Brief Report: Second-line treatment outcomes in patients with advanced NSCLC previously treated with first-line immunotherapy regimens.

In the United States of America, nearly all patients with advanced NSCLC, absent oncogenic drivers, receive some form of immunotherapy (IO) as part of initial treatment. Current national guidelines currently recommend against IO re-challenge if there is disease progression on IO in the first line, but re-treatment with IO is attractive given its favorable toxicity profile and descriptions of durable clinical benefit in a subset of patients treated beyond disease progression on initial IO (Gandara, J Thorac Oncol, 2018). Data in the non-clinical trial setting on the efficacy of IO in sequential lines of treatment after initial IO are lacking. In our large cohort study of patients with advanced NSCLC treated with immunotherapy regimens in the first-line setting, we find that outcomes after second-line treatment did not differ statistically by type of treatment used in the second line. While current prospective clinical trials are investigating several aspects of the utility of continuing immunotherapy and adding novel agents, our study offers data outside of a clinical trial. In addition, with the increased prevalence of adjuvant immunotherapy we urgently need to wrestle with whether to continue immunotherapy in the first-line metastatic setting if a patient experiences disease progression on adjuvant immunotherapy. While this analysis does not directly investigate that question, it does provide hypothesis-generating evidence for further evaluations.