Targeting Trop-2 in Advanced Non–Small Cell Lung Cancer
Based on a single-arm multicenter trial, the antibody-drug conjugate sacituzumab govitecan (IMMU-132) produced responses in patients with pretreated metastatic non–small cell lung cancer. Sacituzumab targets Trop-2, which is expressed in most solid cancers, and govitecan is the active metabolite of irinotecan. These study findings were reported by Rebecca Suk Heist, MD, MPH, of the Department of Thoracic Oncology, Massachusetts General Hospital, Boston, and colleagues in the Journal of Clinical Oncology.
Of the 47 evaluable patients, partial responses to IMMU-132 were reported in 9 patients (19%), with a median duration of response of 6 months. In addition, 11 patients had stable disease for at least 4 months. These responses yielded a clinical benefit rate of 43%.
Furthermore, the level of Trop-2 expression did not appear to be a biomarker of response. More than 90% of the 26 evaluable archived tumor specimens were strongly or moderately positive for Trop-2 on immunohistochemistry.
As for toxicity, grade ≥ 3 adverse events included neutropenia (28%), leukopenia (9%), pneumonia (9%), diarrhea (7%), nausea (7%), fatigue (6%), and febrile neutropenia (4%). The incidence of adverse events seemed to be similar at the two doses evaluated (8 and 10 mg/kg), although there was an increase in grade 3 or 4 neutropenia at the higher dose.