Merck (MRK.US) and Daiichi Sankyo's potential "first-in-class" ADC therapy results announced

Merck (MRK.US) recently announced positive interim results from the dose optimization portion of its ongoing IDeate-Lung01 Phase 2 clinical trial. Analysis showed that ifinatamab deruxtecan (I-DXd), a potential "first-in-class" B7-H3-targeting antibody-drug conjugate (ADC) co-developed with Daiichi Sankyo, achieved a disease control rate (DCR) of 90.5% and an objective response rate (ORR) of 54.8% in patients with extensive-stage small cell lung cancer (ES-SCLC) who had received prior treatment. Detailed data were presented at the 2024 World Conference on Lung Cancer (WCLC24). The related Phase 3 trial, IDeate-Lung02, has been initiated and the first patient was dosed last month. IDeate-Lung01 is a global, multicenter, randomized, open-label Phase 2 trial in two parts designed to assess the safety and efficacy of ifinatamab deruxtecan in patients with ES-SCLC. In the first part (dose optimization), patients who had received at least one line of platinum-based chemotherapy and up to three lines of therapy were enrolled. In the second part (extension), patients who had received at least two lines of systemic therapy were enrolled. In the first part, patients were randomized 1:1 to receive either 8 mg/kg or 12 mg/kg of ifinatamab deruxtecan. In the second part, patients received the recommended expanded dose (12 mg/kg). The primary endpoint was ORR assessed by blinded independent central review (BICR). Secondary endpoints included duration of response (DoR), progression-free survival (PFS), overall survival (OS), DCR, time to response, and overall safety. Intracranial ORR assessed by BICR was an exploratory endpoint.