How are Companion Diagnostics Considered in Economic Evaluations of Oncology Treatments? A Review of Health Technology Assessments

Background Companion diagnostic (CDx) testing is increasingly used to identify eligible patients for targeted treatments. Guidance on how CDx testing should be incorporated into cost-effectiveness models (CEM) is limited. This review evaluated how health technology assessment bodies and research organizations considered CDx in CEMs of targeted therapies in oncology and whether this ultimately impacted their decisions or time from regulatory approval to recommendations. Methods An exhaustive list of approved CDx tests in oncology was compiled. For corresponding indications and treatments, NICE appraisals published between 2016 and 2019 were identified. Then, assessments for the same treatments issued from 11 other agencies were reviewed. Data extracted included background and CDx information, CDx's role in the CEM, and recommendations. Results Twenty-seven NICE appraisals were identified; 15 considered CDx testing in the CEM, while 12 did not, mainly because testing had already been established for the comparators within the same class or in clinical practice from a prior treatment line. Both testing costs and mutation prevalence drove CDx testing costs per patient. The cross-comparison of assessments showed that CDx test characteristics were inconsistently reported. Time from regulatory approval to recommendations was not impacted by CDx cost inclusion in CEMs. Conclusion CDx testing was included in cost-effectiveness models whenever mutation testing was required solely for patients receiving targeted treatment; cost per patient was based on test costs and mutation prevalence. It is unclear if expanded reliance on CDx testing will impact future assessments of targeted therapies. A future update is warranted to track trends over time.