Irinotecan Plus Gemcitabine Results in No Survival Advantage Compared with Gemcitabine Monotherapy in Patients with Locally Advanced or Metastatic Pancreatic Cancer Despite Increased Tumor Response Rate

Purpose: This phase III, randomized, open-label, multicenter study compared the overall survival associated with irinotecan plus gemcitabine (IRINOGEM) versus gemcitabine monotherapy (GEM) in patients with chemotherapy-naive, locally advanced or metastatic pancreatic cancer.

Patients And Methods: IRINOGEM patients received starting doses of gemcitabine 1,000 mg/m2 and irinotecan 100 mg/m2 given weekly for 2 weeks every 3-week cycle. GEM patients received gemcitabine 1,000 mg/m2 weekly for 7 of 8 weeks (induction) and then weekly for 3 of 4 weeks. The primary end point of the trial was survival. Secondary end points included tumor response, time to tumor progression (TTP), changes in CA 19-9, and safety.

Results: In each arm, 180 randomly assigned patients comprised the intent-to-treat population evaluated for efficacy; 173 IRINOGEM and 169 GEM patients were treated. Median survival times were 6.3 months for IRINOGEM (95% CI, 4.7 to 7.5 months) and 6.6 months for GEM (95% CI, 5.2 to 7.8 months; log-rank P =.789). Tumor response rates were 16.1% (95% CI, 11.1% to 22.3%) for IRINOGEM and 4.4% (95% CI, 1.9% to 8.6%) for GEM (chi2 P <.001). Median TTP was 3.5 months for IRINOGEM versus 3.0 months for GEM (log-rank P =.352). However, subset analyses in patients with locally advanced disease suggested a TTP advantage with IRINOGEM versus GEM (median, 7.7 v 3.9 months). CA 19-9 progression was positively correlated with tumor progression. The incidence of grade 3 diarrhea was higher in the IRINOGEM group but grade 3 to 4 hematologic toxicities and quality-of-life outcomes were similar.

Conclusion: IRINOGEM safely improved the tumor response rate compared with GEM but did not alter overall survival.