Unsuccessful rechallenge with nivolumab in a patient with advanced non-small cell lung cancer who had a 6-year complete response and treatment-free period: Case report.

Several predictive factors of immune checkpoint inhibitor response have been reported, but there has not been sufficient exploration of which patients benefit from immune checkpoint inhibitor rechallenge. We report the case of a patient with non-small cell lung cancer who had 6 years of complete response with initial nivolumab treatment. After relapse, however, rechallenge with nivolumab did not result in tumour shrinkage or long-term response. Even in patients who had an exceptional response to the initial immune checkpoint inhibitor, long-term efficacy may not be achieved by immune checkpoint inhibitor rechallenge. Thorough investigation of biomarkers that predict efficacy of immune checkpoint inhibitor rechallenge is warranted.