Results from an ongoing Phase Ib study indicate that treatment with the experimental anti-PD-1 antibody pembrolizumab resulted in high response rates and slowed cancer progression in previously untreated stage IV non–small cell lung cancer (NSCLC). These results were recently presented at the 50th Annual Meeting of the American Society of Clinical Oncology (ASCO 2014) in Chicago in June.1
Lung cancer remains the leading cause of cancer-related deaths worldwide. In the United States, NSCLC accounts for 75–80% of all lung cancers. Although progress has been made in recent years the majority of patients with advanced stage lung cancer still die from their disease. New treatments are sorely needed. Investigators recently reported that the use of pembrolizumab in NSCLC appears promising.
Pembrolizumab belongs to a new class of medicines called PD-1 inhibitors that have generated great excitement for their ability to help the immune system recognize and attack cancer. PD-1 is a protein that inhibits certain types of immune responses. Drugs that block PD-1 may enhance the ability of the immune system to fight cancer. Pembrolizumab works by blocking PD-1. Pembrolizumab is being investigated in more than 30 different cancers, and early studies in melanoma are promising.2
The researchers reported an overall response rate of 26% in previously untreated NSCLC patients. This compares quite favorably with any know chemotherapy regimens in similar patient populations. Importantly, the investigators report that responses are ongoing in 100% of responders with the median duration of response not yet reached after a median of 36 weeks follow-up. Moreover, time to cancer progression also appears to be improved in the interim analysis of pembrolizumab.
These results are preliminary and enrollment is expected to begin this fall in the phase III KEYNOTE-024 study which will compare pembrolizumab with a standard platinum-based chemotherapy in treatment-naive PD-L1 positive, metastatic non–small cell lung cancer patients.
1.Rizvi N, Garon E, Patnaik A,Safety and clinical activity of MK-3475 as initial therapy in patients with advanced non-small cell lung cancer (NSCLC).J Clin Oncol 32:5s, 2014 (suppl; abstr 8007)
2.Ribas A, Hodi FS, Kefford R, et al. Efficacy and safety of the anti-PD-1 monoclonal antibody MK-3475 in 411 patients (pts) with melanoma (MEL). J Clin Oncol 32:5s, 2014.