Gilead’s New Chemotherapy for Metastatic Breast Cancer Demonstrates Increase in Overall Survival

On August 15, Gilead Sciences announced meaningful results from their second analysis of the overall survival of Trodelvy® (sacituzumab govitecan-hziy). Trodelvy treats patients with a specific type of metastatic breast cancer. As a result, Gilead submitted a supplemental Biologics License Application (sBLA) to the U.S. Food & Drug Administration (FDA).

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HR+/HER2- Metastatic Breast Cancer and its Treatment

Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) is the most common breast cancer, accounting for 70% of new cases. The HR+ specific subtype means that the cancer cells have receptors for estrogen or progesterone. These hormones stimulate the growth of the tumors. HER2 indicates the tumor cells’ high production of a protein called HER2/neu. This protein is associated with aggressive types of breast cancer. However, the negative typing means that this production is not present.

About one in three new cases of HR+/HER2- spreads to other parts of the body, becoming metastatic. Currently, the five-year survival rate of patients with metastasized HR+/HER2- is about 30%.

Current HR+/HER2- breast cancer treatments include enzyme inhibitors like Piqray® (alpelisib). Developed by Novartis and approved by the FDA in 2019, Piqray inhibits an enzyme involved in the production of proteins. 

Trodelvy works differently than an inhibitor by directly targeting the cancer cells. Known as an antibody-drug conjugate, Trodelvy delivers chemotherapy to the cancer cells, preventing their spread. 

The TROPiCS-02 Study Shows Increased Longevity in Patients

The TROPiCS-02 study is a global, multicenter, open-label, Phase 3 study evaluating Trodelvy. The study compared Trodelvy to other chemotherapies, including eribulin, capecitabine, gemcitabine, or vinorelbine. The subject of the study was 543 patients with HR+/HER2- metastatic breast cancer previously treated with endocrine therapy. 

The study’s primary endpoint was progression-free survival per Response Evaluation Criteria in Solid Tumors. One of the study’s secondary endpoints examined overall survival in patients treated with Trodelvy. 

Positive primary results of the TROPiCS-02 study shown at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting resulted in the Treatment’s preferred recommendation for HR+/HER2- patients. Another analysis conducted on the secondary endpoint for overall survival proved consistent with prior studies.

Merdad Parsey, MD, Ph.D., Chief Medical Officer at Gilead Sciences, said, “These survival results from the TROPiCS-02 study are important for the breast cancer community, and we are encouraged by the potential this may have in helping patients who otherwise have limited alternatives.”

Based on the results of this study, Gilead Sciences submitted sBLA to the FDA. Should the FDA approve the supplemental application, they will be the first administrative body to approve Trodelvy for Treatment of HR+/HER2- breast cancer patients.

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Author

Max Heirich