Overall response rate at Day 28 after randomization was defined as the percentage participants in each arm demonstrating a complete response (CR) or partial response (PR), based on investigator assessment & according to standard criteria, without requirement for additional systemic therapies for an earlier progression, mixed response or non-response. Scoring of response was relative to the organ stage at the time of randomization.

CR was defined as a score of 0 for the aGvHD grading in all evaluable organs that indicates complete resolution of all signs & symptoms of aGvHD in all evaluable organs without administration of additional systemic therapies for any earlier progression, mixed response or non-response of aGvHD.

PR was defined as improvement of 1 stage in 1 or more organs involved with aGvHD signs or symptoms without progression in other organs or sites without administration of additional systemic therapies for an earlier progression, mixed response or non-response of aGvHD.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

Percentage of all participants in each arm who achieved a complete response (CR) or partial response (PR) at Day 28 (primary endpoint) AND maintained a CR or PR at Day 56 based on investigator assessment and according to standard criteria.

CR was defined as a score of 0 for the aGvHD grading in all evaluable organs that indicates complete resolution of all signs and symptoms of aGvHD in all evaluable organs without administration of additional systemic therapies for any earlier progression, mixed response or non-response of aGvHD.

PR was defined as improvement of 1 stage in 1 or more organs involved with aGvHD signs or symptoms without progression in other organs or sites without administration of additional systemic therapies for an earlier progression, mixed response or non-response of aGvHD.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

ORR at Da4 14 is the percentage of participants who achieved overall response (CR+PR) at Day 14 based on investigator assessment and according to standard criteria.

CR was defined as a score of 0 for the aGvHD grading in all evaluable organs that indicates complete resolution of all signs and symptoms of aGvHD in all evaluable organs without administration of additional systemic therapies for any earlier progression, mixed response or non-response of aGvHD.

PR was defined as improvement of 1 stage in 1 or more organs involved with aGvHD signs or symptoms without progression in other organs or sites without administration of additional systemic therapies for an earlier progression, mixed response or non-response of aGvHD.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

Duration of response was defined for patients who had a CR or PR at Day 28. This was the interval between the date of first documented response of CR or PR (i.e., the start date of response), till the date of progression or addition of systemic therapies for aGvHD on or after Day 28. Death without prior observation of aGvHD progression and onset of chronic GvHD were considered. Duration of response was censored at the last response assessment prior to or at the analysis cut-off date, if no events/competing risk occurred before or at the cut-off date.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization. These were patients to whom study treatment was assigned by randomization and whose overall response was complete response (CR) or partial response (PR).

Weekly cumulative steroid dose for each participant up to Day 56 or discontinuation of randomized treatment. Participants should have undergone tapering of steroids if it had been required. Tapering the immunosuppression therapy was performed in 2 steps: Taper of corticosteroids: initiated not earlier than Day 7, and performed as per institutional guidelines. Only patients with assessments done at each time point are reported. This is the reason that the overall number per treatment is higher and the number of participants with responses vary over time.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

OS was defined as the time from the date of randomization to date of death due to any cause. If a patient was not known to have died, then OS was censored at the latest date the patient was known to be alive (on or before the cut-off date). Results are based on Kaplan Meier (KM) estimates.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

Event-free survival was defined as the time from the date of randomization to the date of hematologic disease relapse/progression, graft failure, or death due to any cause. If a patient was not known to have any event, then EFS was censored at the latest date the patient was known to be alive (on or before the cut-off date). Results are based on Kaplan Meier (KM) estimates.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

FFS was defined as the time from the date of randomization to date of hematologic disease relapse/progression, non-relapse mortality, or addition of new systemic aGvHD treatment.

Probability of FFS with 95% CIs are presented for each treatment group, accounting for onset of chronic GvHD as the competing risk.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

NRM was defined as the time from date of randomization to date of death not preceded by hematologic disease relapse/progression. Hematologic disease relapse/progression was considered a competing risk for NRM with the date of hematologic disease relapse/progression being the earlier of documented hematologic disease relapse/progression or institution of therapy to treat potential hematologic disease relapse/progression. If a patient was not known to have died or to have relapsed/progressed, then NRM was censored at the latest date the patient was known to be alive (on or before the cut-off date). Data is provided based on cumulative probability of hematologic disease relapse/progression.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

MR was defined as the time from date of randomization to hematologic malignancy relapse/progression. Deaths not preceded by hematologic malignancy relapse/progression were considered competing risks. If a patient was not known to have event or competing risks, then MR was censored at the latest date the patient was known to be alive (on or before the cut-off date). Calculated for patients with underlying hematologic malignant disease.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization. Calculated for patients with underlying hematologic malignant disease.

Incidence of cGvHD was the time from date of randomization to onset of cGvHD is the diagnosis of any cGvHD including mild, moderate, severe. Deaths without prior onset of cGvHD and hematologic disease relapse/progression were competing risks. If a patient was not known to have event or competing risks, then the incidence of cGvHD was censored at the latest date the patient was known to be alive (on or before the cut-off date).

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization. Calculated for patients with underlying hematologic malignant disease.

Exposure-efficacy relationship of ruxolitinib in terms of concentration-effect and dose-effect.

ORR was defined as the percentage of participants with a best overall response defined as complete response (CR) or partial response (PR) as assessed by local investigators. CR was defined as a score of 0 for the Acute Graft vs. Host Disease (aGvHD) grading in all evaluable organs that indicates complete resolution of all signs and symptoms of aGvHD in all evaluable organs without administration of additional systemic therapies for any earlier progression, mixed response or non-response of aGvHD.

PR was defined as improvement of 1 stage in 1 or more organs involved with aGvHD signs or symptoms without progression in other organs or sites without administration of additional systemic therapies for an earlier progression, mixed response or non-response of aGvHD.

PK-Efficacy Set: All patients randomized to ruxolitinib treatment arm, who received at least one dose of ruxolitinib, who have post-baseline efficacy data (at least one efficacy parameter) and for whom popPK predictions are available (at least one popPK predicted AUC0-12h).

Exposure-efficacy relationship of ruxolitinib in terms of concentration-effect and dose-effect.

DORR is the percentage of all participants in each arm who achieved a complete response (CR) or partial response (PR) at Day 28 (primary endpoint) AND maintained a CR or PR at Day 56.

CR was defined as a score of 0 for the aGvHD grading in all evaluable organs that indicates complete resolution of all signs and symptoms of aGvHD in all evaluable organs without administration of additional systemic therapies for any earlier progression, mixed response or non-response of aGvHD.

PR was defined as improvement of 1 stage in 1 or more organs involved with aGvHD signs or symptoms without progression in other organs or sites without administration of additional systemic therapies for an earlier progression, mixed response or non-response of aGvHD.

PK-Efficacy Set: PK-Efficacy Set: All patients randomized to ruxolitinib treatment arm, who received at least one dose of ruxolitinib, who have post-baseline efficacy data (at least one efficacy parameter) and for whom popPK predictions are available (at least one popPK predicted AUC0-12h).

Exposure-efficacy relationship of ruxolitinib in terms of concentration-effect and dose-effect. This represents the percentage of Ruxolitinib-exposed participants dead at 24 months.

Overall survival (OS) was defined as the time from the date of randomization to date of death due to any cause. If a patient was not known to have died, then OS was censored at the latest date the patient was known to be alive (on or before the cut-off date).the date of death due to any cause.

PK-Efficacy Set: PK-Efficacy Set: All patients randomized to ruxolitinib treatment arm, who received at least one dose of ruxolitinib, who have post-baseline efficacy data (at least one efficacy parameter) and for whom popPK predictions are available (at least one popPK predicted AUC0-12h).

Percentage of participants who achieved overall response (OR) (CR+PR) at any time point up to and including Day 28 and before the start of additional systemic therapy for aGvHD.

CR was defined as a score of 0 for the Acute Graft vs. Host Disease (aGvHD) grading in all evaluable organs that indicates complete resolution of all signs and symptoms of aGvHD in all evaluable organs without administration of additional systemic therapies for any earlier progression, mixed response or non-response of aGvHD.

PR was defined as improvement of 1 stage in 1 or more organs involved with aGvHD signs or symptoms without progression in other organs or sites without administration of additional systemic therapies for an earlier progression, mixed response or non-response of aGvHD.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization. These were participants whose overall response was complete response (CR) or partial response (PR).

The Functional assessment of Cancer Therapy - Bone Marrow Transplant (FACT-BMT) is a 50-item self-report questionnaire that measures the effect of a therapy on domains including physical, functional, social/family and emotional well-being, together with additional concerns relevant for bone marrow transplantation patients. Patients indicated their response on a scale of 0 to 4 on each statement, with 0 indicating worst score and 4 the best score. All individual scores were combined to calculate the total score. Total score was reported with score range: 0-148 which was calculated as the sum of all unweighted subscale scores. The higher the total score the better the result. Descriptive statistics and change from baseline were calculated in total score at each scheduled assessment time point.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

The EQ-5D descriptive classification consists of five dimensions of health: mobility, self-care, usual activities, anxiety/depression and pain/discomfort. Patients are requested to select the statement which best describes their condition on that day for each dimension. For overall health that day, the EuroQoL-5D-5L scale is numbered from 0 to 100, with 100 being the best health you can imagine and 0 being the worst health you can imagine. Descriptive statistics (mean, standard deviation, median, Q1, Q3, minimum, and maximum) were calculated based on the scored scales at each scheduled assessment time point. In order to measure Quality-of-Life (QoL) among aGvHD patients, and potential changes over time, change from baseline in EuroQol-5D-5L scores at the time of each assessment were also calculated. Missing items data in a scale will be handled based on each instrument manual. No imputation will be applied if the total or subscale scores are missing at a visit.

The Full Analysis Set (FAS) comprised all patients to whom study treatment was assigned by randomization.

AUClast: The AUC from time zero to the last measurable concentration sampling time (tlast) (mass x time x volume-1) AUCinf: The AUC from time zero to infinity (mass x time x volume-1) AUCtau: The AUC calculated to the end of a dosing interval (tau) at steady-state (amount x time x volume-1).

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients was assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

Cmax is the maximum (peak) observed plasma, blood, serum, or other body fluid drug concentration after single dose administration (mass X volume-1).

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients was assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

CL/F is the total body clearance of ruxolitinib from the plasma after a single dose and at steady state.

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients was assayed for Ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

VzF is the apparent volume of distribution during terminal phase after a single dose and at steady state.

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients will be assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

Lambda_z is the smallest (slowest) disposition (hybrid) rate constant (hr-1) may also be used for terminal elimination rate constant (hr-1).

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients will be assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

T1/2 is the elimination half-life associated with the terminal slope of a semi logarithmic concentration-time curve (hr).

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients will be assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

Tmax is the time to reach maximum (peak) plasma, blood, serum, or other body fluid drug concentration after single dose and repeated dose administration (hr).

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients will be assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

Racc is the accumulation ratio (AUC at steady state/AUC Day 1). Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients was be assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS).

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

Minimum concentration (Ctrough) of ruxolitinib and at steady state in corticosteroid refractory acute GVHD patients.

Plasma samples for PK was taken at Day 1 (start of treatment), at Day 7 (week 1) to characterize the PK after first dose, and at steady state by non-compartmental analysis.

The plasma samples from all patients will be assayed for ruxolitinib concentrations using validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS)

The Pharmacokinetic Analysis Set (PAS) included all patients who provided at least one evaluable PK concentration. For a concentration to be evaluable, patients were required to: Take a dose of ruxolitinib prior to sampling, Did not vomit within 2 hours after the last dose of ruxolitinib prior to sampling (for pre dose samples) or did not vomit within 2 hours after ruxolitinib dosing (for post dose samples).

On treatment deaths were collected from the start of treatment up to 30 days after study drug discontinuation, for a maximum duration of 708 days (treatment duration ranged from 6.0 to 678.0) for the RUX arm and 218 days (treatment duration ranged from 1.0 to 188.0 days) for the BAT arm.

Deaths post treatment survival follow up were collected after the on- treatment period, up to approx. 48 months. Patients who didn't die during the on-treatment period and had not stopped study participation at the time of data cut-off (end of study) were censored.

Clinical Database Population: all randomized patients