Multiple Sclerosis Therapeutic Pipeline: Opportunities and Challenges

Pharmacokinetics and Tolerability of the Novel Non-immunosuppressive Fingolimod Derivative, OSU-2S, in Dogs and Comparisons with Data in Mice and Rats

In this study, we characterized the pharmacokinetics of OSU-2S, a fingolimod-derived, non-immunosuppressive phosphatase activator, in mice, rats, and dogs, as well as tolerability and food effects in dogs. Across all species tested, plasma protein binding for OSU-2S was > 99.5%, and metabolic stability and hepatic intrinsic clearance were in the moderate range. OSU-2S did not significantly modulate CYP enzyme activity up until 50 μM, and Caco-2 data suggested low permeability with active efflux at 2 μM. Apparent oral bioavailability in mice was 16% and 69% at 10 and 50 mg/kg, respectively. In rats, bioavailability was 24%, 35%, and 28% at 10, 30, and 100 mg/kg, respectively, while brain/plasma ratio was 36 at 6-h post-dose at 30 mg/kg. In dogs, OSU-2S was well tolerated with oral capsule bioavailability of 27.5%. Plasma OSU-2S exposures increased proportionally over a 2.5-20 mg/kg dose range. After 4 weeks of 3 times weekly, oral administration (20 mg/kg), plasma AUC_last (26.1 μM*h), and C_max (0.899 μM) were nearly 2-fold greater than those after 1 week of dosing, and no food effects were observed. The elimination half-life (29.7 h), clearance (22.9 mL/min/kg), and plasma concentrations of repeated oral doses support a 3-times weekly dosing schedule in dogs. No significant CBC, serum biochemical, or histopathological changes were observed. OSU-2S has favorable oral PK properties similar to fingolimod in rodents and dogs and is well tolerated in healthy animals. This work supports establishing trials of OSU-2S efficacy in dogs with spontaneous tumors to guide its clinical development as a cancer therapeutic for human patients.

Where are the breaks in translation from theory to clinical practice (and back) in addressing depression? An empirical graph-theoretic approach

BACKGROUND

Research in depression has progressed rapidly over the past four decades. Yet depression rates are not subsiding and treatment success is not improving. We examine the extent to which the gap between science and practice is associated with the level of integration in how depression is considered in research and stakeholder-relevant documents.

METHODS

We used a network-science perspective to analyze similar uses of depression relevant terms in the Google News corpus (approximately 1 billion words) and the Web of Science database (120 000 documents).

RESULTS

These analyses yielded consistent pictures of insular modules associated with: (1) patient/providers, (2) academics, and (3) industry. Within academia insular modules associated with psychology, general medical, and psychiatry/neuroscience/biology were also detected.

CONCLUSIONS

These analyses suggest that the domain of depression is fragmented, and that advancements of relevance to one stakeholder group (academics, industry, or patients) may not translate to the others. We consider potential causes and associated responses to this fragmentation that could help to unify and advance translation from research on depression to the clinic, largely involving harmonizing employed language, bridging conceptual domains, and increasing communication across stakeholder groups.

New Approaches to the Diagnosis, Clinical Course, and Goals of Therapy in Multiple Sclerosis and Related Disorders

The diagnosis, categorization, and treatment of multiple sclerosis (MS) and other demyelinating diseases have shifted over the past decade, and many of the fundamental principles of MS pathogenesis and clinical course are being rewritten. Fundamental issues include selecting the right disease-modifying therapy for someone with active disease and how, or even if, patients with purely progressive MS should be treated. This article provides an overview and introduction to the current thinking in MS diagnosis and therapy with an emphasis on the data-driven and proactive approach that has come to define the current state of the art.

A potential impact of Helicobacter pylori-related galectin-3 in neurodegeneration

Neurodegeneration represents a component of the central nervous system (CNS) diseases pathogenesis, either as a disability primary source in the frame of prototype neurodegenerative disorders, or as a secondary effect, following inflammation, hypoxia or neurotoxicity. Galectins are members of the lectin superfamily, a group of endogenous glycan-binding proteins, able to interact with glycosylated receptors expressed by several immune cell types. Glycan-lectin interactions play critical roles in the living systems by involving and mediating a variety of biologically important normal and pathological processes, including cell-cell signaling shaping cell communication, proliferation and migration, immune responses and fertilization, host-pathogen interactions and diseases such as neurodegenerative disorders and tumors. This review focuses in the role of Galectin-3 in shaping responses of the immune system against microbial agents, and concretely, Helicobacter pylori (Hp), thereby potentiating effect of the microbe in areas distant from the ordinary site of colonization, like the CNS. We hereby postulate that gastrointestinal Hp alterations in terms of immune cell functional phenotype, cytokine and chemokine secretion, may trigger systemic responses, thereby conferring implications for remote processes susceptible in immunity disequilibrium, namely, the CNS inflammation and/or neurodegeneration.

Safety and Efficacy of Fingolimod and Natalizumab in Multiple Sclerosis After the Failure of First-Line Therapy: Single Center Experience Based on the Treatment of Forty-Four Patients

BACKGROUND In Poland, natalizumab or fingolimod treatment can be delivered as a second-line therapy to those patients with relapsing-remitting multiple sclerosis (RRMS) who demonstrated no response to interferon or glatiramer acetate treatment for a minimum of one year. MATERIAL AND METHODS Analysis covered 44 RRMS patients switched from first- to second-line therapy. The annualized relapse rate, disability progression (assessed with Expanded Disability Status Scale, EDSS) and MRI results (new or enlarged T2 lesions and new Gd-positive lesions) before and after switching were compared. The occurrence of adverse events was also assessed. RESULTS The annualized relapse rate for second-line therapy was significantly lower than for first-line therapy (0.35±0.74 vs. 2.13±0.87, p=0.00005). Median of EDSS progression with first-line therapy was significantly higher than that with natalizumab or fingolimod treatment (p=0.00002). The mean number of new or enlarged T2 and Gd+ lesions in MRI after one-year second-line treatment was significantly lower in comparison to lesions in MRI performed at the end of the first-line therapy (for T2: 0.61 vs. 4.56, p=0.0004; for Gd+: 0.13 vs. 1.98, p=0.0009). No significant differences in the clinical data, MRI results, and side effects between fingolimod and natalizumab patients have been observed. CONCLUSIONS Treatment with natalizumab or fingolimod as a second-line therapy in RRMS patients is safe and effective. Less restrictive criteria for switching should be considered.

Identification of Nucleoside Analogs as Inducers of Neuronal Differentiation in a Human Reporter Cell Line and Adult Stem Cells

Nucleoside analogs (NSAs) were among the first chemotherapeutic agents and could also be useful for the manipulation of cell fate. To investigate the potential of NSAs for the induction of neuronal differentiation, we developed a novel phenotypic assay based on a human neuron-committed teratocarcinoma cell line (NT2) as a model for neuronal progenitors and constructed a NT2-based reporter cell line that expressed eGFP under the control of a neuron-specific promoter. We tested 38 structurally related NSAs and determined their activity to induce neuronal differentiation by immunocytochemistry of neuronal marker proteins, live cell imaging, fluorometric detection and immunoblot analysis. We identified twelve NSAs, which induced neuronal differentiation to different extents. NSAs with highest activity carried a halogen substituent at their pyrimidine nucleobase and an unmodified or 2'-O-methyl substituted 2-deoxy-β-D-ribofuranosyl residue as glyconic moiety. Cladribine, a purine nucleoside with similar structural features and in use to treat leukemia and multiple sclerosis, induced also differentiation of adult human neural crest-derived stem cells. Our results suggest that NSAs could be useful for the manipulation of neuronal cell fate in cell replacement therapy or treatment of neurodegenerative disorders. The data on the structure and function relationship will help to design compounds with increased activity and low toxicity.

Antiretroviral drugs induce oxidative stress and neuronal damage in the central nervous system

HIV-associated neurocognitive disorder (HAND), characterized by a wide spectrum of behavioral, cognitive, and motor dysfunctions, continues to affect approximately 50 % of HIV(+) patients despite the success of combination antiretroviral drug therapy (cART) in the periphery. Of note, potential toxicity of antiretroviral drugs in the central nervous system (CNS) remains remarkably underexplored and may contribute to the persistence of HAND in the cART era. Previous studies have shown antiretrovirals (ARVs) to be neurotoxic in the peripheral nervous system in vivo and in peripheral neurons in vitro. Alterations in lipid and protein metabolism, mitochondrial damage, and oxidative stress all play a role in peripheral ARV neurotoxicity. We hypothesized that ARVs also induce cellular stresses in the CNS, ultimately leading to neuronal damage and contributing to the changing clinical and pathological picture seen in HIV-positive patients in the cART era. In this report, we show that ARVs are neurotoxic in the CNS in both pigtail macaques and rats in vivo. Furthermore, in vitro, ARVs lead to accumulation of reactive oxygen species (ROS), and ultimately induction of neuronal damage and death. Whereas ARVs alone caused some activation of the endogenous antioxidant response in vitro, augmentation of this response by a fumaric acid ester, monomethyl fumarate (MMF), blocked ARV-induced ROS generation, and neuronal damage/death. These findings implicate oxidative stress as a contributor to the underlying mechanisms of ARV-induced neurotoxicity and will provide an access point for adjunctive therapies to complement ARV therapy and reduce neurotoxicity in this patient population.

Practice patterns of US neurologists in patients with SPMS and PPMS: A consensus study

A modified Delphi process assessed current multiple sclerosis (MS) practice patterns for secondary and primary progressive MS (secondary progressive MS [SPMS] and primary progressive MS [PPMS]). In early 2011, 2 sequential, case-based surveys were administered to 75 US MS specialists to assess treatment practices and patient management. Respondents were from geographically diverse US academic (42%) and community (58%) treatment centers. There was consensus (≥75% agreement in responses) to switch disease-modifying therapies for a patient with SPMS with both MRI activity and disability progression (95%), but no consensus on treatment selection. For PPMS, responses supported diagnosis using spinal MRI (100%) and lumbar puncture (75%) and treatment initiation in patients with brain gadolinium-enhancing lesions with or without spinal cord lesions (85%); however, there was no consensus on treatment initiation with spinal cord lesions alone or initial therapy. The lack of agreement among US MS experts on the best treatment approaches for SPMS or PPMS highlights the need for effective therapies.

Emerging strategies for the treatment of multiple sclerosis

Despite extraordinary advances in the field of neuroimmunology, ideal treatment for patients with multiple sclerosis remains an unmet need. Existing treatments are only partially effective in preventing multiple sclerosis relapses, have a limited impact on the accrual of disability, have not been effective in progressive forms of the disease, and treatment remains preventive rather than restorative. This review provides an overview of emerging therapies and targets, and incorporates strategies for two different approaches to multiple sclerosis: prevention, through immune modulation; and repair, through neuroprotection and remyelination. Agents at all stages of development, from late-stage clinical trials of BG-12, teriflunomide, alemtuzumab, daclizumab and anti-CD20 agents, to novel approaches in preclinical testing, are discussed.