Background: Pharmacogenomics is increasingly important to guide objective, safe and effective individualised prescribing. Opioids, the gold standard for cancer pain relief, are among the commonest medications prescribed in palliative care practice. The influence of pharmacogenomics on opioid response has been increasingly studied, but most of these are in a non-cancer context.
Aims: We aimed to examine the effects of 36 gene variants in advanced cancer to examine associations with pain scores, opioid dose, and adverse effects.
Methods: This Australian-first multi-centre Opioid Pharmaogenomics (OPPtiC) study recruited patients receiving opioids for advanced cancer pain. Clinical data (demographics, opioids), validated instruments (pain and adverse effects), and blood (DNA, opioid pharmacokinetic data) were collected. Univariate and multivariate logistic regression was used to evaluate associations between clinical outcomes (opioid dose, pain, adverse effects), and genotypes of interest.
Results: Fifty-four participants were recruited to the study. Observations on statistically significant associations between gene variants and outcomes of interest will be described, particularly with relating to receptor genes (DRD2, HTR2A, OPRM1, OPRD1), neuroimmune activation pathway genes (ARRB2, BDNF, COMT, IL2, IL6R, MYD88, STAT6, TLR4) and other genes (NF1B, RHBDF2, SLC6A4). The relationship between CYP2D6, oxycodone pharmacokinetics and the study outcomes will also be discussed.
Conclusions: The presence of certain gene variants was observed be associated with clinically and statistically significant differences in opioid dosing, pain scores, and adverse effect outcomes in people with advanced cancer pain.