2 are presented herein. Methods ATT RAC TION-2 was a randomized, double-blind, placebo-controlled, phase 3 trial (49 sites; Japan, South Korea, and Taiwan). The median (min-max) follow-up period was 27.3 (24.1-36.3) months. The primary endpoint was OS. A subanalysis of OS was performed based on best overall response and tumor-programmed death ligand-1 (PD-L1) expression status. Results Overall, 493 of 601 screened patients were randomized (2:1) to receive nivolumab (330) or placebo (163). OS (median [95% confidence interval; CI]) was significantly longer in the nivolumab group (5.26 [4.60-6.37] vs 4.14 [3.42-4.86] months in placebo group) at the 2-year follow-up (hazard ratio [95% CI], 0.62 [0.51-0.76]; P < 0.0001). A higher OS rate was observed in the nivolumab vs placebo group at 1 (27.3% vs 11.6%) and 2 years (10.6% vs 3.2%). The OS benefit was observed regardless of tumor PD-L1 expression. Among patients with a complete or partial response (CR or PR) in the nivolumab group, the median OS (95% CI) was 26.6 (21.65-not applicable) months; the OS rates at 1 and 2 years were 87.1% and 61.3%, respectively. No new safety signals were identified. Conclusions Nivolumab treatment resulted in clinically meaningful long-term improvements in OS in patients with previously treated G/GEJ cancer. The long-term survival benefit of nivolumab was most evident in patients with a CR or PR.