P10.03 Pembrolizumab With or Without Chemotherapy for Advanced Lung Cancer: A Real-World Analysis of Key Prognostic Factors

Immune checkpoint inhibitors alone or in combination with chemotherapy have become standard of care for patients with advanced non-small cell lung cancer (aNSCLC) without driver mutations. This study investigates the real-world performance of immunotherapies in the treatment of patients with aNSCLC. Data on patients diagnosed with aNSCLC between 1/2016 and 9/2020 who received frontline treatment with pembrolizumab alone (IO) or in combination with platinum-based chemotherapy (IO+C) within community health systems were extracted from electronic health records. The Kaplan-Meier estimator was used to assess overall survival (OS) and time-to-next treatment or death (TTNT). Of 739 patients, 82% were White and 12% were Black; 79% had non-squamous histology. Brain and liver metastases were documented in 25% and 10% of patients, respectively; 83% of patients’ tumors were tested for PD(L)-1, 80% for EGFR, and 74% for ALK. Among patients tested for PD(L)-1, 98% (295) of IO and 69% (217) of IO+C patients’ tumors were positive. A greater proportion of IO than IO+C patients were female (52% vs 44%) and fewer had performance status (PS) <2 (44% vs 53%). During the median follow-up of 10 months, 24% of patients received second line therapy and 57% died. IO patients had longer median OS than IO+C patients (Table 1; p=0.02). Median OS was longer for non-squamous than squamous histology in both groups. patients with brain metastases, patients with liver metastases, and patients with PS ≥2 treated with IO had a longer median OS than patients treated with IO+C. TTNT followed a similar pattern. In Cox proportional hazards models adjusted for age, sex, race, year and stage of diagnosis, histology, brain and liver metastasis, smoking, PS, comorbidity and tumor proportion score (TPS), treatment with IO was associated with reduced mortality [HR 0.8; 95% Confidence Interval, (0.6, 1.0); p=0.02] and reduced hazard of initiating next treatment [HR 0.8 (0.7, 1.0); p=0.08].Table 1Summary of findings.IOIO+ChemoNMedian OS, months [95% CI]NMedian OS, months [95% CI]All patients34118 [14, 22]39813 [11, 15]Squamous histology6812 [7, 18]868 [6, 13]Non-squamous histology27320 [14, 24]31215 [12, 17]Liver Metastases21-* [3, -]519 [5, 12]Brain Metastases9014 [5, 18]9511 [7, 17]TPS 1-49%2314 [4, 24]8811 [8, 17]TPS ≥50%19415 [8, 21]5515 [10, 35]TPS unknown7818 [14, -]7412 [4, 24]PS ≥ 2546 [2, 10]504 [2, 6]*Median OS was not reached. Open table in a new tab *Median OS was not reached. In this real-world analysis, frontline IO was associated with longer survival than IO+C. Real-world benefits of IO and IO+C were more modest than reported in clinical trials, particularly in squamous patients. While these findings must be replicated in analyses that control for imbalances in patients characteristics between the two treatment arms, real-world data provide a powerful tool for assessing treatment efficacy outside of the clinical trial setting.