Initial severity and efficacy of risperidone in autism: Results from the RUPP trial

The polymorphisms of candidate pharmacokinetic and pharmacodynamic genes and their pharmacogenetic impacts on the effectiveness of risperidone maintenance therapy among Saudi children with autism

BACKGROUND

Antipsychotics, including risperidone (RIS), are frequently indicated for various autism spectrum disorder (ASD) manifestations; however, "actionable" PGx testing in psychiatry regarding antipsychotic dosing and selection has limited applications in routine clinical practice because of the lack of standard guidelines, mostly due to the inconsistency and scarcity of genetic variant data. The current study is aimed at examining the association of RIS effectiveness, according to ABC-CV and CGI indexes, with relevant pharmacokinetics (PK) and pharmacodynamics (PD) genes.

METHODS

Eighty-nine ASD children who received a consistent RIS-based regimen for at least 8 weeks were included. The Axiom PharmacoFocus Array technique was employed to generate accurate star allele-predicted phenotypes of 3 PK genes (CYP3A4, CYP3A5, and CYP2D6). Genotype calls for 5 candidate PD receptor genes (DRD1, DRD2, DRD3, HTR2C, and HTR2A) were obtained and reported as wild type, heterozygous, or homozygous for 11 variants.

RESULTS

Based on the ABC total score, 42 (47.2%) children were classified as responders, while 47 (52.8%) were classified as nonresponders. Multivariate logistic regression analyses, adjusted for nongenetic factors, suggested nonsignificant impacts of the star allele-predicted phenotypes of all 3 PK genes on improvement in ASD symptoms or CGI scores. However, significant positive or negative associations of certain PD variants involved in dopaminergic and serotonergic pathways were observed with specific ASD core and noncore symptom subdomains. Our significant polymorphism findings, mainly those in DRD2 (rs1800497, rs1799978, and rs2734841), HTR2C (rs3813929), and HTR2A (rs6311), were largely consistent with earlier findings (predictors of RIS effectiveness in adult schizophrenia patients), confirming their validity for identifying ASD children with a greater likelihood of core symptom improvement compared to noncarriers/wild types. Other novel findings of this study, such as significant improvements in DRD3 rs167771 carriers, particularly in ABC total and lethargy/social withdrawal scores, and DRD1 rs1875964 homozygotes and DRD2 rs1079598 wild types in stereotypic behavior, warrant further verification in biochemical and clinical studies to confirm their feasibility for inclusion in a PGx panel.

CONCLUSION

In conclusion, we provide evidence of potential genetic markers involved in clinical response variability to RIS therapy in ASD children. However, replication in prospective samples with greater ethnic diversity and sample sizes is necessary.

The pediatric psychopharmacology of autism spectrum disorder: A systematic review - Part I: The past and the present

Autism Spectrum Disorder (ASD) is a severe and lifelong neurodevelopmental disorder, with high social costs and a dramatic burden on the quality of life of patients and family members. Despite its high prevalence, reaching 1/54 children and 1/45 adults in the United States, no pharmacological treatment is still directed to core symptoms of ASD, encompassing social and communication deficits, repetitive behaviors, restricted interests, and abnormal sensory processing. The purpose of this review is to provide an overview of the state-of-the-art of psychopharmacological therapy available today for ASD in children and adolescents, in order to foster best practices and to organize new strategies for future research. To date, atypical antipsychotics such as risperidone and aripiprazole represent the first line of intervention for hyperactivity, impulsivity, agitation, temper outbursts or aggression towards self or others. Tricyclic antidepressants are less prescribed because of uncertain efficacy and important side effects. SSRIs, especially fluoxetine and sertraline, may be effective in treating repetitive behaviors (anxiety and obsessive-compulsive symptoms) and irritability/agitation, while mirtazapine is more helpful with sleep problems. Low doses of buspirone have shown some efficacy on restrictive and repetitive behaviors in combination with behavioral interventions. Stimulants, and to a lesser extent atomoxetine, are effective in reducing hyperactivity, inattention and impulsivity also in comorbid ASD-ADHD, although with somewhat lower efficacy and greater incidence of side effects compared to idiopathic ADHD. Clonidine and guanfacine display some efficacy on hyperactivity and stereotypic behaviors. For several other drugs, case reports and open-label studies suggest possible efficacy, but no randomized controlled trial has yet been performed. Research in the pediatric psychopharmacology of ASD is still faced with at least two major hurdles: (a) Great interindividual variability in clinical response and side effect sensitivity is observed in the ASD population. This low level of predictability would benefit from symptom-specific treatment algorithms and from biomarkers to support drug choice; (b) To this date, no psychoactive drug appears to directly ameliorate core autism symptoms, although some indirect improvement has been reported with several drugs, once the comorbid target symptom is abated.

Methylphenidate in Autism Spectrum Disorder: A Long-Term Follow up Naturalistic Study

Autism spectrum disorder (ASD) often co-occurs with attention deficit/hyperactivity disorder (ADHD). Although methylphenidate (MPH) efficacy and safety are well-demonstrated for ADHD, evidences are scant in the context of ASD. This naturalistic study aimed to analyze long-term MPH efficacy and safety in 40 ADHD children and adolescents with comorbid ASD, comparing them with 40 ones affected by ADHD without ASD. Treatment lasted from 6 to 156 months (longer than 24 months in more than three quarters of patients). Efficacy and safety were measured by clinical global impression and children global assessment scales; influence of intellectual functioning was examined. Comparisons between groups were made by Wilcoxon or Friedmann tests; relationships between functioning scores and other characteristics were analyzed by ordinal logistic and linear regression. Results demonstrated that MPH in patients with ASD was associated with significative reduction of illness severity, clinical improvement and amelioration of global functioning, without significant differences with patients having ADHD without ASD. The trend of reduction of illness severity and increase of global functioning were favorably related with intellectual functioning. No serious adverse events were reported. The findings showed that long-term MPH was effective and well-tolerated in ADHD children and adolescents with comorbid high functioning ASD.

Clinical Assessment, Genetics, and Treatment Approaches in Autism Spectrum Disorder (ASD)

Autism spectrum disorder (ASD) consists of a genetically heterogenous group of neurobehavioral disorders characterized by impairment in three behavioral domains including communication, social interaction, and stereotypic repetitive behaviors. ASD affects more than 1% of children in Western societies, with diagnoses on the rise due to improved recognition, screening, clinical assessment, and diagnostic testing. We reviewed the role of genetic and metabolic factors which contribute to the causation of ASD with the use of new genetic technology. Up to 40 percent of individuals with ASD are now diagnosed with genetic syndromes or have chromosomal abnormalities including small DNA deletions or duplications, single gene conditions, or gene variants and metabolic disturbances with mitochondrial dysfunction. Although the heritability estimate for ASD is between 70 and 90%, there is a lower molecular diagnostic yield than anticipated. A likely explanation may relate to multifactorial causation with etiological heterogeneity and hundreds of genes involved with a complex interplay between inheritance and environmental factors influenced by epigenetics and capabilities to identify causative genes and their variants for ASD. Behavioral and psychiatric correlates, diagnosis and genetic evaluation with testing are discussed along with psychiatric treatment approaches and pharmacogenetics for selection of medication to treat challenging behaviors or comorbidities commonly seen in ASD. We emphasize prioritizing treatment based on targeted symptoms for individuals with ASD, as treatment will vary from patient to patient based on diagnosis, comorbidities, causation, and symptom severity.

Medical Cannabis in Children

The use of medical cannabis in children is rapidly growing. While robust evidence currently exists only for pure cannabidiol (CBD) to treat specific types of refractory epilepsy, in most cases, artisanal strains of CBD-rich medical cannabis are being used to treat children with various types of refractory epilepsy or irritability associated with autism spectrum disorder (ASD). Other common pediatric disorders that are being considered for cannabis treatment are Tourette syndrome and spasticity. As recreational cannabis use during youth is associated with serious adverse events and medical cannabis use is believed to have a relatively high placebo effect, decisions to use medical cannabis during childhood and adolescence should be made with caution and based on evidence. This review summarizes the current evidence for safety, tolerability, and efficacy of medical cannabis in children with epilepsy and in children with ASD. The main risks associated with use of Δ9-tetrahydrocannabinol (THC) and CBD in the pediatric population are described, as well as the debate regarding the use of whole-plant extract to retain a possible "entourage effect" as opposed to pure cannabinoids that are more standardized and reproducible.

A Focused Review on the Treatment of Pediatric Patients with Atypical Antipsychotics

OBJECTIVES

The use of atypical antipsychotic medications in pediatric patients has become more prevalent in recent years. The purpose of this review is to provide a clinically relevant update of recent selected key publications regarding the use of atypical antipsychotics in this population.

METHODS

Studies reviewed included randomized, double-blind, placebo-controlled medication trials conducted within the past 5 years. A PubMed search was conducted for each of the 11 second-generation antipsychotic medications currently approved by the Food and Drug Administration for use in the United States: clozapine, risperidone, olanzapine, quetiapine, aripiprazole, ziprasidone, paliperidone, asenapine, iloperidone, lurasidone, and cariprazine. Trials published in English with subjects 18 years of age and younger were included in this review. Additional studies, chosen for their significance to clinical practice, were also included at the discretion of the authors.

RESULTS

This review demonstrates that more empiric data are available regarding both the acute efficacy and, to a lesser extent, the longer-term efficacy and tolerability for several of the considered antipsychotic medications. The clinical conditions for which these medications have been studied include schizophrenia, bipolar disorder, Tourette's disorder, and autism spectrum disorder. They have also been used as an adjunctive treatment for disruptive behavior disorders with aggression, which have not responded to treatment with stimulants.

CONCLUSION

Evidence regarding the efficacy and tolerability of antipsychotic medications for mental health disorders in children and adolescents has expanded exponentially in recent years. However, more information is needed so that evidence-based comparisons between medications can be made. In the future, data enabling the selection of medications based upon individual patient characteristics could potentially lead to greater efficacy and efficiency in treating what are frequently debilitating medical conditions. Maladaptive aggression in children, often treated with antipsychotics, is one such area in which there is a dearth of actual information available to the clinician. It is to be hoped that additional, longer-term studies of these medications will further inform evidence-based practice in clinical settings.

Pharmacotherapy of emotional and behavioral symptoms associated with autism spectrum disorder in children and adolescents

Autism spectrum disorder (ASD) is characterized by impairment in social communication and restricted patterns of behavior. Although there is no pharmacological treatment approved by the US Food and Drug Administration (FDA) for the core symptoms of ASD, there is mounting support in the literature for the management of behavioral symptoms associated with this developmental disorder, in particular, irritability and hyperactivity. Aripiprazole and risperidone are currently approved by the FDA for the treatment of irritability in youth with ASD. Though not FDA-approved, methylphenidate and guanfacine are effective for the management of hyperactivity in children with ASD. Selective serotonin reuptake inhibitors are often used in clinical practice to target anxiety and compulsions; however, there is little evidence to support its use in this population. There is a great need for further research on the safety and efficacy of existing psychotropic medications in youth with ASD, as well as the development of new treatment modalities for the core and associated behavioral symptoms.

UGT1A1 polymorphisms associated with prolactin response in risperidone-treated children and adolescents with autism spectrum disorder

The aim of this study was to investigate the association of drug-metabolizing enzyme and transporter (DMET) polymorphisms with the risperidone-induced prolactin response using an overlapping gene model between serum prolactin level and hyperprolactinemia in autism spectrum disorder (ASD) patients. Eighty-four ASD patients who were receiving risperidone for at least 1 month were recruited and then assigned to either the normal prolactin group or the hyperprolactinemia group based on their serum prolactin level. The genotype profile of 1936 (1931 single nucleotide polymorphisms (SNPs) and 5 copy number variation (CNVs) drug metabolism markers was obtained using the Affymetrix DMET Plus GeneChip microarray platform. Genotypes of SNPs used to test the accuracy of DMET genotype profiling were determined using TaqMan SNP Genotyping Assay kits. Eighty-four patients were selected for the allelic association study after microarray analyses (51 in the normal prolactin group, and 33 in the hyperprolactinemia group). An overlapping allelic association analysis of both analyses discovered five DMET SNPs with a suggestive association (P < 0.05) with risperidone-induced prolactin response. Three UGT1A1 SNPs (UGT1A1*80c.-364C > T, UGT1A1*93 c.-3156G > A, and UGT1A1 c.-2950A > G, showed a suggestive association with the risperidone-induced prolactin response and found to be in complete linkage disequilibrium (D' value of 1). In this DMET microarray platform, we found three UGT1A1 variants with suggestive evidences of association with the risperidone-induced prolactin response both measured by hyperprolactinemia and by prolactin level. However, due to the lack of validation studies confirmation and further exploration are needed in future pharmacogenomic studies.

Initial severity of major depression and efficacy of new generation antidepressants: individual participant data meta-analysis

OBJECTIVE

The role of baseline severity as effect modifier in various psychiatric disorders is a topic of controversy and of clinical import. This study aims to examine whether baseline severity modifies the efficacy of various antidepressants for major depression through individual participant data (IPD) meta-analysis.

METHOD

We identified all placebo-controlled, double-blind randomised trials of new generation antidepressants in the acute phase treatment of major depression conducted in Japan and requested their IPD through the public-private partnerships (PPPs) between the relevant academic societies and the pharmaceutical companies. The effect modification by baseline depression severity was examined through six increasingly complex competing mixed-effects models for repeated measures.

RESULTS

We identified eleven eligible trials and obtained IPD from six, which compared duloxetine, escitalopram, mirtazapine, paroxetine or bupropion against placebo (total n = 2464). The best-fitting model revealed that the interaction between baseline severity and treatment was not statistically significant (coefficient = -0.04, 95% confidence interval: -0.16 to 0.08, P = 0.49). Several sensitivity analyses confirmed the robustness of the findings.

CONCLUSION

We may expect as much benefit from antidepressant treatments for mild, moderate or severe major depression. Clinical practice guidelines will need to take these findings into consideration.

Initial symptom severity of bipolar I disorder and the efficacy of olanzapine: a meta-analysis of individual participant data from five placebo-controlled studies

BACKGROUND

The efficacy of antipsychotics across the initial severity range in patients with acute mania remains unclear. Therefore, we examined the influence of baseline severity on the efficacy of olanzapine.

METHODS

We did an individual participant data meta-analysis of double-blind, randomised controlled trials that compared olanzapine with placebo, identified through searches of the ClinicalStudyRequest.com database on Feb 2, 2016. We included patients with acute mania associated with bipolar I disorder. We examined the association between baseline and change scores on the Young Mania Rating Scale (YMRS; range 0-60) up to 3 weeks for olanzapine versus placebo groups using eight increasingly complex competing mixed-effects models for repeated measures.

FINDINGS

We identified 33 reports, five (15%) of which were eligible and contained data for 939 patients (552 received olanzapine; 387 received placebo). The interaction between baseline severity and treatment was significant (β=0·22, 95% CI 0·05-0·39; p=0·013). The greater the baseline severity, the greater the magnitude of the differences between olanzapine and placebo was expected. The mean estimated YMRS scores were reduced at 3 weeks in both groups, but were greater with olazapine than placebo by 2·56 points for patients with a baseline score of 20-25 (9·26 for olanzapine vs 6·70 for placebo; effect size 0·35, 95% CI 0·11-0·60), by 4·74 points for a baseline score of 25-35 (14·25 vs 9·51; 0·58, 0·34-0·86), and by 8·01 points for a baseline score of 35-60 (21·72 vs 13·71; 0·70, 0·31-1·23).

INTERPRETATION

Benefits of olanzapine can be expected for patients across the full spectrum of symptom severity who are likely to be treated for acute mania. Less severely ill patients seem to benefit less in terms of olanzapine efficacy, but still experience the same side-effects as more severely ill patients. Thus, clinicians and patients should carefully consider the benefit-to-risk ratio of olanzapine and its additional, prophylactic effect against relapse in the long term. The generalisability of these results to other antipsychotics, trial designs, and medical conditions remains to be established.

FUNDING

None.

Early Social Enrichment Improves Social Motivation and Skills in a Monogenic Mouse Model of Autism, the Oprm1 (-/-) Mouse

Environmental enrichment has been proven to have positive effects on both behavioral and physiological phenotypes in rodent models of mental and neurodevelopmental disorders. In this study, we used mice lacking the µ-opioid receptor gene (Oprm1^−/−), which has been shown to have deficits in social competence and communication, to assess the hypothesis that early enrichment can ameliorate sociability during development and adulthood. Due to the immaturity of sensory-motor capabilities of young pups, we chose as environmental stimulation a second lactating female, who provided extra maternal care and stimulation from birth. The results show that double mothering normalized the abnormal response to maternal separation in Oprm1^−/− pups and increased social motivation in juveniles and adult knockout mice. Additionally, we observed that Oprm1^−/− mice act as less attractive social partners than wild types, which suggests that social motivation can be modulated by the stimulus employed. This experiment supports previous findings suggesting that early social environmental stimulation has profound and long-term beneficial effects, encouraging the use of nonpharmacological interventions for the treatment of social defects in neurodevelopmental diseases.