Efficacy of letrozole in the treatment of recurrent platinum- and taxane-resistant high-grade cancer of the ovary or peritoneum

Objective: To evaluate the efficacy and safety of letrozole in patients with recurrent platinum- and taxane-resistant estrogen receptor-positive (ER+) high-grade cancer of the ovary or peritoneum. Methods: A single-institution, phase II study was performed in women with recurrent ER+ epithelial carcinoma of the ovary or peritoneum. All patients had measurable disease. Letrozole was administered at a dose of 2.5 mg orally once daily until disease progression or toxicity occurred. Results: Thirty-three patients were enrolled. The median age was 63 years (range, 38 to 83 years). Twenty-three patients (74%) had received three or more prior chemotherapy regimens. The 31 patients evaluable for response received a total of 81 cycles (4 weeks/cycle) of therapy (range, 1 to 14 cycles/patient). The median treatment duration was 8 weeks (range, 4 to 52 weeks). None of the patients had a complete response (CR), 1 (3%) had a partial response (PR), and 7 (23%) had stable disease (SD). The median duration of clinical benefit (SD and PR) was 9 weeks (range, 7 to 46 weeks). The median follow-up for all patients was 25 weeks. All patients were evaluable for toxicity. The most common adverse effects were fatigue (36%) and diaphoresis (21%). No grade 3 or 4 toxicities were reported, and no patients discontinued treatment owing to adverse effects. Eighteen patients (58%) went on to receive additional therapy with other agents. Conclusion: In patients with ER-positive, platinum- and taxane-resistant high-grade ovarian and primary peritoneal cancer treated with letrozole, 26% derived a clinical benefit (SD and PR).