Recombinant follicle‐stimulating hormone (follitropin alfa) for ovulation induction in Japanese patients with anti‐estrogen‐ineffective oligo‐ or anovulatory infertility: results of a phase II dose–response study

Purpose To determine the optimal regimen of recombinant human follicle‐stimulating hormone (r‐hFSH) for ovulation induction (OI) in Japanese women with amenorrhea I or anovulatory infertility. Methods In this randomized, double‐blind, dose‐finding study, women aged 20–39 years were enrolled. Patients underwent a chronic low‐dose step‐up regimen with starting doses of r‐hFSH of 37.5 IU (group L; n = 62), 75 IU (group M; n = 62) or 150 IU (group H; n = 60). Primary endpoint was time to achieve a dominant follicle with mean diameter ≥18 mm. Secondary endpoints included percentage of patients producing a dominant follicle ≥18 mm, achieving ovulation, and biochemical pregnancy. Results Median time to achieve a dominant follicle ≥18 mm was 14 days (group L; 87.7%), 10 days (group M; 98.4%), and 8 days (group H; 94.5%). In group M, ovulation occurred in 95.1% of patients, with pregnancy in 18.0%, compared with 86.0% and 15.8% in group L, and 50.9% and 9.1% in group H, respectively. Twelve patients developed ovarian hyperstimulation syndrome (nine in group H). Most adverse events in groups L and M were mild in severity. Conclusions A starting dose of 75 IU r‐hFSH was associated with a favorable efficacy and safety profile for OI in Japanese women.