Rebif® (interferon beta-1b)

Parent companies: EMD Serono, Inc. and Pfizer Inc

• Administered by subcutaneous injection three times weekly; dosage is 22 or 44 mcg. The 44 mcg dose appears significantly more effective than 22 mcg.


• Approved for relapsing types of MS.


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


• Interferons appear to reduce inflammation by modulating a favorable balance between cells that increase inflammation and cells that decrease it.


• The Rebif new formulation (RNF) is designed to minimize the development of neutralizing antibodies that may decrease the response to treatment. A 96-week study demonstrated that it is better tolerated than the original formulation; it results in less injection-site reactions and pain. Fewer neutralizing antibodies (NABs) were seen with RNF. The completed IMPROVE trial documented the efficacy of RNF in RRMS, as measured by the number of active lesions on MRI at 16 weeks. This formulation is not yet available in the United States, but it may be approved in the near future. An ongoing study will evaluate the effect of RNF on quality of life, tolerability, treatment satisfaction, and injection-site redness.


• A once-weekly dose of Rebif previously demonstrated an effect on delaying CDMS. An ongoing study is looking at the use of Rebif 44 mg four times per week for CIS to confirm its effectiveness in delaying the conversion to CDMS.


• A 96-week trial of methylprednisolone as an add-on to Rebif is reported to significantly reduce the relapse rate in participants who showed clinical activity during interferon therapy.


• Combination and Comparative studies: In one study, the 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 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.


• 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.