MS Treatment Strategies: A Review of Disease-Modifying Therapies
Multiple sclerosis (MS) is a chronic autoimmune condition that affects approximately 2.5 million people worldwide.1 This debilitating disease affects the central nervous system through inflammatory and neurodegenerative mechanisms and environmental and genetic factors seem to be contributory. MS typically begins as a relapsing condition, which later progresses into a secondary progressive phase involving irreversible neurological impairment. Not only is MS costly to treat, it also greatly decreases a patient's quality of life and has been found to reduce a patient's life expectancy by about seven years.
Currently, there are 14 disease-modifying therapies (DMTs) approved in the United States to treat relapsing MS, which are summarized in Table 1.1 DMTs possess immunomodulatory or immunosuppressive properties and have proven to reduce annualized relapse rates (ARR), accumulation of disease burden determined by magnetic resonance imaging (MRI), and decline of neurological function. Although these agents have proven efficacy in patients with relapsing MS, which is the most common disease phenotype, no benefit has been seen in patients with primary progressive MS (PPMS) or secondary progressive MS (SPMS).
Several different strategies to treat MS have been utilized in the past.1 The most common strategy over the past decade involves an “escalation” approach that aims to reduce risk to a patient. In this method, a patient is initiated on a “platform” DMT, such as interferon beta or glatiramer acetate, and, if deemed ineffective, is switched to another platform drug or an agent with higher efficacy. A second approach for treating MS is the “induction” method, where a highly effective DMT is utilized at the beginning stages of the disease, as this is believed to be the “window of opportunity”. After using this agent for a defined period of time, the patient then is either observed or initiated on a lower risk maintenance DMT.
A recent review by Wingerchuk and Weinshenker discusses the evidence about and appropriate use of approved DMTs.1 The authors suggest using an individualized treatment plan for each specific MS patient and that an intermediate approach between escalation and induction strategies should be used. In addition, it is important for clinicians to consider patient related factors, neuroimaging factors, and MS-related clinical factors when choosing an appropriate therapy for a patient.