From OncLive: Keytruda induced an overall response rate of 33% in patients with extensive-stage small cell lung cancer (SCLC), according to findings from the open-label, phase Ib KEYNOTE-028 trial published in the Journal of Clinical Oncology.
“This study is, to our knowledge, the first report to evaluate the immune checkpoint inhibitor pembrolizumab in patients with heavily pretreated (87.5% with 2 or more lines of prior therapy; 37.5% with 3 or more) extensive-stage SCLC,” first author Patrick A. Ott, MD, PhD, clinical director, Center for Immuno-Oncology, Dana-Farber Cancer Institute, and coinvestigators wrote. “Pembrolizumab showed clinically meaningful antitumor activity and overall was well tolerated; the safety was consistent with the reported safety profile in other tumor types.”
The international, nonrandomized, multi-arm, phase Ib KEYNOTE-028 trial (NCT02054806) explored the safety and activity of pembrolizumab (Keytruda) in patients with advanced solid tumors. For the SCLC cohort, 163 patients were screened for enrollment from March 2014 to May 2015. Of those patients, 145 had biopsy samples for PD-L1 evaluation.
PD-L1 expression was assessed by immunohistochemistry, and PD-L1–positive patients had membranous PD-L1 expression in ≥1% of tumor and associated inflammatory cells or positive staining in stroma. Forty-six patients (31.7%) tested positive for PD-L1 expression, but 15 did not meet inclusion criteria. Ultimately, 24 patients were treated.
The median age of the treated patients was 60.5 years (range, 41-80). Fourteen (58.3%) of 24 patients were men. Median follow-up duration was 9.8 months (range, 0.5-24.4). All patients had received prior chemotherapy for SCLC, and 87.5% had received 2 or more prior lines of therapy. All patients had received prior platinum plus etoposide as first-line treatment. Eleven patients (45.8%) received second-line treatment with either topotecan or irinotecan.
Find out more about Small Cell Lung Cancer, which represents about 15 in every 100 diagnosed cases of lung cancer.