Breakthrough Drug for Debilitating Disease
Media release – Star Public Relations
Breakthrough Drug for Debilitating Disease
A new drug, recently approved for use in New Zealand, has been heralded by one of the country’s leading experts as a “substantial step forward” in the treatment of a debilitating disease.
TYSABRI® is a treatment for relapsing remitting multiple sclerosis (MS), a chronic and unpredictable disease of the central nervous system (CNS).
Dr Ernest Willoughby, a neurologist at Auckland City Hospital, is in charge of a trial of Tysabri in Auckland, involving five patients with MS.
Dr Willoughby says Tysabri is one of the biggest advances in MS treatment yet, and has sparked considerable interest among neurologists.
“It has the potential to help everyone with relapsing remitting MS,” he says.
In MS, patches of inflammation in the brain of spinal cord mean electrical impulses cannot be conducted to and from the brain, leading to the symptoms of MS. There is no known cure.
Relapsing remitting MS is the most common form of the disease. Patients experience episodes of increased symptoms, lasting several weeks or months, followed by a remission where the symptoms disappear or reduce.
Data, published in the New England Journal of Medicine, shows that over two years Tysabri treatment reduced relapses by 68% and reduced disability progression by 42%.
Other treatments such as beta-interferon and glatiramer acetate reduce relapses by around one third.
According to Dr Willoughby, neurologists in New Zealand already have restricted access to MS treatment compared to other western countries, and if Tysabri is not funded there is a risk of the country falling even further behind.
“In New Zealand, to qualify for treatment, it is necessary to have frequent relapses and moderate residual disability, so most people early in the course do not qualify.
Dr Willoughby says it is now widely accepted that starting patients on treatment early offers the best chance to prevent patients with relapsing remitting MS from progressing to the most disabling form of the disease - secondary progressive MS.
About 50% of patients with relapsing remitting MS develop secondary progressive MS within 10 to 20 years.
Although there is controversy concerning how the residual damage from relapses relates to the gradual decline in the secondary progressive phase, the belief is that by cutting the number of relapses, Tysabri could help prevent MS worsening later in the course.
However, it cannot fix damage which is already done –highlighting the need for early treatment.
While Tysabri was approved by Medsafe in September (2007), the issue of funding the drug is complex.
Unfunded, a patient would have to pay about $41,000 a year for treatment, a financial burden very few could even consider.
Dr Willoughby says: “Funding is a complicated process. Tysabri is an infused drug, which would normally be given in a hospital setting, and we’re currently looking at the issue that the treatment may be potentially approvable by individual DHBs or hospitals.”
His concern is that, if it is up to individual hospitals to decide whether to fund the drug, and what criteria to place on its use, we will end up with the situation where treatment for MS patients will vary, depending on where they live.
In a bid to prevent this, he says a group of interested neurologists has discussed making an approach to all DHBs in New Zealand to provide limited access to treatment with Tysabri.
However, this in itself is complicated and time-consuming, with each hospital having its own particular processes to go through in such situations.
“We’ve no idea how it will go. But we think it’s appropriate to try and get a consistent national policy on this, which may be difficult.”
Multiple Sclerosis (MS) is an inflammatory disease where the immune system attacks the sheath surrounding the nerves of the central nervous system (the brain, optic nerves and spinal cord). Patches of inflammation heal leaving scars (sclerosis).
Symptoms include blurred vision, weakness, loss of balance, poor coordination, slurred speech, tremors, numbness, chronic fatigue and more. The disease is unpredictable, and different people can have widely varying symptoms.
Patients with relapsing remitting MS experience relapses, also known as ‘exacerbations’ which tend to last between one and three months, interspersed with periods of remission, where the symptoms improve or disappear.
About 50% of persons with relapsing remitting MS, later in the course, go on to develop secondary progressive MS, where the disability gradually progresses. However relapses may still occur.
MS is usually first diagnosed between the ages of 20 and 40, and it affects twice as many women as men. Most people with MS have a normal life-span, but they often face increased disability in later life.
A prevalence study is currently under way in New Zealand and it is believed about 3,500 in New Zealand have MS.
MS is more common the further you go from the Equator, so , for example, it is more prevalent in Invercargill than Northland.
Current available treatments
Treatment for MS includes steroids to treat acute relapses, shortening the attack, and beta-interferons or glatiramer acetate for chronic treatment to help reduce the frequency of relapses.
Beta-interferons and glatiramer acetate are classed as ‘disease modifying therapy’ and reduce the number of relapses by modulating the immune response without generally suppressing immune reactions.
The treatments are given by regular injections, ranging in frequency from daily to weekly. In New Zealand access is restricted to people with frequent relapses and moderate residual disability. Overall the current treatments reduce the number of relapses by about one third.
Tysabri is a monoclonal antibody, which is given by a single, monthly infusion.
Tysabri is designed to prevent potentially damaging immune cells moving from the bloodstream, across the "blood-brain barrier,"into the brain and spinal cord. It does this by attaching itself to a protein on the surface of the immune cells, which would normally enable them to stick to and pass through the blood vessel wall.
According to data that have been published in the New England Journal of Medicine, after two years, Tysabri treatment led to a 68% relative reduction in the annualized relapse rate compared to placebo and reduced the relative risk of disability progression by 42% over two years.
With respect to side effects, the main concern has been that Tysabri increases the risk of progressive multifocal leukoencephalopathy (PML), an opportunistic viral infection of the brain that usually leads to death or severe disability.
The makers withdrew TYSABRI from the US market in February 2005, following its initial approval in November 2004, after three patients (out of about 3000) in the drug’s clinical trials developed PML, and two subsequently died.
Clinical trials were put on hold for a year, in which no further cases were found. In June 2006 the US Food and Drug Administration approved an application for resumed marketing of Tysabri if used on its own. To date PML has occurred only in persons taking Tysabri with other medications affecting the immune system.
Tysabri was reintroduced to the US market in July 2006, under a strict prescribing programme.
Approval in other countries
Tysabri is currently being taken by about 17,000 people worldwide, and is approved in the US, EU, Switzerland, Canada, Australia and Israel.
In Australia the Pharmaceutical Benefits Advisory Committee this month recommended Tysabri for listing on the Pharmaceutical Benefits Schedule. This recommendation is the first step of a process which now sees the decision go before post-election Cabinet for final approval.
Dr Ernest Willoughby
Dr Ernest Willoughby has been Medical Adviser to the New Zealand Multiple Sclerosis Society since 1985, and is patron of the Auckland MS Society.
He is also a member of the International Medical & Scientific Board of the Multiple Sclerosis International Federation (MSIF) and on the executive committee of the MS Forum.
Dr Willoughby has worked as a Neurologist at Auckland Hospital since 1979 and has a consultant private practice. He is Honorary Reader in Neurology at the University of Auckland School of Medicine.