Phase III double-blinded, randomized trial to evaluate the use of black cohosh in the treatment of hot flashes: A North Central Cancer Treatment Group study

Abstract

8013 Background: Hot flashes can cause significant morbidity in post-menopausal women and women undergoing or finished with breast cancer treatment. Based on initial pilot data suggesting black cohosh could be efficacious in the treatment of hot flashes, a phase III trial was initiated. Methods: A double-blind, randomized, cross-over methodology with two 4 week periods, was used to study the efficacy of black cohosh (1 capsule, Cimicifuga racemosa 20 mg BID) for the treatment of hot flashes in women. Participants kept a daily hot flash diary during a baseline week and then during an 8-week cross-over treatment period. Treatment effectiveness was measured using the mean daily numbers of hot flashes and the hot flash scores; the latter measured by assigning points (1–4, for mild to very severe) to each hot flash based on severity and then adding the points for a given time period. The study design provided 80% power to detect a moderate effect size difference (1/2 standard deviation) in the hot flash scores between the two treatment groups. Results: 132 patients were randomized between 10/31/03 - 3/4/04. Data on 80% of patients have been analyzed and are reported here. Toxicity was minimal and not different by treatment group with 83% of patients receiving black cohosh and 76% of patients receiving placebo reporting no adverse events. Patients receiving black cohosh reported a mean decrease in hot flash score (comparing the fourth treatment week to the baseline week) of 20% compared to 27% for patients on placebo (p=0.53). Mean hot flash frequency was reduced 17% on black cohosh and 26% on placebo (p=0.36). Patient treatment preferences were measured after completion of both treatment periods by ascertaining which treatment period, if any, the patient’s preferred: 34% of patients preferred the black cohosh treatment, 38% preferred placebo, and 28% did not prefer either treatment. Conclusion: This trial failed to provide any evidence that black cohosh reduced hot flashes more than the placebo did. No significant financial relationships to disclose.