Study of Efficacy and Safety of Ruxolitinib in Patients With Grade II to IV Steroid-refractory Acute Graft vs. Host Disease

Participants will start with a screening period to assess the eligibility; only participants who meet all the inclusion and none of the exclusion criteria will start study treatment from Day 1 to Week 24 or end of treatment. Following safety follow up visits, participants will receive the long-term follow-up until Month 12.

Key Inclusion criteria

• Male or female Chinese participants aged 12 or older at the time of informed consent. Written informed consent from participant, parent or legal guardian.
• Able to swallow tablets.
• Have undergone alloSCT from any donor source (matched unrelated donor, sibling, haplo-identical) using bone marrow, peripheral blood stem cells, or cord blood.
• Clinically diagnosed Grades II to IV acute GvHD as per standard criteria occurring after alloSCT requiring systemic immune suppressive therapy.
• Evident myeloid and platelet engraftment (confirmed within 48 hours prior to study treatment (ruxolitinib) start):
• Confirmed diagnosis of steroid refractory aGvHD defined as participants administered systemic corticosteroids (methylprednisolone at least 1 mg/kg/day [or equivalent prednisone dose at least 1.25 mg/kg/day]), given alone or combined with calcineurin inhibitors (CNI) and either:

• Progression based on organ assessment after at least 3 days compared to organ stage at the time of initiation of systemic corticosteroid +/- CNI for the treatment of Grade II to IV aGvHD. OR
• Failure to achieve at a minimum partial response based on organ assessment after 7 days compared to organ stage at the time of initiation of systemic corticosteroid +/-CNI for the treatment of Grade II to IV. OR
• Participants who fail corticosteroid taper defined as fulfilling either one of the following criteria:

• Requirement for an increase in the corticosteroid dose to methylprednisolone ≥ 1 mg/kg/day (or equivalent prednisone dose ≥ 1.25 mg/kg/day). OR
• Failure to taper the methylprednisolone dose to < 0.5 mg/kg/day (or equivalent prednisone dose <0.6 mg/kg/day) for a minimum of 7 days.

Key Exclusion criteria

• Has received more than one systemic treatment for steroid refractory aGvHD. Participants who received JAK inhibitor therapy for any indication after initiation of current alloSCT conditioning.
• Clinical presentation resembling de novo chronic GvHD or GvHD overlap syndrome with both acute and chronic GvHD features.
• Failed prior alloSCT within the past 6 months. Presence of relapsed primary malignancy after the alloSCT was performed.
• Presence of an active uncontrolled infection including significant bacterial, fungal, viral or parasitic infection requiring treatment.
• SR-aGvHD occurring after non-scheduled donor lymphocyte infusion (DLI) administered for pre-emptive treatment of malignancy recurrence. Note: Participants who have received a scheduled DLI as part of their transplant procedure and not for management of malignancy relapse are eligible.
• Presence of significant respiratory disease, severely impaired renal function, clinically significant or uncontrolled cardiac disease, unresolved cholestatic and liver disorders (not attributable to aGvHD). Disorders and/or current therapy with medications that interfere with coagulation or platelet function.

Other protocol-defined inclusion / exclusion criteria may apply