Treatment with sacituzumab govitecan induced objective responses and appeared tolerable in patients with metastatic non–small cell lung cancer who had received first-line platinum-based therapy, according to the results from an expansion cohort of a phase 1/2 study presented at the ASCO Annual Meeting.
“This therapy showed efficacy for squamous and non-squamous patients as well as for patients with prior PD-1/PD-L1 therapy,” D. Ross Camidge, MD, PhD, professor in the division of medical oncology and Joyce Zeff chair in lung cancer research at University of Colorado Anschutz Medical Campus, said during a presentation.
Sacituzumab govitecan (IMMU-132, Immunomedics) is an antibody drug conjugate comprised of SN-38 — the active metabolite of irinotecan, a topoisomerase inhibitor — conjugated to an anti–Trop-2 humanized monoclonal antibody.
Trop-2 expression is greater than 80% in most epithelial cancers, including NSCLC.
Camidge and colleagues evaluated the efficacy and safety of sacituzumab govitecan in 34 patients (median age, 62.5 years; men, n = 21) with metastatic NSCLC who had received first-line therapy and were enrolled in an expansion cohort of a phase 1/phase 2 clinical trial.
Most patients (n = 29) had an ECOG performance status score of 1, whereas four had a score of 0 and one had an unknown score. Patients had received a median of three prior lines of chemotherapy (range, 1-7).
All patients received sacituzumab govitecan on days 1 and 8 of a 21-day treatment cycle and underwent tolerance assessments weekly and progression assessments every 8 weeks.
Researchers assigned sacituzumab govitecan in 8-mg/kg (n = 9) or 10-mg/kg (n = 25) doses.
Objective response rate — which included confirmed and unconfirmed responses — was 31% for both dosage groups, 37% for the 8-mg/kg group, and 29% for the 10-mg/kg group.
Thirty-five percent of patients experienced a clinical benefit — defined as a partial response plus stable disease for at least 6 months — at a rate of 50% in the 8-mg/kg arm and 33% in the 10-mg/kg arm.
Median PFS was 3.9 months in the total population, 4.2 months in the 8-mg/kg arm and 3.8 months in the 10-mg/kg arm.
Median OS was not reached in the total study population or either dosage subgroup.
Twenty-four patients have experienced an adverse event. The most common grade three or worse drug-related adverse events included diarrhea (8%) and neutropenia (8%).
No patient developed antibodies, detected via enzyme-linked immunosorbent assay, to the antibody or the drug.
“This therapy has several options to its parent therapy,” Camidge said during a presentation. “Those advantages appear to included enhanced response and reduced toxicity, but further research is required to evaluated safety and efficacy of IMMU-132.”– by Nick Andrews
Camidge DR, et al. Abstract 9011. Presented at: ASCO Annual Meeting; June 3-7, 2016; Chicago.
Camidge reports no relevant financial disclosures. Other researchers report honoraria and research funding from, as well as consultant/advisory roles and employment with, Immunomedics. Please see the abstract for a list of all other researchers’ relevant financial disclosures.