A Cambridge-led clinical trial has found that combining a common diabetes drug with an antihistamine can partially repair nerve damage in people with multiple sclerosis (MS), raising hopes for a new generation of treatments.
The CCMR Two trial tested metformin, widely used for type 2 diabetes, alongside clemastine, an antihistamine previously shown to stimulate myelin repair. Myelin is the fatty sheath that protects nerve fibres, and its loss in MS disrupts electrical signals in the brain and spinal cord, leading to disability.
Seventy people with relapsing MS took part in the six-month study. While the combination therapy did not improve vision or disability scores in that time, tests revealed a small but measurable improvement in nerve conduction speed — electrical signals travelled 1.3 milliseconds faster in those on the drugs than in the placebo group.
“It’s smaller than we were hoping for,” said Dr Nick Cunniffe, the neurologist who led the trial, “but the drugs have a biological effect to promote remyelination.”
Nearly 3 million people worldwide live with MS, including more than 150,000 in the UK. Current treatments target the immune system to slow attacks on myelin but cannot repair damage once it has occurred.
Researchers cautioned that patients should not seek the drugs outside of clinical trials, noting side effects such as fatigue from clemastine and diarrhoea from metformin. Still, experts described the findings as a crucial step.
“These are really positive proof-of-concept results,” said Emma Gray of the MS Society. “We wouldn’t expect to see clinical benefit after only six months. It will take longer.”
Jonah Chan, a neurology professor at the University of California, San Francisco, added: “Remyelination is the critical path to preventing permanent disability in MS. This is the only immediate hope for restoring function.”
Further and longer trials are planned to test whether the approach can lead to meaningful improvements for patients living with the condition.
