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

Progesterone governs endometrial proliferation-differentiation switching and blastocyst implantation

Blastocyst implantation contains the following three processes: apposition, attachment, and invasion of the blastocyst. Ovarian hormone progesterone (P₄) regulates these processes exquisitely. P₄-induced molecular communications between the endometrial epithelium and stroma as well as endometrial proliferation-differentiation switching (PDS) until blastocyst attachment are fundamental steps in blastocyst implantation. Based on the knowledge obtained from the previous studies of mouse models by my group and others, this article outlines how P₄ directs the uterus to complete blastocyst implantation.

CDX2 is essential for human IVF early embryonic development

Human in vitro fertilization (IVF) embryos usually have developmental block at 4-8 cell stages, in which only 30%-50% percent of IVF embryos develop to blastocyst stage. This is the main cause for low efficiency and repeated treatment failure in human fertility therapy. Transcription factor CDX2 is one of the key genes in human early embryonic development, which decides the differentiation from blastomere to trophoblastic lineage. However, the relationship between the developmental block of human IVF embryos and CDX2 is poorly understood. In this study, we showed that CDX2 is crucial for human IVF embryonic development. q-PCR analysis confirmed that the level of CDX2 in developmental block embryos was dramatically decreased. Immunofluorescence analysis further demonstrated that CDX2 protein level in developmental block embryos was significantly decreased compared with that in control embryos. We also addressed whether re-expression of CDX2 could rescue developmental block defects in human IVF developmental block embryos. As expected, these developmental block defects could be partially rescued by overexpression of CDX2 protein. In conclusion, these findings suggest that CDX2 plays an important role in the process of human early embryonic development.

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.