Stem Cell Gene Therapy for Cystinosis
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ClinicalTrials.gov Identifier: NCT03897361 |
Recruitment Status :
Active, not recruiting
First Posted : April 1, 2019
Last Update Posted : March 29, 2023
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Condition or disease | Intervention/treatment | Phase |
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Lysosomal Storage Diseases Cystinosis | Genetic: CTNS-RD-04 or CTNS-RD-04-LB (where the suffix "-LB" stands for LentiBOOST) | Phase 1 Phase 2 |
Cystinosis is a rare inherited recessive disease belonging to the family of Lysosomal Storage Disorders and is characterized by lysosomal accumulation of cystine in all the cells of the body leading to multi-organ failure. Cystinosis has a devastating impact on the affected individuals, primarily children, and young adults, even with cysteamine treatment. The prevalence of cystinosis is 1 in 100,000 to 1 in 200,000. The gene involved in cystinosis is the gene CTNS that encodes for the transmembrane lysosomal cystine transporter - cystinosin. The current standard of care does not prevent the progression of the disease and significantly impacts the quality of life of patients with cystinosis.
For this study, up to 6 subjects meeting eligibility criteria will be transplanted following a 3-cohort staggered treatment design with 2 subjects per cohort. The first 2 cohorts will consist of 4 adults (18 years or older), potentially followed by a cohort consisting of 2 adolescents or adults (> 14 years old). Following the informed consent process, enrolled subjects will be screened to confirm full eligibility for participation. Eligible subjects will undergo hematopoietic stem cell (HSC) mobilization and collection (leukapheresis). A portion of cells will be kept as "back-up" for rescue purpose if necessary, and a portion will be ex vivo gene-modified with a lentiviral vector, pCCL-CTNS or pCDY.EFS.CTNS.T260I, to express CTNS gene (product name: CTNS-RD-04). Clinical manufacturing for patients in Cohort 3 will introduce a transduction enhancer LentiBOOST (product name for these patients will be CTNS-RD-04-LB, where the suffix "-LB" stands for LentiBOOST). The subjects will receive marrow cytoreduction with busulfan prior to infusion of CTNS-RD-04. Subjects will discontinue cysteamine treatment during the assessment period. The assessment follow-up period will include an initial 2 years of active end-point evaluations, where the subjects will be evaluated at 3-, 6-, 9-, 12-, 18- and 24-months post-transplantation. A Long-Term Follow-Up study (LTFU) for a total 15-year follow-up period will be offered to all subjects.
The objectives of this Phase 1/2 clinical study are to assess the safety/tolerability of CTNS-RD-04, and its efficacy through a number of clinical, molecular and biochemical assessments.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 6 participants |
Allocation: | N/A |
Intervention Model: | Single Group Assignment |
Intervention Model Description: | This study will include up to 6 subjects and follows a 3-cohort staggered treatment design with 2 subjects per cohort. The first 2 cohorts will consist of 4 adults (18 years or older), potentially followed by a cohort consisting of 2 adolescents or adults (>14 years old). |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Phase 1/2 Study to Determine Safety and Efficacy of Transplantation With Autologous Human CD34+ Hematopoietic Stem Cells (HSC) From Mobilized Peripheral Blood Stem Cells (PBSC) of Patients With Cystinosis Modified by Ex Vivo Transduction Using pCCL-CTNS or pCDY.EFS.CTNS.T260I Lentiviral Vector and Will Include Transduction Enhancer When Required During Manufacturing |
Actual Study Start Date : | July 8, 2019 |
Estimated Primary Completion Date : | November 2024 |
Estimated Study Completion Date : | November 2024 |

Arm | Intervention/treatment |
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Experimental: Gene Therapy with CTNS-RD-04 or CTNS-RD-04-LB (where the suffix "-LB" stands for LentiBOOST)
This is a single arm study without randomization. Eligible subjects will receive the final product: CTNS-RD-04 or CTNS-RD-04-LB (where the suffix "-LB" stands for LentiBOOST).
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Genetic: CTNS-RD-04 or CTNS-RD-04-LB (where the suffix "-LB" stands for LentiBOOST)
Peripheral blood autologous CD34+ enriched cell fraction transduced with lentiviral vector, pCCL-CTNS or pCDY.EFS.CTNS.T260I, that contains the human CTNS complementary deoxyribonucleic acid (cDNA) sequence. |
- Evaluation of safety - Absence of Severe Adverse Events (SAEs) due to the investigational product [ Time Frame: Up to 24 months post transplant. ]Safety and tolerability will be assessed in terms of incidence and severity of Adverse Events (AEs) and Serious Adverse Events (SAEs)
- Evaluation of safety - Absence of Replication-Competent Lentivirus (RCL) [ Time Frame: Up to 24 months post transplant. ]Safety and tolerability will be measured by number of subjects with Replication Competent Lentivirus (RCL)
- Evaluation of safety - Absence of genotoxicity [ Time Frame: Up to 24 months post transplant. ]Safety and tolerability will be measured by absence of insertional mutagenesis, monoclonal expansion.
- Evaluation of safety - Event-free survival [ Time Frame: Up to 24 months post transplant. ]Safety and tolerability will be measured by Event-free survival over the 24 months after stem cell transplantation
- Evaluation of efficacy - Change in cystine levels [ Time Frame: Up to 24 months post transplant. ]Efficacy will be measured by evaluating the impact of treatment with CTNS-RD-04 on cystine levels in the blood, and cystine crystal counts in the intestinal mucosa and skin, and eye with the help of Mass Spectrometry and Confocal Microscopy.
- Evaluation of efficacy - To evaluate the effect of treatment with CTNS-RD-04 on clinical disease outcomes [ Time Frame: Up to 24 months post transplant. ]
Among other evaluations, clinical efficacy will be measured by evaluating the effect on clinical disease outcomes including:
- Kidney Function (test: measure Serum Cystatin C levels, unit: score from 1 to 5 based on the stage of dialysis); (test: measure serum and urine phosphate levels, unit: mg/dL);
- Vision (test: Pachymetry, unit: millimeter); (test: Anterior Segment - Optical Coherence Tomography, unit: millimeter or millimeter square);
- Muscle strength (test: grip strength, unit: scale between 0/5 and 5/5);
- Pulmonary function (test: Spirometry, unit: percentage);
- Neurological and Psychometric function (test: Beery Test of Visual Motor Integration, neurological examination to evaluate motor coordination, tone, strength, and reflexes, unit: numerical score).
- Evaluation of efficacy - Change in Quality of Life [ Time Frame: Up to 24 months post transplant. ]Efficacy will be measured by evaluating changes in quality of life with the help of Health-Related Quality of Life (HRQoL) which will assess the impact of treatment with CTNS-RD-04 on quality of life.

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
The following criteria must be met by all subjects considered for study participation.
- Cohorts 1 and 2: Male or female subject is ≥ 18 years of age.
- Cohort 3: Male or female subject is ≥ 14 years of age.
- Subject is diagnosed with cystinosis, i.e., early onset of Fanconi syndrome, and history of elevated white blood cell cystine level and/or history of or presence of cystine crystals in the eye.
- Subject has a Karnofsky Performance Status or age-dependent Lansky Performance of ≥ 60.
- If subject has had a kidney transplant, he or she must be at least one-year post kidney transplant status.
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Subject has adequate hematologic function:
- Absolute neutrophil count (ANC) ≥ 1.5 x 1000/mm^3
- Platelet count ≥ 100 x 1000/mm^3
- Hemoglobin ≥ 9.0 gm/dL
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Subject has an adequate hepatic function:
- Bilirubin ≤ 2.0 mg/ dL
- ALT ≤ 3 x institution's upper limit of normal (ULN) U/L
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Subject has an adequate renal function:
a. Serum creatinine <2x ULN mg/dL
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Subject has adequate coagulation:
- PT/aPTT ≤ 1.2 x ULN seconds
- INR ≤ 2
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Subject has adequate thyroid function (with or without thyroid replacement therapy):
- TSH 0.27-4.2 mIU/mL
- Total T4 ≤ 2 x ULN mcg/dL
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If female: female of childbearing potential (i.e., not surgically sterile [tubal ligation, hysterectomy, or bilateral oophorectomy] or not at least 2 years naturally postmenopausal) agrees to remain sexually abstinent or utilize the same acceptable form of highly effective contraception from screening through two years post-transplant.
The acceptable forms of contraception for this study include hormonal contraceptives (oral, implant, transdermal patch, or injection) associated with inhibition of ovulation at a stable dose for at least 3 months prior to screening, barrier (condom with spermicide, diaphragm with spermicide), intrauterine device, or a partner who has been vasectomized for at least 6 months and has documented medical assessment of surgical success of a vasectomy.
Note: males with cystinosis are sterile.
- If male: males must agree to remain sexually abstinent or utilize an acceptable form of highly effective contraception from screening through two years post-transplant.
- Subject is willing and able to comply with the study restrictions and requirements.
- Subject is willing to provide written informed consent/permission/assent prior to participation in the study.
- Subject must be willing to refrain from donating sperm after receiving the conditioning regimen. For subjects planning on (or for whom there is a possibility of) fathering children in the future, sperm banking prior to administration of conditioning regimen will be recommended.
- Subject must be willing to refrain from donating blood, organs, tissues, or cells for transplantation from 30 days prior to screening through any time after CTNS-RD-04 treatment.
- Subject must be willing and must be able (in the judgment of the investigator) to discontinue his or her cysteamine therapy (oral and/or eye drop).
Exclusion Criteria:
- Subject has an active, uncontrolled, acute bacterial, viral, or fungal infection during screening or within 30 days prior to starting the conditioning regimen.
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Subject has positive serology at screening for any of the following:
- Human Immunodeficiency Virus (HIV) 1-2
- Human T-cell Lymphotropic Virus (HTLV) - I/II
- Hepatitis B core and Hepatitis B PCR positive
- Hepatitis C Virus (HCV)
- Rapid Plasma Reagin (RPR)
- Chagas' Disease (T. curzi)
- QuantiferonTB
- Nucleic Acid Test (NAT) for HIV
- West Nile Virus (WNV)
- Subject has a known clinically significant immunodeficiency disorder.
- Subject is a female of childbearing potential that is nursing, planning a pregnancy or has a positive serum pregnancy test.
- Subject has received a prior marrow or stem cell transplantation or is planning to receive one within 90 days of study initiation.
- Subject has had an active bleeding disorder within 90 days prior to screening OR requires anticoagulation therapy prior to treatment with ex vivo gene therapy.
- Subject has an active malignancy or history of malignancy including lymphoma (except primary, cutaneous basal cell or squamous cell cancer appropriately treated prior to transplantation).
- Subject has an end-stage renal disease (defined as GFR <15 mL/min) and is already on a transplantation list or who may be planning to register for a kidney transplant within 90 days of study initiation.
- Subject has impaired pulmonary function (based on FEV1 of <=50% of predicted or DLCO of <=40 % of predicted and gender-specific normal threshold value).
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Subject has impaired cardiac function within 90 days prior to screening including any of the following:
- Myocardial infarction
- Clinically significant abnormal electrocardiogram (ECG)
- Ejection fraction of < 40%
- Uncontrolled arrhythmia
- Other clinically significant heart disease (e.g., congestive heart failure, uncontrolled hypertension, history of labile hypertension).
- Subject has a severe or uncontrolled medical disorder (e.g., pancreatitis, severe liver disease, unstable diabetes mellitus) that would, in the investigators' opinion, impair their ability to receive study treatment and follow the study procedures.
- Subject has a history of allergic reactions attributed to compounds of similar chemical or biologic composition to Busulfan or allergy or contraindication to use of other agents used in the study, including iohexol, acid-citrate-dextrose Formula A (ACDA), G-CSF or plerixafor.
- Subject has a known history of drug or alcohol addiction.
- Subject has undergone major surgery within 90 days (or longer if not fully recovered) prior to screening.
- Subject is receiving cytotoxic or immunosuppressive agents, other than for kidney transplant, within 60 days prior to screening or requires treatment with such agents prior to treatment with ex vivo gene therapy.
- Subject has previously received gene therapy at any time.
- Subject is currently receiving or anticipates receiving another investigational agent, device, or procedure from 30 days prior to screening through study completion.
- Subject has any condition, in the opinion of the investigator, that compromises compliance with study requirements.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03897361
United States, California | |
University of California San Diego | |
La Jolla, California, United States, 92093 |
Principal Investigator: | Stephanie Cherqui, Ph.D. | University of California, San Diego (UCSD) |
Responsible Party: | Stephanie Cherqui, Professor, University of California, San Diego |
ClinicalTrials.gov Identifier: | NCT03897361 |
Other Study ID Numbers: |
018631 |
First Posted: | April 1, 2019 Key Record Dates |
Last Update Posted: | March 29, 2023 |
Last Verified: | March 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Undecided |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Cystinosis Lysosomal Storage Disorders LSD |
Cystinosis Lysosomal Storage Diseases Metabolism, Inborn Errors Genetic Diseases, Inborn Metabolic Diseases |