How effective is Rebif for MS?

Rebif (interferon beta-1a) is an injectable medication that may be used to treat relapsing forms of multiple sclerosis (MS). Its effectiveness was evaluated in clinical studies based on the number of exacerbations (flare-ups). Its effects on disease progression and MRI findings were also studied. Results showed that injecting 22 mcg or 44 mcg three times a week reduced the number of exacerbations compared to placebo (no active medication).

Results from study 1

• Rebif 22 mcg three times a week reduced MS exacerbations by 29% over 2 years.
• Rebif 44 mcg three times a week reduced MS exacerbations by 32% over 2 years.
• 25% of patients taking 22 mcg of Rebif three times a week did not have a flare-up at 2 years, compared to 32% of patients taking the 44 mcg dose and 15% of patients taking a placebo.
• The median time to first MS exacerbation was 7.6 months in patients taking Rebif 22mcg and 9.6 months for patients taking Rebif 44mcg. This is compared to 4.5 months for those taking a placebo.
• MRI PD-T2 lesions were reduced by 1.2% for the 22mcg group and 3.8% for the 44mcg group after 2 years. This is compared to an increase in MRI PD-T2 lesions of 11% seen in the placebo group.

Results from study 2

• 75% of patients taking Rebif 44 mcg were relapse-free at 24 weeks, compared to 63% of patients taking Avonex 30 mcg.
• At 48 weeks, 62% of patients taking Rebif 44 mcg and 52% of patients taking Avonex 30 mcg were relapse-free.
• Patients taking Rebif 44 mcg had less MRI lesions during 24 weeks of treatment compared to patients taking Avonex 30 mcg.