Phase 2 Clinical Trial of SGS-742 Therapy in Succinic Semialdehyde Dehydrogenase Deficiency

• ClinicalTrials.gov Identifier: NCT02019667
• Recruitment Status: Completed
• First Posted: December 24, 2013
• Results First Posted: February 24, 2020
• Last Update Posted: February 24, 2020
• Sponsor: National Institute of Neurological Disorders and Stroke (NINDS)
• Information provided by (Responsible Party): National Institutes of Health Clinical Center (CC) ( National Institute of Neurological Disorders and Stroke (NINDS) )

Study Description

Brief Summary:

Objective:

To perform a clinical trial assessing the safety, tolerability and efficacy of the GABA(B) receptor antagonist SGS-742 in patients with SSADH deficiency.

Study Population:

Twenty-two children and adults with SSADH deficiency.

Design:

Double-blind, cross-over, phase II clinical trial.

Outcome Measures:

The primary outcome measures for drug efficacy will be performance on neuropsychological testing and responses to parent questionnaire. The secondary outcome measure will be TMS parameters of cortical excitation and inhibition. The outcome measures for safety will include clinical examination and neuropsychological tests.

Condition or disease	Intervention/treatment	Phase
Metabolic Disease; Seizures	Drug: SGS-742; Drug: Placebo	Phase 2

Detailed Description:

Objective:

To perform a clinical trial assessing the safety, tolerability and efficacy of the GABA(B) receptor antagonist SGS-742 in patients with SSADH deficiency.

Study Population:

Twenty-two children and adults with SSADH deficiency.

Design:

Double-blind, cross-over, phase II clinical trial. SGS-742 is a GABA (B) receptor antagonist that has shown to be safe and well-tolerated in clinical trials in adults with cognitive impairment. In addition, preliminary data in the SSADH knockout mouse model suggest efficacy in this specific syndrome. The primary outcome measure will be a change in the Auditory Comprehension subtest of the Neuropsychological Assessment Battery Language Module score; the secondary outcome measure will be a change in cortical excitation and inhibition measured by transcranial magnetic stimulation (TMS). Additional evaluations will include neurological and neuropsychological examinations, magnetic resonance spectroscopy and CSF collection to measure GABA levels. The trial will have a baseline phase in which each patient will undergo a neurological examination and a neuropsychological evaluation. During the subsequent treatment phase, patients will be randomized to SGS-742, supplied by IRIX Pharmaceuticals, and based on weight given a maximum tolerated dose not to exceed 600 mg t.i.d. orally, or placebo, each for 6 months. Patients will then have repeat TMS, neurological and neuropsychological evaluations, followed by cross-over to the alternate treatment arm, and re-evaluation after 6 months.

Outcome Measures:

The primary outcome measures for drug efficacy will be performance on neuropsychological testing and responses to parent questionnaire. The secondary outcome measure will be TMS parameters of cortical excitation and inhibition. The outcome measures for safety will include clinical examination and neuropsychological tests.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 19 participants
• Allocation: Randomized
• Intervention Model: Crossover Assignment
• Masking: Triple (Participant, Care Provider, Investigator)
• Primary Purpose: Treatment
• Official Title: Phase 2 Clinical Trial of SGS-742 Therapy in Succinic Semialdehyde Dehydrogenase Deficiency
• Actual Study Start Date: March 31, 2014
• Actual Primary Completion Date: January 31, 2019
• Actual Study Completion Date: April 3, 2019

Arms and Interventions

Arm	Intervention/treatment
Experimental: Placebo; Participants with SSADH Deficiency when on placebo for six months	Drug: Placebo
Experimental: Study Drug; Participants with SSADH Deficiency receiving SGS-742 when on study drug for six months	Drug: SGS-742

Outcome Measures

Primary Outcome Measures :

1. Change From Baseline on the Adaptive Behavior Assessment System (ABAS) Test at the End of the Study Drug and Placebo Treatment Periods [ Time Frame: baseline and six months ]
   The ABAS questionnaire was completed by the participant's parent or caregiver at the end of each six month treatment period.The ABAS provides a comprehensive picture of adaptive skills across the lifespan. The questionnaire addresses Conceptual, Social and Practical skills including communication, self-direction, use of leisure time, health, safety and self-care. The General Adaptive Composite score ranges from <40 to >160 with a lower score representing lower adaptive behavior. The difference between Placebo and Baseline and Study Drug and Baseline were obtained. These values were averaged across individuals to report a mean and a standard deviation of the baseline-to-treatment period change. The means for each treatment can be compared to have a baseline-adjusted treatment effect interpretation. A positive change represents an improvement in adaptive skills compared with baseline and a negative change represents a decline in adaptive skills compared with baseline.

Secondary Outcome Measures :

1. Change From Baseline of TMS Measurement of Motor Threshold at the End of the Study Drug and Placebo Treatment Periods [ Time Frame: Baseline and Six months ]
   Transcranial Magnetic Stimulation (TMS) is a non-invasive technique which applies magnetic pulses to the brain via a coil inducing an electrical current in the brain. Stimulation is typically applied at a sufficient intensity to trigger action potentials in nearby neurons. The motor threshold is defined as the minimum percentage of the stimulator output that evoked a motor evoked potential of more than 50µV in at least 5 out of 10 trials. Motor threshold was measured at the end of the study drug period and the end of the Placebo period. The differences between Placebo and Baseline, and SGS and Baseline were obtained. A decrease from baseline value indicates increased cortical excitability and an increase from baseline value indicates reduced cortical excitability. These values were averaged across individuals to report a mean and standard deviation of this baseline-to-treatment period change. The mean for each treatment can be compared to have a baseline-adjusted treatment effect.
2. Change From Baseline of TMS Measurement of Intracortical Facilitation at the End of the Study Drug and Placebo Treatment Periods [ Time Frame: Baseline and Six months ]
   Transcranial Magnetic Stimulation (TMS) is a non-invasive technique which applies magnetic pulses to the brain via a coil inducing an electrical current in the brain. Stimulation is typically applied at a sufficient intensity to trigger action potentials in nearby neurons. Intracortical facilitation (ICF) and inhibition (ICI) were studied using a paired stimulus paradigm. The motor threshold (MT) was first established. The conditioning stimulus (70% MT) followed by the test stimulus (120% MT) was delivered at an interstimulus interval (ISI) of 10 ms for ICF. Each run consisted of 10 trials, and the amplitude ratio of the mean conditioned Motor Evoked Potential (MEP) to control MEP was determined. A larger amplitude ratio indicates greater cortical excitability. The differences between Placebo and Baseline, and SGS and Baseline were obtained. These values were averaged across individuals to report a mean.
3. Change From Baseline of TMS Measurement of Short Interval Intracortical Inhibition (Short ICI) at the End of the Study Drug and Placebo Treatment Periods [ Time Frame: Baseline and Six months ]
   Transcranial Magnetic Stimulation (TMS) is a non-invasive technique which applies magnetic pulses to the brain via a coil inducing an electrical current in the brain. Stimulation is typically applied at a sufficient intensity to trigger action potentials in nearby neurons. Intracortical facilitation and inhibition were studied using a paired stimulus paradigm. The motor threshold (MT) was first established. The conditioning stimulus (70% MT) followed by the test stimulus (120% MT) was delivered at an interstimulus interval (ISI) of 2 ms for short ICI. Each run consisted of 10 trials, and the amplitude ratio of the mean conditioned Motor Evoked Potential (MEP) to control MEP was determined. A larger amplitude ratio indicates greater cortical excitability. The differences between Placebo and Baseline, and SGS and Baseline were obtained. These values were averaged across individuals to report a mean.
4. Change From Baseline of TMS Measurement of Long Interval Intracortical Inhibition (Long ICI) at the End of the Study Drug and Placebo Treatment Periods [ Time Frame: Baseline and Six months ]
   Transcranial Magnetic Stimulation (TMS) is a non-invasive technique which applies magnetic pulses to the brain via a coil inducing an electrical current in the brain. Stimulation is typically applied at a sufficient intensity to trigger action potentials in nearby neurons.Intracortical facilitation and inhibition were studied using a paired stimulus paradigm. The motor threshold (MT) was first established. The conditioning stimulus (70% MT) followed by the test stimulus (120% MT) was delivered at 100 ms for long ICI. Each run consisted of 10 trials, and the amplitude ratio of the mean conditioned Motor Evoked Potential (MEP) to control MEP was determined. A larger amplitude ratio indicates greater cortical excitability. The differences between Placebo and Baseline, and SGS and Baseline were obtained. These values were averaged across individuals to report a mean.
5. Results of Physical Examination at the End of the Study Drug and Placebo Treatment Periods [ Time Frame: Six months ]
   A physical examination was administered by a physician to subjects at the end of each six month treatment period, i.e., following completion of a six month period on SGS-742 or Placebo. Results of the examination ranged from 0-4 with scores defined as follows: 0=No observation; 1=Stable baseline findings; 2=New asymptomatic finding; 3=Patient reports some worsening of a baseline daily function associated with new finding; 4=Patient unable to carry out a baseline daily function associated with new finding

Eligibility Criteria

• Ages Eligible for Study: 4 Years and older (Child, Adult, Older Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Criteria

• INCLUSION CRITERIA
• Aged 4 years or older
• 4-hydroxybutyric aciduria (gamma-hydroxybutyric aciduria) on two separate tests
• Documented succinic semialdehyde dehydrogenase enzyme deficiency
• Patients must have clinical features consistent with SSADH deficiency including developmental delay especially deficit in expressive language, hypotonia, ataxia, seizures, and other neuropsychiatric symptoms including sleep disturbances , attention deficit, anxiety, obsessivecompulsive disorder, and autistic traits
• During the study, women of child-bearing potential must use a reliable method of birth control until one month after the final drug taper is complete.

EXCLUSION CRITERIA

• Current alcohol use (>14 drinks/wk in men and >7 drinks/wk in women or or recreational drug use
• Contraindications to MRI: metal in the body including pacemakers, medication pumps, aneurysm clips, metallic prostheses (including metal pins and rods, heart valves or cochlear implants), shrapnel fragments, permanent eye liner or small metal fragments in the eye that welders and other metal workers may have
• Claustrophobia
• Cannot lie comfortably flat on the back for up to 2h in the MRI scanner
• Patients with a history of other major medical disorders with clinical fluctuations, or requiring therapy that might affect study participation or drug response such as severe depression or psychoses, renal or hepatic disease.
• Patients requiring treatment with drugs known to affect the GABAergic system, including vigabatrin and benzodiazepines.
• Pregnant and lactating women

Contacts and Locations

Locations

United States, Maryland

National Institutes of Health Clinical Center, 9000 Rockville Pike

Bethesda, Maryland, United States, 20892

United States, Washington

Washington State University

Pullman, Washington, United States

Sponsors and Collaborators

National Institute of Neurological Disorders and Stroke (NINDS)

Investigators

• Principal Investigator: Sara K Inati, M.D.; National Institute of Neurological Disorders and Stroke (NINDS)

  Study Documents (Full-Text)

Documents provided by National Institutes of Health Clinical Center (CC) ( National Institute of Neurological Disorders and Stroke (NINDS) ):

Study Protocol and Statistical Analysis Plan  [PDF] August 8, 2019

More Information

Additional Information:

NIH Clinical Center Detailed Web Page 

Publications:

Al-Essa MA, Bakheet SM, Patay ZJ, Powe JE, Ozand PT. Clinical, fluorine-18 labeled 2-fluoro-2-deoxyglucose positron emission tomography (FDG PET), MRI of the brain and biochemical observations in a patient with 4-hydroxybutyric aciduria; a progressive neurometabolic disease. Brain Dev. 2000 Mar;22(2):127-31.

Arnold S, Berthele A, Drzezga A, Tölle TR, Weis S, Werhahn KJ, Henkel A, Yousry TA, Winkler PA, Bartenstein P, Noachtar S. Reduction of benzodiazepine receptor binding is related to the seizure onset zone in extratemporal focal cortical dysplasia. Epilepsia. 2000 Jul;41(7):818-24.

Arnulf I, Konofal E, Gibson KM, Rabier D, Beauvais P, Derenne JP, Philippe A. Effect of genetically caused excess of brain gamma-hydroxybutyric acid and GABA on sleep. Sleep. 2005 Apr;28(4):418-24.

• Responsible Party: National Institute of Neurological Disorders and Stroke (NINDS)
• ClinicalTrials.gov Identifier: NCT02019667
• Other Study ID Numbers: 140033; 14-N-0033 ( Other Identifier: NIH )
• First Posted: December 24, 2013
• Results First Posted: February 24, 2020
• Last Update Posted: February 24, 2020
• Last Verified: October 2018

• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No

Keywords provided by National Institutes of Health Clinical Center (CC) ( National Institute of Neurological Disorders and Stroke (NINDS) ):

GABA; Seizures; Neurotransmitters

Additional relevant MeSH terms:

Seizures; Metabolic Diseases; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; (3-aminopropyl)(n-butyl)phosphinic acid; Neuroprotective Agents; Protective Agents; Physiological Effects of Drugs; GABA Antagonists; GABA Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action