Rebif and Avonex go head-to-head.

Serono Laboratories is sponsoring the first-ever clinical trial pitting 2 interferon beta-la drugs against each other. The multicenter trial will compare the efficacy of Rebif, an interferon beta-1 a product produced by Ares-Serono, with Avonex, the interferon beta-la produced by Biogen.

The trial is open to men and women with clinically definite relapsing-remitting MS who have not previously taken an interferon drug, have had at least 2 attacks in the past 2 years, and can walk at least 300 feet without using a cane, crutch, or other assistance. Some 35 clinical centers in the U.S. and another 10 in Europe--are expected to participate.

The same but different

Rebif is taken by subcutaneous injection (just under the skin) 3 times a week at a 44-microgram dose. Avonex is taken by intramuscular injection (into the muscle below the skin), once a week, at a lower 30-microgram dose. In this trial, no volunteers will get placebos, or inert look-alike drugs; everyone will be on a proven treatment for relapsing-remitting MS, as Rebif underwent major clinical trials in Europe, Canada, and Australia. However, the health-care professionals who monitor progress will be blind as to which drug a volunteer is taking.

The trial will focus on comparing the effect of the 2 drugs on the people who remain free of MS attacks after 1 year. The burden of MS lesions, or damaged areas within the brain, will be followed with regular MRI scans.

Valuable information

If Rebif proves to have clear advantages over Avonex, the data will be submitted to the FDA in the hope of getting permission to market it in the U.S. earlier than 2003. (See Protecting orphans sidebar.) Regardless of which product proves superior, the study will produce important data on the effects of dose levels and delivery routes for both types of interferon beta-la. For information on study sites and how to volunteer, telephone Serono toll-free at 888-797-4477.

Protecting orphans

Last year, the FDA declined to approve Rebif for sale in the United States because, in their view, the data from clinical trials didn't demonstrate that Rebif gets better results than Avonex in controlling relapsing, remitting MS. The clinical trials for both Rebif and Avonex compared the active drug to inactive placebo injections. Avonex is protected from competition by "me-too" medications until 2003 under the federal Orphan Drug Act.

The Orphan Drug Act is designed to encourage for-profit companies to invest in developing drags for less common conditions--and all 3 of the ABC drugs for MS were developed under its protections. New MS drugs are needed by a relatively limited number of people, as compared to a drug like Viagra, for example. Yet, the expense of drug development and large clinical trials, along with the risk that a promising treatment won't work in practice, is similar whether the pool of potential buyers numbers millions or thousands. Without this marketing protection, most experts say drugs for diseases like MS or Lou Gehrig's disease might never reach the marketplace.