Pacritinib, sold under the brand name Vonjo, is an anti-cancer medication used to treat myelofibrosis.

Common side effects include diarrhea, low platelet counts, nausea, anemia, and swelling in legs.

[2] Pacritinib in indicated to treat adults who have a rare form of a bone marrow disorder known as intermediate or high-risk primary or secondary myelofibrosis and who have platelet (blood clotting cells) levels below 50,000/μL.

[1][2] The effectiveness and safety of pacritinib were demonstrated in a study that included 63 participants with intermediate or high-risk primary or secondary myelofibrosis and low platelets who received pacritinib 200 mg twice daily or standard treatment.

[2] Effectiveness was determined based upon the proportion of participants who had a 35% or greater spleen volume reduction from baseline to week 24.