Medically Reviewed By Sonam Kothari, Written By Tejasvi Parekh
Suramin is a roughly 100-year-old medication discovered to treat diseases such as African sleeping sickness and river blindness — both caused by parasites that affect millions of people, especially in Africa.
Originally designed to fight parasitic infections, researchers are now investigating suramin as an autism therapeutic agent.
This idea was brought by Dr. Robert Naviaux, a researcher from the University of California, San Diego (UCSD). He and his team have a great belief that autism is connected with how cells respond to stress and suramin might be an intervention able to reprogram this stress response to alleviate symptoms of autism.
This has generated both hope and scepticism in the scientific community. In this article, we’ll break down what suramin is, why researchers think it might help with autism, and why some experts are cautious about it.
Suramin was first synthesized in the early 1920s for the treatment of African sleeping sickness, a disease transmitted by the tsetse fly, which attacks the brain and is fatal if not treated in its due time.
The drug could not cross the blood-brain barrier as Suramin succeeded only in arresting the disease if caught early, and before it spread into the brain.
For decades, other parasitic diseases like river blindness caused by parasites that make people blind were treated with suramin.
Though the drug was successful in treating such diseases, further studies have been done on other potential applications, including cancers, viral infections, and even snake bites.
In recent times, scientists have drawn attention to the possible role of suramin as a drug for the treatment of autism.
Let's understand something called the cell danger response, or CDR. A cell danger response is nothing but a fancy name for a defence mechanism in cells; it gets triggered when the body senses a threat-infection, injury, toxin, and what have you.
When this happens, the cell goes into protection mode, blocking communication with other cells and focusing on repairing itself.
Normally, after the danger passes, the CDR turns off, and the cell goes back to its regular job. But in autism, according to Dr. Naviaux, the CDR might get stuck in this “on” position.
This means the cells are constantly in defence mode, which could affect brain function and behaviour, leading to some of the symptoms we see in people with autism.
Dr. Naviaux’s idea is that suramin, a drug that blocks certain signals between cells, could help turn off the CDR, letting cells return to normal and potentially improving the symptoms of autism.
Dr. Naviaux’s theory was first tested in animals. In 2014, he and his team conducted experiments with mice that had been exposed to a fake infection while still in the womb. These mice showed behaviours similar to autism, like social problems and repetitive behaviours.
When the researchers gave these mice a single dose of suramin, their social behaviour improved significantly—and the effects lasted for about five weeks.
This early success encouraged Dr. Naviaux to test suramin in children with autism, leading to a small human trial in 2017. This trial was one of the first steps in figuring out if a suramin could be safe and effective for treating autism.
In 2017, Dr. Naviaux’s team conducted a Phase 1 clinical trial (an early stage of research to test a drug’s safety) involving 10 boys aged 5 to 14 with autism spectrum disorder (ASD).
The goal was to see if a suramin could be given safely to these children and whether it had any effect on their autism symptoms.
In the trial, five boys received a single low-dose infusion of suramin through an IV, and the other five boys received a placebo (a harmless saline solution) as a comparison. The results were promising but also raised important questions.
The boys who received suramin showed improvements in several key areas, like language, social skills, and repetitive behaviours. These changes were measured using tests that evaluate autism symptoms before and after the treatment. One of the main tools used was the Autism Diagnostic Observation Schedule (ADOS), which is widely used to assess autism severity.
Specifically, the boys who received suramin improved by an average of 1.6 points on the ADOS scale, indicating that their autism symptoms had become less severe. The boys in the placebo group, on the other hand, showed no change.
The good news was that suramin didn’t seem to cause any serious side effects in the children, except for a mild rash, which went away on its own.
The trial gave hope that suramin could be used safely in children with autism, but it was a small study, and more research is needed to fully understand the drug’s effects.
The improvements seen in the trial are thought to come from suramin’s ability to block certain signals between cells. These signals, which are triggered by ATP (a molecule that carries energy in cells), are part of the purinergic signalling pathway. When cells are under stress, they release ATP to communicate that there’s a problem.
In autism, this stress signalling may become overactive, keeping cells in defence mode even when they don’t need to be. Suramin works by blocking ATP from sending these signals, which may allow the cells to return to their normal state. In theory, this could reduce the symptoms of autism, as it helps the cells “relax” and resume normal communication.
While the results of the 2017 trial were encouraging, many experts are still cautious about suramin as a treatment for autism. One concern is that suramin, at higher doses, can cause serious side effects, including anaemia (a condition where you don’t have enough healthy red blood cells) and problems with the adrenal glands, which help regulate hormones like cortisol, the body’s main stress hormone.
Dr. David Sulzer, a professor at Columbia University, warns that while suramin is useful for treating parasitic diseases, it’s far from a harmless drug. There is a risk that children taking suramin over a longer period could develop serious health issues.
This is why larger, more extensive trials are needed before suramin can be considered a safe option for treating autism.
Another issue raised by experts is the small sample size of the 2017 trial—only 10 boys participated, which makes it hard to know for sure if suramin works for a larger group of children with autism.
There’s also the possibility that the parents, knowing their child developed a rash after receiving suramin, could have unintentionally reported more positive results, creating a placebo effect.
Finally, some scientists question the whole idea that purinergic signalling plays a big role in autism. Dr. Yong-Hui Jiang, a professor at Duke University, points out that while some children with autism have metabolic issues (problems with how their body processes energy), there’s no solid proof that the purinergic pathway is the root cause of autism.
More research is needed to figure out if this pathway is involved, and if it is, whether suramin is the right treatment.
Despite the doubts, Dr. Naviaux is moving forward with his research. He has filed a patent for his idea of using “antipurinergic therapy” to treat autism and other conditions, and he’s planning a Phase 2 clinical trial that will involve 60 children.
This trial will test suramin’s effects over a longer period (three doses over three months) and should give a clearer picture of the drug’s safety and effectiveness.
To truly know if suramin can be used to treat autism, researchers will need to answer several important questions. First, they need to confirm whether the purinergic pathway is really out of balance in people with autism.
If it is, then finding a biomarker (something in the body that shows this imbalance) will be crucial for identifying which individuals might benefit from suramin. Second, larger trials will be necessary to fully understand the drug’s long-term safety and how well it works in different groups of people.
Suramin’s story is an exciting example of how old drugs can find new uses in modern medicine. While it has long been used to fight parasitic diseases, its potential to treat autism is still in the early stages of research.
The idea that autism could be related to the way our cells respond to stress is intriguing, and Suramin may be able to help by resetting this process.
However, the road ahead is filled with questions and challenges. Until larger, more comprehensive trials are completed, suramin remains an experimental treatment, and families dealing with autism should be cautious.
The potential is there, but much more research is needed before a suramin can be widely considered a safe and effective option for treating autism.
