Information regarding the ideal length of hot flash trials is scarce. In the literature, hot flash trial durations have commonly varied from 4 to 12 weeks. This article is devoted to providing scientific data to better ascertain how long it is necessary to conduct hot flash trials with newer centrally acting agents.
Individual participant data were collected from all known published, through December 2007, randomized, placebo-controlled, double-blinded clinical trials regarding the use of newer antidepressants and gabapentin for hot flash relief. Trials that studied periods longer than 4 weeks were included for this project. Profile analysis was applied to the hot flash activity longitudinal data for each study individually, allowing a comparison of data collected for 6 to 12 treatment weeks versus data collected for only 4 treatment weeks.
Ten studies were identified, five of them fulfilled the eligibility criteria for this investigation, three evaluating gabapentin, and two newer antidepressants. Flatness tests from a profile analysis did not provide any evidence that hot flash activity increased or decreased between week 4 and time periods up to 12 weeks.
Changes in hot flash scores from newer antidepressants and gabapentin are apparent within 4 weeks of therapy. Available data indicate that hot flash treatment efficacy, compared with that of placebo, remains stable for up to 12 weeks of follow-up.
A pooled analysis of individual patient data obtained from five published clinical trials evaluating gabapentin or one of the newer antidepressants was conducted. These trials, which had hot flash data during a baseline week, at 4 weeks, and also at 6 to 12 weeks, supported that results seen at 4 weeks were similar to what was seen at 6 to 12 weeks.
From the 1Mayo Clinic, Rochester, MN; and 2Johns Hopkins School of Medicine, Baltimore MD.
Received October 24, 2008; revised and accepted January 6, 2009.
Financial disclosure/conflicts of interest: Dr. Loprinzi is an investigator and consultant for P&G Pharmaceuticals, a cosultant to Astra Zenica, Novartis, Acrux, a recipient of research grant support form Asta Zenica, Novartis, Acrux and a recipient of honoraria from Organon Australia.
Address correspondence to: Charles L. Loprinzi, MD, Mayo Clinic, Rochester MN. E-mail: firstname.lastname@example.org