JSP191 Antibody Targeting Conditioning in SCID Patients

A Phase 1/2 Study to Evaluate the Safety, Tolerability, and Efficacy of JSP191 for Hematopoietic Cell Transplantation Conditioning to Achieve Engraftment and Immune Reconstitution in Subjects With SCID

A Phase 1/2 study to evaluate the safety, tolerability, and efficacy of an antibody conditioning regimen, known as JSP191, in patients with Severe Combined Immune Deficiency undergoing blood stem cell transplantation

Study Overview

• Status: Terminated
• Conditions: SCID
• Intervention / Treatment: Biological: Humanized anti-CD117 Monoclonal Antibody (JSP191)

Detailed Description

A Phase 1/2 study to evaluate the safety, tolerability, and efficacy of an antibody conditioning regimen, known as JSP191, in patients with SCID undergoing blood stem cell transplantation. Blood Stem Cell transplantation offers the only potentially curative therapy for SCID.

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 SCID patients exit from the bone marrow.

• Study Type: Interventional
• Enrollment (Actual): 23
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90095
      • UCLA Mattel Children's Hospital
    • Palo Alto, California, United States, 94304
      • Lucile Packard Children's Hospital
    • San Francisco, California, United States, 94158
      • UCSF Benioff's Children's Hospital
  • District of Columbia
    • Washington, District of Columbia, United States, 20010
      • Children's National Medical Center
  • Georgia
    • Atlanta, Georgia, United States, 30322
      • Children's Healthcare of Atlanta
  • Maryland
    • Bethesda, Maryland, United States, 20892
      • National Institutes of Health Clinical Center
  • Minnesota
    • Minneapolis, Minnesota, United States, 55455
      • University of Minnesota
  • New York
    • New York, New York, United States, 10065
      • Memorial Sloan Kettering Cancer Center
  • Ohio
    • Cincinnati, Ohio, United States, 45229
      • Cincinnati Children's Hospital Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 3 years and older (Child)
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

1. Typical SCID as defined by Primary Immune Deficiency Treatment Consortia including but not limited to the following subtypes:

   1. T-, B+, NK-: IL-2Rcγ deficient, JAK3-deficient (no longer enrolling)
   2. T-, B-, NK+: RAG1/2 deficient, Artemis-deficient
   3. T-, B+, NK+: IL7Rα deficient, CD3 subunit deficient, CD45 deficient (no longer enrolling) OR Variant SCID with absent or low T cell function, Omenn syndrome, Leaky SCID, Reticular dysgenesis, Adenosine deaminase deficiency, and Purine nucleoside phosphorylase deficiency may be included after consultation with the medical monitor.
2. Patients with human leukocyte antigen (HLA) matched related or unrelated donors
3. Adequate end organ function as defined in study protocol
4. Age ≤ 12 years
5. Prior donor of appropriate age (≥ 5 years old) available for re-collection of stem cells
6. Previous allogeneic Hematopoietic Cell Transplantation HCT (≥ 6 months post initial transplant) with poor graft function

Key Exclusion Criteria:

1. Patients with any acute or uncontrolled infections
2. Patients receiving any other investigational agents, or concurrent biological, chemotherapy, or radiation therapy
3. Patients with active malignancies
4. Active GVHD within 6 months prior to enrollment, or on immunosuppressive therapy for GVHD

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Blood Stem Cell Transplant w/ anti-CD117 conditioning; The study will enroll two groups: Group A: previously transplanted SCID patients; Group B: newly diagnosed SCID. The study plans to assess JSP191 in different dose cohorts. Patients 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.

Biological: Humanized anti-CD117 Monoclonal Antibody (JSP191); Procedure: single intravenous infusion of JSP191 antibody

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phase 1: Safety and tolerability of JSP191 as conditioning therapy in SCID patients undergoing HCT: adverse events	The number of subjects experiencing dose limiting toxicities including adverse events and serious adverse events will be assessed.	Up to 5 years post Donor Cell Transplant (28 days dose limiting toxicity period)
Phase 2: Efficacy of JSP191 as conditioning therapy in SCID patients	To enable engraftment of allogeneic CD34+ hematopoietic cells, as determined by CD15+ donor myeloid chimerism	Up to 24 weeks post Donor Cell Transplant
Phase 2: Efficacy of JSP191 as conditioning therapy in SCID patients	To enable immune reconstitution, as determined by the production of naive T cells	Weeks 36-104 post Donor Cell Transplant

Collaborators and Investigators

• Sponsor: Jasper Therapeutics, Inc.
• Investigators: Principal Investigator: Neena Kapoor, M.D., Children's Hospital Los Angeles; Principal Investigator: Rajni A. Agarwal-Hashmi, M.D., Lucile Packard Children's Hospital; Principal Investigator: Christopher C. Dvorak, M.D., UCSF Benioff's Children's Hospital; Principal Investigator: Joseph H. Oved, M.D., Memorial Sloan Kettering Cancer Center; Principal Investigator: Sharat Chandra, M.D., Children's Hospital Medical Center, Cincinnati; Principal Investigator: Christen L Ebens, M.D., MPH, University of Minnesota; Principal Investigator: Harry L Malech, M.D., National Institutes of Health Clinical Center (CC); Principal Investigator: Shanmuganathan Chandrakasan, M.D., Children's Healthcare of Atlanta; Principal Investigator: Elizabeth D Hicks, M.D., Children's National Research Institute; Principal Investigator: Susan Prockop, M.D., Boston Children's Hospital; Principal Investigator: Theodore B. Moore, M.D., University of California, Los Angeles

Study record dates

Study Major Dates

• Study Start (Actual): March 20, 2017
• Primary Completion (Actual): July 7, 2025
• Study Completion (Actual): July 7, 2025

Study Registration Dates

• First Submitted: November 2, 2016
• First Submitted That Met QC Criteria: November 9, 2016
• First Posted (Estimated): November 15, 2016

Study Record Updates

• Last Update Posted (Actual): July 28, 2025
• Last Update Submitted That Met QC Criteria: July 23, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Keywords: Pediatric; Stem Cells; Immunodeficiency; Transplant; BMT; Bone Marrow Transplantation; GVHD; Chimerism; SCID
• Additional Relevant MeSH Terms: Primary Immunodeficiency Diseases; Genetic Diseases, Inborn; Metabolic Diseases; Immune System Diseases; Infant, Newborn, Diseases; Immunologic Deficiency Syndromes; DNA Repair-Deficiency Disorders; Severe Combined Immunodeficiency; Immunologic Factors; Physiological Effects of Drugs; Antibodies; Antibodies, Monoclonal
• Other Study ID Numbers: JAS-BMT-CP-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Data collected is for future publication

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No