Part 1A is a dose escalation study in patients with small cell lung cancer or large cell neuroendocrine carcinoma with cytologically confirmed, limited or extensive SCLC or LCNEC that have relapsed or refractory limited or extensive disease following no more than 2 prior chemotherapy regimens.
Part 1B is an expansion study where patients will be enrolled and treated in order to further characterize safety and preliminary efficacy in patients with SCLC or LCNEC and further characterize PK, immunogenicity and target expression and possible relationship to clinical outcome.