Stem Cell Mobilization and Apheresis for Life-threatening Blood Disorders

The purpose of this study is to investigate mobilization and collection of HSPCs in patients with bone marrow failure syndromes (BMFS) using granulocyte-colony stimulating factor (otherwise known as Filgrastim) with plerixafor to demonstrate safety and feasibility of collecting HSPCs to advance gene therapy.

Primary objective:

- To characterize the safety of Filgrastim plus plerixafor in participants with bone marrow failure syndromes as determined by the incidence of adverse events (AEs).

Secondary Objectives:

• To characterize the feasibility of HSPC mobilization using Filgrastim plus plerixafor as determined by peripheral blood CD34+ counts.
• To measure the mobilization effects of Filgrastim plus plerixafor in the peripheral blood in participants as determined by peak peripheral blood CD34+ counts.
• To estimate efficacy of Filgrastim plus plerixafor for HSPC mobilization and apheresis collection in participants as determined by the yield of CD34+ cells (CD34+ cells/kg).

Study Overview

• Status: Not yet recruiting
• Conditions: Bone Marrow Failure Syndrome
• Intervention / Treatment: Drug: Filgrastim; Drug: Plerixafor; Procedure: Leukapheresis

Detailed Description

This is a phase I, open-label, single-center study to evaluate the safety of Filgrastim plus plerixafor stem cell mobilization and apheresis in patients with BMFS. This study will include a screening period with labs, physical examination, and bone marrow evaluation at least 6 months prior to mobilization and apheresis, an intervention period that includes mobilization and apheresis of patient HSPCs, and outpatient follow-up within 7-10 days after intervention. Study staff will follow up with the participant via telephone approximately 30 days after mobilization and apheresis. A bone marrow evaluation will be done within 6 months post-intervention.

• Study Type: Interventional
• Enrollment (Estimated): 12
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Alexis Leonard, MD; Phone Number: 888-226-4343; Email: referralinfo@stjude.org

Study Locations

• United States
  • Tennessee
    • Memphis, Tennessee, United States, 38105-2794
      • Saint Jude Children's Research Hospital
      • Contact: Alexis Leonard, MD; Phone Number: 888-226-4343; Email: referralinfo@stjude.org

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participants with a bone marrow failure syndrome with an identified genetic cause willing to donate autologous HSPCs for advancing gene therapy
• Age ≥ 18 years - 25 years

• The following hematological parameters need to be met (regardless of transfusion or growth factor support)

  • Hb > 8 g/dL
  • ANC > 500/mm3
  • Platelet > 30,000/mm3
• Bone marrow evaluation within the preceding 6 months prior to mobilization and apheresis
• Participants should either have a central venous catheter (CVC) in place, be able to undergo apheresis without requiring a CVC, or agree to having a temporary apheresis catheter placed
• Karnofsky score >80
• Negative serologic tests for syphilis, hepatitis B and C, HIV, and HTLV-1/II
• Female participants of childbearing age should have a negative serum pregnancy test within one week of beginning Filgrastim and plerixafor administration

Exclusion Criteria:

• Participant with sickle cell disease
• Participant who has had a prior autologous or allogeneic HSCT
• Active viral, bacterial, fungal, or parasitic infection
• Total bilirubin >2.5x ULN or transaminases >5x ULN
• Moderate or severe renal failure defined as serum/plasma creatinine >1.5 mg/dL and an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 based on the CKD-Epi equation or the St. Jude equation
• Diagnosis of MDS or other hematologic malignancy
• History of malignancy
• Known allergy to or contraindication for Filgrastim or plerixafor administration, or medications routinely administered during apheresis
• Splenomegaly (size greater than upper limit of normal on examination)
• Any disease or concomitant process that is not compatible with the study as per investigator opinion
• Concomitant treatment with alternative investigational agent or participation in another clinical trial with an investigational drug within 5 half-lives of the investigational agent
• Unwillingness to use a highly effective method of contraception for 1 month after plerixafor or GCSF
• Pregnancy
• Inability or unwillingness of research participant to give written informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• 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: BDSTEM Treatment; Participants in this study will receive a twice daily dose of Filgrastim (GCSF) (5 mcg/kg BID) SQ starting on day 1 for 5 days followed by a single dose of SQ plerixafor (0.24 mg/kg) on day 5 followed by collection of CD34+ HSPCs via apheresis. A portion of cells collected from the participant will be stored as backup to be used toward future gene therapy endeavors. The remaining cells will be donated for research studies

Drug: Filgrastim; Administered twice daily dose starting on day 1 for 5 days.; Drug: Plerixafor; Administered on day 5 via IV.; Procedure: Leukapheresis; Peripheral venous access or through a central venous catheter approximately 4-5 hours after the dose of plerixafor is given.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of treatment-emergent adverse events following filgrastim plus plerixafor administration	Safety will be assessed by the incidence, type, and severity of adverse events occurring after administration of filgrastim plus plerixafor in participants with bone marrow failure syndromes.	From initiation of drug administration through Day +7 to +10 follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants achieving peripheral blood CD34+ counts ≥5 cells/µL	Feasibility of hematopoietic stem and progenitor cell mobilization will be assessed by peripheral blood CD34+ cell counts measured after plerixafor administration and prior to or during apheresis.	From initiation of plerixafor administration through completion of apheresis, or 6 hours after drug administration if apheresis is not performed
Peripheral blood CD34+ kinetics following filgrastim plus plerixafor administration	Peripheral blood CD34+ cell counts will be measured after plerixafor administration and prior to or during apheresis.	After plerixafor administration through completion of apheresis, or 6 hours after drug administration if apheresis is not performed
Observed CD34+ cell yield after 1 blood volume apheresis	CD34+ cell yield (CD34+ cells/kg) collected after processing 1 blood volume during apheresis following filgrastim plus plerixafor administration.	At completion of 1 blood volume apheresis on Day 5
Estimated total CD34+ cell yield from projected full-volume apheresis	Estimated total CD34+ cell yield (CD34+ cells/kg) projected from the observed yield after processing 1 blood volume during apheresis.	At completion of 1 blood volume apheresis on Day 5

Collaborators and Investigators

• Sponsor: St. Jude Children's Research Hospital
• Investigators: Principal Investigator: Alexis Leonard, MD, St. Jude Children's Research Hospital

Publications and helpful links

Helpful Links

• St. Jude Children's Research Hospital
• Clinical Trials Open at St. Jude

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): July 1, 2029

Study Registration Dates

• First Submitted: April 16, 2026
• First Submitted That Met QC Criteria: May 8, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Hematologic Diseases; Bone Marrow Diseases; Hemic and Lymphatic Diseases; Bone Marrow Failure Disorders; Peptides; Amino Acids, Peptides, and Proteins; Proteins; Investigative Techniques; Therapeutics; Clinical Laboratory Techniques; Cytological Techniques; Biological Factors; Carbohydrates; Intercellular Signaling Peptides and Proteins; Glycoproteins; Glycoconjugates; Biological Therapy; Cytapheresis; Blood Component Removal; Leukocyte Reduction Procedures; Cell Separation; Colony-Stimulating Factors; Hematopoietic Cell Growth Factors; Cytokines; Granulocyte Colony-Stimulating Factor; Leukapheresis; Filgrastim; plerixafor
• Other Study ID Numbers: BDSTEM

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant de-identified datasets containing the variables analyzed in the published article will be made available (related to the study primary or secondary objectives contained in the publication). Supporting documents such as the protocol, statistical analyses plan, and informed consent are available through the CTG website for the specific study. Data used to generate the published article will be made available at the time of article publication. Investigators who seek access to individual level de-identified data will contact the computing team in the Department of Biostatistics (ClinTrialDataRequest@stjude.org) who will respond to the data request.
• IPD Sharing Time Frame: Data will be made available at the time of article publication.
• IPD Sharing Access Criteria: Data will be provided to researchers following a formal request with the following information: full name of requestor, affiliation, data set requested, and timing of when data is needed. As an informational point, the lead statistician and study principal investigator will be informed that primary results datasets have been requested.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No