Study Uncovers Gene Variation Linked to Response to MS Therapy; May Open Up New Treatment Approaches
Collaborating researchers in the U.S. and Italy have uncovered a gene variant that appears to influence whether a person responds well to interferon beta, a commonly used therapy for relapsing forms of MS. More broadly, the gene may regulate immune activity in unexpected ways, and its discovery may lead to new approaches to stopping inflammation and immune attacks in MS. Drs. Federica Esposito and Filippo Martinelli Boneschi (San Raffaele Scientific Institute, Milan), Philip L. De Jager (Brigham and Women’s Hospital, Boston) and colleagues have published their results in the Annals of Neurology (Early online May 14, 2015). The study was supported by the National MS Society and several other agencies.
Background: For reasons that are unclear, some people with relapsing forms of MS do not respond well to therapy and continue to experience disease activity despite being on a disease-modifying therapy. Previous genetic studies in MS have uncovered over 159 genetic variations that contribute to making people susceptible to developing MS, but these studies haven’t identified genetic variations that influence how a person responds to treatment. Finding a way to identify early in the disease course the best therapy for an individual – a “personalized medicine” approach – is likely to improve outcomes of treatment and quality of life for people living with MS. One of the lead authors of this study, Dr. De Jager, recently won the Barancik Prize for Innovation in MS Research for tackling critical questions like this with the goal of developing personalized treatments and prevention of MS.
This Study: Trying a different approach to search for genetic influences on treatment responses, the investigators first studied a group of individuals with MS who were taking interferon beta or glatiramer acetate. The individuals were classified as being responders, partial responders, or non-responders to their medication based on specific criteria. Then the researchers analyzed their full complement of genes (genome-wide association study) and found one genetic variant that was consistently associated with lack of response to interferon beta. When the researchers repeated this in three other groups of people with MS from Italy, France and the U.S., this finding held up.
The genetic variant (rs9828519) is near a gene (SLC9A9) that controls pH levels (acidity) within cells. The team explored functions of this gene, and found that its activity was diminished in people more likely to have MS relapses. They also conducted laboratory work, finding suggestions that the gene appears to play a role in regulating immune cell activity, and that its loss leads to damaging immune reactions. This suggests the gene may play a broader role in regulating immune activity.
Comment: Although the results of this study are not yet ready for applying to the management of MS, this discovery may lead to new approaches for stopping inflammation and immune attacks in MS. In addition, this study is an important step toward the goal of personalized medicine. The researchers point out that additional research is warranted to confirm their findings and to determine whether the genetic variant is relevant to how well people respond to other MS medications.