To determine whether high-dose biotin increases the risk of clinical relapse and to report the characteristics of the patients who experienced them.

Some observations have suggested that the risk of inflammatory activity may be increased with high-dose biotin in progressive multiple sclerosis (PMS).

IPBio-SeP (Incidence of relapses in patients with biotin-treated PMS) is a French, academic, multicenter, retrospective study, comparing a group of PMS patients treated with high-dose biotin to a control group naive of this drug, within the OFSEP cohort. The analysis was conducted in intention to treat. A propensity score (PS) was created, using the method of the inverse probability of treatment weighting (IPTW), to study the annualized relapse rate (ARR) as the primary endpoint. We present here an intermediate analysis.

594 biotin-treated patients and 320 controls were analyzed with a follow-up of 15 ± 5.9 months. They presented 26 (4.4%) and 24 (7.5%) relapses, respectively (p = 0.2). In univariate analysis, as after application of PS, the ARR was not significantly different between the two groups. With the IPTW, the ARR was 0.049 ± 0.26 in the biotin-treated group versus 0.037 ± 0.18 in the control group (d = 0.05, < 0.2). No patient had more than one relapse during the follow-up, despite biotin continuation in 63.6% of cases. Compared to other biotin-treated patients, those who had a relapse had a lower Expanded Disability Status Scale (EDSS) (p = 0.02) and appeared to have more frequently a secondary progressive MS (SPMS), with a higher ARR during progression and a more recent relapse before baseline. 

This intermediate analysis of the IPBio-SeP study did not show any increased risk of clinical inflammatory activity with high-dose biotin therapy in this population without relapse in the year prior to treatment initiation.