Early clinical trial results from the University of Cambridge suggest that combining a common diabetes drug, metformin, with the antihistamine clemastine may help repair nerve damage in multiple sclerosis (MS).
The CCMR Two trial tested the drugs in 70 people with relapsing MS over six months. Researchers measured how fast electrical signals travelled between the eyes and brain, a process slowed by damage to the myelin sheath — the fatty coating that protects nerve fibres. Patients who took the drug combination showed improved nerve conduction compared with those on placebo, though the benefit was small: just 1.3 milliseconds faster.
“It’s smaller than we were hoping for,” said lead researcher Dr Nick Cunniffe, who nonetheless described the findings as proof that the drugs promote remyelination. “We need to be clear that people do not feel better on these drugs over six months.”
The trial did not demonstrate improvements in vision or disability, and participants reported side effects including fatigue and diarrhoea. Still, researchers believe the results provide a valuable foundation for longer studies.
Emma Gray of the MS Society, which funded the trial, called the outcome a “positive proof of concept” but stressed that clinical benefits are unlikely to appear in such a short timeframe.
Globally, nearly 3 million people live with MS, the most common neurological condition in young adults. Current treatments target the immune system but cannot repair damaged nerves. Clemastine has previously shown modest benefits in boosting myelin repair, and laboratory studies suggested metformin could enhance its effect.
Jonah Chan, a neurology professor at UCSF, said the pursuit of remyelinating drugs remains critical. “Remyelination is the critical path to preventing permanent disability in MS. It is also the only immediate hope for restoring function,” he said, urging continued scientific perseverance despite modest early results.
Researchers cautioned that patients should not attempt to access the drugs outside trials, as they remain under evaluation.
