Results: 88 patients were recruited from 10/28/21 to 12/02/23. Six patients refused treatment and one was ineligible, leaving 81 patients analyzed with a mean age of 68 years. Baseline characteristics were balanced between groups, with patients reporting an average of 10.15 hot flashes per day and moderate hot flashes daily (total score 18.23).
After 6 weeks of oxybutynin, patients taking placebo, low-dose oxybutynin, and high-dose oxybutynin experienced a reduction in hot flash frequency of 2.15, 4.77, and 6.89 hot flashes per day, respectively.
Daily total hot flash scores after 6 weeks of treatment for the same three groups decreased by an average of 4.85, 9.94 and 13.95 points, respectively.
No treatment-related grade 3+ adverse events were observed. The most common grade 2 adverse event associated with oxybutynin was dry mouth.
Conclusions: Oxybutynin is superior to placebo in the treatment of hot flashes in men associated with androgen deprivation therapy and appears to be well tolerated. Compared with patients in the placebo group, patients in the high-dose oxybutynin group, as well as patients in the low-dose group, had a greater reduction in the number of hot flashes per day and a greater reduction in hot flash scores.
https://ascopubs.org/doi/10.1200/JCO.2024.42.17_suppl.LBA12004 .
Randomized, double-blind, placebo-controlled, phase II trial of oxybutynin versus placebo for the treatment of hot flashes in men receiving androgen deprivation therapy.
Hot flashes are one of the most common adverse events affecting quality of life reported by patients receiving androgen deprivation therapy (ADT) for the treatment of prostate cancer. Troubling hot flashes occur in more than 50%-80% of men receiving ADT, and 27% of them report it as the most bothersome side effect.
Oxybutynin is a fairly effective therapy for reducing the frequency and severity of hot flashes in women. Data from a pilot project confirm that this drug may also benefit men with hot flashes associated with ADT.
In this study, patients with prostate cancer receiving ADT with at least 28 hot flashes per week were randomized to receive oral oxybutynin 2.5 mg twice daily, oxybutynin 5 mg twice daily, or placebo for 6 weeks.
The primary endpoint of the study was the change in patient-reported hot flashes (defined by multiplying the number of hot flashes by the average severity of hot flashes (grade 0: none, 1: mild, 2: moderate, 3: severe, and 4: very severe) from baseline level and after 6 weeks, according to the daily diary of hot flashes.