Randomized phase II/III clinical trial of elpamotide for patients with advanced pancreatic cancer: PEGASUS-PC Study

Abstract

Gemcitabine is a key drug for the treatment of pancreatic cancer; however, with its limitation in clinical benefits, the development of another potent therapeutic is necessary. Vascular endothelial growth factor receptor 2 is an essential target for tumor angiogenesis, and we have conducted a phase I clinical trial using gemcitabine and vascular endothelial growth factor receptor 2 peptide (elpamotide). Based on the promising results of this phase I trial, a multicenter, randomized, placebo-controlled, double-blind phase II/III clinical trial has been carried out for pancreatic cancer. The eligibility criteria included locally advanced or metastatic pancreatic cancer. Patients were assigned to either the Active group (elpamotide + gemcitabine) or Placebo group (placebo + gemcitabine) in a 2:1 ratio by the dynamic allocation method. The primary endpoint was overall survival. The Harrington-Fleming test was applied to the statistical analysis in this study to evaluate the time-lagged effect of immunotherapy appropriately. A total of 153 patients (Active group, n = 100; Placebo group, n = 53) were included in the analysis. No statistically significant differences were found between the two groups in the prolongation of overall survival (Harrington-Fleming P-value, 0.918; log-rank P-value, 0.897; hazard ratio, 0.87, 95% confidence interval [CI], 0.486-1.557). Median survival time was 8.36 months (95% CI, 7.46-10.18) for the Active group and 8.54 months (95% CI, 7.33-10.84) for the Placebo group. The toxicity observed in both groups was manageable. Combination therapy of elpamotide with gemcitabine was well tolerated. Despite the lack of benefit in overall survival, subgroup analysis suggested that the patients who experienced severe injection site reaction, such as ulceration and erosion, might have better survival.

Keywords: Advanced pancreatic cancer; elpamotide; immunotherapy; peptide vaccine; phase II/III.

Fig 1

Flow diagram of a phase I clinical trial of gemcitabine and elpamotide (Active group) versus gemcitabine and placebo (Placebo group) for treatment of pancreatic cancer.

Fig 2

Kaplan–Meier estimates of overall survival (a) and progression-free survival (b) in pancreatic cancer patients treated with gemcitabine and elpamotide (Active group) or gemcitabine and placebo (Placebo group), according to treatment group. CI, confidence interval; H-F, Harrington–Fleming test; MST, median survival time.

Fig 3

Kaplan–Meier estimates of overall survival in patients with pancreatic cancer treated with gemcitabine and elpamotide (Active group), according to ulceration at the injection site. CI, confidence interval; H-F, Harrington–Fleming test; MST, median survival time.