The Future of Progressive Multiple Sclerosis Therapies
Introduction: Multiple sclerosis (MS) affects more than a million people in the US. A considerable portion of these patients either begin with primary progressive disease or eventually transition to secondary progressive MS. A progressive disease course is the most critical factor affecting disability accumulation. The relatively recent development of treatments for relapsing multiple sclerosis has had a profound impact on the disease course for many with MS. Unfortunately, therapies for progressive MS have not had the same degree of advancement in general. New insights into the pathophysiology of progressive MS may lead to new treatments.
Observations: In this review, we identify some of the significant challenges encountered in the development of therapies for progressive MS, assess the evidence for use of currently approved therapies for patients with progressive MS, identify some of the current therapies in development from progressive MS, and consider the role for discontinuing therapy in certain patients.
Conclusions: Developing effective disease modifying therapies that slow or stop the gradual accumulation of neurologic disability in progressive MS represents a critical unmet need. As the understanding of the inflammatory and neurodegenerative aspects of MS are better elucidated there may be opportunity for advancement in the treatment of progressive MS.
Conclusions
The development of numerous treatments for RRMS has established an entirely new landscape and disease course for those with MS. While this benefit has not entirely extended to those with progressive MS, those with active disease with superimposed relapses may receive limited benefit from these medications. New insights into the pathophysiology of progressive MS may lead us to new treatments through multiple alternative pathophysiologic pathways. Some early studies using this strategy show promise in slowing the progressive phase. Medication development for progressive MS faces multiple challenges due to lack of a single animal model demonstrating both pathology and clinical effects, absence of phase 1 surrogate biomarkers, and later phase trial endpoints that require large sample sizes and extended study durations. Nevertheless, the increase in number of trials and diversity of therapeutic approaches for progressive MS provides hope for effective therapy. Currently, the heterogeneity of the population with progressive MS requires an individualized treatment approach, and in some of these patients, stopping therapy may be a reasonable consideration. Symptomatic management remains critical for all patients with progressive MS as well as non-pharmacologic approaches that maximize quality of life.
