Rebif® (interferon beta-1a) is in the class of drugs called interferons. There are other treatments available that may sound similar, such as Avonex® (interferon beta-1a) and Plegridy® (peginterferon beta-1a), but they are not the same product. They may differ in many ways, including formulation, method of delivery, frequency, and dose.
Head-to-head is the only way to compare
The only way to know if one drug is more effective than another is to evaluate them in the same study.
relapsing MS treatment
We compared Rebif to Avonex in a head-to-head study called EVIDENCE.* For an average of 64 weeks, Rebif 44 mcg was given to 339 people 3 times a week under the skin, with injections at least 48 hours apart. Avonex 30 mcg was given to 338 people once a week into the muscle.
The results were significant. High-dose, high-frequency Rebif was proven superior to low-dose, low-frequency Avonex in 2 important ways:
The exact correlation between MRI findings and the current or future clinical status of patients, including disability progression, is unknown.
Rebif was proven to work better than another relapsing MS treatment in a class I clinical trial.‡ In fact, the results of this study comparing Rebif with Avonex were one of the reasons that the Food and Drug Administration (FDA) approved Rebif. If you’re currently on Avonex and not doing as well as you expected, talk to your doctor about switching to Rebif.
* The EVIDENCE (EVidence for Interferon Dose-response: European North American Comparative Efficacy) trial was conducted entirely in North America and Western Europe.
† Lesions detected with both T1-weighted gadolinium-enhanced and PD/T2-weighted MRI.
‡ According to the American Academy of Neurology, data from class I studies are collected under the highest scientific standards and are thought to be the most valid.
§ Gadolinium is a contrast medium injected prior to MRI scans. It passes through breaches in the blood-brain barrier and is therefore used to highlight new and active lesions. The usage of gadolinium greatly enhances the sensitivity of a T1-weighted MRI.
Important Safety Information
In the study, side effects between Rebif and Avonex were generally similar. People taking Avonex had more flu-like symptoms than those taking Rebif. People taking Rebif had a greater number of injection site reactions, elevated liver enzymes, and decreased white blood cell counts.Learn more about safety and tolerability
At the end of the head-to-head (comparative) phase of the EVIDENCE study, the 605 remaining people were asked if they wanted to leave the study or keep going in the extension phase. In this phase of the study, which lasted an average of 8 months, 495 people chose to participate; 73% of those taking Avonex 30 mcg chose to take Rebif 44 mcg, whereas 91% of those taking Rebif 44 mcg decided to stay with it.
People who changed from Avonex to Rebif had a 50% further reduction in flare-ups at an average of 8 months.
People who stayed on Rebif had a 26% further reduction in flare-ups at an average of 8 months.
People on Avonex 30 mcg
(1 time a week into the muscle)
People on Rebif 44 mcg
(3 times a week under the skin)