A phase II trial of modified FOLFOX6 as first-line therapy for adenocarcinoma of an unknown primary site.

Purpose: The aim of the study was to assess the clinical activity and toxicity of oxaliplatin and leucovorin in combination with bolus and continuous infusional 5-fluorouracil administered every 2 weeks (modified FOLFOX-6 regimen) to patients with adenocarcinoma of an unknown primary site (ACUP).

Methods: Previously untreated ACUP patients were treated with oxaliplatin (100 mg/m(2)) and leucovorin (200 mg/m(2)) as a 2-h infusion followed by bolus administration of 5-fluorouracil (400 mg/m(2)) and continuous infusion of 5-fluorouracil (2400 mg/m(2)) every 2 weeks.

Results: A total of 23 patients were enrolled and treated with a modified FOLFOX-6 regimen between May 2009 and November 2014. This trial was terminated before the scheduled enrollment due to poor accrual. A total of 134 cycles of mFOLFOX-6 were administered to 23 patients. The median number of cycles of mFOLFOX-6 was 5 (range 1-12). Among 20 patients whose tumor responses were evaluable, seven patients showed a partial response (no complete response), with an objective response rate of 35.0%. The median duration of response was 3.9 months (range 3.0-19.8). The median progression-free survival and overall survival were 3.0 and 9.5 months, respectively (95% confidence interval 1.4-6.7 months and 4.8-26.4 months, respectively). Treatment-related toxicity was manageable.

Conclusions: mFOLFOX-6 showed modest activity in treatment-naïve patients with ACUP. A future, prospective large-scale study incorporating a parallel molecular prediction marker study is warranted.