Study of 225Ac-ABD147 to Establish Optimal Dose in Patients With SCLC and LCNEC of the Lung That Previously Received Platinum-based Chemotherapy

This is an open-label, Phase 1a/b, first-in-human study to assess the safety profile, tolerability, biodistribution, pharmacokinetics (PK), and preliminary antitumor activity of 225Ac-ABD147 in patients with confirmed locally advanced or metastatic small cell lung cancer (SCLC) and large cell neuroendocrine carcinoma (LCNEC) of the lung. All patients must have previously received platinum-based chemotherapy. Phase 1a will determine the safety, tolerability, dosimetry, PK, and the dose of 225Ac-ABD147 for expansion in the Phase 1b portion. In addition to receiving treatment, a subset of patients in Phase 1a will undergo either 111In-ABD147-based or 225Ac-ABD147 dosimetry assessments to confirm tumor specificity, identify biodistribution, and to provide insight into dose absorption into tumor and normal tissues. Phase 1b will evaluate the safety and preliminary efficacy of 225Ac-ABD147 as based on the Phase 1a dose level for expansion by the Safety Review Committee to determine the recommended Phase 2 dose (RP2D).