MPN Workshop of the Carolinas 2024 | Treatment schedule for ruxolitinib in patients with MPNs and how to assess response

So the treatment schedule of ruxolitinib.

It is a twice daily medication. You try to get that 12 hours apart if you can. So because of the half life, it is so incredibly short, if you’re doing once daily dosing, the peaks and valleys end up being very, very high.

Then you start off, I generally start off with what the package insert recommends, I know there are other trials that have started at lower doses and work back up, but the truth is, when you’re assessing response there, you want to have patients who are optimally JAK inhibited. And what does that mean?

Well, I think one nice way of putting it is this RR6 model that’s been published and we often talk about, and what the concept is, is trying to hit that bar of where a patient should be six months after initiation of therapy, and that bar is on 20 twice daily of ruxolitinib, at least a 30% reduction in spleen volume and being transfusion independent.

So if you have a patient who’s been on rux for three/six months and they’re hitting all those boxes, that’s fantastic, their predicted survival looks great and they’re probably going to do very well on this medication for quite some time.

But for every one of these boxes you’re not checking, the survival curve drops pretty dramatically. So at six months, if a patient’s on rux and transfusion dependent or their spleen hasn’t shrunk a whole heck of a lot, or they’re needing transfusions, that’s certainly a time you want to think about alternative therapies.

So to me, I start someone on ruxolitinib and in three months I ask myself, are they on 20 twice daily? Are they transfusion independent? You know, has their spleen shrunk down nicely? And if not, I’m starting to talk with that patient, well, we may need to do something else.