Gilead Sciences’ breast cancer drug receives US FDA approval for third indication

Trodelvy, an antibody–drug conjugate with indications against certain types of cancer, has been approved by the US FDA for a third indication against pre-treated HR+/HER2- metastatic breast cancer.

Metastatic HER2-low tumours, which account for approximately 50–60% of all breast cancers, are those whose cells contain lower levels of HER2 proteins on the cell surface. This type of breast cancer has historically been difficult to treat, and almost one-third of early-stage breast cancer cases eventually become metastatic. Patients with HER2-low/negative metastatic disease present a 5-year survival rate of only 30%. Primary treatment options include endocrine-based therapies but once the cancer is resistant to these therapies, treatment options become limited to single-agent chemotherapies, though the prognosis continues to remain poor. In a study termed the TROPiCS-02 study, Trodelvy demonstrated a survival benefit of 3.2 months versus single-agent chemotherapy that was statistically significant and clinically meaningful. A 34% reduction of disease progression risk or death was also established by researchers. 

Hope Rugo, professor of medicine and Director, Breast Oncology and Clinical Trials Education at the UCSF Helen Diller Family Comprehensive Cancer Center, stated: “Despite decades of advances, people living with pre-treated HR+/HER2- metastatic breast cancer need new treatment options. Nearly all people with this type of breast cancer will eventually develop resistance to endocrine-based therapies and progress on available chemotherapies...This approval is significant for the breast cancer community. We have had limited options to offer patients after endocrine-based therapy and chemotherapy, and to see a clinically meaningful survival benefit of more than 3 months with a quality-of-life benefit for these women is exceptional.” 

Trodelvy, an antibody–drug conjugate, operates by targeting cell surface antigens known as Trop-2 on cancer cells. In the US, it is currently approved for the treatment of inoperable localised or metastatic triple-negative breast cancer and locally advanced or metastatic urothelial cancer in adults who have received prior treatments. Further developments are examining potential investigational use in other metastatic cancer populations and a range of tumour types where Trop-2 is highly expressed. These include metastatic small cell lung cancer, head and neck cancer, and endometrial cancer. 

Chairman and CEO of Gilead Sciences Daniel O’Day added: “We are pleased that Trodelvy [can] now provide new hope for people living with pre-treated HR+/HER2- metastatic breast cancer, building on the transformative role that Trodelvy is already playing for people with metastatic triple-negative breast cancer.” 

Sources:  

1. U.S. FDA Approves Trodelvy® in Pre-treated HR+/HER2- Metastatic Breast Cancer (gilead.com) 

2. Gilead's breast cancer drug gets U.S. FDA approval for third indication | Reuters 

3. Trastuzumab Deruxtecan for Metastatic HER2-Low Breast Cancer - NCI