Stephen Krieger, MD: Cladribine was studied in trials over a decade ago in relapsing multiple sclerosis and it has now been recently approved in the United States. It was approved in Europe for the last couple of years, but the FDA has caught up and has made oral cladribine available for us here in the US. It's very interesting because we've never before in our field had an approval of a drug that was studied so long ago, so it's new for us but there's been long-term follow-up for these patients over the better part of the last decade, and that gives us a little bit more of a sense of the safety record and the track record for this drug.
It was originally denied by the FDA because of concerns from malignancy, and so now over the last 10 years we can say that the malignancy concern hasn't continued to go up such that you know in retrospect, now the FDA can look at it again and say this drug is safe enough to approve. It was studied in pretty early and active MS; the FDA approved it as not a first-line drug, but generally for people who have had a suboptimal response to 1 other therapy.
I think for active relapsing-remitting patients who've had that kind of lack of response to or failure to be treated by a drug, I think it's a very plausible option; it lasts for a long time so it's given as these short courses for 2 years and then the FDA didn't suggest retreating in years 3 or 4 and it left the future rather open.
In principle, one can sort of shut down disease activity with these 2 courses of treatment and perhaps keep it stable for many years, so there's opportunities there for women who may want to have their families because it can shut down the disease and the drug exits the system and it could give them an opportunity to try to conceive; that's always something we think about a lot for young people and young women in particular with MS. It could be an opportunity for someone, let's say who has trouble with compliance, someone who is not going to be able to take an injection all the time or pills once or twice a day because it's given with short courses. These patients need to be followed so I wouldn't give it to a patient that I think is going to be so noncompliant that we won't see them and get their monitoring, but that's another way of ensuring that someone is treated for the long term.