A phase III study of rovalpituzumab tesirine maintenance therapy following first-line platinum-based chemotherapy in patients with extensive disease small cell lung cancer (ED SCLC).

TPS8583Background: SCLC embodies 15-20% of lung cancers. Patients (pts) are staged with either limited or extensive disease; the standard front-line treatment for the latter is chemotherapy with carbo- or cisplatin combined with etoposide or irinotecan. Response rates are high with limited duration. Recurrence may be attributable to chemo-resistant tumor initiating cells (TICs). Delta-like protein 3 (DLL3) is an inhibitory Notch receptor ligand identified as a novel target in SCLC TICs. DLL3 is highly expressed in SCLC but not normal tissue. Rovalpituzumab tesirine (Rova-T) is an antibody-drug conjugate composed of a DLL3-targeting IgG1 monoclonal antibody tethered to a DNA cross-linking toxin. Rova-T has shown activity in recurrent/relapsed ED SCLC patients (Rudin et al., Lancet Oncol, 2016). Given DLL3 expression in TICs, exploration of Rova-T front-line maintenance strategies in ED SCLC is warranted. The postulated mechanism of action of Rova-T and its clinical activity indicate potential to improve pr...