A prospective randomized trial comparing corifollitropin-α late-start (day 4) versus standard administration (day 2) in expected poor, normal, and high responders undergoing controlled ovarian stimulation for IVF

To assess whether corifollitropin-α (CFα) late-start administration (day 4) and standard administration (day 2) can obtain similar oocyte yield and live birth rate. Study design: A randomized controlled trial. Setting: University Hospital IVF Unit. Patients: One hundred thirteen women undergoing IVF. Interventions: Patients distributed in three subgroups (expected poor, normal, or high responders to FSH) were randomized into two treatment arms: (a) CFα late-start: CFα on day 4 + GnRH antagonist from day 8 + (when needed) recFSH from day 11; (b) CFα standard start: CFα on day 2 + GnRH antagonist from day 6 + (when needed) recFSH from day 9. IVF or ICSI was performed as indicated. Results: Considering the whole study group, the late-start regimen obtained comparable oocyte yield (8.9 ± 5.6 vs. 8.8 ± 6.2; p = n.s.), cPR/started cycle (25% vs. 31.6%, p = n.s.), and cumulative live birth rate (LBR)/ovum pickup (OPU) (29.2% vs. 37.7%, p = n.s.) than the standard regimen. The outcome of the two regimens was comparable in the two subgroups of high and normal responders. Differently, in poor responders, oocyte yield was similar, but LBR/OPU was significantly lower with late-start CFα administration that caused 40% cancellation rate due to monofollicular response. ROC curves showed that the threshold AMH levels associated with cycle cancellation were 0.6 ng/ml for late-start regimen and 0.2 ng/ml for standard regimen. Conclusion: CFα may be administered on either day 2 or day 4 to patients with expected high or normal response to FSH without compromising oocyte yield and/or live birth rate. Differently, late-start administration is not advisable for expected poor responders with AMH ≤ 0.6 ng/ml. Trial registration: NCT03816670.