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Recruiting Phase 1, Phase 2 NCT04774536

NCT04774536 Transplantation of Clustered Regularly Interspaced Short Palindromic Repeats Modified Hematopoietic Progenitor Stem Cells (CRISPR_SCD001) in Patients With Severe Sickle Cell Disease

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Clinical Trial Summary
NCT ID NCT04774536
Status Recruiting
Phase Phase 1, Phase 2
Sponsor Mark Walters, MD
Condition Sickle Cell Disease
Study Type INTERVENTIONAL
Enrollment 9 participants
Start Date 2025-08-22
Primary Completion 2030-03-01

Eligibility & Interventions

Sex All sexes
Min Age 12 Years
Max Age 35 Years
Study Type INTERVENTIONAL
Interventions
CRISPR_SCD001

Eligibility Fast-Check

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What to Expect as a Participant

You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.

Phase 1 is the earliest stage of human testing — safety and dosage are the primary focus. Visits are frequent and medical supervision is intensive. You will be among the first people to receive this treatment.

This trial targets 9 participants in total. It began in 2025-08-22 with a primary completion date of 2030-03-01.

⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.

Brief Summary

This is an open label, non-randomized, 2-center, phase 1/2 trial of a single infusion of sickle allele modified cluster of differentiation (CD34+) hematopoietic stem progenitor cells (HSPCs) in subjects with in subjects ≥12 years old to 35 years old severe Sickle Cell Disease (SCD). The study will evaluate the hematopoietic stem cell transplantation (HSCT) using CRISPR/Cas9 edited red blood cells (known as CRISPR\_SCD001 Drug Product).

Eligibility Criteria

Inclusion Criteria: 1. Male or female 12.00 - 34.99 years of age (at time of consent) who have one or more of the following: 1. History of two or more episodes of acute chest syndrome (ACS) in the 2-year period preceding enrollment despite the institution of supportive care measures (i.e. asthma therapy and/or hydroxyurea); ACS is defined as a new radiodensity on chest imaging accompanied by fever and/or respiratory symptoms, treated in the hospital with supplemental oxygen at a minimum. 2. History of at least 4 severe vaso-occlusive pain events in the 2-year period preceding enrollment despite the institution of supportive care measures (i.e. a pain management plan and/or treatment with hydroxyurea); painful episodes related to or any sickle-related acute event are acceptable; a severe painful vaso-occlusive event is defined as receiving analgesic treatment (opioid or other analgesic via parenteral (PN) route) for longer than 24 -hours in a hospital or emergency room (ER) observation unit visit or at least 2 visits in a day unit or ER over 72 hours with both visits requiring parenteral analgesics. 3. 2 or more episodes of splenic sequestration, defined as an acute decrease in hemoglobin by at least 2 g/dL accompanied by splenomegaly in the 2 years before enrollment. 4. Recurrent priapism (episodes lasting at least 4 hours at least twice in the last 12 months or 3 times in the last 24 months before enrollment) recalcitrant to medical treatment 5. Any episode of hepatic sequestration defined as right upper quadrant pain, hepatomegaly, and rapidly decreasing hemoglobin level with hepatic dysfunction within the 2 years before enrollment. 6. Leg ulcer recalcitrant to treatment within 2 years prior to enrollment. 2. Participants must have adequate physical function as measured by all of the following: 1. Karnofsky performance score ≥60. 2. Cardiac function: Left ventricular ejection fraction (LVEF) \>40%; or LV shortening fraction \> 26% by cardiac echocardiogram or by (multiple-gated acquisition) MUGA scan. 3. Pulmonary function: Pulse oximetry with a baseline O2 saturation of ≥85% and diffusion capacity of lung for carbon monoxide(DLCO) \> 40% (corrected for hemoglobin). 4. Renal function: Serum creatinine ≤ 1.5 x upper limit of normal for age and estimated or measured creatinine clearance ≥ 70 mL/min/1.73 m2. 5. Hepatic function: i. Serum conjugated (direct) bilirubin \< 2x upper limit of normal for age as per local laboratory. Participants with hyperbilirubinemia as the result of hyperhemolysis, or a severe drop in hemoglobin post blood transfusion, are not excluded. ii. Alanine aminotransferase (ALT) and aspartate aminotransferase (AS \< 5 times upper limit of normal as per local laboratory. Participants who have liver iron concentration (LIC) on liver MRI of ≥12 mg Fe/g liver dry weight should also have MR elastography (MRE) or Ultrasound elastography obtained. If severe fibrosis is present, no liver biopsy will be performed and participant is excluded. Children with LIC \>12 and negative elastography imaging are eligible if a clinically indicated liver biopsy shows no significant fibrosis. 3. Baseline prothrombin time or partial thromboplastin time \<1.5 ULN except if receiving a prophylactic anticoagulant which causes an elevated prothrombin or partial thromboplastin time. 4. Written informed consent or assent obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study. Exclusion Criteria: 1. Participants with uncontrolled bacterial, viral or fungal infection in the 6 weeks before enrollment (currently taking medication with evidence of progression of clinical symptoms or radiologic findings). 2. Participants with evidence of HIV infection or seropositivity for HIV or active hepatitis B or C. 3. Participants who have received a Hematopoietic Cell Transplant (HCT) 4. Participants who have received a solid organ transplant. 5. Participants who have participated in another clinical trial in which the participant received an investigational or off-label use of a drug or device within 3 months prior to enrollment. 6. Females who are pregnant or breast feeding. 7. Females of child bearing potential (to include all female participants \> 10 years of age, unless postmenopausal for a minimum of 1 year before the time of consent or surgically sterilized) who do not agree to practice two (2) effective methods of contraception at the same time, or who do not agree to practice true abstinence when this is in line with the preferred and usual lifestyle of the subject, from the time of signing of informed consent through 12 months post-stem cell infusion. 8. Males (even if surgically sterilized) who do not agree to practice effective barrier contraception, or who do not agree to practice true abstinence from the time of signing informed consent through 12 months post-stem cell infusion. 9. Participants who have had a stroke OR who are receiving red blood cell (RBC) transfusions to prevent primary stroke or silent cerebral infarction. 10. Patients who have a suitable human leukocyte antigen identical (HLA-ID) sibling donor willing and able to donate bone marrow. 11. Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data. 12. Any non-homozygous sickle hemoglobin (HbSS) genotype of SCD 13. Either or both of the following findings on screening bone marrow aspirate/biopsy: 1. diagnosis of myelodysplastic syndrome (MDS) based on morphology and/or cytogenetics (based on WHO definitions) OR 2. any evidence of a pathogenic clonal variant in any candidate gene detected by a standard, licensed next-generation sequencing clinical assay for gene mutations associated with hematological malignancies. 14. The participant has an identified pathogenic mutation associated with myeloid malignancy as identified by RHP or a variant of unknown significance (VUS) judged to be pathogenic for myeloid malignancy as determined by one or more members of the adjudication panel.

Contact & Investigator

Central Contact

Mark Walters, MD

✉ Mark.Walters@ucsf.edu

📞 (510) 428-3374

Principal Investigator

Mark Walters, MD

PRINCIPAL INVESTIGATOR

UCSF Benioff Children's Hospital Oakland

Frequently Asked Questions

Who can join the NCT04774536 clinical trial?

This trial is open to participants of all sexes, aged 12 Years or older, up to 35 Years, studying Sickle Cell Disease. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.

What phase is the NCT04774536 trial and what does that mean for participants?

Phase 1 trials are the first stage of human testing. The primary goal is to assess safety and determine appropriate dosage levels. Participants are closely monitored. These trials typically involve a small number of volunteers.

Is NCT04774536 currently recruiting?

Yes, NCT04774536 is actively recruiting participants. Contact the research team at Mark.Walters@ucsf.edu for enrollment information.

Where is the NCT04774536 trial being conducted?

This trial is being conducted at Davis, United States, Los Angeles, United States, Oakland, United States.

Who is sponsoring the NCT04774536 clinical trial?

NCT04774536 is sponsored by Mark Walters, MD. The principal investigator is Mark Walters, MD at UCSF Benioff Children's Hospital Oakland. The trial plans to enroll 9 participants.

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ClinicalMetric — Independent clinical trial intelligence platform. Not affiliated with NIH, ClinicalTrials.gov, the U.S. FDA, or any pharmaceutical company, hospital, or clinical research organization. Trial data is sourced from ClinicalTrials.gov for informational purposes only and does not constitute medical advice. Do not make any treatment, enrollment, or health decisions based solely on information found here — always consult a qualified healthcare professional. Full Disclaimer  ·  Last Reviewed: November 2026  ·  Data Methodology