Rebif® (interferon beta 1-a)

Parent companies: EMD Serono, Inc. and Pfizer Inc.

Administered by subcutaneous injection three times weekly; dosage is 22 or 44 mcg.

Approved for relapsing types of MS.

Rebif has been shown to reduce MRI lesion area and activity. It also reduces the frequency of relapses, and slows the progression of disability.

Interferons may affect the immune system by decreasing damaging cells, while increasing cells that suppress inflammation. They may also reduce the transport of potentially damaging immune-system cells from entering the brain.

A 96-week study of the Rebif new formulation (RNF) demonstrates that it is better tolerated than the original formulation; it results in less injection-site reactions and pain, but flu-like reactions were more common. Fewer neutralizing antibodies (NAbs) were seen with RNF. The ongoing IMPROVE trial is evaluating the efficacy of RNF in RRMS, as measured by the number of active lesions on MRI. This formulation is not yet available in the United States.

An ongoing study is looking at the use of Rebif for CIS to confirm its effectiveness in delaying the conversion to CDMS.

In the COGIMUS study, patients on the 44 mcg dose for two years developed less cognitive impairment than those on the 22 mcg dose.

Combination and Comparative studies:
In one study, combination of Rebif with atorvastatin (Lipitor®) increased MRI and clinical disease activity, suggesting that statins may block the therapeutic effects of interferons. However, two other studies did not support this, and more data are needed.

A pilot-study now recruiting will look at the benefit of combining Rebif with Cellcept early in the disease.

A study now recruiting will combine Rebif with minocycline (an inexpensive antibiotic that has immunomodulatory properties); the primary outcome is time to the first documented relapse.

An ongoing three-year Phase II clinical trial is comparing low-dose and high-dose Campath with high-dose Rebif in patients with early, active RRMS. Its primary outcome measure is the time to sustained accumulation of disability and relapse rate.

A comparison of Rebif versus Copaxone showed an equal and robust effectiveness in reducing relapses (primary outcome). Some MRI outcomes were better for the group treated with Rebif.