Pharmacokinetic Interaction Between Fingolimod and Carbamazepine in Healthy Subjects

Drugs used in the treatment of multiple sclerosis during COVID-19 pandemic: a critical viewpoint

Since COVID-19 has emerged as a word public health problem, attention has been focused on how immune-suppressive drugs used for the treatment of autoimmune disorders influence the risk for SARS-CoV-2 infection and the development of acute respiratory distress syndrome (ARDS). Here, we discuss the disease-modifying agents approved for the treatment of multiple sclerosis (MS) within this context. Interferon (IFN)-β1a and -1b, which display antiviral activity, could be protective in the early stage of COVID-19 infection, although SARS-CoV-2 may have developed resistance to IFNs. However, in the hyperinflammation stage, IFNs may become detrimental by facilitating macrophage invasion in the lung and other organs. Glatiramer acetate and its analogues should not interfere with the development of COVID-19 and may be considered safe. Teriflunomide, a first-line oral drug used in the treatment of relapsing-remitting MS (RRMS), may display antiviral activity by depleting cellular nucleotides necessary for viral replication. The other first-line drug, dimethyl fumarate, may afford protection against SARS-CoV-2 by activating the Nrf-2 pathway and reinforcing the cellular defenses against oxidative stress. Concern has been raised regarding the use of second-line treatments for MS during the COVID-19 pandemic. However, this concern is not always justified. For example, fingolimod might be highly beneficial during the hyperinflammatory stage of COVID-19 for a number of mechanisms, including the reinforcement of the endothelial barrier. Caution is suggested for the use of natalizumab, cladribine, alemtuzumab, and ocrelizumab, although MS disease recurrence after discontinuation of these drugs may overcome a potential risk for COVID-19 infection.

Sphingosine-1-Phosphate Receptor Modulators and Oligodendroglial Cells: Beyond Immunomodulation

Multiple sclerosis (MS) is an autoimmune inflammatory disease characterized by demyelination, axonal loss, and synaptic impairment in the central nervous system (CNS). The available therapies aim to reduce the severity of the pathology during the early inflammatory stages, but they are not effective in the chronic stage of the disease. In this phase, failure in endogenous remyelination is associated with the impairment of oligodendrocytes progenitor cells (OPCs) to migrate and differentiate into mature myelinating oligodendrocytes. Therefore, stimulating differentiation of OPCs into myelinating oligodendrocytes has become one of the main goals of new therapeutic approaches for MS. Different disease-modifying therapies targeting sphingosine-1-phosphate receptors (S1PRs) have been approved or are being developed to treat MS. Besides their immunomodulatory effects, growing evidence suggests that targeting S1PRs modulates mechanisms beyond immunomodulation, such as remyelination. In this context, this review focuses on the current understanding of S1PR modulators and their direct effect on OPCs and oligodendrocytes.

Bioequivalence Study of 2 Capsule Formulations of Fingolimod 0.5 mg Assessing Both Parent Drug and Active Metabolite in New Zealand Healthy Subjects (Truncated Design)

Fingolimod is indicated for the treatment of patients with the relapsing-remitting form of multiple sclerosis. The primary study objective was to evaluate the bioequivalence of a test formulation, 0.5 mg fingolimod HCl capsule (Lebrina, Asofarma Sociedad Anónima Industrial y Comercial, Argentina) relative to a reference formulation, 0.5 mg fingolimod capsule (Gilenya, Novartis Pharmaceutical, Australia). In a single-center, randomized, single-dose, single-blinded, 2-way crossover study, 33 New Zealand healthy subjects of both sexes were enrolled to receive a 0.5-mg dose of 3 capsules of each fingolimod formulation under fasting conditions, with a 42-day washout period between administrations. Additional pharmacokinetic information regarding its main active metabolite, fingolimod phosphate, was also provided. The point estimate and 90% confidence intervals of the ratios of maximum concentration and area under the plasma concentration-time curve from time 0 to 72 hours were 99.07 (95.83-102.41) and 97.64 (95.33-100.00) for fingolimod, and 95.60 (90.95-100.49) and 98.54 (96.19-100.96), for fingolimod phosphate. Primary parameters, maximum concentration and area under the plasma concentration-time curve from time 0 to 72 hours for fingolimod and fingolimod phosphate were found to have no significant difference when test and reference formulations were compared. Fingolimod and fingolimod phosphate of both formulations were within the accepted 90% confidence interval limits of 80.00% and 125.00%. No significant differences between the test and reference drug products were detected in any of the pharmacokinetic parameters estimated. Notwithstanding the primary conclusion of bioequivalence is focused on the measurement of the parent compound, compliance with the same criteria by the active metabolite reinforces the comparability between the pharmacokinetic profiles of both formulations (ClinicalTrials.gov Identifier: NCT03757338).