What is Multiple Sclerosis (MS)?
Multiple sclerosis is a chronic, debilitating disease of the central nervous system. While the cause of MS remains elusive, it is thought to be the result of an autoimmune reaction. The immune system attacks and damages the protective protein sheath (known as myelin) that insulates the nerve cells and helps speed the conduction of nerve signals to the brain and spinal cord. Damaged myelin is eventually replaced by scar-like tissue, which causes nerve signals to be slowed or halted.
The progression, symptoms and severity of the disease vary greatly between patients, although it is most often characterised by unpredictable ‘attacks’ or flare-ups in symptoms, followed by periods of remission. Most MS patients experience muscle weakness in their extremities (such as hands and feet) and difficulty with coordination and balance. Other symptoms may include blurred vision, bladder and bowel problems, extreme tiredness, slurred speech and tremors. About half of MS sufferers have difficulties with concentration, attention, memory, and judgment, but intellectual and language abilities are generally spared.
The majority of MS sufferers do not become severely disabled, but, in the worst cases, MS can cause partial or complete paralysis and render a person unable to write, speak, or walk. Although the disease reduces their quality of life, most people with MS have a normal life expectancy. MS affects more women than men, and the average age of onset is 20-40 years.
MS affects about 1.1 million people in the developed world, including 15,000 Australians. The average annual economic cost of MS in the US has been estimated at more than US$7 billion, or about US$34,000 per patient. About 40 per cent of this cost results from medical treatments and most of the balance from indirect costs, including lost earnings.
How is MS currently managed?
Although treatments aimed at delaying the progression of the disease do exist, there is no cure for MS.
In the past, steroids were the principal medications for MS; while steroids cannot affect the course of MS over time, they can reduce the duration and severity of attacks in some patients. Other drugs such as beta interferon are now preferred. The goals of therapy are threefold:
In spite of these advances in treatment, new, more effective therapies are required. To date, the major treatments have concentrated on relieving the symptoms of the disease rather than addressing the underlying cause. Current treatments have limited effectiveness, cause side effects, and are given by injection, which most patients find unpleasant.
What is the company's approach to researching MS?
Our approach
Pharmaxis is developing PXS25/64 to target the underlying disease processes of multiple sclerosis (MS), i.e. preventing damage to the myelin sheath insulating the nerves. We have an active research program designed to identify compounds that prevent the abnormal movement or migration of immune cells (leukocytes or T-cells) from the blood vessels to the surrounding tissue.PXS25/64 has been identified as a selective inhibitor of T-cell migration and has been demonstrated to be effective in rodent models of experimentally-induced MS.
Overall, treatment with PXS25/64 has resulted in a marked reduction in peak severity of signs of MS.Unlike existing approaches to the management of multiple sclerosis, PXS25/64 is delivered orally to humans, rather than by injection.
We believe PXS25/64 prevents the immune cell (leukocyte) from breaking down tissue once it has escaped from the blood stream, thereby preventing the immune cell migrating to its target and contributing to tissue destruction that is the hallmark of diseases such as multiple sclerosis.
