Background The growth in the number of targeted therapies available for the treatment of solid tumors has placed biomarker testing at the heart of clinical practice, especially for non-small lung cancer (NSCLC). Guidelines such as those by the American Society of Clinical Oncology and the European Society for Medical Oncology, recommend that all advanced NSCLC patients be tested for EGFR, ALK, ROS-1 and PD-L1 and that further markers (such as BRAF and KRAS) be included in larger panels. Despite these guidelines, oncologists do not always test NSCLC patients for these biomarkers. This study explores the reasons for not testing and compares these across the US, France, Germany, UK, Italy and Spain (collectively EU5) by examining real-world usage data.

Methods Between September and November 2019, a panel of oncologists (n=65 in US and n=235 in EU5) were asked to report on their practices relating to biomarker testing for 1,110 NSCLC patients through the submission of online, de-identified charts detailing testing for EGFR, ALK, ROS-1, PD-L1, BRAF, KRAS/NRAS, MET, RET, dMMR/MSI, TMB and NTRK. We collected data on 11,116 instances where biomarkers were skipped and recorded physicians’ reasons for not testing (selected from a pre-coded list).

Results Of the reasons provided for not testing in the US (n=2,114) and EU5 (n= 9,002), waiting for progression was selected the most (27% and 25%, respectively). Lack of data regarding clinical utility (18% and 16%) and patients not meeting criteria (13% and 17%) were mentioned next as the top reasons for not testing across both regions. Compared to the US, EU5-based physicians had higher mentions of patients not meeting criteria (17% vs. 13%), tests not being reimbursed (7% vs. 5%) and treatment costs not being reimbursed (6% vs. 4%). The full distribution of reasons is shown in table 1 below.

Conclusions Despite recommendations in guidelines, physicians in the US and EU5 often forgo testing to wait until after progression, because of a perceived lack of clinical utility or because they deem the patient ineligible for testing. While individual countries differ on their approaches to testing - some are more cost sensitive (UK, France) while others are more discerning as to which patients are eligible for testing (Germany) - a concerted effort is needed to educate physicians on the clinical utility of biomarker testing.