Corifollitropin alfa for ovarian stimulation in IVF: a randomized trial in lower-body-weight women.

In this double-blind, double-dummy, randomized, equivalence trial (Ensure), 396 women weighing 60kg or less who underwent controlled ovarian stimulation prior to IVF or intracytoplasmic sperm injection were randomized in a 2:1 ratio to a single dose of 100mug corifollitropin alfa or daily 150IU recombinant FSH (rFSH) for the first 7days of stimulation in a gonadotrophin-releasing hormone antagonist protocol. The mean +/- SD number of oocytes retrieved per started cycle was 13.3 +/- 7.3 for corifollitropin alfa versus 10.6 +/- 5.9 for rFSH. The estimated treatment difference of +2.5 oocytes (95% CI 1.2-3.9) in favour of corifollitropin alfa (P<0.001) was well within the predefined equivalence margin. The median (range) duration of stimulation was 9 (6-15) days in both groups. In 32.8% of the patients, one injection of corifollitropin alfa was sufficient to reach the human chorionic gonadotrophin criterion. The incidence of moderate and severe ovarian hyperstimulation syndrome was 3.4% for corifollitropin alfa and 1.6% for rFSH. A dose of 100mug corifollitropin alfa offers a simplified treatment option for potential normal responder patients with a lower body weight.