Published in:
01-03-2012 | Original Article
A randomized phase II study of two doses of vorinostat in combination with 5-FU/LV in patients with refractory colorectal cancer
Published in: Cancer Chemotherapy and Pharmacology | Issue 3/2012
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Background
Vorinostat is synergistic with 5-FU in vitro and in vivo models. A combination of these two agents was associated with clinical activity in 5-FU refractory colorectal cancer patients in a phase I clinical trial, therefore warranting the conduct of this prospective phase II study.
Patients and methods
Patients with refractory metastatic colorectal cancer were randomized in a two-stage design to receive vorinostat at 800 or 1,400 mg/day once a day × 3, every 2 weeks. 5-FU, preceded by leucovorin, was administered as a bolus followed by a 46-h infusion on days 2 and 3 of vorinostat. A pre-specified 2-month progression-free survival (PFS) rate of 27/43 patients per arm was needed to deem an arm interesting for further investigation.
Results
The high-dose vorinostat arm did not reach the needed efficacy endpoint at completion of the first stage, with only 8 out of 15 patients being alive and progression free at 2 months. The low-dose vorinostat arm proceeded to accrue 43 patients with a 2-month PFS rate of 53% (23 out 43), including one partial response. The median PFS and overall survival on the low-dose arm were 2.4 and 6.5 months, respectively. Both treatment arms were well tolerated. No differences were noted in the pharmacokinetics of vorinostat at the 800- or 1,400-mg dose-levels, suggesting bioavailability saturation.
Conclusions
While the addition of vorinostat to 5-FU resulted in 1 partial response and in some disease stabilizations, the limited activity does not warrant the unselected use of this combination in chemotherapy-refractory colorectal cancer.