A single-arm phase III study exploring the efficacy and safety of LNG-IUS 8, a low-dose levonorgestrel intrauterine contraceptive system (total content 13.5 mg), in an Asia-Pacific population.

Objective: The objective was to evaluate the efficacy and safety of a low-dose levonorgestrel intrauterine system with total content 13.5 mg (average approximately 8 μg/24 h over the first year; LNG-IUS 8; Jaydess®) in an Asia-Pacific population.

Study Design: An open-label, single-arm phase III study conducted at 25 centers in China, Australia and Korea assessed LNG-IUS 8 use over 3 years in nulliparous and parous women (N=1114) aged 18-40 years with regular menstrual cycles (21-35 days). Primary outcome was pregnancy rate, expressed as the Pearl Index. Secondary outcomes included 3-year cumulative failure rate, treatment-emergent adverse events (TEAEs), discontinuation rate, bleeding profile and placement pain.

Results: The full analysis set comprised 925 women (mean age 31.6 years, 6.4% nulliparous). Overall unadjusted Pearl Index was 0.35 (95% confidence interval 0.15-0.70); the 3-year cumulative failure rate was 0.9% (95% confidence interval 0.4-1.9). TEAEs and study drug-related TEAEs were reported in 70.1% and 31.2% of women, respectively. Overall, 27.9% of women discontinued the study, 16.9% due to adverse events. Frequent or prolonged bleeding (World Health Organization criteria) decreased from the first to the twelfth 90-day reference intervals (from 5.0% to 0.7% and from 44.1% to 3.0%, respectively), and the percentage of women with amenorrhea increased over time (from 0.4% to 10.8%). Pain on placement was reported as "none" or "mild" in 91.9% of women.

Conclusions: LNG-IUS 8 was an effective and well-tolerated contraceptive method, providing another option for women in the Asia-Pacific region.

Implications: In this phase III study, LNG-IUS 8 was shown to be highly effective and well tolerated in an Asia-Pacific population and was not associated with any new or unexpected safety events. LNG-IUS 8 provides another contraceptive option for women in the Asia-Pacific region.