Abstract
PURPOSE: Drug resistance inevitably occurs despite the encouraging results of immunotherapy. This study attempted to investigate immunotherapy rechallenge treatment regimens and factors associated with outcomes in patients with non-small cell lung cancer (NSCLC) according to resistance status. METHODS: A retrospective study was conducted on patients with advanced NSCLC who received immune checkpoint inhibitor (ICI) monotherapy and immune rechallenge between March 2016 and December 2022. Primary resistance (RR) was defined by an absence of response after treatment administered for less than 6 months before progression. Acquired resistance (AR) was defined as a response to immunotherapy treatment administered for more than 6 months before progression. Disease progression in as many as three lesions was defined as systemic progression, whereas disease progression in fewer than three lesions was defined as oligo-progression. RESULTS: Of 40 patients, 18 (45%) had primary resistance, and 22 (55%) developed AR. Overall survival (OS) was not reached. A significant difference in progression-free survival (PFS) was observed in individuals rechallenged with ICIs after AR and RR (7.0 months vs. 2.1 months, P = 0.003). Patients receiving interval treatment before rechallenge achieved longer PFS than those who did not (6.2 months vs. 4.0 months, P = 0.027). Multivariate analysis demonstrated that systemic progression was a risk factor significantly associated with PFS after ICI rechallenge (P = 0.006). After AR, ICI rechallenge prolonged the duration of PFS if patients developed oligo-progression (5.4 months vs. 1.1 months, P < 0.001). CONCLUSION: ICI rechallenge is likely to be an option for patients with oligo-progression during rechallenge, particularly after AR.