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

Purpose: Consolidative 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 radiation therapy (RT) with concurrent and consolidative durvalumab. Methods and Materials: This single-arm phase 2 trial enrolled patients with stage III NSCLC (regardless of tumor PDL1 expression), Eastern Cooperative Oncology Group (ECOG) performance status 0-1, adequate pulmonary function, and RT fields meeting standard organ constraints. Participants received 2 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. Results: After 10 patients were enrolled, the trial was closed because of poor clinical outcomes. With a median follow-up of 12 months, 5 patients had disease progression and 8 patients died. Six patients experienced 15 treatment-related, grade ≥3 events, including 1 grade 4 acute kidney injury during consolidation and 2 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 at 12 months was 20% (50% for PDL1≥1% vs 0% for PDL1 unavailable or <1%). Median overall survival was not reached, 10.5 months, and 7 months, for PDL1 ≥1%, <1%, and unavailable, respectively. Conclusions: In PDL1 unselected stage III NSCLC, thoracic RT plus concurrent and consolidative durvalumab is associated with high-grade toxicity and early disease progression.