NCT05618301

A Pilot Safety and Feasibility Study to Evaluate Motixafortide (CXCR4/SDF-1 Inhibition) and Natalizumab (VLA-4/VCAM-1 Inhibition) as a Novel Regimen to Mobilize CD34+ Hematopoietic Stem Cells for Gene Therapies in Sickle Cell Disease (SCD)

Study Summary

Hematopoietic stem cell (HSC)-based gene therapies now offer curative potential for patients with sickle cell disease (SCD), with decreased toxicity compared to allogeneic hematopoietic cell transplantation. However, effective HSC-based gene therapy depends on collecting sufficient HSCs to generate the therapeutic product, and currently available mobilization regimens carry unacceptable risk for patients with SCD or do not reliably yield optimal numbers of HSCs for gene therapy. The investigators hypothesize that HSC mobilization with motixafortide (CXCR4i) alone and the combination of motixafortide plus natalizumab (VLA-4i) will be safe and tolerable in SCD patients. In addition, the investigators hypothesize that combined CXCR4 and VLA-4 blockade with motixafortide plus natalizumab will result in a rapid, robust, and synergistic increase in HSC mobilization to peripheral blood (PB) in patients with SCD, when compared to motixafortide alone.

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Interventions

MotixafortideDRUG
Motixafortide is to be administered as a subcutaneous injection at a dose of 1.25 mg/kg
NatalizumabDRUG
Natalizumab will be administered as an IV infusion at a flat dose of 300 mg
LeukapheresisPROCEDURE
Leukapheresis consisting of a 1 Blood Volume procedure

Study Locations

FacilityCityStateCountry
Washington University School of MedicineSt LouisMissouriUnited States

Official Trial Information

View on ClinicalTrials.gov

Data sourced from ClinicalTrials.gov. Last updated: April 14, 2026