960P - Beyond PACIFIC: Real-world outcomes of adjuvant durvalumab according to treatment received and PD-L1 expression

Background

Adjuvant durvalumab after chemoradiotherapy (CRT) is the standard of care for unresectable stage III non-small cell lung cancer (NSCLC). A posthoc exploratory analysis of PACIFIC revealed no OS benefit in the PD-L1 < 1 % subgroup. The European Medicines Agency approved adjuvant durvalumab for PD-L1 ≥ 1 % NSCLC, while North American health authorities did not make this distinction. We conducted a retrospective review to assess the real-world impact of durvalumab on OS according to PD-L1 tumor proportion score (TPS).

Methods

Patients with locally advanced, unresectable NSCLC treated by CRT, with available PD-L1 TPS, from March 1^st, 2018, to December 31, 2020, at BC Cancer, British Columbia, Canada were included. Patients were divided in two groups, CRT+durvalumab and CRT alone. OS and PFS were analyzed in those two groups and in three subgroups: PD-L1 TPS ≥ 50 %, 1-49 % and <1 %. Kaplan Meier curves and log-rank tests were used to analyze OS. A multivariate survival model was built using Cox regression.

Results

A total of 277/453 (61.1 %) patients treated with CRT had PD-L1 TPS results. Of those, 138 eligible patients received durvalumab and 127 did not, for various reasons. Patient characteristics were well balanced. Median follow-up was 22.3 and 20.2 months. Median OS was not reached in the CRT+durvalumab group and was 30.5 months in the CRT alone group [HR 0.54 (95 % CI 0.38-0.77), p < 0.001]. A multivariate survival analysis identified squamous histology as negatively impacting survival (p < 0.001). The adjusted durvalumab HR for OS was 0.52 (95 % CI 0.36-0.76), p < 0.001. Durvalumab was associated with improved OS in the PD-L1 ≥ 50 % subgroup [HR 0.43 (95 % CI 0.23-0.80), p = 0.008, n = 111] and the 1-49 % subgroup [HR 0.45 (95 % CI 0.24-0.85), p = 0.01, n = 75], but not in the < 1 % subgroup [HR 0.76 (95 % CI 0.41-1.40), p =0.4, n = 79]. PFS findings followed a similar trend.

Conclusions

This study demonstrates a significant improvement in OS associated with durvalumab after CRT in PD-L1 ≥ 1 %, but not in PD-L1 < 1% NSCLC. These findings confirm evidence from a posthoc analysis of PACIFIC in a real-world setting. Variables not accounted for may have biased the survival analysis. A prospective study is needed.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

M. Denault: Financial Interests, Personal, Other, Coverage of travelling expenses to present this abstract at the ESMO 2022 Conference if accepted.: AstraZeneca. J. Feng: Financial Interests, Personal, Other, Coverage of travelling expenses to present this abstract at the ESMO 2022 Conference if accepted.: AstraZeneca. J. Laskin: Financial Interests, Personal, Invited Speaker: Roche, Pfizer, Eli Lilly, Jazz; Financial Interests, Institutional, Research Grant: Roche. S. Sun: Financial Interests, Personal, Advisory Role: AstraZeneca, Bristol Myers Squibb, Merck, Novartis, Pfizer, Takeda. T. Zhang: Non-Financial Interests, Member: ASTRO, CARO, ASCO. C. Ho: Financial Interests, Personal, Advisory Board: AbbVie, Amgen, AstraZeneca, Bayer, BMS, Eisai, EMD Serono, Janssen, Merck, Novartis, Pfizer, Roche, Takeda; Financial Interests, Institutional, Research Grant: AstraZeneca, EMD Serono, Roche; Non-Financial Interests, Principal Investigator: Roche, AstraZeneca, EMD Serono. B. Melosky: Financial Interests, Personal, Advisory Board: Roche, AstraZeneca, Pfizer, Merck, BMS, Novartis, Janzen, Sanofi. All other authors have declared no conflicts of interest.