Efficacy, Safety, and Tolerability of a Levonorgestrel/Ethinyl Estradiol Transdermal Delivery System: Phase 3 Clinical Trial Results

Study (n=2,032) reports levonorgestrel/ethinylestradiol (three consecutive administrations of 7-day patches followed by 7 days off) was effective in preventing pregnancy; number of unintended pregnancies i.e. Pearl Index (95% CI) was 5.8 (4.5-7.5) pregnancies per 100 woman-years

SPS commentary:

Efficacy was found to be reduced in women with BMI ≥30 kg/m2. Rates trended higher as BMI increased; the Pearl Index was 4.3 (2.9–5.8) in women with BMI <30 kg/m2 and 8.6 (5.8–11.5) in women with BMI ≥30 kg/m2.

Results of this phase 3 study supported the FDA approval of Levonorgestrel/Ethinyl Estradiol transdermal patch (TWIRLA®) for prevention of pregnancy in women with BMI <30 kg/m2. Currently in the UK, the combination of levonorgestrel and ethinylestradiol is only available in a tablet formulation.

Contraception