The FDA has granted expanded approval for Gilead Sciences’ Trodelvy (sacituzumab govitecan-hziy) for patients with HR-positive/HER2-negative metastatic breast cancer who have received hormonal therapy and at least two additional therapies in the metastatic setting.
The drug is expected to become a standard of care for these patients, who have had limited treatment options, according to analysts GlobalData.
Trodelvy has been marketed for triple-negative breast cancer since 2021. Sales of the drug rose 79% from $380 million in 2021 to $680 million in 2022. GlobalData’s forecasts project sales to reach 2.8 billion by 2028.
Israel Stern, Oncology & Hematology Analyst at GlobalData, commented: “Patients with HR+/HER2- metastatic breast cancer who are treated with hormone therapy and chemotherapy often develop resistance to these treatments. Trodelvy, an antibody-drug conjugate (ADC) that targets the Trop-2 protein found on the surface of most breast cancer cells, presents a statistically significant improvement in overall survival compared to retreating with chemotherapy.”
In the Phase lll TROPiCS-02 study, Trodelvy showed a superior overall survival (OS) of 3.2 months, as well as a higher median progression-free survival (PFS) compared to those who were treated with chemotherapy.
Competition from another ADC
Stern added: “A challenge for Trodelvy’s market penetration is the approval of AstraZeneca and Daiichi Sankyo’s ADC Enhertu for HER2-low metastatic breast cancer in 2022. The majority of HER2-negative patients display some HER2 expression making them good candidates for Enhertu. Aside from being first-to-market, Enhertu may be more active than Trodelvy and reported impressive results in both OS (median 23.4 months) and PFS in a comparable trial of patients who received prior lines of chemotherapy.”
Although the two drugs target different receptors on the cancer cells, they share a TOP1 inhibitor aimed at interrupting DNA replication resulting in cell death. If a patient develops resistance to one of the drugs due to antigen loss, they may be eligible to receive the other treatment in succession.