157P Durvalumab impacts progression-free survival but not local control in patients with inoperable NSCLC stage III: Real-world data from the Austrian radio-oncological lung cancer study association registry (ALLSTAR)

Unresectable non-small cell lung cancer (NSCLC) UICC III comprises a range of diseases, which entails a variety of treatment approaches. The fact that only 2% of the patients are eligible for prospective randomized control trials poses the question in how far the knowledge gained by these studies reflects daily clinical practice. ALLSTAR is a registry intended to document the real-world clinical practice at the beginning of the widespread use of immunotherapy, especially Durvalumab, for this multi-faceted disease entity. Patients were eligible if they had pathologically verified unresectable NSCLC stage III with a curative treatment option. Chemo-radiation combined with immunotherapy was performed according to local treatment practices at each centre. The co-primary endpoints were progression-free survival (PFS) with a focus on local control (LC) as well as toxicity. Between March 2020 and April 2023, the day of data extraction for the current analysis, 12/14 (86%) Austrian radiation-oncology centres recruited 188 patients with a minimum follow-up of 3 months (median: 15.1; mean number of patients per centre: 17). PD-L1 testing was performed in 173/188 (93%) patients. The median interval between radiotherapy and Durvalumab was 14 days (range: 1 – 65). Median PFS for patients with Durvalumab was 25.8 months (95%-CI: 21.9-not reached) compared to 15.7 months (95%-CI: 13.2-27.8) for those without (HR = 1.88; 95%-CI: 1.16-3.05; log-rank p-value < 0.01). Increased total radiation doses of more than 66 Gy achieved improved 2-year LC (86% versus 60%, HR = 0.41; 95%-CI: 0.17-0.98; log-rank p-value < 0.05), which was corroborated by multi-variate analysis. Except for one case of grade 4 pneumonitis, toxicity was generally low. ALLSTAR revealed the diversity of treatment approaches for NSCLC stage III in Austria at the beginning of the immunotherapy era. It demonstrated that Durvalumab improves PFS without having an impact on LC, which rather depends on histology and total radiation dose.