Research horizons: treatments for progressive MS.

Because progression of MS proceeds quite slowly for most people, clinical trials of treatments for progressive MS take years longer than trials in relapsing-remitting MS. The scientists must wait to see if progression has truly been slowed or stopped, rather than count the number of relapses.

The pharmaceutical companies that have had success with new medications for relapsing-remitting MS are now conducting clinical trials of these drugs for progressive forms of MS.

Betaseron (interferon beta-1b) for secondary progressive MS is in large multicenter trials in the U.S. and in Europe. Results are expected in 2000.

Rebif (interferon beta-1a) for secondary progressive MS is in multicenter clinical trials in Europe.

Avonex (interferon beta-1a) is in a small trial (only 50 people) in primary progressive MS. Data may be available in 1999.

Avonex is also being studied as a preventive treatment for people who have had only one MS-like attack and cannot be definitively diagnosed as having multiple sclerosis. The hope is that treatment might prevent or delay development of definitive MS. This trial may have data to publish in 2001.

On the farther horizon

Peptide therapy -- a treatment that uses injections of fragments of a protein from the T cell surface -- showed some promise in both primary and secondary progressive MS in a very small trial. The data were published last year in Nature Medicine. Larger trials are getting underway now.

T cells are the white blood cells that direct immune activity, and this treatment apparently trains other immune-system cells to deactivate myelin-sensitive T cells.

In MS, some T cells become sensitive to myelin and launch attacks against it. Myelin, the sheathing that normally protects nerve fibers, ends up damaged. Other methods to control T cells are now in the pilot stage of testing.

Antigen/MHC complex binder (Anergix): a synthetic compound designed to cripple the ability of T cells to launch an attack on myelin. The drug makes the T cells incompetent.

T cell vaccination: this involves administering T cells that have been proven to react against myelin and then deactivated with x-rays. Preliminary results suggest that vaccination can reduce the number of brain lesions and deplete the population of myelin-sensitive T cells.

FK 506 (Prograf): this is an oral immune-suppressing drug that successfully prevents rejection of organs in patients who have had transplants. It might slow progressive MS.

Thalidomide: the drug that caused terrible birth defects when it was used to control nausea in pregnancy may prove useful and safe in nonpregnant people who are fighting progressive MS. Thalidomide appears to inhibit an immune-cell secretion called TNF-alpha. TNF-alpha kills cells that make myelin.

The National MS Society is following the progress of these and other pilot studies and will make information about them public when data are released.

Two Types of Progressive MS

Primary progressive: There is no pattern of attacks (or relapses) with periods of recovery remissions) in between. Instead, MS symptoms steadily worsen from the onset. Secondary progressive: After a period of attacks and recovery (or partial recovery), MS symptoms begin steadily worsening, with few or no attacks. For more information, see INSIDE MS, Fall 1996, page 7, or call 1-800-FIGHT MS [1-800-344-4867].