The U.S. FDA has issued a complete response letter for the BLA for Daiichi Sankyo and Merck & Co.'s jointly developed antibody-drug conjugate, patritumab deruxtecan (HER3-DXd).
The partners sought accelerated approval for the treatment of adult patients with locally advanced or metastatic EGFR-mutated non-small cell lung cancer (NSCLC) who have been previously treated with two or more systemic therapies. The CRL was given in response to findings from an inspection of a third-party manufacturing facility, with no issues identified concerning the efficacy or safety data.
Patritumab deruxtecan is a HER3-directed DXd antibody-drug conjugate (ADC) designed to target and treat EGFR-mutated NSCLC. The drug was developed using Daiichi Sankyo’s proprietary DXd ADC technology. The investigational therapy has shown promise in clinical trials, including the HERTHENA-Lung01 phase 2 trial, which demonstrated an objective response rate of 29.8% in 225 patients with advanced NSCLC. The median duration of response was recorded at 6.4 months.
The safety profile observed in the HERTHENA-Lung01 trial was consistent with earlier phase 1 trials. The trial's primary endpoint was ORR, with secondary endpoints including duration of response, progression-free survival, and overall survival.
In 2023, Merck paid Daiichi Sankyo $4 billion upfront in addition to $1.5 billion in continuation payments and potential additional payments of up to $16.5 billion to jointly develop and potentially commercialize three ADC candidates worldwide (ex-Japan) — patritumab deruxtecan (HER3-DXd), ifinatamab deruxtecan (I-DXd), and raludotatug deruxtecan (R-DXd). Ifinatamab deruxtecan is being evaluated as a monotherapy for small cell lung cancer, and raludotatug deruxtecan is in a phase 1 clinical trial for advanced ovarian cancer.
Today’s ADCs market remains busy, with big-ticket deals dominating the headlines and a market poised to reach over $13 billion by 2026.
