Table 4.
Risk of relapse versus placebo over 1 and 2 years (PRISMS/SPECTRIMS)
| Risk of relapse | PRISMS/SPECTRIMS | PRISMS/SPECTRIMS with baseline disease activitya | PRISMS/SPECTRIMS without baseline disease activity | |||
|---|---|---|---|---|---|---|
| Placebo (n = 164) | sc IFN β-1a 44 µg tiw (n = 171) | Placebo (n = 92) | sc IFN β-1a 44 µg tiw (n = 103) | Placebo (n = 72) | sc IFN β-1a 44 µg tiw (n = 68) | |
| Year 1 | ||||||
| Risk of relapse vs placebob | ||||||
| Patients with relapse, n (%) | 90 (54.9) | 77 (45.0) | 66 (71.7) | 59 (57.3) | 24 (33.3) | 18 (26.5) |
| Patients without relapse, n (%) | 74 (45.1) | 94 (55.0) | 26 (28.3) | 44 (42.7) | 48 (66.7) | 50 (73.5) |
| HR vs placebo (95% CI) | 0.696 (0.511–0.947) | 0.659 (0.461–0.942) | 0.759 (0.411–1.402) | |||
| p value | 0.0213 | 0.0223 | 0.3789 | |||
| Year 2 | ||||||
| Risk of relapse vs placebob | ||||||
| Patients with relapse, n (%) | 106 (64.6) | 96 (56.1) | 76 (82.6) | 69 (67.0) | 30 (41.7) | 27 (39.7) |
| Patients without relapse, n (%) | 58 (35.4) | 75 (43.9) | 16 (17.4) | 34 (33.0) | 42 (58.3) | 41 (60.3) |
| HR vs placebo (95% CI) | 0.696 (0.525–0.923) | 0.613 (0.438–0.858) | 0.866 (0.511–1.466) | |||
| p value | 0.0119 | 0.0043 | 0.5917 | |||
CI confidence interval, EDSS Expanded Disability Status Scale, HR hazard ratio, IFN β-1a interferon beta-1a, sc subcutaneous, tiw three times weekly
aActive disease defined as having either ≥ 1 relapse within 2 years before baseline or ≥ 1 gadolinium-enhancing lesion at baseline
bHR and p value based on Cox proportional hazards model, adjusted for number of relapses within 2 years prior, age group (<40 vs ≥ 40 years), and baseline burden of disease (in the EDSS 4.0–6.0 subgroup, adjustment was also made for baseline EDSS)