Pooled efficacy results of estetrol/drospirenone combined oral contraception phase 3 trials
Jeffrey T. Jensen, Andrew M. Kaunitz, Sharon L. Achilles, János Zatik, Steven Weyers, Terhi Piltonen, Л. В. Сутурина, И.А. Аполихина, Céline Bouchard, Melissa J. Chen, Dan Apter, Maud Jost, Jean‐Michel Foidart, Mitchell D. Creinin
Abstract
OBJECTIVE: To evaluate overall and subgroup efficacy of an estetrol (E4) 15 mg drospirenone (DRSP) 3 mg oral contraceptive in a 24/4-day regimen. STUDY DESIGN: We pooled efficacy outcomes from 2 pivotal phase 3 contraceptive trials with E4/DRSP conducted in the United States/Canada and Europe/Russia. We assessed Pearl Index (PI; pregnancies per 100 participant-years) and 13-cycle life-table pregnancy rates in at-risk cycles (confirmed intercourse and no other contraceptive use) among participants 16 to 35 years. We calculated PI by age and further subcategorization (contraceptive history and body mass index [BMI]). We performed multivariable analysis using Cox regression to assess impact of potential confounding factors. RESULTS: of 1.14 (0.64-1.88), 2.19 (1.05-4.03), and 2.27 (0.83-4.94), respectively. In multivariable analysis, we found associations of prior pregnancy (hazard ratio [HR] 3.61[1.56-8.38]), Black race (HR 4.61[1.97-10.80]), age 16 to 25 years (HR 2.37[1.09-5.15]) and compliance <99% of expected pills (HR 4.21[2.04-8.66]) with conception. CONCLUSION: E4/DRSP is an effective oral contraceptive overall and across subgroups stratified by age, contraceptive history, and BMI. Other than compliance, predictors of contraceptive failure are nonmodifiable. IMPLICATIONS STATEMENT: Pooled results from two phase 3 trials demonstrate high contraceptive efficacy of the novel estetrol-drospirenone oral contraceptive. Several non-modifiable risk factors, including prior pregnancy, race, and age, are associated with higher pregnancy risk. Additional research is needed to better understand predictors of combined oral contraceptive failure.