Phase 2 trial of a novel capecitabine dosing schedule in combination with bevacizumab for patients with metastatic breast cancer.

BACKGROUND: Capecitabine has antitumor activity in metastatic breast cancer (MBC); however, its optimal dose and schedule remain unclear. Mathematical modeling predicts that a capecitabine schedule 7 days of treatment followed by 7 days of rest (7-7) will improve efficacy and minimize toxicity. Bevacizumab has demonstrated the ability to improve outcomes when it is added to chemotherapy, including capecitabine, in the first-line and second-line settings. METHODS: Patients with measurable MBC received oral capecitabine (2000 mg twice daily; 7-7), and intravenous bevacizumab (10 mg/kg every 2 weeks). The primary endpoint was the response rate. Secondary endpoints included toxicity, the clinical benefit rate, and progression-free survival (PFS). RESULTS: Forty-one patients were treated. After a median of 7 cycles (range, 1-32 cycles), partial responses were observed in 20% of patients, and stable disease for ≥6 months was noted in 35% patients. The median PFS was 8 months. The most common treatment-related toxicities were hand-foot syndrome (49% grade 2, 20% grade 3/4) hypertension (12% grade 2, 10% grade 3/4), and fatigue (12% grade 2, 2% grade 3/4). Diarrhea (5% grade 2, 0% grade 3/4), nausea (0% grade 2-4), and vomiting (0% grade 2-4) were rare. CONCLUSIONS: Capecitabine administered for 7 days followed by a 7-day rest in combination with bevacizumab had modest efficacy and an acceptable toxicity profile in patients with MBC. Gastrointestinal toxicity with this schedule was minimal.

Feasibility trial of letrozole in combination with bevacizumab in patients with metastatic breast cancer.

PURPOSE: Preclinical models suggest that the use of anti-vascular endothelial growth factor (anti-VEGF) therapy with antiestrogens may prevent or delay the development of endocrine therapy resistance. We therefore performed a feasibility study to evaluate the safety of letrozole plus bevacizumab in patients with hormone receptor-positive metastatic breast cancer (MBC). METHODS: Patients with locally advanced breast cancer or MBC were treated with the aromatase inhibitor (AI) letrozole (2.5 mg orally daily) and the anti-VEGF antibody bevacizumab (15 mg/kg intravenously every 3 weeks). The primary end point was safety, defined by grade 4 toxicity using the National Cancer Institute Common Toxicity Criteria, version 3.0. Secondary end points included response rate, clinical benefit rate, and progression-free survival (PFS). Prior nonsteroidal AIs (NSAIs) were permitted in the absence of progressive disease. RESULTS: Forty-three patients were treated. After a median of 13 cycles (range, 1 to 71 cycles), select treatment-related toxicities included hypertension (58%; grades 2 and 3 in 19% and 26%), proteinuria (67%; grades 2 and 3 in 14% and 19%), headache (51%; grades 2 and 3 in 16% and 7%), fatigue (74%; grades 2 and 3 in 19% and 2%), and joint pain (63%; grades 2 and 3 in 19% and 0%). Eighty-four percent of patients had at least stable disease on an NSAI, confounding efficacy results. Partial responses were seen in 9% of patients and stable disease >or= 24 weeks was noted in 67%. Median PFS was 17.1 months. CONCLUSION: Combination letrozole and bevacizumab was feasible with expected bevacizumab-related events of hypertension, headache, and proteinuria. Phase III proof-of-efficacy trials of endocrine therapy plus bevacizumab are in progress (Cancer and Leukemia Group B 40503).