Early administration of durvalumab after chemoradiotherapy increased risk of pneumonitis in patients with locally advanced non-small cell lung cancer

Aims Durvalumab (Durva) administration after chemoradiation therapy (CRT) in locally advanced non-small-cell lung cancer (NSCLC) is the standard of care, associated with relatively prolonged progression-free (PFS) and overall survival. However, pneumonitis occurs in 73.6% of Japanese patients. This retrospective study aimed to identify factors associated with Durva efficacy and safety, specifically, the risk of pneumonitis. Methods This study included data from 26 consecutive patients with locally advanced NSCLC who underwent CRT followed by Durva. The rates of adverse events and PFS were examined. Results The median PFS time was 15.6 months (95% confidence interval [CI]: 8.7-not available). Patients developed pneumonitis of grade 1, 2, 3, and 4 at the rate of 62%, 27%, 12%, and 0%, respectively. The median PFS time was 6.4 months for patients with programmed death ligand 1 (PD-L1) expression level of <50% and not reached for patients with PD-L1 expression level of >= 50% (hazard ratio [HR], 0.19; 95% CI: 0.04-0.89), which was significantly prolonged. The cumulative incidence of pneumonitis grade 2 or above was significantly higher when the time between the last day of thoracic radiotherapy (TRT) and the start of Durva therapy was within 14 days compared to >14 days (HR: 0.19; 95% CI: 0.06-0.59). This association was statistically significant in multivariate analysis. Conclusions The initiation of Durva therapy within 14 days after TRT may increase the risk of pneumonitis grade 2 or above. Careful observation and suitable treatment are recommended.