MYELODYSPLASTIC SYNDROME; MDSPhase 1NCT04429191
JSP191 Antibody Conditioning Regimen in MDS/AML Subjects Undergoing Allogenic Hematopoietic Stem Cell Transplantation
A Phase 1 study testing Humanized anti-CD117 Monoclonal Antibody (JSP191) in people with MYELODYSPLASTIC SYNDROME; MDS and ACUTE MYELOID LEUKEMIA; AML, run by Jasper Therapeutics, Inc. at 6 sites in United States.
Trial summary
This is a Phase 1a/b study to evaluate the safety and tolerability of an antibody conditioning regimen known as JSP191, in combination with low dose radiation and fludarabine, in subjects with Myelodysplastic Syndrome (MDS) or Acute Myeloid Leukemia (AML) undergoing allogenic blood stem cell transplantation. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- MYELODYSPLASTIC SYNDROME; MDS, ACUTE MYELOID LEUKEMIA; AML
- What is being tested?
- Humanized anti-CD117 Monoclonal Antibody (JSP191)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 32 participants
- Where
- 6 sitesUnited States
- Study dates
- 8 Jul 2020to 13 Jun 2023
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- AML/MDS as defined by specific criteria, including but not limited to the following subtypes:
- AML in CR
- MDS < 5% BM blasts
- MDS 5 - 10% BM blasts
- AML not in CR or MDS > 10% BM blasts
- Patients with human leukocyte antigen (HLA) matched related or unrelated donors
- Adequate end organ function as defined in study protocol
Who cannot join
- Patients with any acute or uncontrolled infections
- Patients receiving any other investigational agents
- Patients with active non-hematologic malignancy
- Prior allogeneic hematologic cell transplantation
Trial locations and contacts
6 sites in 1 country.
6 sites in 1 country
United States6 sites
Rush University Medical Center
Chicago, Illinois, 60612
City of Hope Comprehensive Cancer Center
Duarte, California, 91010
Oregon Health & Science University
Portland, Oregon, 97239
Huntsman Cancer Institute - University of Utah
Salt Lake City, Utah, 84112
Fred Hutchinson Cancer Research Center
Seattle, Washington, 98109
Stanford University
Stanford, California, 94305
About this study
Official title: A Phase 1a/b Study to Evaluate the Safety & Tolerability of JSP191 in Combination With a Regimen of Low Dose Radiation & Fludarabine in Subjects With MDS or AML Undergoing Hematopoietic Cell Transplantation (HCT)
This is a Phase 1a/b study to evaluate the safety and tolerability of an antibody conditioning regimen known as JSP191, in combination with low dose radiation and fludarabine, in subjects with Myelodysplastic Syndrome (MDS) or Acute Myeloid Leukemia (AML) undergoing allogenic blood stem cell transplantation.
Read the detailed description
This is a Phase 1a/b study to evaluate the safety and tolerability of an antibody conditioning regimen known as JSP191, in combination with low dose radiation and fludarabine in subjects with Myelodysplastic Syndrome (MDS) or Acute Myeloid Leukemia (AML) undergoing allogenic blood stem cell transplantation.
Blood Stem Cell transplantation offers the only potentially curative therapy for many forms of Acute Myeloid Leukemia (AML) and for Myelodysplastic Syndrome (MDS). While standard of care conditioning regimens given prior to blood Stem Cell transplantation, such as standard TBI/Flu conditioning are well tolerated, they are associated with increased rates of relapse due to persistence of disease causing Hematopoietic Stem Cells and insufficient graft versus leukemia effect.
The biological conditioning regimen JSP191 is an antibody that binds to CD117. CD117 is the receptor for Stem Cell Factor on blood forming cells. CD117 binding to Stem Cell Factor is critical for survival and maintenance of blood forming stem cells.
The binding of JSP191 to CD117 blocks CD117 from binding to Stem Cell Factor on blood forming stem cells. In the absence of CD117/Stem Cell Factor binding, hematopoietic stem cells that are currently occupying the bone marrow niches in MDS/AML patients are depleted.
This study will investigate the safety and tolerability of adding JSP191 (an anti-CD117 monoclonal antibody therapy) to standard TBI/Flu conditioning regimen in adults with AML and MDS undergoing hematopoietic stem cell transplant.
- Being tested
- Humanized anti-CD117 Monoclonal Antibody (JSP191)
- Keywords
- ACUTE MYELOID LEUKEMIA, AML, MDS, MYELODYSPLASTIC SYNDROME
- Medical subject headings
- Anemia, Refractory, with Excess of Blasts, Leukemia, Myeloid, Acute, Myelodysplastic Syndromes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Humanized anti-CD117 Monoclonal Antibody (JSP191)Biological
Also called JSP191
Procedure: single intravenous infusion of JSP191 antibody
| Study group | Role | What they receive |
|---|---|---|
| Blood Stem Cell Transplant w/ anti-CD117 conditioning | Experimental | The phase 1a portion of the study plans to assess approximately 3 planned dose cohorts of JSP191: 0.3 mg/kg, 0.6 mg/kg, and 1.0 mg/kg to determine the maximum tolerated dose for expansion. Subjects will receive a single dose of intravenous JSP191 antibody followed by monitoring for antibody clearance. Once the antibody has cleared below a certain level, patients will receive stem cell transplant and be monitored for hematopoietic recovery.
The phase 1b portion of the study will enroll additional subjects at the expansion dose in order to further explore the safety, feasibility, and PK of that dose. Receives: Biological: Humanized anti-CD117 Monoclonal Antibody (JSP191) |
What is being measured
The primary outcome is the main question the study is designed to answer.
The number of subjects experiencing adverse events and serious adverse events will be assessed.
The number of subjects experiencing adverse events and serious adverse events will be assessed.
Measured: Up to 1 year post Donor Cell Transplant (28 days dose limiting toxicity period)
The number of dose limiting toxicities will be assessed.
The number of dose limiting toxicities will be assessed.
Measured: Up to 1 year post Donor Cell Transplant (28 days dose limiting toxicity period)
The type of dose limiting toxicities will be assessed.
The type of dose limiting toxicities will be assessed.
Measured: Up to 1 year post Donor Cell Transplant (28 days dose limiting toxicity period)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Jun 2020
- Study start8 Jul 2020
- Primary completion13 Jun 2023
- Study completion13 Jun 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for MYELODYSPLASTIC SYNDROME; MDSStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 32 participants (actual)
Sponsor and investigators
- Lead sponsor
- Jasper Therapeutics, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Lori Muffly, MD,MS, Principal investigator, Stanford UniversityAndrew Artz, MD,MS, Principal investigator, City of Hope Medical CenterBart Scott, MD, Principal investigator, Fred Hutchinson Cancer CenterCatherine Lee, MD, Principal investigator, Huntsman Cancer InstituteArpita Gandhi, MD, Principal investigator, Oregon Health and Science UniversityAnkur Varma, MD,PhD, Principal investigator, Rush University Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04429191
- Sponsor's protocol ID
- JSP-CP-003
- Status last verified
- Sep 2026
- First submitted
- 10 Jun 2020
- Last updated
- 28 Sep 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Muffly L, Lee CJ, Gandhi A, Varma A, Scott BL, Patel SS, Shiraz P, Youn M, Yanagiba C, Arulprakasam J, Le A, Kwon HS, Long-Boyle J, Shizuru JA, Pang WW, Artz AS. Nonmyeloablative conditioning combined with the anti-CD117 antibody briquilimab in older adults with high-risk AML and MDS. Blood. 2026 May 28;147(22):2610-2620. doi: 10.1182/blood.2025031858.
PubMed 41785374
Study at a glance
From the registry record, last updated by the sponsor on 28 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1a/b Study to Evaluate the Safety & Tolerability of JSP191 in Combination With a Regimen of Low Dose Radiation & Fludarabine in Subjects With MDS or AML Undergoing Hematopoietic Cell Transplantation (HCT)
- ClinicalTrials.gov ID
- NCT04429191
- Acronym / sponsor ID
- JSP-CP-003
- Keywords
- ACUTE MYELOID LEUKEMIA, AML, MDS, MYELODYSPLASTIC SYNDROME
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 32 participants (actual)
- Lead sponsor
- Jasper Therapeutics, Inc.Industry (pharma, biotech, devices)
- Study start
- 8 Jul 2020 (actual)
- Primary completion
- 13 Jun 2023 (actual)
- Study completion
- 13 Jun 2023 (actual)
- First posted
- 12 Jun 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a Phase 1a/b study to evaluate the safety and tolerability of an antibody conditioning regimen known as JSP191, in combination with low dose radiation and fludarabine, in subjects with Myelodysplastic Syndrome (MDS) or Acute Myeloid Leukemia (AML) undergoing allogenic blood stem cell transplantation.
Detailed description
This is a Phase 1a/b study to evaluate the safety and tolerability of an antibody conditioning regimen known as JSP191, in combination with low dose radiation and fludarabine in subjects with Myelodysplastic Syndrome (MDS) or Acute Myeloid Leukemia (AML) undergoing allogenic blood stem cell transplantation.
Blood Stem Cell transplantation offers the only potentially curative therapy for many forms of Acute Myeloid Leukemia (AML) and for Myelodysplastic Syndrome (MDS). While standard of care conditioning regimens given prior to blood Stem Cell transplantation, such as standard TBI/Flu conditioning are well tolerated, they are associated with increased rates of relapse due to persistence of disease causing Hematopoietic Stem Cells and insufficient graft versus leukemia effect.
The biological conditioning regimen JSP191 is an antibody that binds to CD117. CD117 is the receptor for Stem Cell Factor on blood forming cells. CD117 binding to Stem Cell Factor is critical for survival and maintenance of blood forming stem cells.
The binding of JSP191 to CD117 blocks CD117 from binding to Stem Cell Factor on blood forming stem cells. In the absence of CD117/Stem Cell Factor binding, hematopoietic stem cells that are currently occupying the bone marrow niches in MDS/AML patients are depleted.
This study will investigate the safety and tolerability of adding JSP191 (an anti-CD117 monoclonal antibody therapy) to standard TBI/Flu conditioning regimen in adults with AML and MDS undergoing hematopoietic stem cell transplant.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Blood Stem Cell Transplant w/ anti-CD117 conditioning | Experimental | Biological: Humanized anti-CD117 Monoclonal Antibody (JSP191)The phase 1a portion of the study plans to assess approximately 3 planned dose cohorts of JSP191: 0.3 mg/kg, 0.6 mg/kg, and 1.0 mg/kg to determine the maximum tolerated dose for expansion. Subjects will receive a single dose of intravenous JSP191 antibody followed by monitoring for antibody clearance. Once the antibody has cleared below a certain level, patients will receive stem cell transplant and be monitored for hematopoietic recovery. The phase 1b portion of the study will enroll additional subjects at the expansion dose in order to further explore the safety, feasibility, and PK of that dose. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- AML/MDS as defined by specific criteria, including but not limited to the following subtypes:
- Patients with human leukocyte antigen (HLA) matched related or unrelated donors
- Adequate end organ function as defined in study protocol
Key exclusion criteria (4 listed)
- Patients with any acute or uncontrolled infections
- Patients receiving any other investigational agents
- Patients with active non-hematologic malignancy
- Prior allogeneic hematologic cell transplantation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Humanized anti-CD117 Monoclonal Antibody (JSP191)Also: JSP191Procedure: single intravenous infusion of JSP191 antibody | Biological | Blood Stem Cell Transplant w/ anti-CD117 conditioning |
Primary outcome
The number of subjects experiencing adverse events and serious adverse events will be assessed.
Time frame: Up to 1 year post Donor Cell Transplant (28 days dose limiting toxicity period)
The number of subjects experiencing adverse events and serious adverse events will be assessed.
The number of dose limiting toxicities will be assessed.
Time frame: Up to 1 year post Donor Cell Transplant (28 days dose limiting toxicity period)
The number of dose limiting toxicities will be assessed.
The type of dose limiting toxicities will be assessed.
Time frame: Up to 1 year post Donor Cell Transplant (28 days dose limiting toxicity period)
The type of dose limiting toxicities will be assessed.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Sep 2026.
- Derived from this study: PubMed 41785374Muffly L, Lee CJ, Gandhi A, Varma A, Scott BL, Patel SS, Shiraz P, Youn M, Yanagiba C, Arulprakasam J, Le A, Kwon HS, Long-Boyle J, Shizuru JA, Pang WW, Artz AS. Nonmyeloablative conditioning combined with the anti-CD117 antibody briquilimab in older adults with high-risk AML and MDS. Blood. 2026 May 28;147(22):2610-2620. doi: 10.1182/blood.2025031858.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Lori Muffly, MD,MS principal investigator
Stanford University
Andrew Artz, MD,MS principal investigator
City of Hope Medical Center
Bart Scott, MD principal investigator
Fred Hutchinson Cancer Center
6 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Humanized anti-CD117 Monoclonal Antibody (JSP191) in people with MYELODYSPLASTIC SYNDROME; MDS and ACUTE MYELOID LEUKEMIA; AML, run by Jasper Therapeutics, Inc. at 6 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 28 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 6 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The number of subjects experiencing adverse events and serious adverse events will be assessed. (time frame: Up to 1 year post Donor Cell Transplant (28 days dose limiting toxicity period)). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04429191, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Sep 2026.