Comparison of follitropin-α and follitropin-δ in expected poor responders: a retrospective analysis

Different gonadotropins (Gn) have been developed to stimulate the ovaries as part of in-vitro fertilization (IVF). Studies comparing these formulations in poor responders are limited. The objective of this study was to evaluate clinical outcomes comparing follitropin-δ to follitropin-α in expected poor responders. Retrospective analysis of IVF cycles in expected poor responders, identified based on the POSEIDON criteria (women with low ovarian reserve - POSEIDON groups 3 and 4) that reached the oocyte collection between January 2020 to December 2022. Clinical outcomes were compared between those using follitropin-δ or follitropin-α and a sub analysis based on POSEIDON subgroup was performed. Chi square, Student's t-test, and Mann-Whitney Test were used. In total, 279 cycles were included. While those using follitropin-δ (N.=49) compared to follitropin-α (N.=230) had more oocytes collected (P=0.002), the number of good quality embryos was similar and clinical outcomes including fresh (24.5% vs. 18.2%, P=0.31) and cumulative live birth rate (30.6% vs. 23.0%, P=0.26) were comparable. Among POSEIDON 3 patients utilizing follitropin-δ, while the number of good quality embryos was higher (P=0.04), pregnancy outcomes were comparable. Among POSEIDON 4 patients using follitropin-δ, there were more MII oocytes (P<0.001) and embryos (P=0.007), however pregnancy outcomes were comparable. The treatment of poor responders is often challenging. Among POSEIDON 3-4 patients undergoing IVF, follitropin-δ appears to result in similar pregnancy outcomes as follitropin-α. Future studies should compare different drug doses and the potential benefits of combination regimens in these well-defined poor ovarian response patients.