What are Disease Modifying Drugs?

Unlike symptomatic therapies, disease modifying drugs are drugs which can alter the progression of MS. They have been shown to reduce the frequency and severity of relapses and slow the development of disability in some people.

There are two types of DMD used in the treatment of MS. These are:

• Beta interferon - which comes in two forms, Beta interferon 1a and Beta interferon 1b
• Glatiramer acetate

Although their effect is quite similar, they work in different ways:

How do these drugs work?
The way the disease modifying drugs are thought to work is based on the idea of MS as an autoimmune disease.

There is no complete understanding of how beta interferon and glatiramer acetate work in the human body. However, research in these areas is improving all the time, and the following is a basic guide.

Beta interferons
Interferons are proteins produced naturally by the human body. They help to fight viral infections and play a vital role in the functioning of the immune system.

There are three types of natural interferon: alpha, beta and gamma. Alpha interferons are used in cancer treatments, and are not thought to be of benefit in treating people with MS. Gamma interferons have been tried in MS, and research showed that they could actually induce MS symptoms.

Beta interferon is known to block the action of gamma interferon, and it is thought that beta interferon acts in MS by reducing both inflammation and the body's autoimmune reaction that is responsible for the inflammation and consequent destruction of myelin.

Two different forms of beta interferon molecule are available as drugs for MS, beta interferon 1a and beta interferon 1b. The differences are due to the manufacturing processes.

Glatiramer acetate
Glatiramer acetate is completely different from beta interferon. It is a laboratory made drug, composed of protein molecules (amino acids) that naturally occur in the human body.

Glatiramer acetate is designed to mimic the effects of the main proteins in myelin. Once injected, the drug is thought to work by connecting to cells in the immune system that can reach the myelin sheath under attack. These cells are thought to switch off inflammation occurring in the central nervous system (brain and spinal cord), and so help brain and spinal column cells recover.

Further details about how the DMDs are taken is given on the following pages.