Mesa Discusses Importance of Pacritinib Accelerated Approval for Myelofibrosis With Severe Thrombocytopenia


Ruben Mesa, MD, spoke about the accelerated approval of pacritinib and its importance for the treatment of myelofibrosis with severe thrombocytopenia.

Ruben Mesa, MD, executive director of Mays Cancer Center, home to the UT Health San Antonio MD Anderson Cancer Center, spoke with CancerNetwork® about the accelerated approval of pacritinib (Vonjo) for intermediate or high-risk primary or secondary myelofibrosis with severe thrombocytopenia. This approval adds to the toolkit of agents to combat JAK2 and other key targets.


Pacritinib is an important addition to the armamentarium we have for treating patients with myelofibrosis, in particular because of the safety and effectiveness that has been seen for a subset of patients with myelofibrosis that have low platelet counts. Myelofibrosis is a chronic leukemia, and it’s driven by genetic mutations such as JAK2,CALR, and MPL.Patients can have difficulties with splenomegaly, symptoms, cytopenias, or risk of progressing to acute leukemia.

Our current state of approvals of ruxolitinib [Jakafi] andfedratinib [Inrebic] have been for individuals with a platelet counts of 50,000/μl or above. Both of those agents can improve splenomegaly or symptoms but have an[adverse] effect of causing anemia or lowering the platelet count, with thrombocytopenia beinga dose-limiting toxicity.

Pacritinib, a JAK2 and IRAK-1 inhibitor, is somewhat distinct in that it can improve splenomegaly and symptoms to very important areas of burden in myelofibrosis. It has been safely used in individuals even with severe thrombocytopenia platelet counts of under 50,000/μl. It can be used, given as full dose, to improve splenomegaly and symptoms. Additionally, there has been improvement in an anemiain some individual’s or even turning from transfusion dependent to transfusion independent. It’s an important additional JAK inhibitor with a unique lanefor individuals with marked thrombocytopenia or the even the broader cytopenic myelofibrosis. I’m excited that to see this come.


CTI BioPharma announces FDA accelerated approval of VONJO (pacritinib) for the treatment of adult patients with myelofibrosis and thrombocytopenia. News release. CTI BioPharma Corp. February 28, 2022. Accessed February 28, 2022.

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