Japanese Trial Shows Improved Survival With Adjuvant S-1 vs Gemcitabine in Resected Pancreatic Cancer


Key Points

  • Adjuvant S-1 improved overall survival vs gemcitabine in patients with resected pancreatic cancer.
  • The 5-year overall survival was 44.1% for S-1 vs 24.4% for gemcitabine.

Updated results of a Japanese phase III trial (JASPAC 01) reported in The Lancet by Uesaka et al showed that adjuvant S-1 was associated with significantly better overall survival compared with gemcitabine in patients with resected pancreatic cancer.

Study Details

In the open-label noninferiority trial, 377 patients (per-protocol population) with resected stage I to III disease were randomized to receive oral S-1 (n = 187) or intravenous gemcitabine (n = 190). S-1 was given at 40 mg to 60 mg (according to body surface area) twice daily for 28 days, followed by a 14-day rest period every 6 weeks for up to four 6-week cycles; gemcitabine was given at 1,000 mg/m2 on days 1, 8, and 15 every 4 weeks for up to six 4-week cycles. The primary endpoint was overall survival in the per-protocol population.

Improved Survival

The study was discontinued in September 2012, when interim analysis showed the prespecified criteria for early discontinuation had been met. At interim analysis, median follow-up was 39 months in the S-1 group and 41 months in the gemcitabine group; the hazard ratio (HR) for death was 0.56, with significance shown for both noninferiority (P < .0001) and superiority (P < .0001) for S-1 vs gemcitabine.

Analysis of data through January 15, 2016, showed 5-year overall survival of 44.1% (95% confidence interval = 36.9%–51.1%) in the S-1 group vs 24.4% (95% CI = 18.6%–30.8%) in the gemcitabine group. The hazard ratio for mortality was 0.57, with significance for both noninferiority (P < .0001) and superiority (P < .0001).

Grade 3 or 4 leukopenia, neutropenia, aspartate transaminase elevation, and alanine transaminase elevation were more common with gemcitabine, and stomatitis and diarrhea were more common with S-1.

The investigators concluded: “Adjuvant chemotherapy with S-1 can be a new standard care for resected pancreatic cancer in Japanese patients. These results should be assessed in non-Asian patients.”

The study was funded by Pharma Valley Center, Shizuoka Industrial Foundation, and Taiho Pharmaceutical.

Narikazu Boku, MD, of the National Cancer Center Hospital, Tokyo, is the corresponding author of The Lancet article.

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