OBJECTIVES:Genetic variation has been proposed as a potential contributor to antidepressant nonresponse, but its role in treatment-resistant depression (TRD) remains unclear. This study used pharmacogenetics (PGx) to characterize genetic variation in TRD and determine whether actionable PGx variation and drug-gene interaction (DGI) mismatch were associated with antidepressant nonresponse and TRD burden. METHODS:This observational study included 158 individuals with TRD recruited from outpatient clinics in Western Australia. Genotype and genotype-predicted phenotypes for CYP2B6, CYP2C19, and CYP2D6 were derived from commercial PGx testing and compared with ethnicity-matched reference populations from ClinPGx. Antidepressant-specific DGIs were classified as actionable or nonactionable according to Clinical Pharmacogenetics Implementation Consortium guidelines, and unsupervised clustering was used to identify clusters based on these actionability profiles. Analyses were performed to determine if actionable PGx variation, cluster membership, or PGx mismatch was associated with TRD burden (number of failed antidepressant trials). RESULTS:PGx variation in the TRD cohort was consistent with population expectations, with no evidence of enrichment for actionable PGx variants. Clustering identified six clusters with distinct and gene-specific patterns of PGx variation independent of demographic and clinical characteristics. However, neither PGx mismatch nor cluster membership were associated with TRD burden. CONCLUSION:These findings suggest that actionable PGx phenotypes are neither enriched in TRD nor associated with greater TRD severity. Rather, the results indicate that TRD does not represent a single, unified PGx-predicted 'poor pharmacological responder' phenotype but instead reflects a biologically heterogeneous collection of distinct PGx profiles.
Methotrexate (MTX) treatment of juvenile idiopathic arthritis (JIA) is complicated by severe intolerance in approximately 30% of patients. MTX intolerance typically presents as nausea (anticipatory and postdose), vomiting, and behavioral symptoms. Although genetic variants in SLCO1B1 have been associated with MTX toxicity in retrospective studies of inflammatory bowel disease, prospective evaluation of this relationship in JIA patients is lacking. This study examined SLCO1B1-MTX intolerance associations accounting for clinical covariates in a prospective observational cohort of patients receiving standard weekly MTX doses (5-25 mg/m2). We performed a zero-inflated Poisson analysis using forward stepwise inclusion of clinical covariates followed by SLCO1B1 alleles. Among 217 JIA patients who completed the MTX Intolerance Severity Score (MISS) survey at 6 ± 2 months post-MTX initiation, the cohort was predominantly female (69.1%), White (76.5%), and received supplementation with folic acid (70.5%). Over 30% of patients met the threshold for MTX intolerance (MISS ≥ 6), and 62.7% of patients reported any MTX intolerance symptoms (MISS > 0). The SLCO1B1*37 allele was associated with lower odds of MISS > 0 (odds ratio = 0.60, P = 0.046) and a lower reported MISS score (incidence rate ratio = 0.74, P < 0.001) among individuals with non-zero intolerance, suggesting protection from MTX intolerance symptoms. These associations were consistent in sensitivity analyses stratified by folic acid supplementation. Further validation of these findings is needed to support future pharmacogenetic-guided MTX dosing strategies, including evaluation of other SLCO1B1 alleles.
OBJECTIVES:Clinical trial evidence is scarce for optimal antiplatelet strategies in patients undergoing intracranial artery stenting with CYP2C19 loss‑of‑function alleles, especially regarding the efficacy‑safety balance. METHODS:This single‑center retrospective study enrolled patients receiving genotype‑guided antiplatelet regimens for intracranial stenting between January and December 2023, with 6‑month follow‑up. Clinical outcomes were compared across CYP2C19 phenotypes. RESULTS:Among 205 patients, 46.8% were normal metabolizers, 40.5% intermediate metabolizers, and 12.7% poor metabolizers. Aspirin-clopidogrel was prescribed for all normal metabolizers, 80.7% intermediate metabolizers, and 19.2% poor metabolizers. No intergroup differences were observed in risks of ischemic stroke/transient ischemic attack (TIA), cardiovascular events, intracerebral hemorrhage (ICH), or any bleeding (all P > 0.05). In intermediate metabolizers and poor metabolizer subgroups, ischemic stroke/TIA rates were 11.1% in the aspirin-clopidogrel group and 9.68% in the aspirin-ticagrelor group, with no significant difference compared to normal metabolizers (4.17%). ICH rates were 1.39% in the aspirin-clopidogrel group and 6.45% in the aspirin-ticagrelor group, showing no significant difference versus normal metabolizers (1.04%). Multivariate logistic analysis found the number of stents (odds ratio [OR] = 2.70; 95% confidence interval [CI] = 0.89-6.95; P = 0.043) was a risk factor for ischemic stroke/TIA. Ticagrelor-based dual antiplatelet therapy (DAPT; OR = 10.57; 95% CI = 1.00-111.7; P = 0.05) and baseline l ow-density lipoprotein cholesterol (LDL-C; OR = 7.22; 95% CI = 1.80-29.01; P = 0.005) were associated with ICH risk. CONCLUSION:Antiplatelet regimens were adjusted for a subset of intermediate metabolizers and poor metabolizers prior to stenting, and the 6-month clinical outcomes were comparable across normal metabolizers, intermediate metabolizers, and poor metabolizers. The stent number was associated with ischemic stroke/TIA risk; baseline LDL-C and ticagrelor-based DAPT with ICH risk. These exploratory findings need validation in adequately powered studies.
BACKGROUND:Risperidone-clozapine response varies substantially in schizophrenia. HTR2A polymorphisms may influence antipsychotic response, but rs6311-rs6313 haplotypes remain unexplored in the Indonesian Batak population. This study evaluated associations of HTR2A rs6311-rs6313 with early risperidone-clozapine response. METHODS:This prospective observational case-control study included 160 Batak inpatients with schizophrenia, comprising 80 responders and 80 nonresponders to risperidone-clozapine therapy. Genetic analyses included Hardy-Weinberg equilibrium (HWE), minor allele frequency (MAF), linkage disequilibrium, genotype and allele association, haplotype, permutation testing, genetic models, and multivariable logistic regression. RESULTS:Genotype distributions conformed to HWE (P > 0.05), with both variants showing a MAF of 0.28 and strong linkage disequilibrium (r2 = 0.969, D' = 0.98). The rs6311 GG/rs6313 CC genotype was significantly associated with nonresponse to risperidone-clozapine therapy [odds ratio (OR) = 3.69, 95% confidence interval (CI): 1.10-12.36; P = 0.034], while the rs6311 G/rs6313 C allele was also associated with nonresponse (OR = 1.71, 95% CI: 1.04-2.80; P = 0.034). The recessive model remained significant after multivariable adjustment (adjusted OR = 3.36, 95% CI: 1.02-11.07; P = 0.046). TA and CG haplotypes remained significant after 10 000 permutations (P = 0.0415 and P = 0.0416), whereas single-marker associations lost significance (P = 0.0607). CONCLUSION:HTR2A variation was associated with early risperidone-clozapine response, with consistent signals under the recessive model and at the haplotype level. Haplotype associations remained significant after permutation correction, suggesting that haplotype analysis may provide a more robust approach for detecting pharmacogenetic contributions to treatment response.
Pre-emptive genotyping and genotype-guided dose adjustments are generally recommended for seven hypofunctional polymorphisms in the DPYD gene that are associated with fluoropyrimidine toxicity. However, targeted genotyping may miss uncommon and population-specific hypofunctional variants. Therefore, in 2021, we replaced conventional targeted genotyping with comprehensive DPYD exome sequencing. The objective of the current study was to identify uncommon hypofunctional variants and assess their association with fluoropyrimidine toxicity. In a cohort of 762 consecutive patients pre-emptively genotyped between 2021 and 2025, among the seven established risk variants, we identified *2A and HapB3 at their expected minor allele frequencies (MAF), but no carriers of any of the five other established risk variants. Interestingly, four patients were heterozygous for the rare missense c.257C>T variant (Pro86Leu; rs568132506), previously associated with fluoropyrimidine toxicity. The MAF (2.62 × 10-3) was similar to that previously described in Middle Eastern populations but 26-fold higher than in the gnomAD global population. Three of the carriers (75%) developed grade 3-4 fluoropyrimidine toxicity after one or two cycles, corresponding to a relative risk of 14.5 (95% confidence interval: 5.0-30.4, P = 0.0009) compared with a control cohort without hypofunctional DPYD variants. Our findings add to the growing body of evidence indicating that DPYD c.257C>T may be associated with severe fluoropyrimidine toxicity. Future studies should examine the clinical utility of including uncommon but potentially actionable variants, such as c.257C>T, into pre-emptive genotyping algorithms. This may be particularly important in multiethnic populations in which these variants can be more prevalent than those variants for which pre-emptive genotyping is generally recommended.
