What is pacritinib?
Pacritinib is a novel JAK2 inhibitor that has an advantage in that it inhibits an additional molecule called ACVR1.
So pacritinib was approved for patients with myelofibrosis that were symptomatic, but also had a platelet count of less than 50,000 per microliter.
Some of the disadvantages of the earlier JAK2 inhibitors were that cytopenias or a decrease in cell counts, particularly the platelets, prohibited the use of JAK2 inhibitors in a select subgroup of patients with myelofibrosis.
Therefore, the advantage of a therapy that is thought to not decrease the platelets has utility in patients with myelofibrosis. And that's where we reach for pacritinib.
So pacritinib has a niche indication for patients with myelofibrosis with platelets less than 50,000 per microliter. And it can be very effective without decreasing the platelets further.
HealthTree • October 22, 2025