Over the last 20 years, precision oncology has changed the treatment landscape for patients with specific cancers and has become a much sought-after goal in oncology drug development. However, recent drug approvals by the United States Food and Drug Administration (FDA) under the auspices of precision oncology may be setting up this therapeutic approach to fail.

Early drug development in precision oncology involved identifying molecular alterations in a specific cancer type (e.g. human epidermal growth factor-2 [HER2] in breast cancer) then developing therapeutic agents to target this specific molecular alteration. This approach is well demonstrated by trastuzumab in HER2+ breast cancer, imatinib in chronic myelogenous leukemia, erlotinib and gefitinib in epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer, and others. While this has been successful, it has only benefited a small proportion of oncology patients.

More recently, next generation sequencing and a better understanding of molecular pathways has expanded the population hypothesized to benefit from precision oncology. However, when approved drug indications are broader than a studied population, the approvals can harm patients and the field of precision oncology.