Pharmacogenetics: FDA Releases Table of Gene-Drug Interactions

The US Food and Drug Administration (FDA) on Thursday published a table identifying more than 50 gene-drug interactions that the agency says are supported by scientific evidence and announced it is considering new approaches to evaluating pharmacogenetic associations.
 
“Consistent with our mission to protect and promote public health, we believe it is important to take steps now to help ensure that claims being made for pharmacogenetic tests offered today are grounded in sound science to avoid inappropriate management of patients’ medications,” said Center for Devices and Radiological Health Director Jeff Shuren and Center for Drug Evaluation and Research Director Janet Woodcock.
 
Background
 
The release of the table comes after years of grappling over how FDA should approach pharmacogenetic (PGx) testing and the broader field of laboratory developed tests (LDTs). In 2018, FDA issued a safety communication and statement advising that many genetic tests purporting to predict a patient’s response to medications have not been reviewed by the agency and may not be supported by scientific or clinical evidence.
 
At the same time, various industry groups, including the American Clinical Laboratory Association (ACLA) and the Coalition to Preserve Access to Pharmacogenomics Information, have pushed back against FDA’s efforts to crack down on pharmacogenetics tests.
 
In a citizen petition filed last month on behalf of the Coalition to Preserve Access to Pharmacogenomics Information, law firm Hyman, Phelps & McNamara called on FDA to revise its safety communication to state that test makers “may communicate information about gene-drug interactions as part of genetic test reports to the extent that such information is supported by adequate evidence and is not contraindicated by information in drug labels.”
 
Pharmacogenetics Associations Table
 
FDA says the table is “intended to provide the agency’s view of the state of the current science in pharmacogenetics” and includes established gene-drug interactions that appear in labeling and some interactions that, while not appearing in labeling, are supported by sufficient scientific evidence.
 
The table also denotes pharmacogenetic associations that may indicate an impact on a drug’s safety or a patient’s response and gene-drug associations for which an impact has not been established.
 
FDA stresses that the table is not complete and that it will continue to review scientific evidence, including guidelines developed by the Clinical Pharmacogenetics Implementation Consortium, to expand the list. The agency has also opened a public docket to solicit comments from stakeholders on specific pharmacogenetic associations that should or should not be considered for the table.
 
The table comes with a host of disclaimers, including that, “Each patient’s genetic makeup is only one of many factors that may impact drug concentrations and response,” and that FDA does not necessarily endorse pharmacogenetic tests for interactions included on the list.
 
FDA also says the table “is not intended to affect current regulatory requirements or policies, including FDA’s policy regarding companion diagnostics. Nor is the table intended to make an assessment on the safe and effective use of, or regulatory requirements for, tests that detect variants in the referenced genes, or to provide comprehensive information on the described gene-drug interactions.”
 
Despite those disclaimers, the list could offer insight to pharmacogenetic test makers on what the agency considers sufficient evidence to support specific pharmacogenetic associations.
 
FDA