Phase II Study of Afatinib in Patients With Tumors With Human Epidermal Growth Factor Receptor 2–Activating Mutations: Results From the National Cancer Institute–Molecular Analysis for Therapy Choice ECOG-ACRIN Trial (EAY131) Subprotocol EAY131-B
Philippe L. Bédard, Shuli Li, Kari B. Wisinski, Eddy S. Yang, Sewanti Limaye, Edith P. Mitchell, James A. Zwiebel, Jeffrey A. Moscow, Robert J. Gray, Victoria Wang, Lisa M. McShane, Larry Rubinstein, David R. Patton, P. Mickey Williams, Stanley R. Hamilton, Barbara A. Conley, Carlos L. Arteaga, Lyndsay N. Harris, Peter J. O’Dwyer, Alice P. Chen, Keith T. Flaherty
Abstract
PURPOSE: -activating mutations. METHODS: single-nucleotide variants or insertions/deletions detected by the National Cancer Institute-Molecular Analysis for Therapy Choice next-generation sequencing assay. Patients had performance status ≤ 1, left ventricular ejection fraction > 50%, grade ≤ 1 diarrhea, and no prior human epidermal growth factor receptor 2 (HER2) therapy. Patients received afatinib 40 mg once daily in 28-day cycles. The primary end point was objective response rate (ORR). Secondary end points were 6-month progression-free survival, overall survival, toxicity, and molecular correlates. RESULTS: A total of 59 patients were assigned and 40 were enrolled. The median age was 62 years, 78% were female, 68% had performance status = 1, and 58% had received > 3 prior therapies. The confirmed ORR was 2.7% (n = 1 of 37; 90% CI, 0.14 to 12.2), and 6-month progression-free survival was 12.0% (90% CI, 5.6 to 25.8). A confirmed partial response occurred in a patient with adenocarcinoma of extra-mammary Paget disease of skin who progressed after cycle 6. Two unconfirmed partial responses were observed (low-grade serous gynecological tract and estrogen receptor-positive/HER2-negative immunohistochemistry breast ductal carcinoma). Of 12 patients with breast cancer, 1 additional patient with lobular carcinoma (estrogen receptor-positive/HER2 fluorescent in situ hybridization) had a 51% reduction in target lesions but progressed because of a new lesion at cycle 6. The most common (> 20%) treatment-related adverse events were diarrhea (68%), mucositis (43%), fatigue (40%), acneiform rash (30%), dehydration (27%), vomiting (27%), nausea (27%), anemia (27%), and anorexia (22%). Four patients (11%) discontinued because of adverse events. CONCLUSION: Although afatinib did not meet the prespecified threshold for antitumor activity in this heavily pretreated cohort, the response in a rare tumor type is notable. The safety profile of afatinib was consistent with prior studies.