MPN Workshop of the Carolinas 2024 | Considerations when selecting between JAK inhibitors for patients with MPNs

I think the observed adverse effects of JAK inhibitors are really one of the main ways that we decide on which one to use in 2024. We all know that they have pretty similar efficacy in terms of reducing spleen size and improving symptom burden, but they each have their kind of unique characteristics that make them appropriate for certain situations. 

So in general, some of them or all of them can cause a little bit of GI toxicity, so nausea, vomiting, diarrhea, at the beginning. But the ones with FLT3 inhibition, so like pacritinib and fedratinib tend to have more of that, and so patients with pre-existing GI conditions, you might be more likely to go with one of the other two.

Recently, with the approval of pacritinib and momelotinib, we have JAK inhibitors approved based on the absence or presence of anemia or thrombocytopenia. So pacritinib is a good option and really the only option for patients with platelet count less than 50,000 at diagnosis. And then momelotinib as well is FDA approved for patients with myelofibrosis and anemia. Both pacritinib and momelotinib inhibit ACVR1, which allows the body to use iron more efficiently and improve anemia.

And so when I’m starting a patient on a JAK inhibitor, I’m looking for all these things- anemia, thrombocytopenia, any baseline nausea, vomiting to make a decision about which one to use.