Gilead’s Trodelvy Faces Another Setback in Breast Cancer Trial

Gilead Sciences’ cancer drug Trodelvy—once seen as a cornerstone of the company’s $21 billion Immunomedics acquisition—has encountered another obstacle in its clinical journey.

The treatment, which targets TROP-2 and has shown promise in multiple cancer settings, failed to meet its primary endpoint in the phase 3 ASCENT-07 trial. The study evaluated Trodelvy as a first-line therapy for patients with HR+/HER2-negative metastatic breast cancer, comparing it with physician’s choice chemotherapy. Gilead reported that Trodelvy did not significantly improve progression-free survival (PFS) compared with chemotherapy.

While the primary goal was missed, Gilead noted a favorable early trend in overall survival (OS) for patients receiving Trodelvy. However, the company emphasized that the OS data are still immature and will continue to be monitored.

The global trial included 654 participants with locally advanced or inoperable HR+/HER2-negative metastatic breast cancer who had already undergone endocrine therapy. Participants were randomized 2-to-1 in favor of Trodelvy, while the control group received various chemotherapy regimens.

Dr. Hope Rugo, director of the Women’s Cancer Program at City of Hope and principal investigator of the trial, highlighted the complexity of this patient group, explaining that HR+/HER2-negative metastatic breast cancer is highly heterogeneous and difficult to treat, especially for those whose disease has progressed through several endocrine therapies.

This outcome marks another clinical setback for Trodelvy, following previous disappointments in bladder cancer and non-small cell lung cancer (NSCLC) studies. Gilead had to withdraw an earlier accelerated approval in bladder cancer after a confirmatory trial failed, and a separate NSCLC trial miss led to a $2.4 billion impairment charge.

Still, not all news has been negative. In 2025, Trodelvy achieved success in the ASCENT-03 study, demonstrating extended survival for certain patients with previously untreated metastatic triple-negative breast cancer (TNBC) who were not eligible for immunotherapy.

Despite mixed clinical results, Gilead continues to view Trodelvy as a potential blockbuster and key component of its oncology portfolio, maintaining optimism for its long-term role in cancer treatment.