We are doing this study to see if taking a prebiotic (dietary supplement) can reduce the risk of acute graft-versus-host disease (a common complication) in people who receive an allogeneic stem cell transplant. This study is important because prebiotics are a common and safe dietary supplement, and there is a need for a safe and effective way to reduce graft-versus-host disease after transplant.

Allogeneic (Donor) Stem Cell Transplant

Adults ages 18-80 who:

• Are scheduled to get an allogeneic stem cell transplant for any type of illness
• Are able to read and write in English
• Are not pregnant or nursing
• Do not have any disease or condition affecting their digestive tract
• Are not using any prebiotic, probiotic, or antibiotic

For more information about who can join this study, please contact the study team at andrea.pires@duke.edu or 919-668-4978.

If you choose to join the study, you will:

• Be randomly asssigned (like a coin flip) to receive the prebiotic (food additive that affects gut bacteria) or a placebo (food additive that does not affect gut bacteria)
• Give stool samples
• Have your skin swabbed
• Have blood draws
• Fill out questionnaires
• Have Cardiopulmonary Exercise Testing (CPET) done
• Have complete body composition testing done
• Have muscle and fat composition testing done using a hand-held ultrasound device
• Complete physical function and cognitive function assessments