Concerning Safety and Efficacy of Concurrent and Consolidative Durvalumab With Thoracic Radiation Therapy in PDL1-Unselected Stage III Non-Small Cell Lung Cancer: Brief Report

Abstract

IntroductionConsolidative durvalumab, an anti-programmed death ligand 1 (PDL1) immune checkpoint inhibitor, administered after concurrent chemoradiation improves outcomes of patients with locally advanced non-small cell lung cancer (NSCLC) without substantially increasing toxicities. We studied a chemotherapy-free regimen of thoracic radiotherapy (RT) with concurrent and consolidative durvalumab. MethodsThis single-arm phase II trial enrolled patients with stage III NSCLC (regardless of tumor PDL1 expression), performance status ECOG 0-1, adequate pulmonary function, and RT fields meeting standard organ constraints. Participants received two cycles of durvalumab (1500 mg every 4 weeks) concurrently with thoracic RT (60 Gy in 30 fractions), followed by up to 13 cycles of consolidative durvalumab. ResultsAfter 10 patients were enrolled, the trial was closed due to poor clinical outcomes. With a median follow-up of 12 months, five patients had disease progression and eight patients died. Six patients experienced 15 treatment-related, grade ≥3 events, including one grade 4 acute kidney injury during consolidation and two fatal pulmonary events. One fatal pulmonary event occurred during the concurrent phase in an active smoker; the other occurred after the first cycle of consolidative durvalumab. The primary endpoint of progression-free survival (PFS) at 12 months was 20% (50% for PDL1≥1% versus 0% for PDL1 unavailable or <1%). Median overall survival (OS) was not reached, 10.5 months, and 7 months, for PDL1 ≥1%, <1%, and unavailable, respectively. ConclusionsIn PDL1 unselected stage III NSCLC, thoracic RT plus concurrent and consolidative durvalumab is associated with high-grade toxicity and early disease progression.