Treatment of GVHD in Hematopoietic Stem Cell Transplant (HSCT) Recipients Using AAT Plus Corticosteroids (CS) Compared With Corticosteroids Alone

The overall response is defined as having a CR or PR at Day 28, along with: being alive, free of any next-line GVHD therapy, and free of escalation of prednisone-equivalent steroid dose to 2.5 milligrams per kilogram (mg/kg)/day or more. The percentage of participants with CR or PR is reported here. Wilson score confidence intervals (CIs) are reported here as a measure of dispersion. The CR was defined as a score of 0 for the GVHD staging in all evaluable organs. The PR was defined as an improvement in one or more organs involved with GVHD symptoms without progression in others. Acute GVHD was graded and assessed for response based on Harris (Mount Sinai Acute GVHD International Consortium [MAGIC]) criteria (stage 0, 1, 2, 3, 4) for skin, liver, upper gastrointestinal (GI) tract, and lower GI tract. Participants who had an escalation of prednisone-equivalent steroid dose to 2.5 mg/kg/day or higher were classified as non-responders (NR).

The DOR was defined as time from the Day 28 response (CR or PR) until the first of the following events occurs: progression of acute GVHD, death, any next-line GVHD therapy, or escalation of prednisone-equivalent steroids to greater than or equal to (>=) 2.5 mg/kg/day. Wald CIs are reported here as a measure of dispersion.

An event of NRM was death without prior evidence of relapse/progression of the primary disease, where relapse/progression was treated as a competing risk. Cumulative incidence of NRM at 6 and 12 months post-randomization is reported here for this outcome measure.

An event for overall survival (OS) was death from any cause, while an event for progression-free survival (PFS) was death from any cause or relapse/progression of the primary disease.

GVHD-free survival was defined as participants being alive, free of acute or chronic GVHD, and free of any next-line GVHD therapy or escalation of steroids to >=2.5 mg/kg/day prednisone or equivalent for treatment of GVHD.

The percentage of participants with CR, PR (including subset with very good partial response [VGPR]), and treatment failure (TF). The designation of TF consisted of participants with NR, mixed response (MR) or progression. The initiation of additional systemic (next-line) GVHD therapies, escalation of prednisone equivalent steroid dose to >= 2.5 mg/kg/day, or death from any cause prior to the assessment timepoint was also considered a TF. Simultaneous Goodman CIs are provided for category proportions for each arm at each assessment time.

The percentage of participants with CR, PR (including subset with VGPR), and TF allowing for treatment with next-line therapy. The designation of TF consisted of participants with NR, MR, or progression. The escalation of prednisone-equivalent steroid dose to >= 2.5 mg/kg/day or death from any cause prior to the assessment timepoint was also considered a TF. Simultaneous Goodman CIs are provided for category proportions for each arm at each assessment time.

The cumulative incidence of Grade 2 to 3 systemic infections. Grade 2 to 3 systemic infections were defined according to the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Manual of Procedures.

The incidence of Grade 3 to 5 TEAEs (per Common Terminology Criteria for Adverse Events [CTCAE] Version 5.0). Wilson score CIs are reported here as a measure of dispersion.

Chronic GVHD was defined per National Institutes of Health (NIH) Consensus Criteria. Diagnosis of chronic GVHD of any severity (mild, moderate, or severe) was considered an event for this outcome measure, where death before cGVHD was treated as a competing risk.

The cumulative incidence of relapse/progression of the primary disease, with death prior to relapse/progression treated as a competing risk. Death without prior relapse/progression was treated as a competing risk for relapse/progression.

The DOR was defined as time from the Day 28 response (CR or PR) until the first of the following events occurs: death, any next-line GVHD therapy, or escalation of prednisone-equivalent steroids to >= 2.5 mg/kg/day. Wald CIs are reported here as a measure of dispersion.