CSF-1R x FLT3 x JAK2 x IRAK1 x ALK2

Background:
Kaposi sarcoma herpesvirus (KSHV)-associated inflammatory cytokine syndrome (KICS) and KSHV-multicentric Castleman disease (MCD) occur in people living with HIV. These diseases cause severe inflammation that can be fatal if not treated.
Objective:
To test a drug (pacritinib) in people with KSHV-associated KICS or MCD.
Eligibility:
People aged 18 years and older with KSHV-associated KICS or MCD. They must have at least one symptom.
Design:
Participants will be screened. They will have a physical exam with blood tests and tests of their heart function. They will have imaging scans. Their ability to perform everyday tasks will be reviewed. In some participants who have Kaposi sarcoma (KS) with KICS or MCD, these individuals may need a bronchoscopy and/or endoscopy of the upper or lower intestine: A flexible tube with a camera and a light source will be inserted through the mouth or anus to see these structures and assess any KS.
Pacritinib is a capsule taken by mouth. Participants will take the drug twice a day, every day, for up to 24 weeks. They will write down each dose in a diary.
Participants will visit the clinic 3 times in the first 4 weeks. Their visits will taper to once every 4 weeks. Imaging scans, blood tests, and other tests will be repeated during these visits. Participants will give samples of saliva. They may opt to allow tissues samples to be taken from their skin and lymph nodes.
Participants will have follow-up visits 7 days and 30 days after their last dose of pacritinib. After that, they will visit the clinic every 3 months for up to 1 year. The physical exam and blood, heart, and imaging tests will be repeated at these visits.

Background:
Myelodysplastic syndrome (MDS) and myelodysplastic/myeloproliferative neoplasm (MDS/MPN) are blood disorders that can cause serious complications in children and adults. MDS and MDS/MPN can also progress to acute myeloid leukemia. Treatments for these disorders are risky and not always effective. Better treatments are needed.
Objective:
To test a study drug (pacritinib) in adults and children with MDS or MDS/MPN.
Eligibility:
Children (aged 12 to 17 years) and adults (aged 18 years and older) with MDS or MDS/MPN.
Design:
Participants will be screened. They will have a physical exam with blood tests. They will have tests of their heart function. They may have a bone marrow biopsy: An area over the hip will be numbed; a needle will be inserted to remove a sample of soft tissue from inside the hipbone.
Pacritinib is a capsule taken by mouth. All participants will take the study drug 2 times a day, every day, in 28-day cycles. They will write down the date and time they take each capsule. Doctors will assign varying dosages of the drug to different participants.
Participants will have clinic visits each week during cycle 1; every 2 weeks during cycle 2; and gradually increasing to every 3 months after cycle 13. Treatment will continue for up to 8 years.
Bone marrow biopsies, heart tests, and other tests will be repeated at intervals throughout the study. Participants will also fill out questionnaires about their quality of life, the symptoms of their disease, and other topics.

VEXAS (vacuoles, E1 ubiqutin-activating enzyme, X-linked, autoinflammatory, somatic syndrome) is a recently described disorder with severe hematologic and rheumatologic manifestations caused by somatic variants in the ubiquitin- activating enzyme gene, UBA1, that is acquired in hematopoietic progenitor cells. Patients are often debilitated by autoinflammatory symptoms and there is currently no standard of care available. There is a clinically unmet need for better therapies in VEXAS Syndrome. There have been no prospective clinical trials of JAK-I in VEXAS syndrome. The investigators hypothesize that pacritinib, as a JAK2/IRAK1 inhibitor with a manageable safety profile in myelofibrosis patients with thrombocytopenia, will improve the autoinflammatory and hematologic manifestations of VEXAS syndrome with a tolerable toxicity profile.
The investigators propose a single arm, pilot Phase 1 study evaluating the safety and tolerability of pacritinib in patients with VEXAS syndrome with an initial safety run-in phase of 6 patients treated with pacritinib 200mg twice daily (BID) on days 1-28 of a continuous 28 day cycle. If no more than 1 patient experiences a dose-limiting toxicity (DLT), the investigators will enroll an expansion cohort to gain additional toxicity and efficacy data, for a total enrollment of 15 patients. If more than 1 patient experiences a DLT during the safety run-in phase, the investigators will decrease the dose to 100 mg BID, and if no more than 1 of 6 patients experiences a DLT, the investigators will complete the expansion cohort as above for up to a total enrollment of 15 patients. If more than 1 patient experiences a DLT at 100 mg BID, the investigators will discontinue the study. Patients will be treated for up to 12 cycles.