Leukemia, Myelomonocytic, Chronic

Ambispective, national, multicenter observational cohort study aimed at characterizing the satellite dysimmune manifestations of clonal hematopoiesis, including Vexas (Vacuoles, E1 enzyme, X-linked, Autoinflammatory and Somatic) syndrome.

The goal of this clinical trial is to learn if pacritinib works better than hydroxyurea to treat advanced proliferative chronic myelomonocytic leukemia in adults. The main questions it aims to answer are: * Does pacritinib improve disease control compared to hydroxyurea? * What medical problems do participants have when taking pacritinib or hydroxyurea? Researchers will compare pacritinib to hydroxyurea to see if pacritinib is more effective and better tolerated in people with advanced proliferative chronic myelomonocytic leukemia. Participants will be randomly assigned to receive either pacritinib twice a day or hydroxyurea for up to 48 weeks. After treatment ends, participants will be followed for up to one year.

The mandate of this MPN registry is to collect clinical information, including molecular results, from consenting patients with a variety of MPNs at different time points during the course of their disease.