Objective: To investigate efficacy and safety of a controlled ovarian stimulation (COS) protocol in which a single dose of Corifollitropin-alfa (CFα) was administered on day 4 of a GnRH-antagonist cycle.
Design: Cohort case-control study.
Setting: University Hospital.
Patients: One hundred twenty-two normally cycling women expected to be normal responders to COS.
Interventions: In 61 patients, CFα (100-150 μg) was injected subcutaneously on day 4 of a spontaneous menstrual cycle; a GnRH-antagonist was added from day 8 (fixed protocol; 0.25 mg/day). If needed to complete follicular maturation, recombinant FSH (rFSH) daily injections (150/200 IU/day) were given from day 11. A control group of 61 matched women was stimulated with daily subcutaneous injections of rFSH (100-150 U/day) from day 4 of the cycle, and received GnRH-antagonist (0.25 mg/day) from day 8. IVF or ICSI was performed according to the sperm characteristics, and 1-2 embryos were transferred in utero under US guidance on day 2.
Main outcome measures: Number of retrieved cumulus-oocyte complexes (COCs), clinical pregnancy rate (PR), implantation rate (IR), ongoing PR at 10 weeks, number of injections/cycle, ovarian hyperstimulation syndrome (OHSS) rate.
Results: No cycle was cancelled and the mean number of retrieved COCs was comparable in patients and controls. About 60% of CF-alfa treated women had no need of daily rFSH addition, and the mean number of injections/cycle was significantly lower in the CF-alfa group than in controls (p < 0.05). The ongoing PR/transfer was 36.8% in CF-alfa group and 37.5% in controls. No patient developed severe OHSS, and the incidence of moderate OHSS was similar in cases and controls.
Conclusions: CFα may be started on day 4 of the cycle obtaining results comparable to those of a COS using day 4-start daily rFSH, with significantly less injections and a similar risk of OHSS.