A clinical trial to investigate the safety and efficacy of a drug therapy for autism has been launched in the US, University of California, San Diego School of Medicine has said in a statement.

The phase 1 clinical trial, which is recruiting 20 participants, will evaluate suramin -- a century-old drug still used for African sleeping sickness -- as a novel treatment for children with a diagnosis of Autism Spectrum Disorder (ASD).

ASD is characterised by social impairments, communication difficulties and restricted, repetitive and stereotyped patterns of behaviour.

"To date, there are no medications that can cure ASD, and very few that can improve its core symptoms," said Robert Naviaux, professor of medicine, pediatrics and pathology at the UC San Diego School of Medicine.

Previous published research by Naviaux and colleagues reported that a single injection of suramin reversed symptoms of ASD in mouse models.

This trial is the first to test suramin in children with ASD.

It is also the first clinical investigation of a novel theory, advanced by Naviaux, that posits autism may be a consequence of abnormal cell communication resulting from abnormal activation of the cell danger response.

Cells threatened or damaged by microbes, such as viruses or bacteria, or by physical forces or by chemicals, such as pollutants, react defensively, a part of the normal immune response, Naviaux said.

Their membranes stiffen. Internal metabolic processes are altered - most notably mitochondria, the cells' critical 'power plants' -- resulting in activation of the cell danger response and reduced communications between cells.

Naviaux said the cell danger response theory does not contradict other research regarding the causes of autism.

Rather, it offers another perspective and, perhaps, a new therapeutic target.

The study will involve 10 to 12 clinical visits over three to four months for each child.

In the trial, suramin will be given as a single dose through an intravenous line. Half of the participating children will receive suramin, half will receive a placebo (saline infusion).

Behavioural and medical tests will be conducted before and after treatment, and include some blood and urine analyses, the statement said.