Ospemifene is a nonsteroidal selective estrogen receptor modulator (SERM) for the treatment of moderate symptomatic vulvar and vaginal atrophy (VVA) due to menopause. A postauthorization safety study is currently examining the incidence of venous thromboembolism (VTE) among postmenopausal women receiving ospemifene or other SERM (raloxifene, bazedoxifene, or tamoxifen, for noncancer indications), or with untreated VVA.
This interim analysis used the US MarketScan Commercial and Medicare Supplemental claims database from 2013 to 2017 to identify incident VTE. The incidence rate and 95% confidence interval of VTE during the first continuous course of treatment (or continuous untreated time for the untreated cohort) were calculated for each cohort overall and by age group, with sensitivity analyses examining incidence in the short term (up to 90 days) and long term (all available follow-up, regardless of treatment changes).
Analyses included 8,188 ospemifene users, 11,777 other SERM users, and 220,242 women with untreated VVA. The incidence per 1,000 person-years and 95% confidence interval of VTE were 3.7 (1.7-7.1) for ospemifene, 11.5 (8.9-14.6) for other SERM, and 11.3 (10.8-11.7) for untreated VVA. Stratification by age and altering the time frame for analysis produced results with similar patterns to the primary analysis.
This interim analysis of an ongoing study suggests a favorable safety profile for ospemifene with respect to VTE. Comparative analyses with covariate adjustment will be performed when data accrual is complete.