In a small, randomized Phase I/II clinical trial (SAT1), researchers at University of California San Diego School of Medicine say a 100–year–old drug called suramin, originally developed to treat African sleeping sickness, was safely administered to children with autism spectrum disorder (ASD), who subsequently displayed measurable, but transient, improvement in core symptoms of autism.

Writing in the journal Annals of Clinical and Translational Neurology, first author Robert K. Naviaux, MD, PhD, professor of medicine, pediatrics and pathology at UC San Diego School of Medicine and colleagues describe a novel double–blind, placebo–controlled safety study involving 10 boys, ages 5 to 14 years, all diagnosed with ASD.

Five of the 10 boys received a single, intravenous infusion of suramin, a drug originally developed in 1916 to treat trypanosomiasis and river blindness, both caused by parasites. The other five boys received a placebo. The trial followed earlier testing in a mouse model of autism in which a single dose of suramin temporarily reversed symptoms of the neurological disorder.

The results in humans were equally notable, though the purpose of the SAT1 trial was fundamentally to test the researchers’ underlying theory about a unifying cause for autism and to assess the safety of suramin, which is not an approved treatment of ASD. In fact, there are no approved drugs to treat the core symptoms of ASD.

All five boys who received the suramin infusion displayed improvements in language and social behavior, restricted or repetitive behaviors and coping skills. Assessment of improvements was based upon observational examinations and interviews using standardized tests and questionnaires, such as the Autism Diagnostic Observation Schedule, 2nd edition (ADOS–2), the Expressive One Word Picture Vocabulary Testing (EOWPWT), the Aberrant Behavior Checklist (ABC), the Autism Treatment Evaluation Checklist (ATEC), the Repetitive Behavior Questionnaire (RBQ) and the Clinical Global Impression (CGI) questionnaire.

The researchers found that ADOS–2 scores were improved in the suramin treatment group at six weeks, but not in the placebo group. Specifically, ADOS–2 scores improved by –1.6 points in the suramin group, but did not change in the placebo. Children who have a score of 6 or lower in ADOS–2 may have milder symptoms but no longer meet the formal diagnostic criteria for ASD. A score of 7 to 8 indicates the child is on the autism spectrum. Nine and above classifies the child as autistic.

Suramin treatment was also associated with improvements in the ABC, ATEC and CGI measurements, but not RBQ. The most changed behaviors, the authors said, were social communication and play, speech and language, calm and focus, repetitive behaviors and coping skills.

Participating families also reported benefits among the children who received suramin. “We saw improvements in our son after suramin that we have never seen before,” said the parent of a 14–year–old who had not spoken a complete sentence in 12 years.

“Within an hour after the infusion, he started to make more eye contact with the doctor and nurses in the room. There was a new calmness at times, but also more emotion at other times. He started to show an interest in playing hide–and–seek with his 16–year–old brother. He started practicing making new sounds around the house. He started seeking out his dad more.

“We have tried every new treatment out there for over 10 years. Nothing has come close to all the changes in language and social interaction and new interests that we saw after suramin. We saw our son advance almost three years in development in just six weeks.”