The Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to patritumab deruxtecan (HER3-DXd) for the treatment of patients with metastatic or locally advanced EGFR-mutated non-small cell lung cancer (NSCLC) with disease progression on or after treatment with a third-generation tyrosine kinase inhibitor (TKI) and platinum-based therapies.

Patritumab deruxtecan is a potential first-in-class HER3-directed antibody drug conjugate. The investigational treatment consists of a fully human anti-HER3 IgG1 monoclonal antibody attached to a topoisomerase I inhibitor payload (an exatecan derivative, DXd) via a stable tetrapeptide-based cleavable linker.

The designation was based on data from the dose escalation portion and 2 expansion cohorts of a 3-cohort phase 1 study ( Identifier: NCT04676477) of patritumab deruxtecan. Preliminary evidence showed that treatment with patritumab deruxtecan had a clinically meaningful and durable tumor response in patients with locally advanced or metastatic TKI-resistant, EGFR-mutated NSCLC.

“The Breakthrough Therapy Designation for patritumab deruxtecan acknowledges the need for new treatment approaches to overcome resistance and improve survival in patients with metastatic TKI-resistant, EGFR-mutated non-small cell lung cancer,” said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. “We are proud that the FDA has once again recognized our innovative science and technology and we look forward to bringing this potential first-in-class HER3 directed antibody drug conjugate to patients with this specific type of lung cancer as quickly as possible.”


  1. Patritumab deruxtecan granted US FDA Breakthrough Therapy designation in patients with metastatic EGFR-mutated non-small cell lung cancer. News release. Daiichi Sankyo Company, Limited. December 23, 2021. Accessed December 27, 2021. 
  2. Patritumab deruxtecan data at ASCO demonstrates tumor response across multiple resistance mechanisms in patients with advanced EGFR-mutated NSCLC. News release. Daiichi Sankyo Company, Limited. June 4, 2021. Accessed December 27, 2021.