Prospective multicenter phase II study of gemcitabine plus cisplatin in patients with unresectable gallbladder cancer

Purpose: To evaluate the efficacy and safety of gemcitabine plus cisplatin in Japanese patients with unresectable gallbladder cancer (GBC). Methods: Chemo-naïve patients with histologically proven unresectable GBC were enrolled in this study. The patients received gemcitabine (1000 mg/m²) and cisplatin (25 mg/m²) on days 1 and 8, every 21 days. A response assessment was done by CT scan every 4 weeks. The primary end points were to determine the response rates [RR; complete response (CR) + partial response (PR)] and the disease control rate [DCR; CR + PR + stable disease (SD)]. The secondary end points were to evaluate toxicity, progression-free survival (PFS), and overall survival (OS). Results: From March 2012 to February 2015, 14 patients from seven different institutions were enrolled in the study, and 13 cases were evaluable for assessment. Eleven cases (84.6%) had distant metastases, and 8 cases (61.5%) had obstructive jaundice. There was no CR, 1 PR (7.7%), 11 SD (84.6%), and 1 progressive disease (PD) (7.7%). The RR was 7.7%, whereas the DCR was 92.3%. The median PFS was 3.1 months, the median OS was 6.2 months, and the one-year survival rate was 0%. Grade 3 hematologic toxicity was observed in three cases (23%), but all of them recovered upon drug withdrawal, and there was no treatment-related death. Conclusion: Although gemcitabine plus cisplatin has a high DCR (92.3%) and relatively low toxicity, the RR is less than 10%, and development of new therapies is desired for the treatment of unresectable GBC.