Natalizumab treatment shows low cumulative probabilities of confirmed disability worsening to EDSS milestones in the long-term setting.

Abstract Background Though the Expanded Disability Status Scale (EDSS) is commonly used to assess disability level in relapsing-remitting multiple sclerosis (RRMS), the criteria defining disability progression are used for patients with a wide range of baseline levels of disability in relatively short-term trials. As a result, not all EDSS changes carry the same weight in terms of future disability, and treatment benefits such as decreased risk of reaching particular disability milestones may not be reliably captured. The objectives of this analysis are to assess the probability of confirmed disability worsening to specific EDSS milestones (i.e., EDSS scores ≥3.0, ≥4.0, or ≥6.0) at 288 weeks in the Tysabri Observational Program (TOP) and to examine the impact of relapses occurring during natalizumab therapy in TOP patients who had received natalizumab for ≥24 months. Methods TOP is an ongoing, open-label, observational, prospective study of patients with RRMS in clinical practice. Enrolled patients were naive to natalizumab at treatment initiation or had received ≤3 doses at the time of enrollment. Intravenous natalizumab (300 mg) infusions were given every 4 weeks, and the EDSS was assessed at baseline and every 24 weeks during treatment. Results Of the 4161 patients enrolled in TOP with follow-up of at least 24 months, 3253 patients with available baseline EDSS scores had continued natalizumab treatment and 908 had discontinued (5.4% due to a reported lack of efficacy and 16.4% for other reasons) at the 24-month time point. Those who discontinued due to lack of efficacy had higher baseline EDSS scores (median 4.5 vs. 3.5), higher on-treatment relapse rates (0.82 vs. 0.23), and higher cumulative probabilities of EDSS worsening (16% vs. 9%) at 24 months than those completing therapy. Among 24-month completers, after approximately 5.5 years of natalizumab treatment, the cumulative probabilities of confirmed EDSS worsening by 1.0 and 2.0 points were 18.5% and 7.9%, respectively (24-week confirmation), and 13.5% and 5.3%, respectively (48-week confirmation). The risks of 24- and 48-week confirmed EDSS worsening were significantly higher in patients with on-treatment relapses than in those without relapses. An analysis of time to specific EDSS milestones showed that the probabilities of 48-week confirmed transition from EDSS scores of 0.0–2.0 to ≥3.0, 2.0–3.0 to ≥4.0, and 4.0–5.0 to ≥6.0 at week 288 in TOP were 11.1%, 11.8%, and 9.5%, respectively, with lower probabilities observed among patients without on-treatment relapses (8.1%, 8.4%, and 5.7%, respectively). Conclusions In TOP patients with a median (range) baseline EDSS score of 3.5 (0.0–9.5) who completed 24 months of natalizumab treatment, the rate of 48-week confirmed disability worsening events was below 15%; after approximately 5.5 years of natalizumab treatment, 86.5% and 94.7% of patients did not have EDSS score increases of ≥1.0 or ≥2.0 points, respectively. The presence of relapses was associated with higher rates of overall disability worsening. These results were confirmed by assessing transition to EDSS milestones. Lower rates of overall 48-week confirmed EDSS worsening and of transitioning from EDSS score 4.0–5.0 to ≥6.0 in the absence of relapses suggest that relapses remain a significant driver of disability worsening and that on-treatment relapses in natalizumab-treated patients are of prognostic importance

Safety and efficacy of natalizumab in Belgian multiple sclerosis patients: subgroup analysis of the natalizumab observational program

Natalizumab (Tysabri(®)) is highly efficacious in controlling disease activity in relapsing multiple sclerosis (MS) patients. As it is one of the more recent therapies for MS, there remains a need for long-term safety and efficacy data of natalizumab in a clinical practice setting. The Tysabri observational program (TOP) is an open-label, multicenter, multinational, prospective observational study, aiming to recruit up to 6,000 patients with relapsing-remitting MS from Europe, Canada and Australia. The objectives of this study are to collect long-term safety and efficacy data on disease activity and disability progression. We report here the interim results of the 563 patients included in TOP between December 2007 and 2012 from Belgium. This patient cohort was older at baseline, had longer disease duration, higher neurological impairment, and a higher baseline annualized relapse rate, when compared to patients included in the pivotal phase III AFFIRM trial. Nevertheless, the efficacy of natalizumab was comparable. The annualized relapse rate on treatment was reduced by 90.70 % (p < 0.0001) with a cumulative probability of relapse of 26.87 % at 24 months. The cumulative probabilities of sustained disability improvement and progression at 24 months were 25.68 and 9.01 %, respectively. There were no new safety concerns over the follow-up period. Two cases of progressive multifocal leukoencephalopathy were diagnosed. Our results are consistent with other observational studies in the post-marketing setting.status: publishe

Safety and efficacy of natalizumab in Belgian multiple sclerosis patients: subgroup analysis of the natalizumab observational program

Natalizumab (Tysabri(®)) is highly efficacious in controlling disease activity in relapsing multiple sclerosis (MS) patients. As it is one of the more recent therapies for MS, there remains a need for long-term safety and efficacy data of natalizumab in a clinical practice setting. The Tysabri observational program (TOP) is an open-label, multicenter, multinational, prospective observational study, aiming to recruit up to 6,000 patients with relapsing-remitting MS from Europe, Canada and Australia. The objectives of this study are to collect long-term safety and efficacy data on disease activity and disability progression. We report here the interim results of the 563 patients included in TOP between December 2007 and 2012 from Belgium. This patient cohort was older at baseline, had longer disease duration, higher neurological impairment, and a higher baseline annualized relapse rate, when compared to patients included in the pivotal phase III AFFIRM trial. Nevertheless, the efficacy of natalizumab was comparable. The annualized relapse rate on treatment was reduced by 90.70 % (p < 0.0001) with a cumulative probability of relapse of 26.87 % at 24 months. The cumulative probabilities of sustained disability improvement and progression at 24 months were 25.68 and 9.01 %, respectively. There were no new safety concerns over the follow-up period. Two cases of progressive multifocal leukoencephalopathy were diagnosed. Our results are consistent with other observational studies in the post-marketing setting