By Fineline Cube 
Partners Merck, Sharp & Dohme (MSD; NYSE: MRK) and Daiichi Sankyo (TYO: 4568) announced the voluntary withdrawal of the marketing filing in the US for their HER3-directed antibody-drug conjugate (ADC) patritumab deruxtecan. The decision affects the treatment of locally advanced or metastatic EGFR-mutated non-small cell lung cancer (NSCLC) in patients previously treated with two or more systemic therapies. The filing was initially supported by results from the Phase II HERTHENA-Lung01 trial.
Background and Clinical Trial Results
The move follows the failure of the confirmatory Phase III HERTHENA-Lung02 trial to meet its overall survival (OS) endpoint. The trial evaluated patritumab deruxtecan monotherapy versus doublet chemotherapy, consisting of platinum plus pemetrexed induction chemotherapy followed by pemetrexed maintenance chemotherapy, in patients with EGFR-mutated (exon 19 deletion or L858R mutated) advanced NSCLC after disease progression with a third-generation EGFR tyrosine kinase inhibitor (TKI) treatment. The decision to withdraw the filing was made following discussions with the US Food and Drug Administration (FDA).
Company Statements and Future Plans
“EGFR-mutated non-small cell lung cancer has proven to be difficult-to-treat in the second-line metastatic setting and beyond,” said Ken Takeshita, MD, global head of R&D at Daiichi Sankyo. “While we are disappointed with the overall survival results of HERTHENA-Lung02, we are conducting further biomarker analyses to better identify patients that may benefit from patritumab deruxtecan to guide our continued development in lung cancer. We remain confident in the broad development program of this HER3-directed antibody-drug conjugate, which currently includes multiple clinical trials across 15 types of cancer.”-Fineline Info & Tech