In October, the FDA granted priority review for the proprietary antibody-drug conjugate trastuzumab deruxtecan (DS-8201), on the back of results from the Destiny-Breast01 trial. Now the AZ/Daiichi Sankyo partnership has announced significant results for HER2-positive metastatic breast cancer patients, who had already received two or more prior HER2-targeting therapies following positive results, from the phase 2 Destiny-Breast01 study. In patients treated with the drug as a monotherapy, who had already received a median of six prior treatments for their metastatic disease, objective response rate was 60.9%. Disease control rate was 97.3% with a median duration of response of 14.8 months, and median progression-free survival of 16.4 months.

The drug's safety profile however highlighted that it can be harmful as 13.6% of patients experienced confirmed treatment-related interstitial lung disease and the death of four patients was attributed to ILD. It is hoped that the strength of the 60.9% response in patients who have already endured various treatments will prevail over the negative side-effects.

“Very positive phase 2 Destiny-Breast01 results for the AZ/Daiichi Sankyo collaboration.“

AZ’s EVP of oncology R&D, José Baselga, said: “The clinically meaningful and durable responses seen among these patients illustrate the potential of trastuzumab deruxtecan to establish a new standard of care. These results are impressive, as women with this advanced stage of breast cancer have already endured multiple prior therapies for HER2-positive metastatic breast cancer.”