Randomized Crossover Feasibility Trial of Helminthic Trichuris Suis Ova vs. Placebo for Repetitive Behaviors in Adult Autism Spectrum Disorder

Objectives: Inflammatory mechanisms are implicated in the etiology of Autism Spectrum Disorder (ASD), and use of the immunomodulator Trichuris Suis Ova (TSO) is a novel treatment approach. This pilot study determined the effect sizes for TSO vs. placebo on repetitive behaviors, irritability and global functioning in adults with ASD. Methods: A 28-week double-blind, randomized two-period crossover study of TSO vs. placebo in 10 ASD adults, ages 17 to 35, was completed, with a 4-week washout between each 12-week period at Montefiore Medical Center, Albert Einstein College of Medicine. Subjects with ASD, history of seasonal, medication or food allergies, Y-BOCS ≥ 6 and IQ ≥70 received 2500 TSO ova or matching placebo every two weeks of each 12-week period. Results: Large effect sizes for improvement in repetitive behaviors (d = 1.0), restricted interests (d = 0.82), rigidity (d = 0.79), and irritability (d = 0.78) were observed after 12 weeks of treatment. No changes were observed in the social-communication domain. Differences between treatment groups did not reach statistical significance. TSO had only minimal, non-serious side effects. Conclusions: This proof-of-concept study demonstrates the feasibility of TSO for the treatment of ASD, including a favorable safety profile, and moderate to large effect sizes for reducing repetitive behaviors and irritability.