Anastrozole vs. clomiphene citrate in infertile women with ovulatory dysfunction: A phase II, randomized, dose-finding study

Objective: To determine an effective multiple-dose regimen of anastrozole compared with clomiphene citrate (CC) to induce follicular growth and ovulation in infertile women with ovulatory dysfunction. Design: Phase II, prospective, randomized, double-blind, multicenter, dose-finding, noninferiority study. Setting: Outpatient. Patient(s): Infertile women (n = 271) with ovulatory dysfunction, aged 18-40 years, with body mass index <37 kg/m². Intervention(s): Five days of anastrozole at 1, 5, or 10 mg/d or CC at 50 mg/d. Main Outcome Measure(s): The primary endpoint was the ovulation rate (mid-luteal phase serum P level ≥10 ng/mL or clinical pregnancy) in the first treatment cycle (cycle 1). Result(s): In cycle 1 the ovulation rates for anastrozole at 1, 5, and 10 mg/d were 30.4% (n = 24), 36.8% (n = 28), and 35.9% (n = 14), respectively, compared with 64.9% (n = 50) for CC at 50 mg/d. In up to three cycles of treatment, cumulative ovulation rates did not differ between groups. No cases of ovarian hyperstimulation syndrome were reported, and both anastrozole and CC were well tolerated. Conclusion(s): In terms of ovulation rates, 5-day anastrozole at 1, 5, and 10 mg/d was less effective than CC at 50 mg/d for cycle 1 (noninferiority was not shown).