Interferon β-1b and glatiramer acetate effects on permanent black hole evolution

Objective: To compare interferon beta-1b (IFN beta-1b) and glatiramer acetate (GA) on new lesion (NL) (gadolinium-enhancing, new T2) evolution into permanent black holes (PBH)-a marker of irreversible tissue damage-in patients with relapsing-remitting multiple sclerosis (RRMS). Methods: BEYOND was a large, phase III, clinical trial comparing IFN beta-1b 250 mu g, IFN beta-1b 500 mu g, and GA (2: 2: 1). Patient scans were reexamined post hoc for PBH in a rater-blinded manner. Two predefined coprimary endpoints compared IFN beta-1b 250 mu g with GA: first, number of PBH per patient at year 2 evolving from year 1 NL, then proportion of year 1 NL evolving into PBH at year 2. IFN beta-1b 500 mu g and GA were compared in an exploratory fashion. Results: Approximately 90% (1,957/2,244) of patients had NL at year 1 with follow-up at year 2. Mean numbers of PBH per patient at year 2 evolving from year 1 NL were lower for IFN beta-1b 250 mu g than GA (0.30 vs 0.43; p = 0.0451). The proportion of NL evolving into PBH was similar (IFN beta-1b 250 mu g vs GA: 21.6% vs 23.5%; p > 0.20). For IFN beta-1b 500 mu g, both the mean PBH number per patient at year 2 evolving from year 1 NL (0.26 vs 0.43; p = 0.0037) and proportion of NL evolving into PBH (16.3% vs 23.5%; p = 0.0409) were lower relative to GA. Conclusion: IFN beta-1b affected PBH development to a similar or better extent than GA. IFN beta-1b favorably influences an MRI outcome indicative of permanent tissue destruction in the brains of patients with multiple sclerosis. Classification of evidence: This study provides Class III evidence that IFN beta-1b is associated with a reduction in MRI PBH formation and evolution compared with GA between years 1 and 2 of treatment. Neurology (R) 2011;76:1222-1228