Phase I/II trial of dexverapamil, epirubicin, and granulocyte-macrophage-colony stimulating factor in patients with advanced pancreatic adenocarcinoma

Abstract

Background: The purpose of this study was to determine the maximum tolerated dose (MTD) of a cytotoxic regimen consisting of the second-generation chemosensitizer dexverapamil (DVPM), high dose epirubicin, and recombinant human granulocyte-macrophage-colony stimulating factor (GM-CSF) in pancreatic carcinoma.

Patients and methods: Twenty-eight previously untreated patients with locally advanced or metastatic adenocarcinoma of the pancreas were studied. Treatment consisted of oral DVPM at a dose of 1000-1200 mg/day for 3 days, epirubicin administered as an intravenous bolus injection on Day 2 with an initial dose of 90 mg/m2, and a dose of GM-CSF of 400 micrograms administered subcutaneously from Day 5s through 14. Epirubicin dose escalation levels were 90, 105, 120 and 135 mg/m2. Consecutive cohorts of four to eight patients were planned at each dose level. Treatment cycles were repeated every 3 weeks.

Results: Hematologic toxicity, specifically granulocytopenia, constituted the dose-limiting toxicity with an MTD of 120 mg/m2 for epirubicin. Despite routine supportive therapy with GM-CSF, four, two, and five patients experienced Grade 4 granulocytopenia during their first two treatment courses at levels 105, 120, and 135 mg/m2, respectively. Grade 4 granulocytopenia was observed in two, three, and one additional patients during subsequent courses with these levels. Nonhematologic toxicity was uncommon, generally modest, and did not correlate clearly with the anthracycline dose. Dexverapamil-related cardiovascular symptoms occurred frequently, but they never resulted in serious toxicity requiring active medical intervention or permanent discontinuation of therapy. Nine of 28 patients achieved partial responses to this therapy. Stable disease was observed in nine patients, and tumor progress occurred in 10.

Conclusion: The MTD of epirubicin for this regimen with DVPM and GM-CSF was 120 mg/m2 every 3 weeks. Though it remains uncertain whether the encouraging response activity observed in this disease-oriented Phase I study was, in fact, due to successful modulation of multidrug resistance, these results suggest that this regimen is likely to be an effective and tolerable treatment strategy for patients with pancreatic cancer, which should be evaluated further.