Corifollitropin alfa, a long-acting follicle-stimulating hormone agonist for the treatment of infertility.

Corifollitropin alfa is being developed by Schering-Plough Corp as an injectable, long-acting follicle-stimulating hormone (FSH) agonist for the treatment of infertility. A single dose of corifollitropin alfa could initiate and sustain multifollicular growth in patients undergoing controlled ovarian stimulation, such as during in vitro fertilization or intracytoplasmic sperm injection. The agent comprises an alpha-subunit, which is identical to that of FSH, and a beta-subunit, which is produced by the fusion of the C-terminal peptide from the beta-subunit of chorionic gonadotropin to the beta-subunit of FSH. Corifollitropin alfa has a longer half-life compared with FSH and thus requires less frequent dosing. The drug was well tolerated and does not appear to be associated with any serious adverse events or the formation of antibodies. The initial results from a large, phase III, double-blind clinical trial indicated that the ongoing pregnancy rate achieved with corifollitropin alfa treatment was high and similar to the rate established with daily treatment of recombinant FSH. The number of oocytes retrieved following the administration of corifollitropin alfa was slightly higher compared with the number observed with daily recombinant FSH treatment. Thus, corifollitropin alfa has the potential to serve as a viable fertility agent and to gain a place in the infertility market.