Benefit/Risk Study Results: Focus on Muscle Weakness

Published on Mon, 11/16/2015

As part of our investment in the development of effective treatments for myotonic dystrophy, we are trying to better understand how people with DM weigh the benefits of new treatments against the risks.  To do this, we worked with a company called Silicon Valley Research Group to develop a survey that presented a series of hypothetical new treatments and asked that people choose the side-effects that concerned them the most and the least for.  This type of analysis is called “Max-Diff Analysis” or sometimes “Best-Worst Scaling” and has been used in other benefit-risk studies and by the Food and Drug Administration (FDA).  The method generates robust statistics to determine, on average, what risks people are or are not willing to accept for a given benefit.  The FDA has indicated that it is very interested in this type of information.  

The survey showed that reversing, stopping or slowing the progression of muscle weakness were the most preferred benefits, in that order.  The side effects people were most willing to tolerate overall for any benefit were loss of appetite and a small increase in tiredness. 

People in the study also completed the short version of the Myotonic Dystrophy Health Index (MDHI) to rate the severity of their myotonic dystrophy.  Scores were grouped into mild, moderate and severe categories.  For the majority of benefits, those with all levels of severity were similar in their willingness to tolerate side effects except that those with more severe myotonic dystrophy were less willing to risk liver failure for any type of therapeutic benefit.  Also, those with the highest severity rating for their myotonic dystrophy were more willing to tolerate an increase in tiredness if the drug could stop or reduce myotonia.  The data reported here are based on the survey responses from those with DM1.  The responses from those with DM2 are being analyzed now.

These results were presented on September 17th at the MDF-sponsored regulatory workshop on therapeutic development for myotonic dystrophy, which was attended by FDA staff.  Next steps will likely include an in-depth follow-on study that looks at the benefit-risk preferences of caregivers and younger people with myotonic dystrophy.  We are also investigating ways to collect “qualitative” data, such as stories and open-ended comments, on the benefit-risk preferences of those with myotonic dystrophy.  Ultimately this information will be made available to FDA reviewers through various mechanisms with the goal of incorporating the view of those with myotonic dystrophy and their families into the decision-making process about new therapies.