A Study to Assess the Safety, Tolerability, and Efficacy of ST-400 for Treatment of Transfusion-Dependent Beta-thalassemia (TDT)

Status: Recruiting
DFCI Protocol ID:

This is a single-arm, multi-site, single-dose, Phase 1/2 study to assess ST-400 in 6 subjects with transfusion-dependent β-thalassemia (TDT) who are ≥18 and ≤40 years of age. ST-400 is a type of investigational therapy that consists of gene edited cells. ST-400 is composed of the patient's own blood stem cells which are genetically modified in the laboratory using Sangamo's zinc finger nuclease (ZFN) technology to disrupt a precise and specific sequence of the enhancer of the BCL11A gene (which normally suppresses fetal hemoglobin production in erythrocytes). This process is intended to boost fetal hemoglobin (HbF), which can substitute for reduced or absent adult (defective) hemoglobin, and is done without the use of integrating viral vectors. ST-400 is then infused back into the patient after receiving conditioning chemotherapy to make room for the new cells in the bone marrow, with the aim of producing new erythrocytes with increased amounts of HbF. The primary objective is to understand safety and tolerability of ST-400, and secondary objectives are to assess the effects on HbF levels and transfusion requirements.

Conducting Institutions:

Children's Hospital Boston, Dana-Farber Cancer Institute

Overall PI:

Alessandra Biffi, MD, Boston Children's Hospital

Site-responsible Investigators:


Children's Hospital Boston: Colleen Dansereau, Colleen.dansereau@childrens.harvard.edu

Eligibility Criteria

Inclusion Criteria:

Informed Consent
Clinical diagnosis of TDT with ≥ 8 documented RBC transfusion events per year on an annualized basis in the 2-years prior to screening
Confirmed beta-thalassemia diagnosis by molecular genetic testing
Clinically stable and eligible to receive conditioning chemotherapy
Able and willing to use double barrier method of contraception for at least 3 months prior to ST-400 infusion and through 6 months post-transplant
Exclusion Criteria:

Previous history of autologous or allogeneic blood stem cell transplantation or solid organ transplantation
Pregnant or breastfeeding female
Medical contraindication to apheresis
Significant liver, lung, heart, or kidney dysfunction
Diagnosis of HIV or evidence of active HBV or HCV
History of significant bleeding disorder or uncontrolled seizures
History of active malignancy in past 5 years (non-melanoma skin cancer or cervical cancer in situ permitted)
Currently participating in another clinical trial using an investigational study medication, or recent participation in such a trial
Previous treatment with gene therapy

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