Tissue-Agnostic Drug Development

The U.S. Food and Drug Administration (FDA) has approved drugs to treat patients with tumor types based on a single anatomic site, such as renal cell carcinoma or melanoma, rather than on a biomarker alone. This standard approach is based on a number of factors, including heterogeneity of drug effects in different biomarker-positive tumor types. Additionally, drug development for some drugs was primarily directed toward a specific genomic abnormality in a specific tumor type (e.g., drugs for anaplastic lymphoma kinase ALK fusion-positive non-small cell lung cancer). In such cases, differences in biology, differences in natural histories of different cancers, differences in mutation frequencies among cancers, or differences in concomitant therapies may have necessitated diverse development considerations. As described in U.S. regulations 21 CFR 201, CFR 201.57(c)(2), the indications and usage section of drug labeling "must state that a drug is indicated for the treatment, prevention, mitigation, cure, or diagnosis of a recognized disease or condition or of a manifestation of a recognized disease or condition, or for the relief of symptoms associated with a recognized disease or condition." Such regulations, however, do not require that disease be defined solely as a specific tumor type. This manuscript will highlight scientific/biologic issues, clinical trial designs, and regulatory issues pertaining to the development of drugs agnostic of tumor type. Although the manuscript will discuss regulatory considerations as understood by the authors regarding tissue-agnostic drug development, it should not be considered formal or binding FDA guidance or policy.