Two double-blind RCTs were included (n=299).
Exacerbation: at 12 months, data favour copolymer 1 (OR 0.17, 95% CI: 0.05, 0.51, p=0.002)), while at 24 and 35 months the effect was not significant.
Progression: copolymer 1 significantly decreased the odds of progression at 24 months (OR 0.57, 95% CI: 0.34, 0.95, p=0.031) and 35 months (OR 0.50, 95% CI: 0.28, 0.90, p=0.019). Heterogeneity was not noted in either result.