A current thought in the MS therapeutics community is that drugs that enhance remyelination may be more effective in reducing long-term disability. This hypothesis is based on the observation that disability in MS increases with age as the capacity of oligodendrocytes to remyelinate decreases.1 Additional support for this hypothesis comes from extensive preclinical studies showing that promoting remyelination either by transplanting myelinating stem cells2,3 or by pharmacologic enhancement of endogenous myelination processes reduces clinical severity in animal models of MS.4,5 In this issue of Neurology® Neuroimmunology & Neuroinflammation, Tran et al.6 take this possibility to its exciting next step by reporting the results of the phase I clinical trial of the first drug aimed at promoting myelin repair.
The drug under study is a monoclonal antibody named BIIB033. Monoclonal antibodies are becoming very popular therapeutic agents due to their high affinity and specificity to their target, which results in safe and selective treatments. In addition, their advantageous patent protection compared to traditional drugs and their straightforward (although expensive) development process make these novel therapeutics much coveted by pharmaceutical companies. In the current article, the authors report that the drug under study is safe and the rate of adverse events low, which is the main goal of phase I trials. These timely results are important for physicians and patients considering enrolling in the already-ongoing phase II trial.