AstraZeneca, Daiichi Sankyo Win FDA Approval for Trastuzumab Antibody Conjugate

AstraZeneca and Daiichi Sankyo said Monday they received FDA approval for their [fam-] trastuzumab deruxtecan-nxki, which will be marketed as Enhertu. [Fam-] trastuzumab deruxtecan is an antibody—drug conjugate (ADC) designed to delivery cytotoxic chemotherapy to cancer cells via a human epidermal receptor 2 (HER2) antibody attached to a novel topoisomerase I inhibitor payload and a tetrapeptide-based linker.

The approval is for the treatment of adult patients with unresectable or metastatic HER2-positive breast cancer who have received 2 or more prior anti-HER2-based regimens.

The company recently presented results from its pivotal phase 2 study, DESTINY-Breast01, at the at the San Antonio Breast Cancer Symposium in San Antonio, Texas and also published in The New England Journal of Medicine.

The companies said in a statement the clearance came under Accelerated Approval based on tumor 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,” the companies said.

In DESTINY, 184 female patients with HER2-positive metastatic breast cancer received 5.4 mg/kg of Enhertu as a monotherapy; all patients previously were treated with prior trastuzumab, ado-trastuzumab emtansine, and 66% had prior pertuzumab.

The phase 2 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 August 1, 2019.

In addition, patients had 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.