Table 2.

Summary of current challenges to companion diagnostic implementation and recommendations for change.

Challenge	Recommendation
Confusion caused by approval of multiple assays for single biomarker	Robust assay concordance studies performed by independent commercial and academic laboratories Efficacy data from multiple biomarker tests to be generated in pivotal clinical trials, to enable comparison of patient benefit
Confusion caused by “approved assay” terminology in drug labeling	Suggest “analytically validated assay” instead, with clear guidance on what constitutes validation For simpler, single target genetic mutations, new diagnostic tests for existing biomarkers could be approved based on analytic performance only
Lack of clarity on biomarker selection criteria in drug label	Consultation with recognized academic associations involved in biomarker testing, e.g., Association for Molecular Pathology (AMP), International Association for the Study of Lung Cancer (IASLC), College of American Pathologists (CAP), and European Society of Pathology (ESP) prior to labeling discussions
Access to approved assay for drug/diagnostic co-registration not granted	Permit approved companion diagnostics to be used “off the shelf” in approved indication with no requirement for partnership between a diagnostic supplier and a pharmaceutical company. Remove requirement for supplemental PMA. All testing should be in compliance with CAP/CLIA (or equivalent outside the United States)
Lack of innovation in diagnostics due to “first past the post” diagnostic defining intended use population	Permit the use of new diagnostics in phase III studies, even for SoC arm. Ideally, the risk/benefit would be informed by clinical data, with efficacy data for the approved diagnostic included in the pivotal study