Merck, Daiichi pull lung cancer filing after FDA pushback deals another blow to $4B deal

Key Points:

• Daiichi Sankyo and Merck & Co. have withdrawn their accelerated approval filing for the antibody-drug conjugate ifinatamab deruxtecan (I-DXd) in extensive-stage small cell lung cancer (ES-SCLC) after the FDA determined the data were insufficient.
• The accelerated approval request was based on phase 2 data from the IDeate-Lung01 trial, which enrolled 187 previously treated ES-SCLC patients, but the FDA found the evidence did not meet their standards.
• Merck expressed disappointment but indicated they may resubmit with additional data from the nearly completed phase 3 IDeate-Lung02 trial.
• The withdrawal affects the competitive landscape, potentially benefiting Amgen’s DLL3xCD3 T-cell engager Imdelltra and GSK’s B7-H3-directed ADC risvutatug rezetecan, which showed positive phase 3 results in China.
• This setback adds to previous challenges for the Daiichi-Merck ADC partnership, which has seen prior FDA rejections and withdrawals, delaying anticipated returns on their $4 billion collaboration investment.