SOPHIA Trial: Adding Margetuximab or Trastuzumab to Chemotherapy in Breast Cancer
Posted: Thursday, July 11, 2019
The phase III SOPHIA trial compared two monoclonal antibodies—margetuximab and trastuzumab—in combination with chemotherapy in patients with HER2-positive metastatic breast cancer. Hope S. Rugo MD, of the University of California, San Francisco, and colleagues, found that the margetuximab combination therapy improved progression-free survival over the trastuzumab combination therapy. Overall survival data from this trial, which was presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 1000), are not yet mature.
A total of 756 patients with HER2-positive metastatic breast cancer were randomly assigned to treatment with margetuximab (n = 536) or trastuzumab (n = 270 patients) plus chemotherapy (standard-dose capecitabine, eribulin, gemcitabine, or vinorelbine). Patients had previously received pertuzumab and one to three lines of anti-HER2 therapies.
The group that received margetuximab had a longer progression-free survival than the group that received trastuzumab (median 5.8 vs. 4.9 months, hazard ratio = 0.76). In fact, a differential benefit in progression-free survival was noted in patients who had a 158F allele on CD16A genotyping (median 6.9 vs. 5.1 months, hazard rtio = 0.68). In addition, the objective response rate was higher with margetuximab than trastuzumab (22% vs. 16%) in the 524 patients who had measurable disease at baseline.
As for toxicity, in the 529 patients who received study therapy, safety profiles were comparable. A total of 52% of patients treated with margetuximab had grade ≥ 3 adverse events compared with 48% of those treated with trastuzumab.
Disclosure: The study authors’ disclosure information may be found at coi.asco.org.
