Can we prevent or dealy the onset of SPMS? Not with interferon-beta. #MSBlog #MSResearch #ClinicSpeak
"Analysis of the MSers in the British Columbia MS Register below shows that treatment with interferon-beta did not prevent or delay the onset of SPMS. This data is not consistent with other data sources (MSBase, Italian, French and extension studies). Critics argue that the BC register is an outlier. I am not informed enough to comment. But the data confirms my own clinical impression that on average the majority of MSers on interferon-beta become SP with time. The question that can't be answered here is there a subgroup that does better? Are there responders? Will this study change our practice? Probably no. In an era when our treatment goal has moved to treat-2-target of NEDA we won't leave non-responders or sub-optimal responders on interferon-beta and wait for them to become SP."
BACKGROUND AND PURPOSE: Beta-interferons (IFNβ) are the most widely prescribed drugs for MSers. However, whether or not treatment with IFNβ can delay secondary progressive MS (SPMS) onset remains unknown. Our aim was to examine the association between IFNβ exposure and SPMS onset in MSers with relapsing-remitting MS (RRMS).
METHODS: A retrospective cohort study using British Columbia (Canada) population-based clinical and health administrative data (1985-2008) was conducted. RRMSers treated with IFNβ (n = 794) were compared with untreated contemporary (n = 933) and historical (n = 837) controls. Cohort entry was the first clinic visit during which MSers became eligible for IFNβ treatment (baseline). The outcome was time from baseline to SPMS onset. Cox regression models with IFNβ as a time-dependent exposure were adjusted for sex, and baseline age, disease duration, disability, *socioeconomic status and *comorbidities (*available for the contemporary cohorts only). Additional analyses included propensity score adjustment.
RESULTS: The median follow-up for the IFNβ-treated, untreated contemporary and historical controls were 5.7, 3.7 and 7.3 years, and the proportions of MSers reaching SPMS were 9.2%, 11.8% and 32.9%, respectively. After adjustment for confounders, IFNβ exposure was not associated with the risk of reaching SPMS when either the contemporary or the historical untreated cohorts were considered (hazard ratio 1.07; 95% confidence interval 0.93-1.48, and hazard ratio 1.04; 95% confidence interval 0.74-1.46, respectively). Further adjustments and the propensity score yielded results consistent with the main analysis.
CONCLUSIONS: Amongst MSers with RRMS, use of IFNβ was not associated with a delayed onset of SPMS.