Extensive studies of a drug have found that it can have a major impact on the progression of some types of multiple sclerosis (MS).

MS is a chronic disease of the central nervous system, which causes a gradual degeneration of the nerves. This results in a progressive deterioration in various functions controlled by the nervous system, such as vision, speech and movement.

Around 2.3 million people worldwide are affected, including 8,000 people in Ireland. There is currently no cure.

However, three studies involving the drug, ocrelizumab, found that it can reduce the number of relapses experienced by people with relapsing forms of MS - the most common type of the disease.

The results revealed that the drug was superior to the current most well-established MS therapy, reducing the annual relapse rate by almost 50% when compared with the current therapy over a two-year period.

The drug also appeared to significantly delay disability progression and MS-related inflammation and brain injury in those affected.

Meanwhile, it also appears to benefit those with primary progressive MS (PPMS), which make up 10-15% of all MS cases. PPMS is characterised by steadily worsening symptoms, usually without distinct relapses or periods of remission.

The research found that ocrelizumab reduced the progression of disability in those affected, as well as the volume of chronic inflammatory brain lesions.

The results of the three studies were presented to the European Committee for Treatment and Research in MS in Barcelona and the manufacturers, Roche, are now seeking marketing authorisation for the drug in the treatment of relapsing MS and PPMS.

"This is a very important development for the MS community in Ireland and around the world. Ocrelizumab is the first investigational medicine to significantly reduce disability progression in people with primary progressive MS - a form of MS with no approved treatments," commented Roche Ireland's medical director, Dr Mike Starnawski.