A Controlled Trial of Growth Hormone in Phelan-McDermid Syndrome and Idiopathic Autism

Icahn School of Medicine at Mount Sinai32 enrolled

Overview

This clinical trial will use growth hormone as a novel treatment for Phelan-McDermid syndrome (PMS) and idiopathic autism. A double-blind, placebo-controlled crossover trial design will be used in 30 children with idiopathic autism and 15 children with PMS to evaluate the the effects of growth hormone on visual evoked potentials (VEPs), socialization, language, and repetitive behaviors. The researchers expect to provide evidence for the feasibility of using VEPs in PMS, and to show support for growth hormone in ameliorating clinical symptoms of ASD.

This study will show that select electrophysiological markers in PMS are relevant to iASD and predictive of treatment response with growth hormone. The long-term goal is to optimize treatment selection in iASD by establishing biological signature(s) derived from PMS. The expected outcome is to establish the feasibility of electrophysiological biomarkers for use in clinical trials in PMS and iASD, demonstrate efficacy of growth hormone in PMS and iASD, and to define a biological profile that will mark a subset of patients with iASD likely to show clinical response to growth hormone. The study will enroll 45 children (15 PMS; 30 iASD; age 2-12 years) and administer growth hormone/placebo as once daily subcutaneous injection for 12 weeks at standard doses. The study team will monitor baseline anthropometric measures, laboratory parameters for growth, IGF-1 levels, and bone age throughout the study. Evaluations will include validated behavioral scales. Visual evoked potentials (VEPs) will be used as biomarkers of visual sensory reactivity. Growth Hormone is approved by the FDA for the treatment of children with short stature due to primary growth hormone deficiency, among several other indications. It is being used off-label in the current study and is not FDA approved for use in PMS or ASD.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Interventions

Growth HormoneDRUG

Growth hormone will be administered subcutaneously once daily. A starting dose of 0.15 mg/kg/week divided daily for 2 weeks to ensure safety and tolerance. The dose will then be increased to 0.3 mg/kg/week for 10 weeks. Doses will be titrated based on IGF-1 levels and monitored every four weeks up to a maximum dose of 0.45 mg/kg/week based on the package insert.

SalineDRUG

Placebo (saline) will be administered subcutaneously once daily.

Eligibility

Sex: ALLMin age: 2 YearsMax age: 12 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Children between 2 and 12 years of age * Open epiphyses on bone age x ray * Must be on stable medication and psychosocial treatment regimens for at least three months prior to enrollment, assuming the concomitant medication is safe for use with Growth Hormone * No prior use of Growth Hormone or IGF-1 * ASD group: Meet DSM-5 criteria for Autism Spectrum Disorder confirmed by the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2); absence of known pathogenic copy number variants * PMS group: Known pathogenic deletions or mutations in SHANK3 gene diagnosed by array CGH and/or direct sequencing Exclusion Criteria: * Closed epiphyses * Active or suspected neoplasia * Intracranial hypertension * Hepatic insufficiency * Renal insufficiency * Cardiomegaly/valvulopathy * History of allergy to growth hormone or any component of the formulation (mecasermin) * Patients with comorbid conditions who are deemed too medically compromised to tolerate the risk of experimental treatment with growth hormone (including severe obesity, sleep apnea, and various acute health conditions) * Visual problems that preclude the use of VEP

Outcomes

Primary Outcomes

Visual Evoked Potentials (VEP)

A noninvasive technique to evaluate the functional integrity of visual pathways in the brain from the retina to the visual cortex via the optic nerve/optic radiations. The VEP is recorded from the head's surface, over the visual cortex, and is extracted from ongoing EEG through signal averaging. VEPs reflect the sum of excitatory and inhibitory postsynaptic potentials occurring on apical dendrites which modulate excitatory and inhibitory signals received by the pyramidal cells.