In a single-center phase II study reported in JAMA Oncology, Matsuda et al found that adding the EGFR inhibitor panitumumab (Vectibix) to neoadjuvant chemotherapy produced high pathologic complete response (pCR) rates in patients with primary triple-negative inflammatory breast cancer.
The study included 40 patients enrolled at MD Anderson Cancer Center between 2010 and 2015 who were treated with neoadjuvant therapy consisting of one dose of panitumumab (2.5 mg/kg) followed by four cycles of panitumumab (2.5 mg/kg), nab-paclitaxel (Abraxane; 100 mg/m2), and carboplatin two times area under the curve weekly and then four cycles of fluorouracil (500 mg/m2), epirubicin (100 mg/m2), and cyclophosphamide (500 mg/m2) every 3 weeks.
The primary endpoint was pCR. Patients had a median age of 57 years and 72% were postmenopausal. Nineteen patients had triple-negative breast cancer and 21 had hormone receptor (HR)-positive disease.
pCR was achieved in 11 patients overall (28%), including in 8 (42%) of 19 with triple-negative disease and 3 (14%) of 21 with HR-positive disease. pEGFR (P = .05) and COX-2 expression (P = .05) were associated with increased likelihood of pCR.
During treatment with panitumumab, nab-paclitaxel, and carboplatin, 10 patients (25%) were hospitalized for treatment-related toxic effects, including 5 with neutropenia-related events. The most common nonhematologic adverse event was skin rash. No treatment-related deaths were reported.
The investigators concluded, “This combination of panitumumab and chemotherapy showed the highest pCR rate ever reported in triple-negative [inflammatory breast cancer]. A randomized phase II study is ongoing to determine the role of panitumumab in patients with triple-negative [inflammatory breast cancer] and to further validate predictive biomarkers.”
The study was supported by a grant from the National Institutes of Health, Breast Cancer Research Foundation, Amgen, Celgene, and National Cancer Institute grants.
Naoto T. Ueno, MD, PhD, of Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, is the corresponding author for the JAMA Oncology article.
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