Real-World Treatment Patterns Before and After Receiving PD-L1 Test Results in Patients with Advanced Non-small Cell Lung Cancer (aNSCLC)

Background: The National Comprehensive Cancer Network and the European Society for Medical Oncology guidelines for NSCLC support the first-line (1L) use of some immune checkpoint inhibitor (ICI) therapies alone or with chemotherapy (chemo) over chemo alone in patients with programmed cell death-ligand 1 (PD-L1) expression ≥50%. Recent data from an observational study suggests overall survival and progression-free survival may be similar for these 2 ICI treatment options.

Objectives: Some oncologists may initiate treatment with chemo ± ICI and adjust treatments after receiving PD-L1 test results. In this study, we evaluated these adjustments.

Methods: A retrospective cohort study using the Flatiron Health electronic health records database was conducted among adult patients diagnosed with aNSCLC (1 January 2015 to 30 November 2020) who received ≥1 valid PD-L1 result ≥30 days after initiating 1L therapy. We compared treatments administered before and within 45 days of receiving PD-L1 results.

Results: Of the 1748 identified patients with aNSCLC for whom 1L therapy was initiated before PD-L1 results, 659 (37.7%), 500 (28.6%), and 589 (33.7%) had negative ( < 1%), low (1—49%), or high (≥50%) PD-L1 expression, respectively. Across all PD-L1 expression levels, >50% of patients initiated chemo alone (negative: 54.8%, low: 57.0%, high: 51.4%). After PD-L1 test results, >70% of patients with negative/low PD-L1 expression remained on their initial regimen (negative: 79.2%, low: 76.5%). Among high PD-L1 expressers, 54.5% initiating chemo before PD-L1 testing stayed on the same regimen after testing; 21.5% of patients added ICI therapy, and 12.9% switched to ICI alone. Among high PD-L1 expressers that were on ICI+chemo (n=205) before PD-L1 testing, few patients (12.2%) discontinued chemo after testing.

Conclusions: Despite guidelines recommending ICI treatment in patients with aNSCLC with PD-L1 ≥50%, at least half of patients were started on chemo alone prior to obtaining PD-L1 test results, and the majority of patients remained on the same regimen after receiving their test results; few patients discontinued chemo after initiating ICI+chemo. Further research is needed to investigate the role of PD-L1 testing in treatment choice and impact on outcomes in the 1L setting of aNSCLC.