A Randomized Hybrid-Effectiveness Trial Comparing Pharmacogenomics (PGx) to Standard Care: The PGx Applied to Chronic Pain Treatment in Primary Care (PGx-ACT) Trial

Abstract

This trial aimed to identify the effects of providing pharmacogenomic (PGx) results and recommendations for patients with chronic pain treated in primary care practices compared to standard care. An open-label, prospective, largely virtual, type-2 hybrid effectiveness trial randomized participants to PGx or standard care arms. Adults with pain ≥ 3 months who were treated with tramadol, codeine, or hydrocodone enrolled. Alternative analgesics were recommended for CYP2D6 intermediate or poor metabolizers (IM/PMs). Prescribing decisions were at providers' discretion. The trial randomized 253 participants. A modified intent-to-treat primary analysis assessed change in pain intensity over 3 months among IM/PMs (PGx: 49; Standard care: 57). The PGx and standard care arms showed no difference in pain intensity change (−0.10 ± 0.63 vs. −0.21 ± 0.75 standard deviation; p = 0.74) or PGx-aligned care (69% vs. 63%; standardized difference [SD] = 0.13). In IM/PMs, secondary analyses of pain intensity change suggested improvements with PGx-aligned (n = 70; −0.21 ± 0.70) vs. unaligned care (n = 36; −0.06 ± 0.69) (SD = −0.22), with this difference increasing when examining IM/PMs with an analgesic change (aligned: n = 31, −0.28 ± 0.76; unaligned: n = 36, −0.06 ± 0.69; SD = −0.31). This approach to PGx implementation for chronic pain was not associated with different prescribing (i.e., similar proportions of PGx-aligned care) or clinical outcomes. Secondary analyses suggest that prescribing aligned with PGx recommendations showed a small improvement in pain intensity. However, the proportion of patients with a clinically meaningful improvement (≥ 30%) in pain intensity was similar. Future efforts should identify effective implementation methods.