LONDON – Real-world data show that the disease-modifying multiple sclerosis drug alemtuzumab is as effective as natalizumab for preventing relapse and disability progression in patients with relapsing-remitting multiple sclerosis.

Three separate analyses of data involving more than 4,000 patients included in the MSBase Registry and from seven European MS centers showed that alemtuzumab (Lemtrada) was also more effective than subcutaneous interferon beta-1a (IFN beta-1a; Rebif) and fingolimod (Gilenya) for relapse prevention.

“We have seen that alemtuzumab is superior to IFN beta-1a subcutaneous administration in suppressing relapse activity and, in patients with a perilously high level of relapse activity, also in suppressing the probability of reaching disability progression and increasing the probability of reaching disability regression,” Tomas Kalincik, MD, said at the annual congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS).

Furthermore, “alemtuzumab was superior to fingolimod in suppressing annualized relapse rates, and comparable to natalizumab (Tysabri) in controlling relapse activity and limiting the probability of disability progression,” said Dr. Kalincik of the University of Melbourne.

Head-to-head trials of MS therapies are lacking, so the aim of the observational study was to compare the treatment effectiveness of alemtuzumab versus natalizumab, IFN beta-1a, and fingolimod. Specifically, the aim was to look at the annualized relapse rate (ARR), cumulative hazard of relapses, and 6-month Expanded Disability Scale Score (EDSS) progression and regression. Propensity score matching was used to make the comparisons between alemtuzumab and the other MS treatments.

Patient data were retrospectively taken from the MSbase database, which includes prospectively collected data from more than 41,000 patients with MS treated at 119 centers in 35 countries. For inclusion in the present analysis, patients had to have definite relapsing-remitting multiple sclerosis, a baseline EDSS of 0-5.5, age of 65 years or younger, and duration of MS of 10 years or less, as well as one or more relapses in the previous year. Patients also needed to have a minimum follow-up of 12 months before and 6 months after they started treatment, and a minimum of two post-baseline visits that were 6 months apart.

Of 15,763 patients with definite MS who commenced treatment with one of the four MS therapies being considered, 4,332 met all the inclusion criteria. Of these, 189 were treated with alemtuzumab, 1,160 with natalizumab, 2,155 with IFN beta-1a, and 828 with fingolimod. Dr. Kalincik noted that the alemtuzumab patient data were combined from seven European MS centers and not the MSBase database.

Versus interferon beta-1a

The first data analysis involved 124 alemtuzumab-treated patients and 219 IFN beta-1a-treated patients with 5 years’ follow-up. Compared with IFN beta-1a, alemtuzumab was associated with an overall lower 5-year ARR of 0.2 versus 0.5 (P less than .001). The annual relapse rates by each individual year were also all significantly lower with alemtuzumab, and the cumulative hazard ratio (HR) of relapses was 0.42 (P less than .001), indicating an almost 60% reduction in relapses over time.

In terms of disability progression, alemtuzumab did not show an advantage over IFN beta-1a, which is in contrast to the findings of its pivotal trials, Dr. Kalincik observed. However, alemtuzumab was found to have an advantage over IFN beta-1a therapy in a secondary analysis if patients had highly active disease, defined as either three or more relapses over a 2-year period or two or more relapses over a 1-year period. The HR for confirmed disability progression was 0.64 (P = .016). Patients with on-treatment relapses within the previous year also fared better if treated with alemtuzumab, with a HR of 3.9 (P = .028) for confirmed disability regression.

Versus fingolimod

The second data analysis involved 114 alemtuzumab-treated patients and 195 fingolimod-treated patients with 3 years’ follow-up. When compared with fingolimod, there was again a much lower ARR overall (0.15 vs. 0.3; P less than .001) at 3 years, and at years 1, 2, and 3 individually (P less than .05). There was a nonsignificant 40% reduction in the relapse rate over time.

“For the disability outcomes, we haven’t seen any statistically significant difference, neither between the 6-month confirmed disability progression nor the 6-month confirmed disability regression,” Dr. Kalincik reported.

Versus natalizumab

The third and final analysis involved 138 alemtuzumab-treated patients and 223 natalizumab-treated patients with 4 years’ follow-up. There were no significant differences found in either the ARR overall (0.2 for both treatments; P = .8) or by follow-up year, and the cumulative hazard of relapses was the same.

Although there was no significant difference in confirmed disability progression at 6 months between the two treatments, there was a significant difference observed for the confirmed 6-month disability regression that favored natalizumab during the first year of treatment, Dr. Kalincik said. After 1 year, this potential advantage disappeared, he observed.

A large number of sensitivity analyses were performed and “largely confirm” the outcomes of the primary analyses.

Limitations include the lack of MRI data, and it was not possible to evaluate the relative safety of treatments.

Dr. Kalincik disclosed ties with Roche, Genzyme, Novartis, Merck, Biogen, WebMD Global, Sanofi, Teva, and BioCSL.

Alemtuzumab, natalizumab found equally effective for relapsing-remitting MS