Gilead Sciences (Nasdaq: GILD) announced that the European Commission has granted marketing authorization for Trodelvy (sacituzumab govitecan-hziy) as a monotherapy for adult patients with unresectable or metastatic triple-negative breast cancer (TNBC) who have not received prior systemic therapy for metastatic disease and are not candidates for PD-1 or PD-L1 inhibitor therapy.

The approval covers the European Union's 27 member states, as well as Norway, Iceland and Liechtenstein. According to Gilead, Trodelvy is the first antibody-drug conjugate (ADC) to receive approval in first-line metastatic TNBC in these markets.

The authorization is based on data from the Phase 3 ASCENT-03 study, which showed a 38% reduced risk of disease progression or death in patients who are not candidates for PD-1/PD-L1 inhibitors when treated with Trodelvy compared to standard chemotherapy. The study used a crossover design that allowed patients in the chemotherapy arm to receive Trodelvy after disease progression.

Gilead has also submitted a supplemental filing to the European Medicines Agency for Trodelvy in combination with Keytruda (pembrolizumab) for patients with PD-L1 positive unresectable locally advanced or metastatic TNBC, based on data from the Phase 3 ASCENT-04 study. That application is currently under review.

In the United States, Gilead has submitted supplemental filings to the Food and Drug Administration for Trodelvy as a first-line treatment for metastatic TNBC, both as a single agent and in combination with Keytruda or Keytruda Qlex. Those applications remain pending.

TNBC accounts for approximately 15% of all breast cancers. The five-year survival rate for women with metastatic TNBC is 12%, compared with 28% for other types of metastatic breast cancer, according to the press release.

Trodelvy carries a boxed warning for severe neutropenia and diarrhea. More than 75,000 breast cancer patients have been treated with Trodelvy since 2020, according to Gilead.