On December 16, 2020, the FDA granted approval to margetuximab-cmkb (Margenza, MacroGenics) in combination with chemotherapy for the treatment of adult patients with metastatic HER2-positive breast cancer who received ≥2 prior anti-HER2 regimens.
This approval is based on efficacy results from the randomized, multicenter, open-label SOPHIA trial. A total of 536 patients with metastatic breast cancer were enrolled in the trial and randomized 1:1 to receive margetuximab plus chemotherapy or trastuzumab plus chemotherapy.
The main efficacy outcome measures were progression-free survival (PFS) and overall survival (OS). Additional measures were objective response rate (ORR) and duration of response (DOR).
Median PFS was 5.8 months (95% CI: 5.5, 7.0) in the margetuximab arm versus 4.9 months in the control arm (HR 0.76; 95% CI: 0.59, 0.98; P = .033).
Additionally, ORR was 22% (95% CI: 17, 27) in the margetuximab arm compared to 16% (95% CI: 12, 20)) in the control arm. Median DOR was 6.1 months (95% CI: 4.1, 9.1) and 6 months (95% CI: 4.0, 6.9), respectively.
The most common adverse events (>10%) associated with margetuximab plus chemotherapy are fatigue/asthenia, nausea, diarrhea, vomiting, constipation, headache, pyrexia, alopecia, abdominal pain, peripheral neuropathy, arthralgia/myalgia, cough, decreased appetite, dyspnea, infusion-related reactions, palmar-plantar erythrodysesthesia, and extremity pain.—Janelle Bradley
Source: US Food and Drug Administration. FDA approves margetuximab for metastatic HER2-positive breast cancer. December 16, 2020. https://www.fda.gov/drugs/drug-approvals-and-databases/fda-approves-margetuximab-metastatic-her2-positive-breast-cancer. Accessed December 17, 2020