Everyone’s favorite little blue pill may offer more than just a boost in the bedroom.
New research suggests the erectile dysfunction drug Viagra could help treat a devastating neurological disorder that primarily strikes young children — most of whom die before the age of three.
The study was small, so scientists caution the findings are still preliminary. Still, the results could offer a much-needed spark of hope for families facing the rare genetic disorder with no approved therapies to slow its course.
Part of the challenge is just how rare Leigh syndrome is, affecting only about one in every 40,000 births.
“The low case numbers make it difficult to research the disease and present some obstacles in our urgent search for effective therapies,” Dr. Markus Schuelke, lead clinical scientist, said in a press release.
The need for solutions is urgent. Leigh syndrome is caused by genetic mutations that prevent mitochondria — the cell’s power plants — from producing enough energy. Over time, this starves critical tissues, particularly the brain and muscles, of the fuel they need to function.
The first signs usually appear in infancy or early childhood, though in rare cases the disease can emerge in adolescence or adulthood.
Early symptoms can include vomiting, diarrhea and difficulty swallowing. As the disorder worsens, patients may develop more serious complications such as loss of motor skills, developmental delays, seizures, breathing problems and feeding difficulties — often leading to an early death.
That’s where sildenafil, the active ingredient in Viagra, may come in.
In the study, researchers added the drug to lab-grown cells taken from Leigh syndrome patients.
They found it switched on genes tied to brain development and reduced some of the harmful molecular changes seen in the disease.
Further experiments confirmed the results. In miniature, three-dimensional models that mimic the human brain, sildenafil boosted nerve cell growth. The drug also improved energy metabolism and extended life span in mice and pigs carrying Leigh syndrome mutations.
“Based on these results, we decided to administer the drug as part of an individual therapeutic trial in six patients with Leigh syndrome,” said Dr. Alessandro Prigione, senior author of the study.
“Another decisive factor was the fact that detailed safety data was available for the long-term use of sildenafil in children, as the active ingredient is already approved for other pediatric disorders,” he continued.
While sildenafil is best known for treating erectile dysfunction, it’s also used to treat children with pulmonary arterial hypertension, a rare condition that causes high blood pressure in the arteries of the lungs.
For the study, researchers recruited six Leigh syndrome patients who began taking sildenafil between the ages of 9 months and 38 years. Within just a few months, their muscular strength and ability to move improved.
“For example, in the case of a child undergoing sildenafil treatment, the walking distance increased tenfold, from 500 to 5,000 meters,” Schuelke explained.
The researchers also found the patients bounced back faster from metabolic crises — life-threatening emergencies that occur when the body cannot properly convert food into energy, causing dangerous toxins to build up in the blood.
One patient stopped having seizures after starting the medication, and two others showed small improvements in cognitive ability.
“Such effects significantly improve the quality of life of Leigh syndrome patients,” Schuelke said.
Scientists believe sildenafil may help by improving mitochondrial function and strengthening neurons, allowing cells to better cope with the severe energy-production problems that drive the disease.
Overall, sildenafil was well tolerated, although one patient had to stop taking it because of a rash.
“While we will have to confirm these initial observations in a more comprehensive study, we are very pleased to have found a promising drug candidate for the treatment of this serious hereditary disease,” Schuelke said.
The research team is already planning the next phase. Schuelke and Prigione are finalizing plans for a larger clinical trial set to launch later this year, aiming to enroll 60 to 70 patients across several European countries to test sildenafil against a placebo.
But for now, Prigione urged families not to try the medication on their own until more research is done.
“If a patient or physician wants to use it, we are happy to collaborate,” he told Science.
