To determine whether interferon beta (IFN-beta) therapy might have a beneficial effect on arthritis, we evaluated the effect of IFN-beta on collagen type II-induced arthritis (CIA) in rhesus monkeys and conducted a pilot study in patients with rheumatoid arthritis (RA).
Four rhesus monkeys with CIA were treated with 10 x 10(6) U (MIU)/kg mammalian cell-derived recombinant IFN-beta (Rebif; Ares-Serono) s.c. daily for 1 week. Subsequently, 12 patients with active RA were treated for 12 weeks with purified natural fibroblast IFN-beta (Frone, Ares-Serono) s.c. 3 times weekly at the following dosages: 6 MIU (n = 4), 12 MIU (n = 4) and 18 MIU (n = 4).
Rapid clinical improvement during IFN-beta therapy was observed in three of the four rhesus monkeys with CIA. There was also a marked decrease in serum C-reactive protein (CRP) levels with a subsequent increase after discontinuation of the treatment in all monkeys. The 10 RA patients who completed the study exhibited on average gradual improvement of tender and swollen joint counts, patient's assessment of pain, and patient's and doctor's global assessment (all P < 0.05). The health assessment questionnaire and serum CRP levels also tended to decrease, but this was not statistically significant; 40% of the patients fulfilled the ACR criteria for 20%, improvement, whereas none fulfilled the ACR criteria for 50% improvement 12 weeks after initiation of treatment. There was no clear dose response relationship.
The data suggest that IFN-beta treatment has a beneficial effect on arthritis.