Multiple Sclerosis Health Center

New Oral MS Drugs May Be on the Horizon

Cladribine for MS

In a third study, Gavin Giovannoni, MB, PhD, of  Barts and the London School of Medicine and Dentistry at Queen Mary University of London and his colleagues evaluated more than 1,300 MS patients who were randomly assigned either two or four short courses of oral cladribine or a placebo. The treatment course included one or two pills a day for four or five days, totaling 8 to 20 days of treatment annually.

Over the nearly two-year study period, nearly 80% of those on the low-dose cladribine were relapse-free, nearly 79% of those on the higher dose were relapse-free, but just 61% of those on placebo were relapse-free.

Giovannoni calls the results excellent. "This means that four out of five people are disease-free in terms of relapses," he tells WebMD.

Cladribine by injection is already approved for treating leukemia under the brand name Leustatin. Shingles occurred in 20 of the patients taking cladribine vs. none in the placebo group.

Other Opinions

''This is really big news," says John Richert, MD, executive vice president for research and clinical programs at the National Multiple Sclerosis Society, New York. MS patients often grow tired of having to have drugs injected, he says, and so stop taking them. "Having oral therapies available increases the likelihood that people will be willing to start the drug early in the course of their disease and continue on the drugs with good compliance long term."

But Richert expressed some caveats about side effects. One side effect of cladribine involves cancer cases. Three cancers occurred in patients in one study getting the low-dose cladribine. "This has to be followed up long term, as the authors note," Richert says.

And, he says, the data on the drugs are confined to the form of MS known as relapsing-remitting. Eventually, some patients with relapsing-remitting make a transition into secondary-progressive MS, in which the disease worsens more steadily. Others have progressive disease from the beginning known as primary-progressive MS, while others have progressive-relapsing MS.

In an accompanying editorial, William Carroll, MD, of Sir Charles Gairdner Hospital in Perth, Australia,  calls the new drugs a welcome addition to treatment options but also notes that the existing therapies remain ''very effective, particularly when they are administered early."

He points out that side effects of the new drugs -- including infections, cancers, and low white blood cell counts -- must be weighed against their benefits. Other side effects included herpes zoster (shingles) infections and herpes virus infections; in some cases they were more frequent in those getting the new drugs and in some cases not.

Both drugs work by reducing the number of potentially aggressive lymphocytes, a type of white blood cell, available to enter the central nervous system, although they do so in different ways.

Merck-Serono supported the cladribine study; Novartis Pharma supported the fingolimod studies. Carroll, the editorial author, reports receiving honoraria from Merck-Serono and fees from other pharmaceutical companies. Cohen, who led one fingolimod study, reports receiving consulting fees form Novartis, and Ludwig Kappos, MD, who led the other fingolimod study, has gotten consulting or advisory fees from Novartis and Merck Serono and others. Giovannoni, who led the cladribine study, reports receiving consulting fees from Merck Serono, Novartis, and others.