- 21 years after enrolment, 98.4% (366/372) of patients were identified and 81 deaths recorded (21.8%). As reported previously, those originally randomized to IFNB-1b 250 mcg had a significant reduction in all-cause mortality over LTF compared with placebo (hazard ratio [HR]=0.532, P=0.0173).
- Assignment to IFNB-1b 250 mcg and several baseline characteristics (EDSS score, T2 burden of disease), third ventricle size on MRI (a marker of atrophy or shrinkage of the brain) were predictive of mortality.
- On-study characteristics (EDSS progression from baseline to year 2, annualized relapse rate over 2 years, MRI T2 activity at Year 2) were also predictive of mortality.
- The hazard ratio (HR) for the treatment effect on mortality was stable and independent of the baseline variables’ effects.
- On-study MRI characteristics were consistently found not to be predictive of mortality, and the predictive value of other on-study clinical parameters varied.
- When taking all factors into account the IFNB-1b 250 mcg treatment effect on mortality was maintained (HR=0.533).
- Similar results for all analyses were seen with IFNB-1b 50 mcg or low dose IFNB-1b.
Conclusions: There was a significant survival advantage in this cohort of patients receiving early IFNB-1b treatment versus placebo. The treatment-related increase in survival was unchanged by the inclusion of baseline variables.
“This abstract is quite complex and you may find it difficult to interpret. The bottom line is that starting treatment with interferon beta 3-years earlier, compared to MS’ers in the placebo-arm, increased their chance of being alive at 21 years by ~50%. In addition, the number of relapses in the 2-years on the trial also predicted mortality; another reason to reduce relapses early on in the course of MS and necessarily within the first 2-years.”