Rationale and Design of a Single-Arm, Phase 2, Multi-Center Study of Chemo-Immunotherapy Followed by Hypo-Fractionated RT and Maintenance Immunotherapy in Patients With Unresectable Stage III NSCLC: The DEDALUS Trial

Introduction/background: This single-arm, phase 2, multi-center, study aims to assess the safety and efficacy of a regimen of induction chemo-immunotherapy followed by de-intensified, hypo-fractionated thoracic radiotherapy (RT) given concurrently with durvalumab and maintenance durvalumab in patients with unresectable, stage III NSCLC. Material and methods: we will enroll 45 patients with unresectable stage III NSCLC, any PD-L1, deemed ineligible for concurrent CRT by a thoracic oncology multidisciplinary team, and candidate to sequential chemoradiation followed by durvalumab. Results: Primary endpoint is safety, defined by the incidence of grade 3 and 4 possibly related adverse events (PRAEs) within 6 months from the initiation of treatment. The secondary objectives are PFS and OS (median and 12 months). Ancillary endpoints are molecular response evaluated by cfDNA isolation baseline, after chemo-immuno RT and at progression, and radiomics analysis on CT scans at baseline and before maintenance. Conclusion: DEDALUS phase 2 trial explores the safety and efficacy of a novel sequence of chemo-radiation (with de-intensified RT) plus the anti-PD-L1 agent durvalumab in patients with stage III unresectable NSCLC who are candidates to sequential chemoradiation plus maintenance immunotherapy.