Optimizing GVHD Prophylaxis After Allogeneic Hematopoietic Cell Transplantation

The health-related quality of life will be assessed using the Functional Assessment of Cancer Therapy-Bone Marrow Transplantation (FACT-BMT) trial outcome index (TOI). The FACT-BMT is a validated, patient-reported questionnaire that measures physical and functional well-being specifically in bone marrow transplant recipients. Higher scores indicate better quality of life. The primary outcome is to compare the FACT-BMT TOI scores between the attenuated-dose PTCy arm and the high-dose PTCy arm at 3 months post-transplant.

Karnofsky Performance Scale (KPS) is a validated tool ranging from 0 (death) to 100 (normal activity). Higher scores indicate better functional status.

Activities of Daily Living (ADL) measures basic self-care tasks such as bathing and dressing. The typical total score ranges from 0 to 6, with higher scores indicating better functional status.

Change in Instrumental Activities of Daily Living (IADL) assesses more complex tasks (e.g., handling finances). Total scores typically range from 0 to 8 or 0 to 14 (depending on the version), with higher scores indicating greater independence.

The Fried Frailty Index assesses five components (weight loss, exhaustion, grip strength, walking speed, and physical activity). A higher total score indicates greater frailty.

This is a brief test of visuospatial and executive function, typically scored on accuracy of clock drawing/placement (range 0-8). Higher scores suggest better cognitive performance.

The number of falls, if any, will be collected since baseline. Results will be analyzed as the proportion of participants experiencing ≥1 fall over the time frame, or as the difference in mean (or median) number of falls between arms.

Body Mass Index (BMI) is calculated as weight (kg) / [height (m)]² (kg/m²). Higher or lower values do not necessarily indicate "better" or "worse" status by themselves but will be compared between arms for changes from baseline.

The Geriatric Depression Scale-15 (GDS-15) is a 15-item screening tool for depression in older adults (scores 0-15). Higher scores indicate more severe depression.

Graft-Versus-Host Disease (GRFS) is defined as the time from transplant to the first occurrence of grade III-IV acute GVHD, chronic GVHD requiring systemic immune suppression, disease relapse or progression, or death from any cause. An event is counted when any of these conditions are met. The GRFS at 1 year post-transplant will be compared between the two treatment arms.

Overall Survival (OS) is defined as survival from the date of transplant until death from any cause. Event-Free Survival (EFS) is defined as survival from the date of transplant without disease relapse or progression. The study will compare the proportion of participants alive (for OS) and without relapse or progression (for EFS) at 1 year post-transplant between the two treatment arms

Transplant-related mortality (TRM) is defined as death from causes other than disease relapse or progression. The study will estimate and compare the cumulative incidence of TRM at 1 year post-transplant between the two treatment arms.

Acute graft-versus-host disease (GVHD) of grade II-IV is assessed using the Mount Sinai acute GVHD grading system. The study will estimate and compare the cumulative incidence of grade II-IV acute GVHD at 1 year post-transplant between the two treatment arms.

Chronic GVHD is assessed using the NIH chronic GVHD grading system, which includes both classical chronic GVHD and overlap syndrome. The study will estimate and compare the cumulative incidence of chronic GVHD at 1 year post-transplant between the two treatment arms.

Hematologic recovery is evaluated by time to neutrophil engraftment (absolute neutrophil count ≥ 500/mm³ for three consecutive days) and platelet engraftment (platelet count ≥ 20,000/mm³ or ≥ 50,000/mm³ without transfusion for seven days). The study will describe and compare the cumulative incidence and kinetics of neutrophil and platelet recovery by days +28 and +100 post-transplant between the two treatment arms.

Adverse events will be graded using the NCI Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. The study will assess and compare the incidence of grade III or higher adverse events by day +100 post-transplant between the two treatment arms.

Infections will be graded according to Blood and Marrow Transplant Clinical Trials Network (BMT CTN) criteria. The study will estimate and compare the cumulative incidence of grade II or higher infections by 6 months post-transplant between the two treatment arms.