AstraZeneca (LON:AZN) and Daiichi Sankyo’s (OTCMKTS:DSNKY) Enhertu (fam-trastuzumab deruxtecan-nxki) showed a dramatic survival benefit in the pivotal DESTINY-Breast04 Phase 3 study focused on a subset of breast cancer patients. The DNA topoisomerase I inhibitor improved median overall survival by more than six months compared to chemotherapy in the study. In addition, the drug met the primary endpoint of progression-free survival in the study, cutting the risk of disease progression or death by 49% compared to chemotherapy.
AstraZeneca reports that the therapy could potentially redefine treatment for roughly half of breast cancer patients.
The DESTINY-Breast04 study focused on previously-treated patients with HER2-low unresectable or metastatic breast cancer.
AstraZeneca notes that Enhertu is the first HER2-focused therapy to show a survival benefit in the patient demographic.
Enhertu met the primary endpoint of progression-free survival in patients with HR-positive disease, reducing the risk of disease progression or death by 49% compared to chemotherapy.
Enhertu is the first HER2-directed therapy to demonstrate a survival benefit in this population, potentially redefining treatment for approximately half of all patients with breast cancer.
“The results of DESTINY-Breast04 show for the first time that a HER2-directed therapy can provide a survival benefit to patients with low HER2 expression, indicating we must reconsider the way we categorize patients with metastatic breast cancer,” said Dr. Shanu Modi, medical oncologist, Memorial Sloan Kettering Cancer Center and principal investigator of the study. “The efficacy seen with Enhertu also reinforces the potential to establish a new standard of care for more than half of all patients with breast cancer currently categorized as having HER2-negative disease, but who actually have tumors with low HER2 expression.”
In 2021, Enhertu drove $214 million in revenue for AstraZeneca.
In January, FDA granted Enhertu priority review for HER2-positive positive metastatic breast cancer.
In April, Enhertu (trastuzumab deruxtecan) won its fifth breakthrough therapy designation from the FDA.