Brief report: Pilot single-blind placebo lead-in study of acamprosate in youth with autistic disorder

RATIONALE

An excitatory/inhibitory (E:I) imbalance marked by enhanced glutamate and deficient gamma-aminobutyric acid (GABA) neurotransmission may contribute to the pathophysiology of autism spectrum disorders (ASD).

OBJECTIVES

We report on the first single-blind placebo lead-in trial of acamprosate, a drug with putative mechanisms restoring E:I imbalance, in twelve youth with ASD.

MATERIALS AND METHODS

We conducted a 12-week single-blind, placebo lead-in study of acamprosate in youth age 5-17 years with autistic disorder.

RESULTS

Six of nine subjects who received active drug treatment were deemed treatment responders (defined by a score at final visit of "very much improved" or "much improved" on the Clinical Global Impressions Improvement scale) and ≥25% improvement on the Aberrant Behavior Checklist Social Withdrawal subscale.

CONCLUSION

Future larger-scale dose finding studies of acamprosate in ASD may be warranted given this preliminary indication of benefit.

Impact of acamprosate on behavior and brain-derived neurotrophic factor: an open-label study in youth with fragile X syndrome

RATIONALE

Fragile X syndrome (FXS) is an inherited form of developmental disability and a single gene cause of autism. As a disorder with increasingly understood pathophysiology, FXS is a model form of developmental disability for targeted drug development efforts. Preclinical animal model findings have focused targeted drug treatment development in FXS on an imbalance between excessive glutamate and deficient gamma-aminobutyric acid (GABA) neurotransmission.

METHODS

We conducted a prospective open-label 10-week trial of acamprosate in 12 youth aged 6-17 years (mean age: 11.9 years) with FXS.

RESULTS

Acamprosate use (mean dose: 1,054  ±  422 mg/day) was associated with treatment response (defined by a Clinical Global Impressions Improvement (CGI-I) scale score of "very much improved" or "much improved") in nine of 12 (75 %) subjects. Improvement was noted in social behavior and inattention/hyperactivity using multiple standard behavioral outcome measures. No significant adverse effects or changes in vital signs, including weight or laboratory measures, occurred during treatment with acamprosate. Additionally, pre- and post-treatment blood biomarker analyses looking at brain-derived neurotrophic factor (BDNF) levels found a significant increase in BDNF with treatment. In our pilot sample, treatment response did not correlate with change in BDNF with treatment.

CONCLUSIONS

Acamprosate was generally safe and well tolerated and was associated with a significant improvement in social behavior and a reduction in inattention/hyperactivity. The increase in BDNF that occurred with treatment may be a useful pharmacodynamic marker in future acamprosate studies. Given these findings, a double-blind, placebo-controlled study of acamprosate in youth with FXS is warranted.