How Are We Evaluating the Cost-Effectiveness of Companion Biomarkers for Targeted Cancer Therapies? A Systematic Review
Abstract Background Despite the increasing economic assessment of biomarker-guided therapies, no clear agreement exists whether existing methods are sufficient or whether different methods might produce different cost-effectiveness results. This study aims to examine current practices of modeling companion biomarkers when assessing the cost-effectiveness of targeted cancer therapies. It highlights the challenges in methods and data requirements faced in the evaluation of biomarker tests which do not necessarily arise with the evaluation of pharmaceutical drugs.Methods A literature search was performed using Medline, Embase, EconLit, Cochrane library. Articles published from 2014 to 2018 were searched. Economic evaluations on biomarker-guided therapies with companion diagnostics in cancer were searched. Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines followed. Studies were selected by pre-specified eligibility criteria using PICO framework. To make studies more comparable, data were synthesized under ten categories of key areas of methods where consensus deemed lacking.Results Eighteen papers were included in this review. Three out of eighteen studies found to be of good quality regarding incorporating the characteristics of companion biomarkers in economic evaluations. However, many evaluations focused on a pre-selected patient group with a specific biomarker status instead of including all patients with a disease regardless of their biomarker status. Companion biomarker characteristics captured in evaluations were often limited to the cost or the accuracy of the test. Often, only the costs of biomarker testing were modelled. Clinical outcomes or utilities were often difficult to include due to the limited data generated by clinical trials. We found that no consistency and consensus existed to the methods of existing economic evaluations of companion cancer biomarkers for targeted therapies. It was also shown that conflicting cost-effectiveness results were likely depending on what comparator arm was chosen and what comparison structure was designed in the model.Conclusion We found that there was no consistent approach applied in assessing the value of biomarkers and including the characteristics of biomarkers in an economic evaluation of targeted oncology therapies. Currently, many EEs fail to capture the full value of companion biomarkers beyond sensitivity/specificity and cost related to biomarker testing.