Pharmacogenetic testing in the Veterans Health Administration (VHA): policy recommendations from the VHA Clinical Pharmacogenetics Subcommittee

The Veterans Health Administration (VHA) Clinical Pharmacogenetics Subcommittee is charged with making recommendations about whether specific pharmacogenetic tests should be used in healthcare at VHA facilities. We describe a process to inform VHA pharmacogenetic testing policy. After developing consensus definitions of clinical validity and utility, the Subcommittee identified salient drug–gene pairs with potential clinical application in VHA. Members met monthly to discuss each drug–gene pair, the evidence of clinical utility for the associated pharmacogenetic test, and any VHA-specific testing considerations. The Subcommittee classified each test as strongly recommended, recommended, or not routinely recommended before drug initiation. Of 30 drug–gene pair tests reviewed, the Subcommittee classified 4 (13%) as strongly recommended, including HLA-B*15:02 for carbamazepine-associated Stevens–Johnston syndrome and G6PD for rasburicase-associated hemolytic anemia; 12 (40%) as recommended, including CYP2D6 for codeine toxicity; and 14 (47%) as not routinely recommended, such as CYP2C19 for clopidogrel dosing. Only half of drug–gene pairs with high clinical validity received Subcommittee support for policy promoting their widespread use across VHA. The Subcommittee generally found insufficient evidence of clinical utility or available, effective alternative strategies for the remainders. Continual evidence review and rigorous outcomes research will help promote the translation of pharmacogenetic discovery to healthcare.