Tremelimumab plus durvalumab prior to chemoradiotherapy in unresectable, locally advanced non-small cell lung cancer: the Induction trial.

Background: The phase I Induction trial (NCT04287894) assessed the feasibility and safety of induction immunotherapy (IIT) prior to concurrent chemoradiotherapy (cCRT) in patients with locally advanced non-small cell lung cancer (NSCLC). Methods: Patients with unresectable stage II/III NSCLC were eligible for inclusion. Patients received either one cycle of tremelimumab (75mg) with two cycles of durvalumab (1500mg) in cohort I, one cycle of tremelimumab (300mg) with two cycles of durvalumab in cohort II or one cycle of tremelimumab (300mg) with one cycle of durvalumab in cohort III. After IIT, a comprehensive radiological and pathological restaging was performed followed by cCRT. The combined primary endpoint was feasibility and safety of IIT-cCRT. Results: Fifteen of seventeen included patients were treated per-protocol. IIT-cCRT was completed in 13/15 of the patients within the predefined feasibility criteria. Grade ≥3 immune-related adverse events (irAEs) occurred in 7/15 patients, of which 6 were treated in the high-dose tremelimumab cohorts, thereby violating the safety criteria in cohorts II and III. The low-dose tremelimumab cohort (I) complied with safety criteria. Eleven patients had multilevel N2 or N3 disease at baseline, eight of these patients were downstaged to either N0/1 or single level N2 after IIT. Multiparametric MRI accurately identified nodal downstaging in 7/7 patients. Conclusion: Induction with high-dose tremelimumab plus durvalumab prior to cCRT in unresectable locally advanced NSCLC was associated with unacceptable toxicity, although ITT resulted in clinically relevant nodal downstaging in 8/11 of patients with baseline multilevel N2 or N3 disease. Multiparametric MRI showed potential evaluating treatment response.