Autologous CD34+ Hematopoietic Stem Cells Transduced ex Vivo With Elongation Factor 1 Alpha Shortened (EFS) Lentiviral Vector Encoding for the Human ADA Gene

Study Overview
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Brief Summary
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The aim of this study is to assess the safety and efficacy of autologous transplantation of hematopoietic stem cells (CD34+ cells) from the bone marrow (BM) of ADA-deficient SCID infants and children following human ADA cDNA transfer by the EFS-ADA lentiviral vector. The level of gene transfer in blood cells and immune function will be measured as endpoints.

Detailed Description
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The study is open to twenty (20) infants and children diagnosed with ADA-deficient SCID who did not have a medically eligible, human leukocyte antigen (HLA)-identical sibling donor for bone marrow transplantation. The EFS-ADA lentiviral vector with the human ADA cDNA will be used to transduce autologous CD34+ cells from the bone marrow of these subjects. The subjects will receive 4 mg/kg busulfan prior to re-infusion of their gene-modified cells. Safety is the primary endpoint. During the follow-up phase, the investigators aim to determine whether the cells could engraft and produce mature cells that contain and express the corrected ADA gene in the absence of pegademase bovine (PEG-ADA) enzyme replacement therapy (ERT), which will be withheld at Day +30 following transplant. Efficacy studies to evaluate the level of immune reconstitution, will be performed in the first and second years of the study.

Official Title
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Autologous Transplantation of Bone Marrow CD34+ Stem/Progenitor Cells After Addition of a Normal Human ADA Complementary DNA (cDNA) by the EFS-ADA Lentiviral Vector for Severe Combined Immunodeficiency Due to Adenosine Deaminase Deficiency (ADA-SCID)

Conditions
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ADA-SCID

Intervention / Treatment
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* Genetic: Infusion of autologous EFS-ADA LV CD34+ (OTL-101)
* Drug: busulfan
* Drug: PEG-ADA ERT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: -Children ≥ 1.0 months of age with a diagnosis of ADA-deficient SCID based on A. Decreased ADA enzymatic activity in erythrocytes, leukocytes, skin fibroblasts, or in cultured fetal cells to levels consistent with ADA-deficient SCID as determined by reference laboratory or confirmed ADA gene mutation(s) known to cause disease , AND B. Evidence of severe combined immunodeficiency based on either: Family history of first order relative with ADA deficiency and clinical and laboratory evidence of severe immunologic deficiency, OR Evidence of severe immunologic deficiency in subject prior to institution of immune restorative therapy, based on lymphopenia (absolute lymphocyte count <400 cells/mcL) OR absence or low number of T cells (absolute CD3+ count <300 cells/mcL) OR severely decreased T lymphocyte blastogenic responses to phytohemagglutinin (either <10% of lower limit of normal controls for the diagnostic laboratory, <10% of the response of the normal control of the day, or stimulation index <10) Ineligible for matched sibling allogeneic bone marrow transplantation: absence of a medically eligible HLA-identical sibling, with normal immune function, who may serve as an allogeneic bone marrow donor Signed written informed consent according to guidelines of the Institutional Review Board (IRB) (UCLA Office of Human Research Protection Program and National Human Genome Research Institute (NHGRI) IRB Exclusion Criteria: Age ≤ 1.0 months Appropriate organ function as outlined below must be observed within 60 days of entering this trial. Hematologic Anemia (hemoglobin < 10.5 g/dl at < 2 years of age, or < 11.5 g/dl at > 2 years of age). Neutropenia (absolute granulocyte count <500/mm3. Thrombocytopenia (platelet count < 150,000/mm3, at any age). International Normalised Ratio (INR) or Prothrombin Time (PT) > 2 times the upper limits of normal or Partial Thromboplastin Time (PTT) > 2.33 times the upper limit of normal (patients with a correctable deficiency controlled on medication will not be excluded). Cytogenetic abnormalities on peripheral blood or bone marrow or amniotic fluid (if available). Prior allogeneic Hematopoietic Stem Cell Transplant (HSCT) with cytoreductive conditioning Infectious a. Evidence of infection with HIV-1, hepatitis B, Hepatitis C, or parvovirus B 19 by DNA Polymerase Chain Reaction (PCR) within 90 days prior to bone marrow harvest. If other infection is present, it must be under control (e.g. stable or decreasing viral load) at the time of screening Pulmonary Resting O2 saturation by pulse oximetry < 95% on room air. Chest x-ray indicating active or progressive pulmonary disease. Cardiac Abnormal electrocardiogram (EKG) indicating cardiac pathology. Uncorrected congenital cardiac malformation with clinical symptomatology. Active cardiac disease, including clinical evidence of congestive heart failure, cyanosis, hypotension. Poor cardiac function as evidenced by LV ejection fraction < 40% on echocardiogram. Neurologic Significant neurologic abnormality by examination. Uncontrolled seizure disorder. Renal Renal insufficiency: serum creatinine >= 1.2 mg/dl, or >= 3+ proteinuria. Abnormal serum sodium, potassium, calcium, magnesium, phosphate at grade III or IV by Division of AIDS Toxicity Scale. Hepatic/GI: Serum transaminases > 5 times the upper limit of normal (ULN). Serum bilirubin > 2 times ULN. Serum glucose > 1.5 times ULN. Intractable severe diarrhea. Oncologic Evidence of active malignant disease other than dermatofibrosarcoma protuberans (DFSP) Evidence of DFSP expected to require anti-neoplastic therapy within the 5 years following the infusion of genetically corrected cells Evidence of DFSP expected to be life limiting within the 5 years following the infusion of genetically corrected cells Known sensitivity to Busulfan General Expected survival < 6 months. Pregnant. Major congenital anomaly. Ineligible for autologous HSCT by the criteria at the clinical site. Other conditions which in the opinion of the principal investigator and/or co-investigators, contra-indicate the bone marrow harvest, the administration of busulfan, infusion of transduced cells or indicate the patient or patient's parents/primary caregivers inability to follow protocol.

Ages Eligible for Study
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Minimum Age: 1 Month
Maximum Age: 17 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Gene Therapy<br>Infusion of autologous EFS-ADA Lentiviral (LV) CD34+ cells | Genetic: Infusion of autologous EFS-ADA LV CD34+ (OTL-101)<br>* autologous EFS-ADA LV CD34+ cells (OTL-101) are infused intravenously<br>* Other names: OTL-101;Drug: busulfan<br>* Busulfan is used for non-myeloablative conditioning<br>Drug: PEG-ADA ERT<br>* PEG-ADA ERT is discontinued at Day +30 (-3/+15 days) after successful engraftment<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Survival (OS) of Subjects Treated With Investigational Medicinal Product (IMP) (1 Year) | Overall survival is defined as the percentage of subjects alive at 12 months post- treatment with OTL-101 or HSCT | 12 months | 
| Event-free Survival (EvFS) of Subjects Treated With Investigational Medicinal Product (IMP) (1 Year) | Event-free survival is defined as the percentage of subjects alive with no event, an event being the resumption of PEG-ADA ERT or the need for a rescue allogeneic Hematopoietic Stem Cell Transplant (HSCT), or death. | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| OS of Subjects Treated With Investigational Medicinal Product (IMP) (2 Years) | OS is defined as the percentage of subjects alive at 24 months post- treatment with OTL-101 or HSCT | 24 months | 
| EvFS of Subjects Treated With Investigational Medicinal Product (IMP) (2 Years) | Event-free survival is defined as the percentage of subjects alive with no event, an event being the resumption of PEG-ADA ERT or the need for a rescue allogenic Hematopoietic Stem Cell Transplant (HSCT), or death. | 24 months | 
| Vector Copy Number (VCN) in Peripheral Blood (PB) Granulocytes. | Vector copy number in the PB granulocyte fraction that was T cell depleted, is a surrogate for amount of engrafted genetically modified Hematopoietic stem cell (HSC) that are producing granulocytes every 3-5 days. VCN analysis was performed by Droplet Digital PCR (ddPCR) on DNA extracted from peripheral blood granulocytes. | 24 months | 
| VCN in Peripheral Blood Mononuclear Cells (PBMCs) | PBMC VCN is a measure of the accumulation of peripheral blood leukocytes arising from engrafted, genetically modified HSC. VCN analysis was performed by ddPCR on DNA extracted from PBMC. | 24 months | 
| ADA Activity in Erythrocytes | ADA enzyme activity measured to assess the amount of functional gene product produced from the normal ADA transgene delivered by EFS-ADA LV; persistence of ADA enzyme activity over time demonstrates successful engraftment and differentiation of genetically modified HSC. | 24 months | 
| Reduction in Deoxyadenosine Nucleotide (dAXP) in Erythrocytes | Decreased dAXP levels coincide with increased ADA enzyme activity, detoxification was used to demonstrate functional ADA enzyme production from the introduced ADA transgene. The threshold for detoxification was <100 μmol/L. | 24 months | 
| Change From Baseline in CD3+ T Cell Counts (2 Years) | Immune reconstitution was assessed by change in CD3+ T Cell counts at baseline to Month 24. | 24 months | 
| Number of Single Integration Sites Representing >30% of the Total Integration Sites (2 Years) | Vector Integration Site Analysis (VISA) allowed determination of the distribution of vector integration sites in each subject's genome, as well as the relative clonal abundance. VISA was to be considered abnormal for a subject if, in 2 or more instances during the course of follow-up, a single integration site was found to represent >30% of the total integration sites detected. | 24 months | 
| Severe Infection Rate Excluding the First Three Months After Treatment | The infections of interest in this study were severe infections or opportunistic infectious episodes, defined as infections requiring hospitalization or prolonging hospitalization and/or documented infections by opportunistic pathogens. Infections that took place in the first 3 months of follow-up post treatment were excluded from calculations to avoid possible bias introduced in the data by the effects of conditioning. | 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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gene therapy, hematopoietic stem cell, ADA-SCID, lentiviral vector