Every-other-day interferon beta-1b versus once-weekly interferon beta-1a for multiple sclerosis (INCOMIN Trial) II: analysis of MRI responses to treatment and correlation with NAb

Abstract

Background In RRMS, clinical exacerbations are usually associated with different types of active lesions at MRI, including: hyperintense lesions on T1-weighted post-gadolinium sequences; new hyperintense lesions or enlarging old lesions on PD/T2-weighted scans; or new hypointense lesions on T1-weighted pre-Gd sequences. Objective/methods Primary outcome was the occurrence of patients with at least one active MRI lesion of the different types indicated above during treatment with 250 mg every other day (EOD) interferon beta (IFNβ)-1b or 30 mg once weekly (OW) IFNβ-1a in outpatients with RRMS (INCOMIN Trial). Results The number of patients with at least one ‘active’ lesion, evaluated over the two-year follow-up, was significantly (P=0.014) lower in the EOD IFNβ-1b arm (13/76, 17%) then in the OW IFNβ-1a arm (25/73, 34%). NAb frequency over two-year follow-up was 22/65 (33.8%) in the EOD IFNβ-1b arm and 4/62 (6.5%) in the OW IFNβ-1a arm, significantly greater in the EOD IFNβ-1b arm. Conclusions The development of MRI active lesions is strongly reduced by EOD-IFNβ-1b compared with OW-IFNβ-1a, indicating that EOD-IFNβ-1b is more effective than OW-IFNβ-1a in reducing ongoing inflammation and demyelination in MS. Logistic regression showed that NAb status did not affect the risk of MRI activity.