A study of the efficacy and toxicity outcomes of extended durvalumab dosing in patients with stage III unresectable non-small cell lung cancer (NSCLC) during the COVID-19 pandemic

Abstract

BackgroundDurvalumab following chemoradiation in unresectable stage III non-small cell lung cancer (NSCLC) has led to improved outcomes. The schedule of administration has been determined by pharmacokinetic studies. This study evaluates real-world efficacy and safety outcomes of extended dosing (ED) vs. standard dosing (SD) of durvalumab. MethodsStage III NSCLC patients treated at the Cancer center of Southeastern Ontario with consolidative durvalumab from March 2017-December 2020 were included. Patient characteristics and outcomes were evaluated through retrospective review. Comparisons were made using chi-square and t-tests. Kaplan-Meier curves were used to analyze overall survival (OS). ResultsA total of 35 patients were included; 15 (43%) switched to ED. Distant recurrence rates were higher in the ED group (53% vs. 20%, p = 0.07), with no differences in the sites of disease recurrence. A similar proportion of patients were alive in the ED vs. SD group (93% vs. 80%, p = 0.3), with no significant difference in OS. There were less grade 3 or greater immune-related adverse events in the ED group (0% vs. 20%). Treatment discontinuation occurred in 47% vs. 50% in the ED vs. SD groups, respectively, owing to toxicity in 20% of patients in the ED group vs. 40% in the SD group. ConclusionsExtended dosing has similar efficacy and toxicity to standard dosing; however, there was a higher rate of toxicity necessitating discontinuation in the SD group, which may have impacted the clinical decision-making to switch to ED. Our data is limited by a small sample size and should be further validated in larger cohorts.