Biweekly low-dose sequential gemcitabine, 5-fluorouracil, leucovorin, and cisplatin (GFP): A highly active novel therapy for metastatic adenocarcinoma of the exocrine pancreas

Phase II studies have suggested an improved response rate and acceptable toxicity profile associated with gemcitabine combinations compared to gemcitabine alone for treatment of metastatic adenocarcinoma of the pancreas. The GFP regimen (gemcitabine, 5-fluorouracil, leucovorin, and cisplatin) is based on laboratory evidence of disease-specific chemotherapy interaction. This retrospective analysis examined the outcome of 49 consecutive patients with histologically confirmed metastatic pancreatic adenocarcinoma treated between July 1998 and September 2000. Day 1 treatment consisted of gemcitabine 500 mg/m² over 30 minutes and then leucovorin 300 mg bolus, 5-fluorouracil (5-FU) 400 mg/m² bolus, followed by infusional 5-FU 600 mg/m² over 8 hours. Day 2 consisted of leucovorin 300 mg bolus, 5-FU 400 mg/m² bolus, followed by cisplatin 50-75 mg/m² over 30 minutes and then infusional 5-FU 600 mg/m² over 8 hours. Treatment was administered every 2 weeks. Median patient age was 61.5 years, 74% were men, and 20 patients had refractory disease (11 patients had disease progression upon gemcitabine-based therapy). Grade 3-4 toxic effects (% patients) consisted of neutropenia (30%), thrombocytopenia (14%), anemia (8%), and neutropenic fever (2%). Grade 3-4 nonhematological toxicities (% patients) consisted of neuropathy (14%), ototoxicity (8%), nephrotoxicity (6%), nausea/vomiting (14%), and mucositis (10%). The majority of dose reductions were made for neuropathy or cytopenias. Filgrastim and erythropoietin were given as needed to promote dose intensity. Eight patients attained a partial response (PR) by RECIST criteria. Fourteen had stable disease (SD). Two patients attaining PR and two attaining SD had progressive disease with prior gemcitabine-based therapy. The median time to disease progression (TTP) from GFP start was 9 weeks. For all 49 patients, the median overall survival (OS) from GFP start was 10.6 months, 12-month survival was 46%, and 24-month survival was 30%. Notably, upon disease progression, 31 patients continued to receive the GFP regimen with irinotecan 80 mg/m² inserted on day 1 following gemcitabine, the G-FLIP regimen (gemcitabine, 5-fluorouracil, leucovorin, irinotecan, and cisplatin). Measured from G-FLIP initiation, the TTP for the 31 patients treated sequentially was 10 weeks, and for the 14 patients attaining SD or PR the TTP was 25 weeks. The median overall survival measured from GFP initiation was 11.8 months. The response rate, non-cross resistance, TTP, OS, and tolerability warrant prospective development of this novel combination. This experience also demonstrates that adding a single new drug such as irinotecan to the same first-line chemotherapy combination upon disease progression may be an important alternative for the treatment of relapsed/resistant cancer.