Survival in MS: a randomized cohort study 21 years after the start of the pivotal IFNß-1b trial.

OBJECTIVE: To examine the effects of interferon beta (IFNß)-1b on all-cause mortality over 21 years in the cohort of 372 patients who participated in the pivotal randomized clinical trial (RCT), retaining (in the analysis) the original randomized treatment-assignments. METHODS: For this randomized long-term cohort study, the primary outcome, defined before data collection, was the comparison of all-cause mortality between the IFNß-1b 250 µg and placebo groups from the time of randomization through the entire 21-year follow-up interval (intention-to-treat, log-rank test for Kaplan-Meier survival curves). All other survival outcomes were secondary. RESULTS: After a median of 21.1 years from RCT enrollment, 98.4%(366 of 372) of patients were identified, and, of these, 81 deaths were recorded (22.1% [81 of 366]). Patients originally randomly assigned to IFNß-1b 250 µg showed a significant reduction in all-cause mortality over the 21-year period compared with placebo (p = 0.0173), with a hazard ratio of 0.532 (95% confidence interval 0.314-0.902). The hazard rate of death at long-term follow-up by Kaplan-Meier estimates was reduced by 46.8% among IFNß-1b 250 µg-treated patients (46.0% among IFNß-1b 50 µg-treated patients) compared with placebo. Baseline variables did not influence the observed treatment effect. CONCLUSIONS: There was a significant survival advantage in this cohort of patients receiving early IFNß-1b treatment at either dose compared with placebo. Near-complete ascertainment, together with confirmatory findings from both active treatment groups, strengthens the evidence for an IFNß-1b benefit on all-cause mortality. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that early treatment with IFNß-1b is associated with prolonged survival in initially treatment-naive patients with relapsing-remitting multiple sclerosis.

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

OBJECTIVE: To compare interferon ß-1b (IFNß-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 IFNß-1b 250 µg, IFNß-1b 500 µg, and GA (2:2:1). Patient scans were reexamined post hoc for PBH in a rater-blinded manner. Two predefined coprimary endpoints compared IFNß-1b 250 µg 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. IFNß-1b 500 µg 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 IFNß-1b 250 µg than GA (0.30 vs 0.43; p = 0.0451). The proportion of NL evolving into PBH was similar (IFNß-1b 250 µg vs GA: 21.6% vs 23.5%; p > 0.20). For IFNß-1b 500 µg, 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: IFNß-1b affected PBH development to a similar or better extent than GA. IFNß-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 IFNß-1b is associated with a reduction in MRI PBH formation and evolution compared with GA between years 1 and 2 of treatment.