A study of rovalpituzumab tesirine in frontline treatment of patients with DLL3 expressing extensive small cell lung cancer.

TPS2598 Background: Treatment and survival of SCLC patients (pts) has remained mostly unchanged over past decades with high response rates to initial therapy (cisplatin/carboplatin + etoposide), but relapse is near universal with median survival < 1 year in extensive disease. Delta-like protein 3 (DLL3) is an inhibitory ligand of the Notch receptor family identified as a novel target in high-grade neuroendocrine tumors, and is highly expressed in SCLC but not in normal tissue. Rovalpituzumab tesirine (Rova-T™) is an antibody-drug conjugate targeting DLL3. A Phase I study of Rova-T monotherapy in 2 nd and 3 rd line SCLC pts demonstrated encouraging antitumor activity with an ORR of 18% in all pts, and an ORR of 38% in DLL3-high pts (Rudin et al., Lancet Oncol, 2016.). Methods: This is a Phase I, open-label, multicenter study (NCT02819999; no pts enrolled as of 7 February 2017).In Phase Ia (escalation), 15-34 previously untreated DLL3-high pts will be enrolled and randomized to 1 of 4 cohorts. The primary objective of the Phase Ia portion is assessment of safety and dose-limiting toxicities (DLTs). Phase Ib (expansion) will enroll up to 2 cohorts of 30 pts each, and its primary objective is to characterize antitumor activity of the selected cohort(s). Secondary objectives (Phase Ia/b) include assessment of pharmacokinetics and anti-therapeutic antibodies against Rova-T, and characterization of antitumor activity (Phase Ia). Eligible pts: adults with histologically or cytologically confirmed extensive DLL3-high SCLC based on immunohistochemistry; ECOG 0-1; and life expectancy ≥ 12 weeks. Clinical trial information: NCT02819999. [Table: see text]