Safety and Efficacy of a 24-Cycle Administration of a Drospirenone-Only Pill in Japanese Women.

AIM: We conducted a 24-cycle study to evaluate long-term safety of 4 mg of drospirenone (DRSP), a progestin-only pill (POP), for contraception in Japanese women.

METHODS

A multicenter, single-arm 24-cycle study was conducted in women who participated in the 13 cycle study of DRSP. In each cycle, 4 mg of DRSP tablet was administered orally once daily for 24 consecutive days, followed by a placebo tablet for 4 days.

RESULTS

In this 24-cycle study, the total number of DRSP exposure cycles was 3878. Fifty-two subjects (100.0%) experienced treatment-emergent adverse events (TEAEs), and 50 (96.2%) experienced adverse drug reactions. All TEAEs were mild or moderate with no severe events. The most common TEAE was intermenstrual bleeding, which occurred in 49 (94.2%) subjects. Although 50.0% of the subjects had risk factors for venous thromboembolism (VTE), no VTE-related TEAEs were observed. No TEAEs led to discontinuation of the study. During 3878 exposure cycles, pregnancy occurred in one subject. The overall Pearl index [95% CI] was 0.34 [0.01, 1.87], and the cumulative pregnancy rate was 0.4%.

CONCLUSIONS

In this study, the safety of DRSP, the first POP in Japan, was evaluated in Japanese women for 24 cycles. The DRSP-only pill provides a new option for contraception for Japanese women, including those at risk of developing VTE.