A Phase I/II GVHD Prevention Trial Combining Pacritinib With Sirolimus-Based Immune Suppression

GVHD is a common problem that occurs after transplant despite the use of standard immune suppressive medications (these are called sirolimus and tacrolimus). GVHD can result in skin rash, nausea, vomiting, diarrhea, and liver damage. Severe GVHD can be life-threatening. In this study, investigators will add a medication called pacritinib to the combination of sirolimus and tacrolimus to see if this approach can more effectively prevent GVHD. Pacritinib is a medicine used to treat a disease of the bone marrow called myelofibrosis Pacritinib turns off a switch in cells called Janus Kinase 2 (JAK2). Pacritinib is an investigational medicine used in several clinical trials and not FDA approved. JAK2 is an important regulator of inflammation. This inflammation is thought to contribute to GVHD. Pacritinib is able to turn this inflammation off by inhibiting JAK2. Research has shown that blocking JAK2 prevents GVHD in mice and also reduces severe GVHD in transplant patients. Doctors at Moffitt have identified that inflammation from JAK2 is an important cause of GVHD, and is present well before patients develop GVHD symptoms. This trial will study how well pacritinib turns off inflammation during the transplant and if it prevents GVHD when added to our standard medicines. Pacritinib will begin the day of the participant's transplant (Day 0) and will continue until 70 days after the transplant. Sirolimus will be given the day before transplant and continued daily for at least one year. Tacrolimus will begin 3 days before transplant and will be given for at least 50 days.