誤訳ではないかと原文を読んでみました。Subgroup analyses suggested that the magnitude and direction of treatment effect in patients with OS-MS and C-MS was similar, albeit not significant due to small sample size.となっていますので、訳に間違いはありません(Pさん、疑ってスミマセン)。
A total of 42/95 (44.2%) in the 250 μg group and 32/93 (34.4%) in the 50 μg group were relapse-free at the end of the study(623ページ)
The proportion of relapse-free patients was 28% (5/18) in the 50 μg group and 27% (6/22) in the 250 μg group in patients with OS-MS, compared to 36% (27/75) in the 50 μg group and 49% (36/73) in the 250 μg group in patients with C-MS. (624ページ)