People with multiple sclerosis may someday have the option of taking a pill for the disease instead of the injections available now.

But the oral treatments under study also carry potentially dangerous side-effects, two new studies suggest.

The studies in Thursday's New England Journal of Medicine suggest the oral drugs work to reduce relapses and deterioration of the neurodegenerative disease, which attacks the brain and spinal cord. Symptoms of MS include inflammation, paralysis and problems with speech, memory and concentration.

'The studies in this issue of the Journal provide a new horizon for patients with relapsing-remitting multiple sclerosis.'— Dr. William Carroll

Current treatment therapies, which include the injection of drugs such as interferon, show good results but become tiresome for the patients in the long term, researchers say.

This leads some patients to look to oral treatments, even with some increased risk, said Dr. Jock Murray, a neurologist at Dalhousie University's MS research centre in Halifax.

One of the new studies tested cladribine, made by Merck Serono, which is already sold to treat a rare blood cancer. The other tested fingolimod, a daily MS pill being developed by Novartis.

The two-year study of cladribine involved 1,300 people with multiple sclerosis. Half got the pill, the other half a placebo. Those taking the drug were half as likely to relapse and 30 per cent less likely to have worsening disability, Dr. Gavin Giovannoni of Queen Mary University in London and his colleagues found.

Side-effect questions

Between 20 per cent and 30 per cent of those taking cladribine developed low white blood-cell counts, and there also were more cases of shingles, the study found.

The second study, by Dr. Jeffrey Cohen of the Neurologic Institute in Cleveland and colleagues, followed 1,200 MS patients, who were given either fingolimod or an injection of interferon, the standard treatment.

There was less brain shrinkage, a sign of worsening disease, among those taking fingolimod. About 20 per cent of those taking the pill had relapses compared with 30 per cent for the injection group. There were also more shingles cases in the fingolimod group.

Nine per cent of those on fingolimod had serious side-effects, compared with six per cent for the interferon. Two people on fingolimod died of herpes infections and eight had skin cancers. There were also more heart problems in the fingolimod group. For instance, 2.7 per cent had bradycardia or a slow heart rate, compared with 0.7 per cent for the standard treatment.

"As with other new therapies for MS, there are better results but increased risks," Murray said.

Treatment options

Until the side-effects of cladribine and fingolimod are better understood, doctors will likely continue using injection treatments, said Dr. Neil Lava, the director of Emory University's multiple sclerosis clinic.

An editorial in the New England Journal of Medicine accompanying the research welcomed the findings.

"The studies in this issue of the Journal provide a new horizon for patients with relapsing-remitting multiple sclerosis and a welcome increase in the range of treatment options," wrote Dr. William Carroll of Sir Charles Gairdner Hospital in Perth, Australia.

The two drugs work in different ways by targeting T cells, which are involved in the immune system's attack on myelin — the protective coating around nerve cells that becomes damaged in multiple sclerosis.

Cladribine causes active T cells to undergo apoptosis, the most common type of cell death. Fingolimod causes a receptor on the surface of T cells to stop working properly, so the cells can no longer respond to signals directing them to attack nerves in MS.

The pills for MS will not be available immediately, Murray said, because they have not been approved by regulators in the United States or Canada. If approved in Canada, provincial funding for the drugs would be another step.

Merck Serono filed for U.S. approval in late November. Novartis said in mid-December that its FDA filing for fingolimod was imminent.

Each company financed the studies of their drugs. Authors involved in each study reported receiving fees from drug companies.

With files from The Associated Press