Interferon beta, an anti-inflammatory therapy for patients with Relapsing Remitting Multiple Sclerosis(RRMS), is also used for patients with the secondary progressive type.
Although it remains unclear how either beta-1a or beta-1b interferons (IFNs) work in MS, these therapies have been well established in RRMS. Currently, IFNs' therapies are also the first line treatment for Secondary Progressive Multiple Sclerosis (SPMS), since other drugs, such as mitoxantrone, have a worse risk/benefit profile. A major unanswered question is whether and to what extent IFNs are really effective in SPMS.
The main objective of this review was to verify whether IFNs in patients with SPMS are more effective than placebo in reducing the number of patients who experience disability progression during the 2-3 years follow-up.
Among the pertinent literature, only five studies met the criteria of the inclusion in the review, comprising a total of 3122 participants (1829 treated with IFN and 1293 with placebo).
Overall, these results show that IFNs are unable to retard the progression once it is established, making INFs not useful in the secondary progressive phase of the disease.
The well known adverse events related to IFNs' treatment such as injection site reactions, influenza like syndrome, and leukopenia occurred frequently also in SPMS patients, while serious and life-threatening adverse events were not increased in the treated group of patients.
Because this review has considered well designed studies with a high number of patients, the authors believe that its results give conclusive evidence on the clinical efficacy of IFN beta versus placebo in patients with SPMS. Research focused on innovative drugs is mandatory.