Emerging oral drugs for relapsing-remitting multiple sclerosis.

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS), traditionally considered to be an autoimmune, demyelinating disease. The last two decades have witnessed the introduction of several therapies for MS. At present, there are five licensed first-line, disease-modifying drugs (DMDs) in MS and two second-line treatments. Nevertheless, in clinical practice DMDs or immunosuppressive treatments are frequently associated with suboptimal response in terms of efficacy and several side effects leading to poor patient adherence.

AREAS COVERED

Since MS is a chronic disease, DMDs require long-term, regular injection or monthly parenteral infusions, which may be uncomfortable and inconvenient for the patient. Thus, there is an important need for new therapeutic strategies, especially those that may offer greater patient satisfaction in order to optimize therapeutic outcomes. Currently, five oral therapies are in Phase III development or have recently been approved for the treatment of relapsing-remitting MS: cladribine and fingolimod, the first approved in Russia and Australia, the latter is more widespread. Fumaric acid (BG-12), teriflunomide (A77126 or HMR1726) and laquinimod (ABR-215062) are in Phase III trials. Details of these five drugs will be covered in this review.

EXPERT OPINION

Preliminary results indicate that oral medications are as effective as, or possibly more effective than, current injectable formulations. It is believable that improved outcomes will translate into higher real and perceived efficacy rates and contribute to improved adherence. The decision to switch established patients from injectable to oral medications will be made on balancing the efficacy and tolerability of the patient's existing therapy and their compliance history, even though safety is likely to become the most important factor in the future development of MS drugs.