Pharmacokinetics and follicular dynamics of corifollitropin alfa versus recombinant FSH during ovarian stimulation for IVF

Abstract

A single injection of corifollitropin alfa can replace seven daily injections of recombinant FSH (rFSH) using a gonadotrophin-releasing hormone antagonist protocol in ovarian stimulation prior to IVF or intracytoplasmic sperm injection. This double-blind randomized controlled trial assessed the pharmacokinetics and pharmacodynamics of 150μg corifollitropin alfa versus daily 200IU rFSH in 1509 patients. Comparative analyses were performed on serum concentrations of FSH immunoreactivity (pharmacokinetics), and the number and size of growing follicles, and inhibin B and oestradiol concentrations as biomarkers of ovarian response (pharmacodynamics). The rate of follicular development was similar in both treatment groups. By stimulation day 8, 33% of patients treated with corifollitropin alfa reached the criterion for human chorionic gonadotrophin (HCG) injection. The number of follicles ⩾11mm was slightly higher after corifollitropin alfa compared with daily rFSH at stimulation day 8 (difference, 1.2; 95% confidence interval (CI) 0.5-1.8; P<0.01) and on the day of HCG injection (difference, 2.1; 95% CI 1.4-2.8; P<0.01). The rise of inhibin B and oestradiol concentrations was similar in both treatment groups. Although the pharmacokinetics of corifollitropin alfa and rFSH are quite different their pharmacodynamic profiles at the dosages used are similar. A single injection of corifollitropin alfa can replace seven daily injections of recombinant FSH (rFSH) using a gonadotrophin-releasing hormone antagonist protocol in ovarian stimulation prior to IVF or intracytoplasmic sperm injection. The objective of this study was to compare the pharmacokinetics and pharmacodynamics of corifollitropin alfa versus daily rFSH. A total of 1509 patients were randomized in a double-blind, controlled trial to either a single injection of 150μg corifollitropin alfa or to daily injections of 200IU rFSH for the first 7 days of ovarian stimulation. Serum levels of FSH immunoreactivity were analysed (pharmacokinetic analysis), together with the number and size of growing follicles and serum inhibin B and oestradiol concentrations as biomarkers of the ovarian response (pharmacodynamic analysis). Serum FSH immunoreactivity levels were higher up to stimulation day 5 for corifollitropin alfa compared with the daily rFSH regimen but were similar from day 8 onwards, when patients started rFSH if the criteria for human chorionic gonadotrophin were not yet reached. Corifollitropin alfa treatment resulted in a similar growth rate of follicles though a slightly higher number of follicles were recruited compared with daily rFSH. It is concluded that the pharmacokinetics of corifollitropin alfa and rFSH are quite different but their induced pharmacodynamic effects at the dosages used are similar.

Trial registration: ClinicalTrials.gov NCT00696800.