In two previous randomized trials, the adjustment of chemotherapy delivery to circadian rhythms improved tolerability and anticancer activity compared with constant-rate infusion during 5 days in patients with metastatic colorectal cancer.Patients and Methods
For this multicenter randomized trial, it was hypothesized that a chronomodulated infusion of fluorouracil, leucovorin, and oxaliplatin for 4 days (chronoFLO4) would improve survival by 10% compared with conventional 2-day delivery of the same drugs (FOLFOX2). Patients were treated every 2 weeks with intrapatient dose escalation.Results
Baseline characteristics were similar in both arms for the 564 patients (36 institutions, 10 countries). Median survival was 19.6 months (95% confidence limit [CL] = 18.2, 21.2) with chronoFLO4 and 18.7 months with FOLFOX2 (95% CL = 17.7, 21.0; P = .55). The main dose-limiting toxicities were diarrhea for chronoFLO4 and neutropenia for FOLFOX2. The analysis of survival predictors showed that sex was the single most important factor (P = .001). In women, the risk of an earlier death with chronoFLO4 was increased by 38% compared with FOLFOX2, with median survival times of 16.3 and 19.1 months (P = .03), respectively. In men, the risk of death was decreased by 25% with chronoFLO4 compared with FOLFOX2, with median survival times of 21.4 and 18.3 months (P = .02), respectively.Conclusion
Both regimens achieved similar median survival times more than 18 months with an acceptable toxicity. The chronomodulated schedule produced a survival advantage over FOLFOX in men. The strong sex dependency of optimal scheduling of fluorouracil, leucovorin, and oxaliplatin calls for translational investigations of determinants related to the patient's molecular clock.