medwireNews: Researchers suggest that alemtuzumab is comparable to natalizumab for controlling multiple sclerosis (MS) activity and superior to fingolimod and interferon beta.
The observational study, published in The Lancet Neurology, is based on clinical data obtained from 71 MSBase centers and six non-MSBase centers for patients with relapsing–remitting MS.
In all, 189 were given alemtuzumab (12–24 mg intravenously once daily for 5 days [cycle 1] or for 3 days [cycle 2]), 2155 were given interferon beta (44 µg subcutaneously three times per week), 828 received fingolimod (0.65 mg orally once daily), and 1160 were given natalizumab (300 µg intravenously every 4 weeks).
The researchers then did three separate pair-matched analyses of alemtuzumab versus interferon beta, fingolimod, and natalizumab, based on the individual’s propensity of having any one of the compared therapies, to adjust for baseline differences.
The annualized relapse rate (ARR) was significantly lower for 189 patients given alemtuzumab than for 282 patients given interferon beta treatment, at 0.19 versus 0.53. A superior rate with alemtuzumab was also seen in 114 patients when compared with 195 patients given fingolimod, at 0.15 versus 0.34.
The comparison of alemtuzumab treatment in 138 patients with natalizumab treatment in 223 patients showed a similar ARR, however, at 0.20 and 0.19, respectively.
“Together with natalizumab, alemtuzumab represents a viable option for patients requiring highly effective immunotherapy for multiple sclerosis,” say Thomas Kalincik (University of Melbourne, Victoria, Australia) and colleagues.
Given the findings, they suggest that treatment decisions between alemtuzumab and natalizumab should be “primarily governed by their safety profiles.”
The study participants were all aged 65 years or younger and had experienced relapsing–remitting MS for no more than 10 years. Their Expanded Disability Status Scale score at baseline was 6.5 or below.
The risk of disability accumulation over 5 years of follow-up was similar for patients taking alemtuzumab as it was for those taking interferon beta, fingolimod, or natalizumab. But patients taking alemtuzumab had a reduced likelihood for disability improvement compared with patients taking natalizumb, with a hazard ratio over the whole follow-up of 0.35.
The study researchers note that it is possible that their study was underpowered to detect clinically significant differences in disability accrual or improvement.
And Maria Pia Sormani and Alice Laroni, both from the University of Genoa in Italy, point out in a related comment that improvement in disability has been previously reported for natalizumab and alemtuzumab, but “whether this is a direct or indirect effect of the treatment is unclear.”
Overall, the findings were largely concordant with those of the original pivotal clinical trials. And Sormani and Laroni note that in the case of alemtuzumab versus interferon and alemtuzumab versus fingolimod the superiority of alemtuzumab was slightly higher in the current study.
This is “somewhat surprising,” they say “because the effectiveness of a drug is usually diluted in a real-life situation compared with the efficacy achieved in a randomised clinical trial.”
The commentators point out two limitations that should be taken into account when interpreting the findings. The first is a lack of magnetic resonance imaging data, which they say is a “major determinant of treatment choice,” and the second a difference in the pattern of discontinuation of alemtuzumab compared with the other three drugs, making treatment persistence incomparable.
By Lucy Piper
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