Biomarker testing patterns and trends among patients with metastatic lung cancer.

e13667 Background: Guidelines for biomarker testing of metastatic lung cancer patients aid oncologists in making targeted treatment decisions. Despite evidence demonstrating the benefits of genomic and immune biomarker identification in these patients, variations in testing exist. This population-based, retrospective, observational study examined trends in testing rates and timing, assessing associations between testing and patient characteristics, sociodemographic factors, and regional patterns using insurance claims data. Methods: We evaluated patterns of biomarker testing in the IBM MarketScan database between 1/1/2013-12/31/2018. Inclusion criteria consisted of lung cancer patients with an initial diagnosis of metastasis within the study period, continuous insurance coverage from 12 months before to 4 months post-diagnosis, and biomarker testing (EGFR, ALK, ROS1, BRAF V600E, NTRK, PD-L1) within 4 months of diagnosis. Temporal trends were evaluated by the Cochran-Armitage method. Multivariate logistic regression evaluated associations between testing rates and patient-specific factors (i.e., age, gender, comorbid conditions), insurance type, and region (i.e., Northeastern, North central, Southern, and Western) in the United States (US). Results: Of the 8977 patients with metastatic lung cancer, 1040 (12%) had claims for biomarker testing. During the study period, testing rates increased significantly, from 8.4% in 2013 to 20.6% in 2018 (P <.0001); the likelihood of testing increased by year (2014, OR 1.20, 95% CI 0.97 - 1.48 vs. 2018, OR 2.83, 95% CI 2.26 - 3.54). Of patients tested, 25.8% (N = 268) were tested on the day of diagnosis, 70.7 % (N = 735) within 30 days, and 85.6% (N = 890) within 60 days. A lower likelihood of testing was associated with increasing age (OR = 0.97, 95% CI 0.96 - 0.98), enrollment in preferred provider health plans (OR 0.69, 95% CI 0.53 – 0.93), or pre-existing comorbidities of congestive heart failure (OR 0.76, 95% CI 0.59 – 0.98) or diabetes (OR 0.82, 95% CI 0.68 – 0.99). Testing was more likely to occur in females (OR 1.24, 95% CI 1.09 – 1.42), age < 55 years (OR 1.67, 95% CI 1.32 – 2.12) or residence in Northeastern US (OR 1.26, 95% CI 1.05 -1.51). Conclusions: Biomarker testing rates for an insured cohort of metastatic lung cancer patients increased significantly over time, but the likelihood of testing varied based on age, sex, insurance type, comorbidities, and region. Results of this study may inform policy or outreach strategies by highlighting population-based factors influencing biomarker testing rates.