This week, Daiichi Sankyo and Merck shared promising results from the ongoing IDeate-Lung01 phase 2 trial of ifinatamab deruxtecan in extensive-stage small cell lung cancer (ES-SCLC).
The trial reported an objective response rate of 54.8% in the 12 mg/kg cohort, compared to 26.1% in the 8 mg/kg cohort. The median overall survival was 11.8 months for the higher dose and 9.4 months for the lower dose. Also, intracranial responses were observed in patients with brain lesions and based on these findings, the 12 mg/kg dose was selected for the expansion phase of the trial.
Ifinatamab deruxtecan is a B7-H3-directed antibody-drug conjugate (ADC) that works by binding to the B7-H3 protein, commonly overexpressed in cancer cells. Once bound, the drug is internalized into the cancer cell, where it releases a potent chemotherapy agent, causing targeted DNA damage and leading to cancer cell death. This mechanism allows for a more precise attack on cancer cells while sparing healthy tissues.
Last month, Daiichi Sankyo and Merck announced the expansion of their ADC partnership to co-develop and co-commercialize Merck’s investigational T-cell engager, MK-6070, which targets the DLL3 protein. This partnership builds on an earlier $22 billion deal to develop ADC drug candidates like patritumab deruxtecan, ifinatamab deruxtecan, and raludotatug deruxtecan.
MK-6070, currently in phase 1/2 trials, is being studied for small cell lung cancer (SCLC) and neuroendocrine tumors. The companies will also explore combining MK-6070 with Daiichi Sankyo’s ifinatamab deruxtecan for certain SCLC patients. As part of this expanded collaboration, Merck will receive $170 million upfront, with both companies sharing development costs and profits, except in Japan, where Daiichi Sankyo will receive royalties.