Real-World Testing Landscape and Costs of Companion Diagnostics and Comprehensive Genomic Profiling Across Nine Solid Tumors in Japan: A 10-Year Analysis

INTRODUCTION: This study aimed to examine utilization, testing sequences, and associated genomic testing costs of companion diagnostics (CDx) and comprehensive genomic profiling (CGP) among Japanese patients with nine representative solid tumors. METHODS: This retrospective study used anonymized data, from Medical Data Vision Co., Ltd. (MDV; January 2015-March 2025) and JMDC Inc. (JMDC; January 2015-January 2025), for patients with solid tumors of nine cancer types who underwent CDx and/or CGP testing or received any cancer treatment. Patient demographics, distribution and testing sequences of CDx and CGP, and associated genomic testing costs per patient were evaluated. RESULTS: Proportions of CDx and CGP testing varied across nine cancer types. Most patients underwent CDx testing once or twice, although some cohorts, particularly with non-small cell lung cancer (NSCLC), were tested thrice or more. Biliary tract cancer demonstrated the highest proportions for CGP testing alone, and both CDx and CGP testing. For both CDx and CGP testing, the greatest median costs were observed for ovarian and breast cancers, with bimodal peaks near US dollars (USD) 4000 and USD 5000. Median CDx costs were equal to or higher for patients who underwent both CDx and CGP testing compared with those who had CDx testing alone, particularly in breast, pancreatic, prostate, and ovarian cancers. For CDx testing alone, NSCLC, ovarian cancer, and prostate cancer had the highest costs, with a small peak near USD 1333. These results were mostly consistent across databases. CONCLUSIONS: Multiple CDx testing followed by CGP testing increased genomic testing costs per patient. Early implementation of CGP testing could reduce redundant testing and associated delays in treatment, thereby contributing to lower overall healthcare costs and more efficient treatment selection amid rapid advances in targeted therapies.