Key clinical point: Margetuximab + chemotherapy vs. trastuzumab + chemotherapy improved progression-free survival (PFS) with an acceptable safety profile in patients with ERBB2-positive advanced breast cancer (ERBB2+ ABC) who progressed on 2 or more prior anti-ERBB2 therapies.
Major finding: Margetuximab + chemotherapy prolonged PFS with a 24% relative risk reduction vs. trastuzumab + chemotherapy (median PFS, 5.8 vs. 4.9 months; hazard ratio, 0.76; P = .03). Safety was comparable between the groups. Infusion-related reactions were higher with margetuximab vs. trastuzumab (13.3% vs. 3.4%; P less than .001) but were mostly prevalent at cycle 1 and resolved within 24 hours.
Study details : Findings are from the phase 3 SOPHIA trial including 536 patients with ERBB2+ ABC who had progressive disease after 2 or more prior anti-ERBB2 therapies. Patients were randomly allocated to receive either margetuximab + chemotherapy (n = 266) or trastuzumab + chemotherapy (n = 270).
Disclosures: This study was supported by MacroGenics, Inc. The lead author reported ties with MacroGenics, Roche, Pfizer, Novartis, Lilly, Merck, Seattle Genetics, Odonate Therapeutics, Eisai, Sermonix Pharmaceuticals, Immunomedics, Daiichi Sankyo, Puma, and Samsung. Other investigators reported owning stocks of, being an employee of, receiving support from, and/or consulting for various pharmaceutical companies including MacroGenics.
Source: Rugo HS et al. JAMA Oncol. 2021 Jan 22. doi: 10.1001/jamaoncol.2020.7932 .