University of Glasgow scientists headed by Professor Peter Kennedy, have produced a new pill to treat sleeping sickness that avoids the risks of death caused by conventional intravenous drugs. 

Image of the Kenyan Nyaza Province tsetse-fly clearing provided by the National Archive

Researchers in the University's Institute of Infection, Immunity & Inflammation have created a safer version of the drug by combining melarsoprol with cyclodextrins molecules that surround it.  This allows the treatment to be administered orally which increases the drugs solubility and releases it more slowly in the gut.

'Melarsoprol is very effective at killing the parasites but, when given intravenously, it probably does this too quickly, which is in part why we think it is so dangerous.  By controlling the rate of release of the drug with this new oral formulation, we believe we make it safer,”  Professor Kennedy said.

Sleeping sickness, or trypanosomiasis is passed to humans by the tsetse flies carrying the trypanosome parasite. The infection, that can last for years before it enters the brain causing inflammation, swelling and death.  Endemic in thirty-six sub-Saharan countries, it is thought that 60 million people are at risk of infection. 

The University said that this new research is the most clinically important in the 20 years of our trypanosome research group. It has the potential of a major therapeutic advance and would also have a significant socio-economic impact because the duration of inpatient treatment would be shorter.

Sleeping sickness is nearly always fatal if left untreated.  Once the disease has crossed the blood-brain barrier and entered the central nervous system the most commonly used treatment is an intravenous course of the arsenic-based drug melarsoprol.  Treatment is protracted, excruciatingly painful and frequently fatally toxic.  It is estimated that 30,000 people are currently infected.

"Melarsoprol has a low solubility in water, it is dissolved in propylene glycol and administered intravenously. The result is a highly toxic drug that kills 5% of patients receiving it and leaves many others permanently brain-damaged.  This new research is the most clinically important in the 20 years of our trypanosome research group. It has the potential of a major therapeutic advance and would also have a significant socio-economic impact because the duration of inpatient treatment would be shorter and some patients might even be eventually treated at home," Professor Kennedy said.

The research is supported by the Medical Research Council and requires additional funding in order to progress to trials in Uganda.