Clinicians’ perspective on use of immune checkpoint inhibitors and related biomarkers for solid tumors

ABSTRACT Background Immune checkpoint inhibitors (ICIs) are a valuable treatment option for patients with malignant tumors, but only selected patients respond to ICIs. Available biomarkers are of limited use in guiding ICI therapy. Objective To examine clinicians’ perspective on the use of ICIs and biomarkers for treatment of malignant tumors and to identify unmet needs related to their use. Methods We conducted in-depth telephone interviews of eight oncologists, and 100 oncologists completed online surveys. Results Oncologists have a positive attitude toward use of ICIs, and 98% of them prescribe them in all approved indications. Clinicians report that only about half of the patients with solid tumors responded to treatment, overestimated the response rate to ICIs across most types of tumors they treat compared with data in the literature. They ranked the lack of reliability of biomarkers to guide treatment (rating of 4.4 out of 7) as the top challenge with use of ICIs, followed by lack of overall efficacy and toxicity or occurrence of immune-related adverse events. The biomarkers most often used by survey participants were: a comprehensive panel including driver mutations and tumor mutational burden(69% of respondents), programmed cell death ligand-1 (PD-L1) expression (62%), and microsatellite instability (MSI) (56%). Oncologists indicated that they ordered biomarkers for each type of cancer according to their perceived usefulness of each biomarker in predicting the outcomes for ICI therapy, being more likely to use those perceived as useful or very useful. Conclusion Clinicians indicate that more reliable therapy-response prediction biomarkers would have a great impact on treatment decisions for patients with solid tumors, reducing unnecessary treatments, side effects, and health care expenditures.