ESTRO 2024 - Abstract Book

S1819

Clinical - Lung

ESTRO 2024

According PACIFIC Trial, Durvalumab 10 mg/kg every 2 weeks for 1 year after radio (RT)-chemotherapy (ChT) has improved overall survival (OS) in unresectable locally advanced (LA) NSCLC. Subsequently, a 20 mg/kg 4-weekly regimen was approved. Whereas the pharmacokinetics data suggest that 2- weekly and 4-weekly administration intervals are equivalent, the clinical impact is unknown. The study goal was to assess the real-world effectiveness of durvalumab, comparing the safety profile of the two regimens.

Material/Methods:

LA-NSCLC PD- L1 ≥1% patients treated with curative intent RT-ChT followed by at least one administration of durvalumab from December 1, 2017 to June 30, 2023 were included in this retrospective study. Patients fit for concurrent RT-ChT received conventional RT, while patients unfit for concurrent schedule received stereotactic ablative radiotherapy (SAbR) after neoadjuvant ChT according to START-NEW-ERA phase II trial (1). Durvalumab dosing schedule, toxicity, local recurrence-free survival (LR-FS), regional recurrence-FS, distant progression-FS, disease- FS and OS were collected. Comparisons between treatment groups were made using Fisher ‘s exact test. Kaplan-Meier curves and log-rank test were used to analyze survival outcomes. A total of 14 patients were included in the 2- weekly group and 12 patients in the 4-weekly group. 18 received sequential ChT-SAbR and 12 concurrent RT-ChT. The median follow-up was 23 months (range,16-36). 6/12 (50%) and 1/14 (7%) patients who had received durvalumab 4-weekly and 2-weekly, respectively, stopped durvalumab due to G3 pneumonitis (p=0.026). There was no significant difference in safety profile based on RT schedule (conventional vs. SAbR). The median LR-FS was not reached, 1-y and 3-y LR-FS rates were 96% and 57%. The median DP-FS was not reached, 1-y and 3-y DP-FS rates were 100% and 54%. The median DFS was 24 months (range,14-35), 1-y and 3-y DFS rates were 96% and 23%. The median OS was not reached; 1-y and 3-y OS rates were 91% and 76%. Results:

Conclusion:

Our clinical outcomes confirm the Durvalumab effectiveness in this cohort of LA-NSCLC patients. Although pharmacokinetics data suggest the equivalent safety profile of 2-weekly and 4-weekly administration interval of durvalumab, in our experience there was higher G3 pneumonitis in 4-weekly group.

Keywords: LA-NSCLC; durvalumab; toxicity

References:

1. Int J Radiation Oncol Biol Phys, Vol. 115, No. 4, pp.886-896, 2023

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