The antimalarial drug hydroxychloroquine is “a promising treatment candidate” for slowing the progression of a rare form of multiple sclerosis (MS). In a small trial, patients who received the drug were less likely to significantly worsen over a period of 18 months.


MS is a lifelong condition that affects the brain and spinal cord. It is an autoimmune disease, meaning the body is attacked by its own immune system. Patients with MS often experience problems with vision, balance and co-ordination, and walking can become difficult. The cause of MS is unknown, and there is no cure for MS. For the most common type, there are treatments that can slow the progression of the disease. In this case, the therapies can slow the worsening of disability.

However, 1 in 10 patients has a form called ‘primary progressive MS’. Unlike the most common type, there are no periods of remission and instead the symptoms gradually worsen and accumulate over time.

“With primary progressive MS, there is no good treatment to stop or reverse the progression of disease. The disability progressively worsens through time,” said Dr Marcus Koch, of the Department of Clinical Neurosciences at the University of Calgary, who led the study with Dr Wee Yong.

“Dr Yong’s research team, with whom we closely collaborate, has been screening a large number of generic drugs over several years and the results with hydroxychloroquine show some promise. Our trial is a preliminary success that needs further research. We hope sharing these results will help inspire that work, specifically larger scale clinical trials into the future.”

The researchers followed 35 patients over a period of 18 months between November 2016 and June 2018, and prescribed them two doses of hydroxychloroquine a day. After six and 18 months, they timed how long it took the patients to walk 25 feet (7.6m). They expected at least 40 per cent of the patients to worsen significantly over the time, based on ongoing trial data, but in fact only eight did.

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Hydroxychloroquine gained fame in 2020 as a potential treatment for COVID-19, with US President Donald Trump saying he took it to ward off the virus despite warnings that doing so may be unsafe. A recent paper, which has not been peer-reviewed, found no evidence that the drug is an effective treatment for COVID-19.

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Sara RigbyOnline staff writer, BBC Science Focus

Sara is the online staff writer at BBC Science Focus. She has an MPhys in mathematical physics and loves all things space, dinosaurs and dogs.