This study states that Patients with LSCLC were assigned to receive four cycles of cisplatin and etoposide chemotherapy with one of 3 TRT regimens starting with either the first or second cycle of chemotherapy. The interim endpoint was the cumulative highest toxicity calculated from a scoring system based on treatment-related grade 3 and higher toxicity and the ability to complete therapy in the experimental arms.The final interim analysis was performed after 70 patients accrued to each experimental cohort, and a difference in treatment related toxicity scoring was not found (p = 0.739). Severe esophageal toxicity was comparable in both cohorts. Pulmonary toxicity was low overall, though 4 patients (5.7 %) on the 61.2 Gy arm developed grade 4 dyspnea, which was not observed in the 70 Gy arm. A protocol mandated decision was made to discontinue the 61.2 Gy arm following review of toxicity with the Data and Safety Monitoring Board.

A randomized trial design using a planned early interim toxicity analysis to discriminate between experimental treatment arms is feasible in a phase III setting. Refinement of the design could increase the likelihood of detecting clinically meaningful differences in toxicity in future studies.

Reference link-