Low-dose 17-beta estradiol matrix transdermal system in the treatment of moderate-to-severe hot flushes in postmenopausal women

This prospective, multicenter, randomized, double-masked, parallel-group study assessed the efficacy, safety, and tolerability of a low-dose (0.0375 mg/d) estradiol matrix transdermal delivery system for the treatment of moderate-to-severe postmenopausal hot flushes. Healthy women with moderate- to-severe postmenopausal hot flushes were included in the study. Estradiol matrix or matching placebo patches were administered over three 4-week treatment cycles, and responses were assessed over a 12-week treatment period. Two hundred fifty-seven patients (130 receiving estradiol, 127 receiving placebo) were included in the intent-to-treat population, 242 of whom were assessable for efficacy. Efficacy measures, including change from baseline in mean number of hot flushes per 24 hours in the last 2 weeks of cycle 1 (weeks 3 and 4), change from baseline in mean number of hot flushes in 4 weeks of cycles 2 (weeks 5 through 8) and 3 (weeks 9 through 12), and change from baseline in mean overall severity of hot flushes in the last 2 weeks of cycle 1, the 4 weeks of cycles 2 and 3 revealed significantly greater improvement with the estradiol matrix than with placebo at all time points (P < 0.001). Patients' global assessments of treatment effectiveness also significantly favored the estradiol matrix over placebo (P < 0.001). Overall, both test patches were well tolerated, with individual adverse effects reported by similar proportions of patients in both groups. The incidence of application-site reactions was identical (3.1%) in both groups. The estradiol matrix was associated with a higher frequency of estrogen- related effects, such as breast pain (estradiol matrix, 10%; placebo, 0.8%). All other drug-related adverse effects were reported in ≤3.1% of patients in both groups. Simple endometrial hyperplasia was found in 2 patients receiving estradiol matrix but none of the patients receiving placebo. The lowest available dosage of this estradiol matrix transdermal delivery system (0.0375 mg/d) provided significant relief from moderate-to-severe postmenopausal hot flushes and was well tolerated.