This is a single-site, randomized, acute dose-response study to determine whether STX209 produces a dose-dependent significant change in MEG target parameters compared to baseline as well as compared to placebo treatment.
Recent evidence from magnetoencephalographic (MEG) studies in ASD have pointed to abnormalities (specifically, delays) in auditory evoked neuromagnetic responses (e.g. M100 - see Roberts et al., 2010, and mismatch field, MMF - see Roberts et al., 2011) as well as abnormalities in the oscillatory behavior of auditory cortex, especially in the gamma band (30-50Hz), at rest and in response to simple auditory stimuli (see Gandal et al., 2010 and Cornew et al., 2012; Edgar et al., 2013). The local circuitry underlying such evoked activity and oscillations, and synaptic transmission in general, requires an appropriate balance of excitation and inhibition, mediated by glutamate and GABA, respectively. One model of the neural oscillatory deficits in ASD suggests that impaired regulatory control by inhibitory interneurons onto pyramidal cells underlies abnormal auditory latency and oscillatory electrophysiological measures. As such, electrophysiological deficits are interpreted in terms of local circuitry abnormalities, with inferences at the molecular level of imbalances in the activity of glutamate and GABA. A candidate therapeutic for ASD has been developed - STX209, a GABA-B agonist. Since this pharmaceutical targets synaptic activity that has clear electrophysiological correlates, one goal of this proposal is to assess the responsiveness (sensitivity to change) of MEG measures to acute administration of STX209 at various doses in adolescents on the autism spectrum. The study also aims to establish the nature of the putative relationship between such electrophysiologic markers and GABA and glutamate levels using MEGAPRESS spectrally-edited magnetic resonance spectroscopy (MRS).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
25
A randomized acute dose-response design will be employed with a total study duration of 3 weeks. At each visit, baseline MEG will be obtained followed by acute single-dose drug/placebo administration, followed 60 minutes later by repeat MEG. Each participant will receive a single dose of placebo in random order and a single dose of STX209 from smallest to largest (15mg, and 30mg). MRI and MRS will be performed immediately following MEG to provide an anatomic basis for source localization as well as to assess acute effects of STX209 administration on MRS estimates of GABA and glutamate. The STX209 (15mg) intervention is the "low dose"
A randomized acute dose-response design will be employed with a total study duration of 3 weeks. At each visit, baseline MEG will be obtained followed by acute single-dose drug/placebo administration, followed 60 minutes later by repeat MEG. Each participant will receive a single dose of placebo in random order and a single dose of STX209 from smallest to largest (15mg, and 30mg). MRI and MRS will be performed immediately following MEG to provide an anatomic basis for source localization as well as to assess acute effects of STX209 administration on MRS estimates of GABA and glutamate. The placebo intervention is the non-active placebo control dose
Children's Hospital of Phladelphia
Philadelphia, Pennsylvania, United States
M50 Latency (Left Hemisphere)
The latency of the M50 auditory evoked response component arising from the left cerebral hemisphere
Time frame: 1 hour per intervention followed by a 1 week washout for a total of three weeks
M50 Latency (Right Hemisphere)
The latency of the M50 auditory evoked response component arising from the right cerebral hemisphere
Time frame: 1 hour per intervention followed by a 1 week washout for a total of three weeks
Steady State Inter Trial Coherence (Left Hemisphere)
The inter trial coherence (ITC) of auditory steady state response arising from the left cerebral hemisphere
Time frame: 1 hour per intervention followed by a 1 week washout for a total of three weeks
Steady State Inter Trial Coherence (Right Hemisphere)
The inter trial coherence (ITC) of auditory steady state response arising from the right cerebral hemisphere
Time frame: 1 hour per intervention followed by a 1 week washout for a total of three weeks
GABA (Left Hemisphere)
GABA/Cr ratio arising from a voxel in the left superior temporal gyrus
Time frame: 1 hour per intervention followed by a 1 week washout for a total of three weeks
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A randomized acute dose-response design will be employed with a total study duration of 3 weeks. At each visit, baseline MEG will be obtained followed by acute single-dose drug/placebo administration, followed 60 minutes later by repeat MEG. Each participant will receive a single dose of placebo in random order and a single dose of STX209 from smallest to largest (15mg, and 30mg). MRI and MRS will be performed immediately following MEG to provide an anatomic basis for source localization as well as to assess acute effects of STX209 administration on MRS estimates of GABA and glutamate. The STX209 (30mg) intervention is the "high dose"