Pharmacogenetics (PGx) is the study of how an individual’s genetic makeup affects their drug response and metabolism. An understanding of PGx could help clinicians make prescribing decisions and has the potential to be implemented in routine care worldwide. PGx has understandably been gaining traction and support, with pharmacogenomic elements being implemented into many international Genomic studies.
Yesterday, the FDA released a list of gene-drug associated variants that they believe have enough scientific evidence to suggest that subgroups of patients are likely to have an altered drug metabolism and deserve clinical consideration. Although they claim the table is not intended to affect the current policies for testing and recognise that many factors should be taken into consideration by practitioners; the FDA has released the list as they “felt it is important to provide clinicians, patients and test developers with the information now while we continue to review the scientific evidence”.
The table can be found here and is limited to pharmacogenetic associations that are related to drug metabolising enzyme gene variants, drug transporter gene variants and gene variants that are associated with a predisposition to adverse events. Recognising that the list is incomplete, they have stated that they will update the resource periodically and have asked stakeholders to offer specific comments on pharmacogenetic associations that FDA should or should not include in the table with the evidence supporting it.
This comes after the FDA warned against the alteration of treatment plans based upon results of unapproved pharmacogenetic tests in October 2018, after becoming aware of pharmacogenetic tests without being supported by enough scientific evidence. With some of these tests being for medications to treat seizures and pain, including opioids, it remains a concern for the FDA that these tests do not affect the safe use of such medications.
Naturally, regulatory bodies are increasing the focus on evidence-based practice, and this list stems from a collaboration between the FDA’s Centre for Devices and Radiological Health and Centre for Drug Evaluation and Research, with the intent to provide the agency’s view on the state of Pharmacogenetics.
The FDA is also exploring further approaches for evaluating gene-drug association evidence, including a “community-based collaborative approach” to continue engaging with stakeholders for improved evidence-based pharmacogenetic testing.