1471P - Immunotherapy prolongs long-term real-world survival compared to chemotherapy for metastatic non-small cell lung cancer: A propensity score-matched analysis

Background

Survival benefit of immunotherapy (IO) has been demonstrated in clinical trials for patients with metastatic non-small cell lung cancer (mNSCLC) but no real-world study was found in literature to measure the long-term treatment effect compared to chemotherapy (CT). This retrospective and observational study aimed to evaluate whether IO has improved the long-term real-world overall survival (rwOS) and real-world time to receive next line of therapy (rwTTNT) in mNSCLC based on Flatiron Health oncology database.

Methods

Electronic health records of patients who received either IO (IO mono or IO+CT) or CT in first line (1L) and second line (2L) treatment from January 1, 2015 and onwards were extracted. Eligible patients were selected to match based on a developed propensity score to balance covariates that may confound the treatment effect. The effect of IO rwOS and rwTTNT was estimated using Cox regression. Subgroup analysis was performed to assess effect modification of known prognostic factors in mNSCLC.

Results

A total of 16,856 1L patients and 6,570 2L patients were included in the analysis. Patient characteristics between IO and CT arms were balanced after 1:1 propensity score matching with replacement. The maximum follow-up was 7.1 years for 1L and 7.3 years for 2L. Among 1L IO patients, median rwOS was 10.8 months (95% CI: 10.5 – 11.2) (vs. 1L CT: 9.0 [95% CI: 8.7 – 9.3]) with hazard ratio (HR) 0.84 (95% CI: 0.80 – 0.89). The HR for rwTTNT was 0.54 (95% CI: 0.51 – 0.57). Among 2L IO patients, median rwOS was 8.9 months (95% CI: 8.6 – 9.4) (vs. 2L CT: 8.3 [95% CI: 7.8 – 9.0]) with HR 0.91 (95% CI: 0.84 – 0.98). The HR for rwTTNT was 0.74 (95% CI: 0.69 – 0.79). Subgroup analyses among IO patients showed better survival outcomes for patients with younger age, low ECOG score, low comorbidity index, no history of smoking, PD-L1 positivity, and high PD-L1 expression level. The treatment effects increased over time and persisted until the end of the follow-up period.

Conclusions

IO was associated to prolong overall survival and delay receiving next line of therapies in mNSCLC patients. The significant survival benefits were found even after several years of follow-up.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Karolinska Institute.

Funding

AstraZeneca.

Disclosure

K. Kim: Financial Interests, Institutional, Full or part-time Employment: AstraZeneca Nordic AB. M. Sweeting: Financial Interests, Institutional, Full or part-time Employment: AstraZeneca UK. All other authors have declared no conflicts of interest.