2124 - Randomized Phase II Trial of Hypofractionated IMRT with 2.5 Gy/Fxn vs. Standard-Fractionated IMRT, Concurrent with Carboplatin/paclitaxel and Followed By Consolidation Durvalumab, for Patients with St

R. D. Mali¹, P. Thomas², G. N. Gan³, F. Wang¹, C. Sutton⁴, Y. Cao¹, A. Katz⁵, and K. Reddy¹; ¹Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, ²University of Kansas School of Medicine, Kansas City, KS, ³Department of Radiation Oncology, The University of Kansas Medical Center, Kansas City, KS, ⁴University of Kansas Cancer Center, Kansas City, KS, ⁵Department of Population Health, University of Kansas Medical Center, Kansas City, KS

Purpose/Objective(s): Loco-regional failure remains a major challenge for Stage III NSCLC patients who received standard of care standard fractionated chemoradiotherapy (CRT). Furthermore, dose escalation using standard fractionation has also not improved outcomes. Hypofractionated IMRT (HypoRT) is the current standard of care in many other cancers and allows escalation of biological effective dose without increasing overall treatment time. HypoRT at 2.5 Gy/fraction with concurrent chemotherapy for NSCLC has been reported to be a tolerable regimen with respect to treatment-associated toxicities. To determine whether HypoRT with chemotherapy can improve locoregional control in Stage III NSCLC, we are conducting a randomized trial comparing this regimen against standard of care CRT. The primary objective is to compare locoregional control (freedom from intrathoracic tumor progression based on RECIST 1.1 criteria) at 18 months. Secondary endpoints include comparison of acute and late toxicities, progression-free survival, overall survival, and patient-reported quality of life (EORTC QLQ-C30 and OLQ-LC29). Materials/

Methods: This study is a prospective, two arm, randomized Phase II trial comparing IMRT to 62.5 Gy (2.5 Gy/fxn) vs. 60 Gy (2 Gy/fxn), both concurrent with weekly carboplatin (AUC 2) and paclitaxel (45 mg/m2) and followed by consolidation durvalumab (1500 mg q 4 weeks x 1 yr), for patients with Stage III NSCLC, ECOG = 2 and eligible to receive concurrent chemoRT as judged by the treating radiation oncologist and medical oncologist. Pleural effusions must be tapped and confirmed to be cytologically negative. We hypothesize that hypofractionated IMRT will improve locoregional control at 18 months by 10% compared to standard fractionated IMRT. Using an optimal design for a single stage two-arm randomized phase II clinical trial, in which the total sample sizes are minimized under multiple constraints using the standard errors of the estimated events rates, approximately 50 pts total will be enrolled. To date, 20 patients have been enrolled, with a median age of 69 years, 65% M/35% F. 65%, 30% and 5% of patients enrolled have had Stage IIIA, IIIB, and IIIC NSCLC, respectively with 65% adenocarcinoma and 35 % squamous cell carcinoma.
Results: TBD
Conclusion: TBD