Autism or autism spectrum disorder (ASD) affects 1–2% of children in the United States.
Now a breakthrough pilot study has found that a 100-year-old drug called suramin actually reverses, albeit temporarily, some of the symptoms of autism.
The study’s findings are published as “Low-dose suramin in autism spectrum disorder: a small, phase I/II, randomized clinical trial” in the journal Annals of Clinical and Translational Neurology, May 26, 2017, authored by Robert K. Naviaux, M.D. and Ph.D., of U.C. San Diego School of Medicine, and 19 co-authors.
Below is the article’s Abstract:
No drug is yet approved to treat the core symptoms of autism spectrum disorder (ASD). Low-dose suramin was effective in the maternal immune activation and Fragile X mouse models of ASD. The Suramin Autism Treatment-1 (SAT-1) trial was a double-blind, placebo-controlled, translational pilot study to examine the safety and activity of low-dose suramin in children with ASD.
Ten male subjects with ASD, ages 5–14 years, were matched by age, IQ, and autism severity into five pairs, then randomized to receive a single, intravenous infusion of suramin (20 mg/kg) or saline. The primary outcomes were ADOS-2 comparison scores and Expressive One-Word Picture Vocabulary Test (EOWPVT). Secondary outcomes were the aberrant behavior checklist, autism treatment evaluation checklist, repetitive behavior questionnaire, and clinical global impression questionnaire.
Blood levels of suramin were 12 ± 1.5 μmol/L (mean ± SD) at 2 days and 1.5 ± 0.5 μmol/L after 6 weeks. The terminal half-life was 14.7 ± 0.7 days. A self-limited, asymptomatic rash was seen, but there were no serious adverse events. ADOS-2 comparison scores improved by −1.6 ± 0.55 points (n = 5; 95% CI = −2.3 to −0.9; Cohen’s d = 2.9; P = 0.0028) in the suramin group and did not change in the placebo group. EOWPVT scores did not change. Secondary outcomes also showed improvements in language, social interaction, and decreased restricted or repetitive behaviors.
The safety and activity of low-dose suramin showed promise as a novel approach to treatment of ASD in this small study.
The authors write that “Suramin was first synthesized in 1916, making it one of the oldest manmade drugs still in medical use. It is used to treat African sleeping sickness (trypanosomiasis), and remains on the World Health Organization list of essential medications.”
The beneficial effects of Suramin on autism symptoms were first noted in mouse studies, which showed that low-dose suramin was effective in treating ASD-like symptoms and did not produce toxicity even when used for at least 4 months.
From mouse studies, Dr. Naviaux et al. graduated to a controlled, double-blind experiment of a small sample of ten boys with ASD, wherein the boys were randomly selected to be in the control or experimental group. The boys in the experimental group were injected with a single low dose of suramin; the boys in the control control received a placebo of saline solution. The design was double blind, i.e., neither the boys nor the experimenters knew who received suramin vs. saline.
The study was authorized by the U.S. Food and Drug Administration. No safety concerns were found.
Parents reported that after suramin treatment, the rate of language, social, behavioral, and developmental improvements continued to increase for 3 weeks, then gradually decreased toward baseline over the next 3 weeks. None of these improvements occurred in the five children who received placebo.
The limitations of the study are the small sample size and the temporary effects of the single dose of suramin which subsided and eventually disappeared after 6 weeks.
The researchers conclude that future studies will be needed to confirm these findings in larger numbers of children with ASD, and to evaluate whether a few doses of suramin given over a few months are safe and might facilitate continued improvements. They caution that:
Careful clinical trials will be needed over several years at several sites to learn how to use low-dose suramin safely in autism, and to identify drug–drug interactions and rare side effects that cannot currently be predicted. We strongly caution against the unauthorized use of suramin.