Phase II trial of huN901-DM1 in patients with relapsed small cell lung cancer (SCLC) and CD56-positive small cell carcinoma

18084 Background: HuN901-DM1, a humanized antibody-maytansinoid immunoconjugagte, binds to CD56 which is expressed in almost all cases of SCLC as well as in other small cell carcinomas (SCC), neuroendocrine carcinomas, and multiple myeloma. The immunoconjugate binds to its target antigen, is internalized, then releases DM1. Methods: Patients with relapsed SCLC and CD56- positive SCC of other sites are treated with huN901-DM1 given as an intravenous infusion at 60 mg/m2/week for four consecutive weeks every six weeks. The study consists of two stages. Fourteen patients were initially enrolled. The occurrence of an objective response among the initial 14 patients prompted expansion to a total of 35 evaluable patients. Clinical response is evaluated by RECIST criteria. Results: To date, thirty patients have been treated in the study. Four patients experienced drug related serious adverse events (SAEs). Three patients had severe headache after the initial infusion of study drug. Symptoms markedly improved aft...