Anastrozole vs. clomiphene citrate in infertile women with ovulatory dysfunction: a phase II, randomized,...

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.

Phase II, prospective, randomized, double-blind, multicenter, dose-finding, noninferiority study.

Outpatient.

Infertile women (n = 271) with ovulatory dysfunction, aged 18-40 years, with body mass index <37 kg/m(2).

Five days of anastrozole at 1, 5, or 10 mg/d or CC at 50 mg/d.

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).

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.

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).