Enhertu Treatment for HER2-Positive Breast Cancer Shows Positive Results From Phase 3 Trial

Nearly 94.1% of individuals treated with the drug in the DESTINY-Breast03 study were still alive at the 1-year mark, according to a statement from AstraZeneca.

Positive results from the DESTINY-Breast03 phase 3 trial showed that Enhertu (trastuzumab deruxtecan), the HER2-directed antibody drug conjugate (ADC) from AstraZeneca and Daiichi Sankyo Company, Limited demonstrated a higher progression-free survival (PFS) rate versus trastuzumab emtansine (T-DM1), according to a statement from AstraZeneca.

“The early survival data, which evaluated Enhertu against another HER2-directed ADC, showed that nearly all patients treated with Enhertu were alive after a year and is a positive indication of the potential of this medicine to transform the treatment of HER2-positive metastatic breast cancer” Ken Takeshita, global head of research and development at Daiichi Sankyo, said in the statement.

Nearly 94.1% of individuals treated with Enhertu were still alive at the 1-year mark compared with 85.9% of individuals treated with T-DM1.

At the interim analysis, Enhertu had a 72% reduction in the risk of death or disease progression compared with T-DM1. At the 15.5- and 13.9-month marks of both the Enhertu and T-DM1 groups, the median PFS rate for individuals treated with Enhertu had not been reached compared with the 6.8 months for the T-DM1 group.

In the secondary endpoint of PFS, individuals treated with Enhertu had a3-fold improvement of 25.1 months compared with 7.2 months for T-DM1.

There was also a strong improvement toward the overall survival with Enhertu.

However, investigators noted in the statement that the analysis was not yet mature and is not statistically significant.

“These landmark data will form the basis of our discussions with global health authorities to potentially bring Enhertu to patients with previously treated HER2-positive metastatic breast cancer as a more effective treatment option as soon as possible,” Takeshita said.

The results were presented in a Presidential Symposium at the European Society for Medical Oncology Congress 2021.

Reference

Enhertu reduced the risk of disease progression or death by 72% vs. trastuzumab emtansine (T-DM1) in patients with HER2-positive metastatic breast cancer. AstraZeneca. News release. September 18, 2021. Accessed September 20, 2021. https://www.astrazeneca.com/media-centre/press-releases/2021/enhertu-reduced-the-risk-of-disease-progression-or-death-by-72-vs-trastuzumab-emtansine-t-dm1-in-patients-with-her2-positive-metastatic-breast-cancer.html