Neutralizing antibody production against Rebif® and ReciGen® in Relapsing-Remitting Multiple Sclerosis (RRMS) patients and its association with patient's disability.

INTRODUCTION: Human recombinant interferon beta (IFN-β) is one of the first line treatments for Relapsing-Remitting Multiple Sclerosis (RRMS). However, the production of neutralizing antibodies (NAb) can impair its function. The aim of this study was to investigate the production of neutralizing antibodies against Rebif® and ReciGen® (two brands of IFN-β-1a) and to evaluate its correlation with Expanded Disability Status Scale (EDSS).

MATERIALS AND METHODS: Serum samples of 71 RRMS patients (34 in ReciGen®, 37 in Rebif® group) were collected. Neutralizing antibody was measured by Myxo-virus resistance protein A (MxA) assay using A549 cell line. The MxA concentration was measured by enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS: The median period of treatment with IFN-β-1a was 18 months in ReciGen® and 24 months in Rebif® arms. The percentage of patients with positive titer of neutralizing antibody (NAb+) had no statistically significant difference between groups (P = 0.6). In both ReciGen® and Rebif® groups, the increase in EDSS score was significantly higher in NAb+ patients compared to NAb- patients (p ≤ 0.05). The duration of using ReciGen® or Rebif® for >24 months was influential in the NAb positivity (OR = 3.78).

CONCLUSION: Receiving interferon beta-1a for >24 months is correlated with higher possibility of NAb production. The type of IFN-β used in the study had no significant impact on NAb positivity. In addition, both groups had comparable EDSS score changes, and NAb status of patients was correlated with their EDSS score.