Efficacy and safety of drospirenone as a progestin-only pill in Japanese women: A phase III study

Abstract

Aim

To evaluate the efficacy and safety of 4 mg of drospirenone (DRSP), a progestin-only pill (POP), for contraception in Japanese women.

Methods

This was a multicenter, open-label, single-arm study. The dosing period of DRSP was 13 cycles, each lasting for 28 days. In one cycle, 4 mg of DRSP was administered orally once daily for the first 24 days, followed by a placebo for 4 days.

Results

Data from 276 subjects were analyzed, with a total of 3319 DRSP exposure cycles. Pregnancy occurred in one subject. The overall Pearl Index [95% CI] was 0.39 [0.01, 2.18], and the cumulative pregnancy rate [95% CI] was 0.40% [0.06, 2.81]. Of the 276 subjects, 273 (98.9%) experienced treatment-emergent adverse events (TEAEs) and 264 (95.7%) experienced adverse drug reactions. All TEAEs were mild or moderate, with no severe events. The most common TEAE was intermenstrual bleeding (irregular uterine bleeding) (89.5%). Although 31.9% of the subjects had risk factors for venous thromboembolism (VTE), no VTE-related TEAEs were observed. The incidence of unscheduled bleeding [95% CI] across all cycles was 91.6% [87.7, 94.3].

Conclusions

DRSP, the first POP in Japan, is effective and safe as a contraceptive in Japanese women. It provides a new contraceptive option for Japanese women, including those at risk of VTE for whom combined oral contraceptives are contraindicated.