Assessment of Clemastine Fumarate as a Remyelinating Agent in Acute Optic Neuritis (ReCOVER)

Optic neuritis is an inflammatory, demyelinating disease of the optic nerve. It is most often characterized by visual loss or blurred vision along with dyschromatopsiaaccompanied by pain (especially with eye movement) and no demonstrable evidence of an alternate diagnosis such as ischemia or retinal disease. It can also be associated with a swollen optic disc (Optic Neuritis Study Group 1991, Hutchinson, W.M. 1976) and optic nerve enhancement on MRI (Kupersmith 2002). Functional high-throughput screening for compounds that promote remyelination presents a major unmet need in the therapeutic arsenal for multiple sclerosis and other demyelinating conditions such as optic neuritis. Screening for myelin repair is problematic, as functional remyelination requires the presence of intact neuronal axons. Standard methods are not suited for high-throughput formats. We performed a detailed screen of over 1500 FDA approved small molecule drugs to identify agents that could be promising for remyelination. Engineered with conical dimensions, our micropillar technology permitted resolution of the extent and length of membrane wrapping from a single 2-dimensional image. Confocal imaging acquired from the base to the tip of the pillars allows for the fluorescence detection of concentric wrapping observed as "rings" of myelin membrane. The platform was formatted in 96-well plates, amenable to semi-automated random acquisition and automated detection and quantification. Upon initiating a screen of 1500 bioactive molecules, we identified Clemastine as a compound that potentially enhances oligodendrocyte differentiation and remyelination. We then validated this and other drugs in preclinical assays as well as in animal models of primary myelination and remyelination after inflammatory and chemical demyelination. Together, our findings illustrate the proof of concept for a novel high-throughput screening platform for potential regenerative therapeutics in MS (Chan JR et al. 2014). This study is intended to assess for clinical evidence of remyelination using Clemastine Fumarate in patients with acute inflammatory injury causing demyelination of the anterior visual pathway as a consequence of acute demyelinating optic neuritis. The study is designed to assess tolerability and clinical efficacy of Clemastine using outcomes intended to assess for (a) adverse events and (b) recovery of myelin. This study is complementary to an earlier study evaluating clemastine in chronic demyelinated optic neuropathy and serves as part of a proof of concept program intended to evaluate methods for conducting remyelination trials in MS.