Phase III trial of 8% vaginal progesterone gel for luteal phase support in Japanese women undergoing in vitro fertilization and fresh embryo transfer cycles.

Aim: This study evaluated the efficacy and safety of vaginal progesterone gel that was administered daily for luteal phase support as part of in vitro fertilization/embryo transfer (IVF/ET) cycles in Japanese women. Methods: This was a phase III, multicenter, open-label, single-arm trial in Japanese women undergoing IVF/ET, using the Japanese Society of Obstetrics and Gynecology 2009 registry as a historical control. The primary objective was to demonstrate the non-inferiority, with regard to the clinical pregnancy rate per ET, of vaginal progesterone gel that was administered once daily, compared with the historical standard value in IVF/ET cycles in Japan. The biochemical pregnancy (positive serum β-hCG pregnancy test but no clinical pregnancy) rate per ET also was investigated, as were the safety and tolerability of the vaginal progesterone gel. Results: Of the 178 women who were enrolled, 123 underwent IVF/ET. The clinical pregnancy rate per ET was non-inferior in the prospective arm, compared with the historical population. The biochemical pregnancy rate per ET was 7.3%. The safety profile of the vaginal progesterone gel was as expected, with no new safety issue identified. Conclusion: The vaginal progesterone gel was efficacious, with a safety profile as expected, in this study in Japanese women undergoing IVF/ET cycles.