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Updated May 2026 · ClinicalTrials.gov

RECRUITINGPhase 1 / Phase 2INTERVENTIONAL

Repeat Peripheral Blood Stem Cell Transplantation for Patients With Sickle Cell Disease and Falling Donor Myeloid Chimerism Levels

Repeat Peripheral Blood Stem Cell Transplantation for Patients With Sickle Cell Disease or Beta-Thalassemia and Falling Donor Myeloid Chimerism Levels

Repeat Peripheral Blood Stem Cell Transplantation for Patients With Sickle Cell Disease and Falling Donor Myeloid Chimerism Levels (NCT04008368) is a Phase 1 / Phase 2 interventional studying Myeloid Chimerism, sponsored by National Heart, Lung, and Blood Institute (NHLBI). RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

Important: This information is not medical advice. Talk to your doctor about whether a clinical trial is right for you.

About This Trial

Background: Sickle cell disease can often be treated with blood stem cell transplants. But for some people the disease returns. This study will give a second transplant to people whose disease has returned but still have some donor cells in their body. Objective: To cure people s sickle cell disease by giving a second treatment that makes more room in their bone marrow for donor cells. Eligibility: People ages 4 and older with sickle cell disease who had a transplant but the disease returned, and their donor relatives. Donors can be 2 years of age or older. Design: Participants will be screened with medical history, physical exam, and blood tests. Recipients will also be screened with heart and breathing tests, x-rays, a bone marrow sample, and teeth and eye exams. They must have a caregiver. Donors will have 7-8 visits. They will take a drug for 5-6 days to prepare them for the donation. For the donation, blood is taken from a vein in the arm or groin. The stem cells are collected. The rest of the blood is returned. This may be repeated. Recipients will get a long IV line in their arm or chest for about 1-2 months. They will take drugs to help their body accept the donor cells. They will get the donor cells and red blood cell transfusions through the line. They will stay in the hospital about 30 days after the transfusion of donor cells. In first 3 months after the infusion, recipients will have many visits. Then they will have visits every 6 months to 1 year for 5 years. During those visits they will repeat some of the screening tests....

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For Myeloid Chimerism, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 32 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

* Who May Qualify: Inclusion criteria- recipient 1. Patient with history of SCD or beta thalassemia who previously underwent allogeneic hematopoietic stem cell transplantation (HSCT) 2. Patient with recurrent SCD defined as HbS greater than or equal to 50% for donors with sickle cell trait and greater than or equal to 10% for donors with HbAA with recurrent clinical manifestations (for example but not limited to recurrent painful crises, acute chest syndrome, priapism, or severe anemia) or patients with recurrent beta thalassemia defined as clinical manifestations such as transfusion-dependence or evidence of extramedullary hematopoiesis. The HbS requirement may be waived by the PI or designee for reasons such as the patient is requiring chronic transfusion therapy or otherwise meets clinical criteria for return of SCD. 3. Persistent donor chimerism levels 4. Age greater than or equal to 4 years 5. Negative beta-HCG 6. Ejection fraction greater than or equal to 35% 7. DLCO greater than or equal to 35% (Note: This criterion may be omitted in young children (e.g. near the age of 5 years old) or other individuals who may have difficulty understanding or complying with the instructions for accurate testing.) Inclusion- donor Related donor from original transplant, deemed suitable and eligible, and willing to donate, per clinical evaluations who are additionally willing to donate blood for research. Related donors will be evaluated in accordance with existing Standard NIH Policies and Procedures for determination of eligibility and suitability for clinical donation. Age \>= 2 years \<80 years old Who Should NOT Join This Trial: Exclusion criteria- recipient 1. ECOG performance status of 3 or more or if \<16 years of age Lansky score of 50 or lower. 2. Evidence of uncontrolled bacterial, viral, or fungal infections (currently taking medication and progression of clinical symptoms) within one month prior to signing the consent ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language
* INCLUSION CRITERIA: Inclusion criteria- recipient 1. Patient with history of SCD or beta thalassemia who previously underwent allogeneic hematopoietic stem cell transplantation (HSCT) 2. Patient with recurrent SCD defined as HbS greater than or equal to 50% for donors with sickle cell trait and greater than or equal to 10% for donors with HbAA with recurrent clinical manifestations (for example but not limited to recurrent painful crises, acute chest syndrome, priapism, or severe anemia) or patients with recurrent beta thalassemia defined as clinical manifestations such as transfusion-dependence or evidence of extramedullary hematopoiesis. The HbS requirement may be waived by the PI or designee for reasons such as the patient is requiring chronic transfusion therapy or otherwise meets clinical criteria for return of SCD. 3. Persistent donor chimerism levels 4. Age greater than or equal to 4 years 5. Negative beta-HCG 6. Ejection fraction greater than or equal to 35% 7. DLCO greater than or equal to 35% (Note: This criterion may be omitted in young children (e.g. near the age of 5 years old) or other individuals who may have difficulty understanding or complying with the instructions for accurate testing.) Inclusion- donor Related donor from original transplant, deemed suitable and eligible, and willing to donate, per clinical evaluations who are additionally willing to donate blood for research. Related donors will be evaluated in accordance with existing Standard NIH Policies and Procedures for determination of eligibility and suitability for clinical donation. Age \>= 2 years \<80 years old EXCLUSION CRITERIA: Exclusion criteria- recipient 1. ECOG performance status of 3 or more or if \<16 years of age Lansky score of 50 or lower. 2. Evidence of uncontrolled bacterial, viral, or fungal infections (currently taking medication and progression of clinical symptoms) within one month prior to signing the consent 3. Patients with fever or suspected minor infection should await resolution of symptoms before signing the consent 4. Major anticipated illness or organ failure incompatible with survival from PBSC transplant 5. Pregnant or breastfeeding 6. History of secondary malignancies (other than localized skin cancer) 7. Donor-specific HLA antibodies with mean fluorescent intensity \>= 2,000 Exclusion- donor None

Treatments Being Tested

DEVICE

CliniMACS CD34 Reagent

Haploidentical recipients will receive CD34-selected cells using Miltenyi CliniMACS(R) CD34+ cell selection kits. The target CD34+ cell dose is at least 10 x 106/kg, and the minimum CD34+ cell dose is 5 x 106/kg. All of the cells collected during the apheresis procedure will be given. The cells will be cryopreserved and stored until the day of transplant.

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

National Institutes of Health Clinical Center
Bethesda, Maryland, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT04008368), the sponsor (National Heart, Lung, and Blood Institute (NHLBI)), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT04008368 clinical trial studying?

Background: Sickle cell disease can often be treated with blood stem cell transplants. But for some people the disease returns. This study will give a second transplant to people whose disease has returned but still have some donor cells in their body. Objective: To cure people s sickle cell disease by giving a second treatment that makes more room in their bone marrow for donor cells. Eligibility: People ages 4 and older with sickle cell disease who had a transplant but the disease returned, and their donor relatives. Donors can be 2 years of age or older. Design: Participants will be … The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT04008368?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT04008368?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT04008368. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT04008368. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.