Ahmed Zayed Obeidat MD, PhD, and Mark S. Freedman, HBSc, MSc, MD, CSPQ, FAAN, FRCPC, discuss the use of oral cladribine in the treatment of MS.
Mark S. Freedman, HBSc, MSc, MD, CSPQ, FAAN, FRCPC: With regard to cladribine, cladribine is unique in this class of oral drugs because unlike the other ones, which have to be maintained to have an effect on the disease, cladribine does not. It’s been termed an immune reconstitution treatment because of the way it’s given. You give it up front in a dosing in the first year, you give a second course in the second year, and then you stop. A total empiric dosage of 3.5 mg/kg has been shown to give a durable effect irrespective of the lymphocyte count, which recovers within a year or so of the treatment. That durable effect can last at least 4, 5, 6 years, and patients don’t need to take any other drugs. So, you’re not constantly immunosuppressing them. You’ve given them a couple of quick bouts of immunosuppression, and that changes something in the immune system. That’s been looked at now, but we just don’t know what the change is.
Ahmed Zayed Obeidat, MD, PhD: The exact change.
Mark S. Freedman, HBSc, MSc, MD, CSPQ, FAAN, FRCPC: Clearly the cells that have come back are not attacking anymore, so the reconstitution of the entire immune system is now different than it was before. That’s the notion of the immune reconstitution treatment. It may be that that’s not enough to hold the patients long term, but you can always give additional courses. This is really lending itself as an opportune therapy for at least 2 different groups of patients that I’ve heard of. One is the young woman with sort of an aggressive picture. Someone who may say, “I just got married, and we really want to have children. Maybe we can hold off therapy, and I’ll have children.” There’s no guarantee that they get pregnant right away, as pregnancy itself can be very good for MS [multiple sclerosis]. But here you are a little nervous because they’re at high risk of having another attack, and they could be very disabled. So here’s a drug that if you start it today, at 18 months from today, you can get pregnant. I try to convince the patient to, “Let me take care of this disease for 18 months. Can you hold off 18 months to have a child?” Often the answer is yes.
Ahmed Zayed Obeidat, MD, PhD: The answer is yes.
Mark S. Freedman, HBSc, MSc, MD, CSPQ, FAAN, FRCPC: Then they’re free to go, and you know you’ve given them something that will be enduring past the pregnancy and maybe for the rest of their disease.
The other is when your patient is older. I got this notion from colleagues in the United States, I never thought about it because you have a different indication down here for oral cladribine than we do. It was given as an indication for secondary progressive disease; we don’t have that in Canada. My colleague told me, you’ve got patients who are older and you don’t want to suppress them for a long time, but you want to take 1 last shot at getting rid of all the inflammation.
Ahmed Zayed Obeidat, MD, PhD: It’s like the exiting strategy.
Mark S. Freedman, HBSc, MSc, MD, CSPQ, FAAN, FRCPC: It’s kind of like the Hail Mary pass in football. So here’s a 50-year-old, we think they’re starting to progress, maybe we’ll just hit them with this course of cladribine and knock out whatever’s left of the inflammation, and then look for the durable response. I quite frankly like that idea, and now I’m starting to do it Canada.
Ahmed Zayed Obeidat, MD, PhD: It’s clinically MRI active, secondary progressive MS.
Mark S. Freedman, HBSc, MSc, MD, CSPQ, FAAN, FRCPC: We can get by with that, we can get the drug for that.
Ahmed Zayed Obeidat, MD, PhD: That’s one of the ways to use it.
Transcript edited for clarity