Symptoms may be mild such as numbness in the limbs or severe (pain, spasticity, loss of vision, fatigue and bladder and bowel dysfunction). Multiple sclerosis affects around 350,000 people in the US with approximately 200 new cases diagnosed each week.

MS is a disease of the white matter of the brain and spinal cord, characterised by an inflammatory response to myelin, the fatty insulation of nerve cells (axons). Electrical impulses are sent along nerves to communicate signals to and from the brain, updating it on sensory inputs and instructing the body to carry out a task. Myelin insulates the axons to ensure that these messages are conducted without interacting with other nerve axons.

With MS, inflammation occurs in the nerves in random patches called plaques. This process is followed by destruction of myelin, and as a consequence, impulses travel over the axon very slowly, if at all. There is also electrical interference between axons, and the efficiency of message transmission is reduced or totally lost.

While the cause of MS is not known, the consensus is that it is an autoimmune disease, whereby the immune system turns against a component of the normal body as if it were foreign.

Combative immune cells which penetrate into the central nervous system destroy the myelin sheath, which causes the nerve impulses to be slowed down or even halted and leads to the symptoms of MS.

The release of chemicals, called cytokines, from the immune cells is also believed to destroy the cells that produce new myelin (oligodendrocytes), which often accompanies the long-term disease. In recent years, there has been substantial progress in understanding the pathogenetic mechanisms of the disease and in developing techniques to monitor treatment.

ATL1102 - Existing & Future Therapy for Multiple Sclerosis   

There is no known cure for MS - the goals of therapy are to improve recovery from attacks, to prevent or lessen the number of relapses and their severity, and to reduce disease progression.

Until recently, steroids were the principal medication for MS - while steroids cannot affect the progression of MS, they can reduce the duration of attacks . The US FDA has recently approved several new drugs: interferon beta-1a, interferon beta-1b and glatiramer acetate which have been shown to reduce relapse rates.

The beta-interferons have become the first choice treatment in patients. However there is still a number of unresolved issues including long-term effects, and the occurrence and relevance of neutralizing antibodies.

The anti-cancer drug, Novantrone is approved for MS, and has been shown to reduce the relapse rate by two-thirds, although serious side effects are a problem for long term use.

Tysabri® (natalizumab) a monoclonal antibody which targets the immune system protein (VLA-4),  has been recently approved in the US and Europe as a monotherapy treatment for relapsing forms of multiple sclerosis (MS) to slow the progression of disability and reduce the frequency of clinical relapses.  The drug has been associated with causing progressive multifocal leukoencephalopathy (PML), a rare and frequently fatal, demyelinating disease of the central nervous system.  This has lead to the drug's restricted indication in the US and Europe.

There is clearly a need to create more effective and safer treatments for Multiple Sclerosis and consequently there are a number of new therapies under development.


ATL1102 - Market Value

Global drug sales for MS exceeded US$5 billion in 2005.