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A drug, SER-155, to reduce the risk of infection and graft-versus-host disease (GVHD) after allogeneic (cells from a donor) blood or marrow transplant (BMT)


18 and older

Phase 1

13 Locations


Clinical Trial Goal

To find out if SER-155 is safe and works well to reduce infection and GVHD after allogeneic BMT

You may be able to join this trial if you:

  • Are 18 years old or older
  • Have a disease that can be treated with allogeneic BMT. Some examples include:
    • Blood cancer:
      • Acute biphenotypic leukemia 
      • Acute lymphoblastic leukemia (ALL) 
      • Acute myeloid leukemia (AML) 
      • Chronic lymphocytic leukemia (CLL) 
      • Chronic myeloid leukemia (CML) 
      • Multiple myeloma 
      • Myelodysplastic syndromes (MDS) 
      • Myelofibrosis 
      • Non-Hodgkin lymphoma (NHL)
      • T-cell leukemia
      • T-cell lymphoma
      • Another cancer that allogeneic BMT may treat
    • Other disorder for which allogeneic BMT is known to be a possible treatment
  • Are not planning to have an allogeneic BMT using umbilical cord blood (UCB)
  • Have not been treated with CAR T-cell therapy
  • Agree to have other standard tests done to see if you can be in the clinical trial 

Trial Details

SER-155 is a drug made from naturally occurring, healthy bacteria that will replace the bacteria in the gut, which may reduce the risk of infections and GVHD after allogeneic BMT.
Vancomycin is an antibiotic used to treat and prevent bacterial infections.

There are 2 parts to this trial. Part 1 is now fully enrolled. You'll be in Part 2.
  • Part 1: Everyone gets SER-155 and vancomycin - Completed
  • Part 2: Random assignment to group 1 or group 2 (see below)

In part 2 of this trial, you’ll be randomized to 1 of 2 groups. Once you’re randomized, you and the clinical trial doctors won’t know which group you’re in:
  • Group 1 – SER-155 and vancomycin
  • Group 2Placebo and placebo

Randomized means doctors will use a computer to assign you to either group. A computer assigns you by chance, like flipping a coin or drawing a name out of a hat. You, your doctor or the clinical trial doctor won’t have any control over which group you’ll be assigned. This means you won’t be able to choose your group.
If you are randomized to Group 1, you’ll get:
  • SER-155 – Given 1 time each day
  • Vancomycin – Given 4 times each day
If you are randomized to Group 2, you’ll get: 
  • SER-155 Placebo  – Given 1 time each day
  • Vancomycin Placebo – Given 4 times each day

You may continue treatment for as long as the clinical trial doctors think it’s best for your health. You'll have biopsies and/or scans to see how well the treatment is working. The clinical trial doctors will check your health for 1 year.

The Food and Drug Administration (FDA) has not yet approved SER-155.


Bina Tejura, MD, 617-945-9626,


Banner Health - MD Anderson Medical CenterRecruiting

Gilbert, Arizona
Investigator Site

Mayo Clinic - ScottsdaleRecruiting

Scottsdale, Arizona
Investigator Site

City of HopeRecruiting

Duarte, California

University of California, Los Angeles - Division of Hematology-OncologyRecruiting

Marina Del Rey, California
Investigator Site

Georgetown (MedStar Health)Not yet recruiting

Washington, District of Columbia

Mayo Clinic - JacksonvilleRecruiting

Jacksonville, Florida
Investigator Site

University of Florida - Division of Hematology & OncologyRecruiting

Gainesville, Florida
Investigator Site

University of Chicago Medical CenterRecruiting

Chicago, Illinois
Investigator Site

Harvard Medical School - Massachusetts General Hospital Cancer CenterRecruiting

Boston, Massachusetts
Investigator Site

Mayo Clinic - RochesterRecruiting

Rochester, Minnesota
Investigator Site

Memorial Sloan Kettering Cancer CenterRecruiting

New York, New York
Investigator Site

University of North Carolina Chapel HillRecruiting

Chapel Hill, North Carolina
Investigator Site

Fred Hutchinson Cancer Research CenterRecruiting

Seattle, Washington
Investigator Site record

NCT04995653. First posted on 8/9/21

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