Deonovic, Benjamin

Aims: The primary aim of this study was to determine whether CYP2D6 phenotypes are associated with atomoxetine treatment outcomes in children and adolescents with attention-deficit hyperactivity disorder. Patients and Methods: Patients 21 years and younger with a known CYP2D6 genotype and a prescription for atomoxetine were included in this electronic health record review. The primary outcome was defined as discontinuation of atomoxetine due to a lack of efficacy or due to toxicity. CYP2D6 activity scores were adjusted to account for phenoconversion if patients were concomitantly taking a CYP2D6 inhibitor medication. Results: Of 108 patients that met inclusion criteria, including 13 poor, 30 intermediate, 61 normal, and 4 ultra-rapid CYP2D6 metabolizers after adjusting for phenoconversion. Normal/ultrarapid metabolizers were significantly more likely to discontinue atomoxetine due to lack of efficacy (subdistribution hazard ratio [sHR] = 1.9, p = 0.04), while poor/intermediate metabolizers were significantly more likely to stop due to toxicity (sHR 0.4, p = 0.03). A significant nonlinear effect of adjusted activity score on likelihood of discontinuation due to lack of efficacy ( p < 0.001) or toxicity ( p < 0.001) was identified, where higher CYP2D6 activity scores were associated with more discontinuation due to lack of efficacy and lower activity scores were associated with more discontinuation due to toxicity. When CYP2D6 genotype was available prior to prescribing atomoxetine in intermediate/poor metabolizers, lower median initial doses were observed (0.5 mg/kg/day) compared to those who underwent CYP2D6 genotyping after the initial atomoxetine prescription (0.8 mg/kg/day). Conclusion: Patients with normal or increased CYP2D6 phenotypes may be more likely to discontinue atomoxetine due to a lack of efficacy, while those with reduced function CYP2D6 phenotypes may be more likely to discontinue atomoxetine due to toxicity.

Abstract Background Coagulation markers are used to guide clinical anticoagulation decisions. We aimed to identify circulating metabolites that are associated with coagulation markers in children with congenital heart disease (CHD). Methods Plasma samples were separated from whole blood under consistent conditions. Untargeted metabolomic data were measured in plasma from up to 203 young patients (age range: 0 days-24 years) with CHD before cardiac surgery. Coagulation markers included activated partial thromboplastin time (aPTT), prothrombin time (PT), and activated clotting time (ACT). Weighted Gene Co-expression Network Analysis (WGCNA) was performed to explore metabolite modules (clusters). Associations of metabolites with the coagulation markers were assessed cross-sectionally with regression models, with false discovery rate (FDR) correction for multiple comparison. Associations between coagulation markers and ‘eigenmetabolites’ from WGCNA modules were assessed by correlation analysis. Results A total of 776 metabolites were included in the final analysis. Among these, 20 metabolites were associated with PT and one (valine) with ACT (FDR q value < 0.05). Among the metabolites associated with PT, the top three were retinol, 1-palmitoyl-GPI (16:0), and X-25371 (identity unknown). One module from WGCNA with metabolites from the lipid super pathway was correlated with PT (P = 0.004). Conclusion In this first attempt to identify novel metabolites for coagulation markers, we report 21 metabolites associated with PT or ACT in children with CHD. Future studies are needed to replicate these findings in independent cohorts and to elucidate the biological mechanisms linking these metabolites to hemostatic regulation.