Gemcitabine in the second-line therapy of patients with carcinoma of unknown primary site: a phase II trial of the Minnie Pearl Cancer Research Network.

The purpose of this study was to evaluate the activity of single-agent gemcitabine in previously treated patients with carcinoma of unknown primary site. Between January 1997 and October 1998, 39 patients were enrolled in this multicenter Phase II trial performed in the Minnie Pearl Cancer Research Network. Twenty-seven patients (69%) had adenocarcinoma or poorly differentiated adenocarcinoma; 35 patients (90%) had previously received treatment with chemotherapy regimens containing both a platinum agent and a taxane. Only 21% of patients had ever responded to previous therapy. Gemcitabine 1000 mg/m2 was administered intravenously on days 1, 8, and 15 of each 28-day course. Three of 36 evaluable patients (8%) had partial responses, and 9 patients (25%) had minor responses or stable disease with improved symptoms. The median time to progression for patients with partial responses or stable disease/improved symptoms was 5 months. Treatment was well tolerated, with uncommon grade 3 or 4 toxicity. Gemcitabine produced a low objective response rate in this refractory patient population, although approximately one-third of patients experienced symptomatic improvement. Treatment with gemcitabine was well tolerated. Because gemcitabine has activity against a variety of adenocarcinomas, further evaluation of this agent as part of first-line therapy for patients with carcinoma of unknown primary site is appropriate.