Pharmacogenomic testing: aiding in the management of psychotropic therapy for adolescents with autism spectrum disorders

Impact of Pharmacogenomics on Pediatric Psychotropic Medication Prescribing in an Ambulatory Care Setting

Objective: Evidence for pharmacogenomic (PGx) guided treatment in child and adolescent psychiatry is growing. This study evaluated the impact of PGx testing on psychotropic medication prescribing in an ambulatory child and adolescent psychiatry and a developmental pediatrics clinic. Methods: This was a single-center, retrospective, descriptive analysis of patients who underwent PGx testing between January 2015 and October 2022 at a child and adolescent psychiatry clinic or developmental pediatrics clinic. The primary outcome was the proportion of patients with at least one psychotropic medication modification made 6-month posttesting that could be attributed to CYP2C19, CYP2D6, HLA-B*15:02, or HLA-A*31:01. Secondary outcomes included reason for testing, types of therapeutic modifications made, and whether the therapeutic modifications concorded with PGx guidelines. Results: A total of 193 patients were analyzed. The average age was 10 ± 4 years old, 60% were male, 78% were Caucasian. Sixty-eight percent had a primary diagnosis of a neurodevelopmental disorder, namely autism spectrum disorder (51%), and attention-deficit/hyperactivity disorder (14%). The reasons for PGx testing included medication inefficacy (34%), medication intolerance (20%), and family request (19%). At the time of PGx testing, 37% of patients were taking ≥1 psychotropic medication with PGx annotation. Overall, 35 PGx-related therapeutic modifications were made in 32 (17%) patients. These included continuing current PGx medication (6.2%) and starting PGx medication (5.2%). These modifications mainly involved antidepressants. Out of these 35 PGx-related therapeutic modifications, 94% were concordant with PGx guidelines. Among 29 patients who were prescribed at least one CYP2D6 inhibitor, 25 (86%) underwent CYP2D6 phenoconversion. Conclusions: It is critical to apply pediatric age-specific considerations when utilizing PGx testing in child and adolescent psychiatry. PGx testing stewardship could provide a framework to guide the clinical utility of PGx in a pediatric population with mental health conditions, including neurodevelopmental disorders.

Pharmacogenetic Testing in Patients with Autism Spectrum Disorder Evaluated in a Precision Medicine Clinic

OBJECTIVE

This study investigated outcomes of pharmacogenetic testing of youth with autism spectrum disorder (ASD) referred to a precision medicine clinic and explored associations between patient characteristics and pharmacogenomic testing results.

METHODS

Records for patients diagnosed with ASD and subsequently referred to a pediatric hospital's precision medicine clinic between July 1, 2010, and June 30, 2020, were reviewed. Pharmacogenetic testing results were abstracted focusing on CYP2D6 and CYP2C19. In addition, we compiled counts of patients' co-occurring diagnoses, histories of adverse drug reactions (ADRs), previously trialed ineffective medications, and previous psychiatric medication changes. Logistic regression models were fit to examine CYP2C19 and CYP2D6 metabolizer status as functions of patient demographics and prereferral medication histories.

RESULTS

Of 202 patients (mean age = 12.18 yrs), 66% were referred to precision medicine because of poor medication response. Among patients with pharmacogenomic testing results for CYP2D6, 9% were classified as poor metabolizers; among patients with results for CYP2C19, 10% were classified as rapid/ultrarapid metabolizers. Patient demographics and medication response history did not predict pharmacogenomic results. However, the number of co-occurring diagnoses positively predicted the number of nonpsychiatric ADRs and a higher probability of CYP2D6 poor metabolizer status; moreover, nonpsychiatric ADRs positively predicted CYP2C19 rapid/ultrarapid metabolizer status.

CONCLUSION

In one of the largest reported samples of youth with ASD clinically referred for pharmacogenetic testing, we observed high variability in medication response and yield for actionable results. Our findings suggest potential clinical utility for pharmacogenetic testing and introduce possible clinical profiles associated with metabolizer status.

PGx in psychiatry: Patients' knowledge, interest, and uncertainty management preferences in the context of pharmacogenomic testing

OBJECTIVE

Pharmacogenomic testing (PGx) is expanding into psychiatric care. PGx could potentially offer a unique benefit to psychiatric patients, providing information about patients' reaction to medications that could reduce the time and financial burdens of drug optimization. The aims of this study were to: (1) examine psychiatry patients' familiarity and interest in PGx, and (2) explore how Uncertainty Management Theory relates to PGx testing in psychiatry.

METHOD

We surveyed psychiatric patients, measuring their PGx familiarity and interest, attitudes toward PGx testing, and preference for managing illness uncertainty.

RESULTS

We analyzed data from 598 patients. Patients' familiarity of PGx was low, but interest was high. Thirty percent of patients were familiar with the test from communication with their healthcare provider or their own online health information seeking. A preference for seeking information was a significant positive predictor of testing interest (p < .001).

CONCLUSION

Psychiatric patients were interested in PGx testing, regardless of their uncertainty management preferences.

PRACTICE IMPLICATIONS

This study is one of the first to examine psychiatric patients' perspectives on PGx testing in mental health care. Our findings show that psychiatric patients are interested in the test and are familiar enough with PGx to be included in future research on the topic.

Pharmacogenetic Testing: Why Is It So Disappointing?

Pharmacogenetic testing to aid in making decisions about prescribing medications was approved by the U.S. Food and Drug Administration in 2005 and gradually became a common practice. However, an innovation that was thought to help individualize prescribing psychotropic medications with fewer trials and errors soon became a disappointment to clinicians. Current pharmacogenetic testing assesses how the liver metabolizes drugs through the cytochrome p 450 system; however, much of the variability in how a drug affects an individual also relies on the pharmacodynamics of the drug (i.e., the specific ways the drug changes the body). The current article discusses the advantages and disadvantages of pharmacogenetic testing to aid in prescribing psychotropic medications. [Journal of Psychosocial Nursing and Mental Health Services, 57(4), 9-12.].

Clinical utility of pharmacogenetic testing in children and adolescents with severe mental disorders

This is a retrospective cohort study of 20 children and adolescents to evaluate the clinical utility of a pharmacogenetic decision support tool. Twenty children and adolescents underwent pharmacogenetic testing between June 2014 and May 2017. All children and adolescents were evaluated at Puerta de Hierro University Hospital-Majadahonda (Madrid, Spain). We report the proportion of patients achieving clinical improvement, amelioration of side effects, and changes in number of drugs. Data normality was assessed with the Shapiro–Wilk test, and changes of pre- and post-pharmacogenetic testing were analyzed with the Wilcoxon test for paired samples. A two-sided p value threshold of 0.05 was considered for significance. Pharmacogenetic testing helped to improve the clinical outcome as measured by the Clinical Global Impressions (CGI) Scale in virtually all children (95%; 19 out of 20 children). The CGI improvement (CGI-I) was 2 (0.79) (range 1–4), 2.1 (0.56) (range 1–3), and 1.9 (0.99) (range 1–4) in foster and non-foster care children, respectively. Pharmacogenetic testing also helped to reduce the number of children using polypharmacy (from 65 to 45%), the mean number of drugs per children (from 3.3 to 2.4 drugs, p = 0.017), and self-reported relevant side effects (p = 0.006). Pharmacogenetic testing helped to improve the clinical outcome, and to reduce polypharmacy and the number of drugs used in children and adolescents with severe mental disorders. More evidence using robust (i.e., clinical trials) independent studies is required to properly determine the clinical utility and cost-effectiveness of pharmacogenetic testing tools in children and adolescents with mental disorders.