Dr. Aaron Miller responds:

Multiple sclerosis is an extremely variable disease. No expert, especially early on in the disease, can reliably predict whether it will progress, and if so, at what rate and manner. We know that in the short term we can reduce flare-ups and progression of the disease in people who start treatment early. We don't really have hard long-term data to back that up, but most experts, based on their experience, strongly believe that to be the case.

If a person has been doing well over the past five to 10 years, it's highly likely he or she will continue to do well. Conversely, if a person has been progressing and continues to progress, it's likely that this pattern will continue. Of course, there are always exceptions.

On the positive side, we believe that with current drugs—and almost certainly with better treatments coming down the road over the next few years—the number of people with MS who are going to end up with significant gait impairment is going to be substantially reduced.