OBJECTIVES : Pembrolizumab was the first programmed cell death receptor ligand 1 (PD-L1) inhibitor approved 10/2016 for first line monotherapy in mNSCLC patients with high PD-L1 expression (Tumor Proportion Score (TPS) ≥ 50%). Pembrolizumab with pemetrexed and carboplatin (immuno-oncology (IO) + chemotherapy) was approved 5/2017 for nonsquamous disease. The primary study objective is to describe patient characteristics and treatment patterns of Medicare Fee-for-Service (FFS) patients with mNSCLC.

METHODS : A retrospective cohort analysis was conducted among Medicare FFS beneficiaries diagnosed with mNSCLC 10/2015-6/2017 and treated with regimens classified as an NCCN Guideline Category 1 or 2A recommendation. Patients were followed from date of metastatic disease to: death, loss of Medicare coverage, or end of follow-up. PD-L1 expression was available for a subset of patients using linked diagnostic testing results from Prognos. Baseline characteristics, 1LoT, and PD-L1 expression level were measured (PD-L1 negative = TPS <1.0%; PD-L1 positive = TPS ≥1%).

RESULTS: A total of 41,431 patients were included (51.1% female; mean age: 74.3 years; mean follow up: 12 months). Of the 2,476 patients with confirmed PD-L1 expression, 66.3% were PD-L1 positive. Patients with positive/negative PD-L1 expression were similar in age, sex and comorbidities. Across the full study sample (n=41,431), the most common 1LoT included: doublet chemotherapy (43.4%), IO monotherapy (19.7%), single agent chemotherapy (14.6%), tyrosine kinase inhibitors (TKI) (10.7%), IO + chemotherapy (1.0%), or other regimens (10.3%). Among patients with PD-L1 positive tumors, the most common 1LoT were doublet chemotherapy (42.6%), pembrolizumab monotherapy (25.5%) or TKI (9.5%); patients with PD-L1 negative tumors commonly received doublet chemotherapy (54.9%) or TKI (14.0%).

CONCLUSIONS : Treatments in Medicare population were largely in line with NSCLC treatment guidelines. As expected, doublet chemotherapy was the most commonly prescribed 1LoT. Additional research will explore economic outcomes associated with 1LoT selection by PD-L1 status.