Abstract

Extending the natalizumab interval after the 24th administration could reduce the risk of progressive multifocal leukoencephalopathy (PML). The objective is to evaluate the noninferiority of the efficacy of an extended interval dosing (EID) compared with the standard interval dosing (SID) of natalizumab. It is an observational, multicenter (14 Italian centers), retrospective cohort study, starting from the 24th natalizumab infusion to the loss of follow-up or 2 years after baseline. Patients were grouped in 2 categories according to the mean number of weeks between doses: < 5 weeks, SID; ≥ 5 weeks, EID. Three hundred and sixty patients were enrolled. Median dose interval (MDI) following 24th infusion was 4.7 weeks, with a bimodal distribution (modes at 4 and 6 weeks). Two hundred and sixteen patients were in the SID group (MDI = 4.3 weeks) and 144 in the EID group (MDI 6.2 weeks). Annualized relapse rate was 0.060 (95% CI = 0.033-0.087) in the SID group and 0.039 (95% CI = 0.017-0.063) in the EID group. The non-inferiority of EID versus SID was satisfied. In conclusion, there is no evidence of a reduced efficacy of natalizumab in an EID setting. This observation confirms previous results and together with the emerging evidence of a reduced risk of PML associated to an EID, supports the need of a randomized study to assess the need to change the standard of the natalizumab dosing schedule.

Keywords: Multiple sclerosis; efficacy; extended dose; natalizumab; progressive multifocal leukoencephalopathy.

Abstract

Background: The introduction of oral disease-modifying therapies (DMTs) for relapsing-remitting multiple sclerosis (RRMS) changed algorithms of RRMS treatment.

Objectives: To compare the effectiveness of treatment with dimethyl fumarate (DMF) and teriflunomide (TRF) in a large multicentre Italian cohort of RRMS patients.

Materials and methods: Patients with RRMS who received treatment with DMF and TRF between January 1st, 2012 and December 31st, 2018 from twelve MS centers were identified. The events investigated were "time-to-first-relapse", "time-to-Magnetic-Resonance-Imaging (MRI)-activity" and "time-to-disability-progression".

Results: 1445 patients were enrolled (1039 on DMF, 406 on TRF) and followed for a median of 34 months. Patients on TRF were older (43.5 ± 8.6 vs 38.8 ± 9.2 years), with a predominance of men and higher level of disability (p < 0.001 for all). Patients on DMF had a higher number of relapses and radiological activity (p < .05) at baseline. Time-varying Cox-model for the event "time-to-first relapse" revealed that no differences were found between the two groups in the first 38 months of treatment (HRt < 38DMF = 0.73, CI = 0.52 to 1.03, p = 0.079). When the time-on-therapy exceeds 38 months patients on DMF had an approximately 0.3 times lower relapse hazard risk than those who took TRF (HRt>38DMF = 3.83, CI = 1.11 to 13.23, p = 0.033). Both DMTs controlled similarly MRI activity and disability progression.

Conclusions: Patients on DMF had higher relapse-free survival time than TRF group after the first 38 months on therapy.

Keywords: Dimethyl fumarate; Efficacy; Multiple sclerosis; Safety; Teriflunomide.

Abstract

An ever-expanding number of disease-modifying drugs for multiple sclerosis have become available in recent years, after demonstrating efficacy in clinical trials. In the real-world setting, however, disease-modifying drugs are prescribed in patient populations that differ from those included in pivotal studies, where extreme age patients are usually excluded or under-represented. In this multicentre, observational, retrospective Italian cohort study, we evaluated treatment exposure in three cohorts of patients with relapsing-remitting multiple sclerosis defined by age at onset: paediatric-onset (≤18 years), adult-onset (18-49 years) and late-onset multiple sclerosis (≥50 years). We included patients with a relapsing-remitting phenotype, ≥5 years follow-up, ≥3 Expanded Disability Status Scale (EDSS) evaluations and a first neurological evaluation within 3 years from the first demyelinating event. Multivariate Cox regression models (adjusted hazard ratio with 95% confidence intervals) were used to assess the risk of reaching a first 12-month confirmed disability worsening and the risk of reaching a sustained EDSS of 4.0. The effect of disease-modifying drugs was assessed as quartiles of time exposure. We found that disease-modifying drugs reduced the risk of 12-month confirmed disability worsening, with a progressive risk reduction in different quartiles of exposure in paediatric-onset and adult-onset patients [adjusted hazard ratios in non-exposed versus exposed >62% of the follow-up time: 8.0 (3.5-17.9) for paediatric-onset and 6.3 (4.9-8.0) for adult-onset, P < 0.0001] showing a trend in late-onset patients [adjusted hazard ratio = 1.9 (0.9-4.1), P = 0.07]. These results were confirmed for a sustained EDSS score of 4.0. We also found that relapses were a risk factor for 12-month confirmed disability worsening in all three cohorts, and female sex exerted a protective role in the late-onset cohort. This study provides evidence that sustained exposure to disease-modifying drugs decreases the risk of disability accumulation, seemingly in a dose-dependent manner. It confirms that the effectiveness of disease-modifying drugs is lower in late-onset patients, although still detectable.

Keywords: clinical trials; clinically isolated syndrome; demyelination; multiple sclerosis epidemiology; neuroinflammation.