On April 5, the FDA granted accelerated approval to AstraZeneca and Daiichi Sankyo’s ENHERTU (trastuzumab deruxtecan) for adult patients with unresectable or metastatic HER2-positive (IHC3+) solid tumors who have received prior systemic treatment and have no satisfactory alternative treatment options. ENHERTU, which is now FDA-approved for five indications, is a specifically engineered HER2-directed antibody drug conjugate (“ADC”) discovered by Daiichi Sankyo and jointly developed and commercialized with AstraZeneca. This is the first tumor-agnostic approval of a HER2-directed therapy and ADC by the FDA.

The U.S. regulatory submission for ENHERTU was reviewed under the Real-Time Oncology Review (“RTOR”) program and Project Orbis, two initiatives of the FDA which are designed to bring safe and effective cancer treatments to patients as early as possible. RTOR allows the FDA to review components of an application before submission of the complete application. Project Orbis provides a framework for concurrent submission and review of oncology medicines among participating international partners. As part of Project Orbis, ENHERTU is also under review for the same indication by regulatory authorities in Australia, Brazil, and Singapore.

This approval follows AstraZeneca and Daiichi Sankyo’s recent victory at the PTAB, where they successfully invalidated several claims of Seagen’s U.S. Patent No. 10,808,039, which Seagen had previously asserted over ENHERTU in federal district court.

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