Dr. Rugo on the Benefit of Margetuximab Plus Chemotherapy in HER2+ Metastatic Breast Cancer

Hope S. Rugo, MD, a professor in the Department of Medicine (Hematology/Oncology) and director of Breast Oncology and Clinical Trials Education at University of California San Francisco Helen Diller Family Comprehensive Cancer Center, discusses the benefit of margetuximab-cmkb (Margenza) in patients with HER2-positive breast cancer who have received prior HER2-targeted therapies.

In the phase 3 SOPHIA trial (NCT02492711), patients were randomized to receive either margetuximab or trastuzumab (Herceptin) in combination with a variety of chemotherapy agents, according to Rugo. Patients who received margetuximab experienced a statistically significant progression-free survival benefit (PFS) benefit, which was the primary end point of the trial.

However, it's not clear how clinically meaningful the PFS difference is between the 2 arms, Rugo says. In the investigator-assessed PFS end point, with a cutoff of September 2019, the absolute PFS benefit of margetuximab over trastuzumab was under 2 months, Rugo notes. As the hazard ratio was 0.71 and the P value was .0006, it's a highly statistically significant outcome, although this may not be readily apparent if one is examining the differences in median PFS, Rugo concludes.

The combination of margetuximab plus chemotherapy was approved by the FDA in December 2020 based on the results from SOPHIA.