Schering-Plough Corp., announced that corifollitropin alfa, its experimental, sustained follicle stimulant (SFS) met its primary endpoints in the phase III Engage trial, according to data presented during a Schering-Plough-sponsored symposium at the 24th annual meeting of the European Society of Human Reproduction and Embryology (ESHRE) in Barcelona, Spain.

The ongoing pregnancy rate, the primary endpoint of this non-inferiority trial, obtained in the 150 mcg corifollitropin alfa treatment arm (38.9 per cent per started cycle) was similar to that achieved in patients receiving 200 IU recombinant FSH (follitropin beta) (38.1 per cent per started cycle). The number of oocytes retrieved (co-primary endpoint) was within the limits of clinical equivalence, and the estimated difference of +1.2 was in favour of the corifollitropin alfa 150 mcg treatment arm.

Engage is the largest double-blind fertility trial ever performed. Engage was a non-inferiority trial designed to compare corifollitropin alfa 150 mcg to 200 IU follitropin beta. A total of 1,509 patients (>60 kg) at 34 IVF clinics in North America and Europe were randomized to receive either corifollitropin alfa 150 mcg or a daily dose of 200 IU recombinant FSH, followed by recombinant FSH (maximum 200 IU/day) from stimulation day 8 onward. Starting on stimulation day 5, all patients were scheduled to receive 0.25mg gonadotropin-releasing hormone (GnRH) antagonist until triggering of final oocyte maturation by a urinary human chorionic gonadotropin (hCG). The primary endpoint was ongoing pregnancy rate assessed at 10 weeks or more after embryo transfer. The number of oocytes retrieved was the co-primary endpoint. The incidence of ovarian hyperstimulation syndrome (OHSS) was similar between both groups, 7.0 per cent in the corifollitropin alfa group (1.9 per cent severe) and 6.3 per cent in the follitropin beta group (1.3 per cent severe).

Corifollitropin alfa is being developed as a potential treatment in Controlled Ovarian Stimulation (COS) for the development of multiple follicles and pregnancy in women participating in an Assisted Reproductive Technology (ART) program. The corifollitropin alfa regimen is being developed in a GnRH antagonist protocol.

Schering-Plough is an innovation-driven, science-centered global health care company. Through its own biopharmaceutical research and collaborations with partners, Schering-Plough creates therapies that help save and improve lives around the world. The company applies its research-and-development platform to human prescription and consumer products as well as to animal health products.