Clinical Research Directory

Inclusion Criteria: 1. Voluntary written informed consent; aged 18 to 70 years, inclusive; male or female. 2. Prior allogeneic hematopoietic stem cell transplantation (allo-HSCT) with documented myeloid engraftment. 3. Patients with grade II-IV steroid-refractory acute graft-versus-host disease (aGvHD). 4. Karnofsky Performance Status (KPS) score ≥ 60, with an expected survival of greater than 6 months. 5. Absence of uncontrolled infection or severe hepatic, renal, pulmonary, or cardiac disease. 6. Male participants must agree to practice abstinence or use contraception; female participants must have a negative pregnancy test and agree to use dual methods of contraception. 7. Able to swallow tablets. 8. Able to comply with study and follow-up procedures. Exclusion Criteria: 1. Has received more than one systemic treatment for aGvHD other than corticosteroids +/- CNI (prophylaxis or treatment). 2. Has previously received chimeric antigen receptor (CAR) T-cell therapy. 3. Has previously received JAK inhibitor therapy after allogeneic hematopoietic stem cell transplantation (allo-HSCT). 4. Clinical presentation resembling de novo chronic GvHD or GvHD overlap syndrome with both acute and chronic GvHD features. 5. Failed prior alloHSCT within the past 6 months. 6. Presence of severe respiratory disease, severe renal impairment, clinically significant or uncontrolled cardiac disease, unresolved cholestasis, and hepatic disease (not attributable to aGvHD). 7. Presence of an active uncontrolled infection including significant bacterial, fungal, viral or parasitic infection requiring treatment. Infections are considered controlled if appropriate therapy has been instituted and, at the time of screening, no signs of progression are present.Progression of infection is defined as hemodynamic instability attributable to sepsis, new symptoms, worsening physical signs or radiographic findings attributable to infection. Persisting fever without other signs or symptoms will not be interpreted as progressing infection. 8. Evidence of active viral infection (confirmed by peripheral blood viral load) including CMV, EBV, HHV-6, HBV, or HCV. Patients with pre-transplant positive serology results indicative of high risk for viral reactivation must have negative viral load results within 28 days prior to enrollment. Patients whose immune status is unknown or uncertain (e.g. serologies not obtained prior to transplant) must have viral load results confirming no evidence of active viral infection within 28 days prior to enrollment. 9. Presence of relapsed primary malignancy, or who have been treated for relapse after the alloHSCT was performed, or who may require rapid immune suppression withdrawal as pre-emergent treatment of early malignancy relapse. 10. Has participated in any other clinical trials within 28 days before first administration.