ClinicalTrials.gg
RecruitingNCT07216443Updated Jul 7, 2026

Trial of Orca-T Following Reduced Intensity or Nonmyeloablative Conditioning in Patients With Acute Myeloid Leukemia or Myelodysplastic Syndrome

A Phase 2 interventional study of Orca-T in Leukemia, Myeloid, Acute, Myelodysplastic Syndromes and Mixed Phenotype Acute Leukemia, sponsored by Orca Biosystems, Inc.. Recruiting at 6 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-07.

Sponsored by Orca Biosystems, Inc. · Phase 2, Interventional, and Treatment

From the registry’s dates

  • Started Dec 2025; still recruiting 11 months later.
Phase
Phase 2
Study type
Interventional
Enrollment
80
Allocation
Non-randomized
Ages
18 Years and older
Sex
All
01

Study summary

This study will evaluate the safety, tolerability, and efficacy of Orca-T in participants undergoing reduced intensity or non-myeloablative allogeneic hematopoietic cell transplantation (alloHCT) for hematologic malignancies. Orca-T is an allogeneic stem cell and T-cell immunotherapy biologic manufactured for each patient (transplant recipient) from the mobilized peripheral blood of a specific, unique donor. It is composed of purified hematopoietic stem and progenitor cells (HSPCs), purified regulatory T cells (Tregs), and conventional T cells (Tcons).

Read the detailed description

This study is a multicenter, open-label phase 2 trial of Orca-T in adults with acute myeloid leukemia or myelodysplastic syndrome who are not able to receive myeloablative (high intensity) conditioning and are eligible for reduced intensity conditioning (RIC)-alloHCT or non-myeloablative (NMA)-alloHCT with an 8/8 human leukocyte antigen (HLA)-matched related or unrelated donor. The trial is designed to further characterize the safety and tolerability of Orca-T and to perform an initial assessment of the efficacy of Orca-T in participants eligible for RIC-alloHCT or NMA-alloHCT.

Participants will receive Orca-T after the investigator's choice from the RIC and NMA regimens followed by single-agent graft-versus-host disease (GVHD) prophylaxis with tacrolimus.

Prior to the initiation of this study (the SERENE-T Study), a phase 1 study (clinicaltrials.gov number: NCT05088356) was conducted to examine the safety and efficacy of Orca-T in participants receiving RIC-alloHCT. Participants have also been treated previously with Orca-T during an ongoing phase 1b/3 study (NCT05316701 and NCT04013685) in participants receiving a MAC regimen. The results of these studies have prompted Orca Bio to further evaluate Orca-T in participants receiving RIC or NMA.

02

Conditions studied

  • Leukemia, Myeloid, Acute
  • Myelodysplastic Syndromes
  • Mixed Phenotype Acute Leukemia

Keywords

  • Leukemia, Myeloid, Acute
  • Myelodysplastic Syndromes
  • Mixed Phenotype Acute Leukemia
  • Therapy-Related Myelodysplastic Syndrome
  • Hematopoietic Stem Cell Transplantation
  • Humans
  • Graft vs Host Disease
  • SERENE-T
  • ORCA-T
  • Disease
  • Pathologic Processes
  • Neoplasms by Histologic Type
  • Neoplasms
  • Hematologic Diseases
  • Bone Marrow Diseases
  • Precancerous Conditions
  • Neoplasms by Site
  • Disease Attributes
  • Immunoproliferative Disorders
  • Immune System Diseases
  • Leukemia
  • Preleukemia
  • Hematologic Neoplasms
  • Syndrome
  • Acute Disease
03

In context

Leukemia, Myeloid, Acute

3,667 studies on the registry are indexed under Leukemia, Myeloid, Acute; 816 are open to participants now.

This study's planned enrollment of 80 is above the median of 40 across 3,005 interventional studies indexed under Leukemia, Myeloid, Acute.

Browse Leukemia, Myeloid, Acute studies →

Lead sponsor

Orca Biosystems, Inc. is the lead sponsor of 5 studies on the registry; 3 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Age ≥18 years at the time of enrollment
  2. Diagnosed with 1 of the following diseases:

    1. Acute myeloid, or mixed phenotype leukemia in complete remission (CR) or CR with incomplete hematologic recovery (CRi), with or without the presence of known minimal residual disease.
    2. Myelodysplastic syndrome that is indicated for alloHCT per the 2017 International Expert Panel recommendations and/or therapy-related/secondary MDS as defined by the World Health Organization (WHO) classification of myeloid , with ≤10% blast burden in the bone marrow.
  3. Planned to undergo 1 of the following preparative regimens as per Investigator discretion:

    1. RIC cohort: Planned RIC-alloHCT including RIC regimen with TBI/thiotepa/fludarabine
    2. NMA cohort: Planned NMA-alloHCT including NMA regimen with fludarabine/cyclophosphamide/TBI
  4. Identified related or unrelated donor who is an 8/8 match for HLA-A, -B, -C, and -DRB1
  5. Estimated ≥30 mL/minute
  6. Cardiac at rest ≥40% or shortening fraction of ≥22% by echocardiogram or radionuclide scan (MUGA)
  7. Diffusing capacity of the lung for carbon monoxide (adjusted for ) ≥40%
  8. Negative serum or urine β-HCG test in persons of
  9. (ALT)/aspartate transaminase (AST) \<5 times the (ULN)
  10. Total \<3 × ULN
  11. Deemed ineligible for a fully myeloablative alloHCT per assessment of the principal investigator

Exclusion criteria

Exclusion Criteria:

  1. Prior alloHCT
  2. Currently receiving or other therapy. Topical corticosteroids or oral systemic corticosteroid doses less than or equal to 10 mg/day are allowed.
  3. Planned donor lymphocyte infusion (DLI)
  4. Planned pharmaceutical in vivo or ex vivo T-cell depletion
  5. Recipient-positive antidonor HLA antibodies against a mismatched allele in the selected donor
  6. performance score \<60%
  7. For RIC cohort only: HCT-Specific Comorbidity Index (HCT-CI) ≥6
  8. Uncontrolled bacterial, viral, or fungal infection (currently taking antimicrobial therapy and with progression or no clinical improvement) at the time of enrollment
  9. Seropositive for -1 or -2, HTLV-1 or -2, surface antigen, or antibody unless previously treated with curative therapy and are HCV NAT negative
  10. Known allergy or to or intolerance of tacrolimus
  11. Documented allergy or hypersensitivity to iron dextran or bovine, murine, algal, or Streptomyces avidinii proteins
  12. Any uncontrolled disease requiring active immunosuppressive treatment
  13. Concurrent within 1 year except nonmelanoma skin cancer that has been curatively resected
  14. Psychosocial circumstances that preclude the participant being able to go through transplantation or participate responsibly in follow-up care
  15. Persons who are pregnant or breastfeeding
  16. Person of (POCBP) or men who have sexual contact with POCBP who are unwilling to use effective forms of or abstinence for 1 year after transplantation.
  17. Any serious medical condition or abnormality in clinical laboratory tests that, in the investigator's or medical monitor's judgment, precludes the recipient's safe participation in and completion of the trial or which could affect compliance with the protocol or interpretation of results
Terms in these criteria, in plain language(17)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Cancer (malignancy)

Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.

Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.

GFR and eGFR (kidney filtering)

GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².

Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.

LVEF (left ventricular ejection fraction)

The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).

Childbearing potential

Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).

Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

ULN (upper limit of normal)

The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.

“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.

Bilirubin

A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.

Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Karnofsky performance status (KPS)

A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.

Studies often ask for 60 or 70 and above. Your doctor gives the score.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

Hypersensitivity

An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.

Autoimmune disease

A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.

Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Single group
Masking
None (open label)
Enrollment
80 participants (estimated)

Study arms

  • Experimental
    Orca-T

    Participants will receive \[RIC or NMA conditioning\] + Orca-T + single-agent tacrolimus based on eligibility and investigator's choice of conditioning regimen.

    Biological: Orca-T

Interventions

  • BiologicalOrca-T

    An allogeneic stem cell and T-cell immunotherapy biologic

06

What researchers measure

Primary outcomes

  1. RIC Cohort: GVHD-free and relapse-free survival (GRFS)

    GRFS is defined as the time from the date of transplantation to the date of death from any cause, relapse, the first onset of grade 3 or 4 acute GVHD (graded per MAGIC criteria), or the first onset of moderate or severe chronic GVHD (graded per NIH consensus criteria), whichever is earliest.

    Time frame: Day 0 through day +365 after transplantation

  2. NMA Cohort: Incidence of neutrophil engraftment

    Incidence of neutrophil engraftment is defined as achieving an ANC ≥500/mm3 for 3 consecutive days by day +28. The first of the 3 days will be designated the day of engraftment. If the ANC never drops below 500/mm3, day +1 will be designated the day of engraftment.

    Time frame: Day 0 through day +28 after transplantation

  3. NMA Cohort: Time to neutrophil engraftment

    The first of the 3 days will be designated the day of engraftment. If the ANC never drops below 500/mm3, day +1 will be designated the day of engraftment.

    Time frame: Day 0 through day +28 after transplantation

Secondary outcomes

  1. Safety of Orca-T

    The incidence of graft failure, grade ≥3 acute GVHD (per MAGIC criteria), grade ≥4 infection (per CTCAE v5.0), manufacturing failure, and non-relapse mortality for each cohort.

    Time frame: Day 0 through day +100 after transplantation

  2. Incidence of serious infections

    The incidence of grade ≥3 infection (per CTCAE v5.0)

    Time frame: Day 0 through day +365 after transplantation

  3. Severity of serious infection

    The severity of grade ≥3 infection (per CTCAE v5.0)

    Time frame: Day 0 through day +365 after transplantation

  4. Overall survival

    The rate of overall survival for each cohort.

    Time frame: Day 0 through day +730 after transplantation

  5. Non-relapse mortality

    The rate of non-relapse mortality for each cohort

    Time frame: Day 0 through day +730 after transplantation

  6. Relapse-free survival

    The rate of relapse-free survival for each cohort.

    Time frame: Day 0 through day +730 after transplantation

  7. Chronic GVHD-free survival

    The rate of chronic GVHD-free survival for each cohort

    Time frame: Day 0 through day +730 after transplantation

  8. GVHD-free and relapse-free survival (GRFS)

    The rate of GRFS for the NMA cohort.

    Time frame: Day 0 through day +730 after transplantation

  9. Incidence of acute GVHD

    The incidence of acute GVHD (all grades) for each cohort

    Time frame: Day 0 through day +180 after transplantation

  10. Severity of acute GVHD

    The severity of acute GVHD (all grades) for each cohort

    Time frame: Day 0 through day +180 after transplantation

  11. Time to onset of acute GVHD

    Time to first onset of grade 2 through 4 acute GVHD

    Time frame: Day 0 through day +180 after transplantation

  12. Incidence of chronic GVHD

    The incidence of chronic GVHD (all grades)

    Time frame: Day 0 through day +730 after transplantation

  13. Severity of chronic GVHD

    The severity of chronic GVHD (all grades)

    Time frame: Day 0 through day +730 after transplantation

  14. Time to onset of acute GVHD

    Time to first onset of moderate or severe chronic GVHD

    Time frame: Day 0 through day +730 after transplantation

  15. RIC cohort: Incidence of neutrophil engraftment

    The incidence of neutrophil engraftment in the RIC cohort.

    Time frame: Day 0 through day +28 after transplantation

  16. RIC cohort: Time to neutrophil engraftment

    Time to neutrophil engraftment in the RIC cohort.

    Time frame: Day 0 through day +28 after transplantation

  17. Incidence of platelet engraftment

    The incidence of platelet engraftment.

    Time frame: Day 0 through day +50 after transplantation

  18. Time to platelet engraftment

    Time to platelet engraftment.

    Time frame: Day 0 through day +50 after transplantation

  19. Incidence of steroid-refractory acute GVHD

    The incidence of steroid-refractory acute GVHD for each cohort.

    Time frame: Day 0 through day +180 after transplantation

  20. Incidence of steroid-refractory chronic GVHD

    The incidence of steroid-refractory chronic GVHD for each cohort.

    Time frame: Day 0 through day +730 post-transplant

07

Study locations

6 of 6 sites recruiting
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 7, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT07216443
Lead sponsor
Orca Biosystems, Inc.
Responsible party
Sponsor
First posted
Oct 14, 2025
Start date
Dec 9, 2025
Primary completion
Nov 2027 (estimated)
Completion
Dec 2028 (estimated)
Last update
Jul 7, 2026

Study contacts

Chief Medical Officer
Contact
info@orcabio.com
650-246-9601
Medical Director
Contact
info@orcabio.com
650-246-9601

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Interested in this study?

Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.

Contact study team

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Studies of the drug tested here: Partially Engineered T-regulatory Cell Donor Graft TRGFT-201

Start the discussion