FDA grants accelerated approval for Enhertu to treat unresectable or metastatic HER2-positive breast cancer. Daiichi Sankyo + AstraZeneca

AstraZeneca and Daiichi Sankyo Company, Limited announced that the FDA has approved Enhertu (fam-trastuzumab deruxtecan-nxki) for the treatment of adult patients with unresectable or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 based regimens in the metastatic setting.This indication is approved under Accelerated Approval based on tumour response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial

Enhertu is a HER2-directed antibody-drug conjugate (ADC) and the FDA approval is based on the results of the registrational Phase II trial DESTINY-Breast01 of Enhertu (5.4mg/kg) monotherapy in patients with HER2-positive metastatic breast cancer. All patients received prior trastuzumab, trastuzumab emtansine and 66% had prior pertuzumab. The Phase II trial results showed a confirmed objective response rate of 60.3% (n=111, 95% CI 52.9-67.4) including a 4.3% complete response rate (n=8) and a 56.0% partial response rate (n=103). A median duration of response of 14.8 months (95% CI 13.8-16.9) was demonstrated as of 1 August 2019. In addition, a median progression-free survival of 16.4 months (95% CI 12.7-not estimable), based upon a median duration of follow up of 11.1 months, was recently presented at the San Antonio Breast Cancer Symposium and published online in The New England Journal of Medicine.