Aplastic anemia (AA) is a life-threatening bone marrow failure disorder characterized by pancytopenia and hypocellular bone marrow, with immune-mediated destruction of hematopoietic stem and progenitor cells (HSPCs) playing a central role in its pathogenesis. Although immunosuppressive therapy (IST) and hematopoietic stem cell transplantation (HSCT) have improved survival, a significant proportion of patients remain refractory, relapse after treatment, or lack suitable donors for transplantation. Therefore, novel therapeutic strategies are urgently needed.

Chimeric antigen receptor T (CAR-T) cell therapy has demonstrated remarkable efficacy in hematologic malignancies. CD7 is an early surface marker of T-lineage cells and is dispensable for T cell development and function, making it a promising therapeutic target. This exploratory study aims to investigate the molecular and cellular mechanisms of CD7-CAR-T therapy in AA patients by analyzing multi-omics changes before and after treatment.

This is a prospective, single-center, single-arm, open-label study enrolling patients with relapsed or refractory severe aplastic anemia. Participants will receive autologous CD7-CAR-T cells following lymphodepletion. Multi-omics profiling, including genomics, transcriptomics, proteomics, and immunophenotyping, will be performed on patient samples before and after infusion. The primary objective is to explore dynamic molecular changes associated with treatment response and disease progression. Secondary objectives include safety evaluation and preliminary assessment of efficacy.

Findings from this study may provide mechanistic insights into CD7-CAR-T therapy in AA and inform the development of innovative immunotherapies for bone marrow failure syndromes.

This is a single-center, single-arm, prospective clinical study evaluating the safety and efficacy of CD7-directed CAR-T cell therapy in adult patients with refractory or relapsed severe aplastic anemia (SAA). SAA is an acquired bone marrow failure disorder characterized by pancytopenia and hypocellular marrow without malignant infiltration. Standard immunosuppressive therapy (IST) has improved survival, but approximately 30% of patients fail initial treatment, and relapse or progression to myelodysplastic syndrome or acute myeloid leukemia remains a clinical challenge. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) improves outcomes for younger patients but is limited by donor availability and graft-versus-host disease risks.

Eligible participants are adults (≥18 years) with ECOG performance status 0-1, life expectancy ≥3 months, and refractory or relapsed SAA after IST, or ineligible for, lacking access to, or refusing allo-HSCT. Key laboratory criteria include creatinine ≤2.5× upper limit of normal, total bilirubin ≤3× ULN, ALT and AST ≤3× ULN, and baseline oxygen saturation ≥90%. Patients must have suitable venous access for leukapheresis and comply with contraception requirements if of reproductive potential. Exclusion criteria include active infections, severe cardiovascular disease, recent malignancy (except certain adequately treated cancers), pregnancy or breastfeeding, HIV, HBV, HCV above specified thresholds, or hypersensitivity to CAR-T components.

The study consists of four stages: patient screening and enrollment; preconditioning including leukapheresis, CAR-T cell manufacture, and chemotherapy; CD7-CAR-T cell infusion with inpatient monitoring; and long-term follow-up. Patients receive a lymphodepletion regimen with fludarabine and cyclophosphamide prior to a single infusion of CD7-CAR-T cells at 3×10^6 cells/kg. Safety assessments, including monitoring for cytokine release syndrome and other adverse events, will be conducted closely during hospitalization. Efficacy assessments include complete blood counts, bone marrow evaluation, and multi-omics analysis of immune cell subsets and cytokine profiles at defined intervals.

Participants will be followed up for up to 3 years post-infusion, with intensive monitoring in the first 6 months and periodic assessments thereafter to evaluate disease status, CAR-T cell persistence, long-term safety, and quality of life. The primary endpoint is overall response rate (ORR), with secondary endpoints including progression-free survival (PFS), overall survival (OS), and safety outcomes. This study aims to provide the first evaluation of CD7-CAR-T therapy in refractory or relapsed SAA patients, potentially offering a novel therapeutic option for this high-risk population.

Inclusion Criteria:

Age ≥18 years at the time of informed consent, of Chinese nationality. ECOG performance status 0-1, with an expected survival time ≥3 months.

Diagnosis of severe aplastic anemia (SAA) and meeting at least one of the following:

Relapsed or refractory after standard therapy without achieving complete remission.

Ineligible for, without access to, or refusing allogeneic hematopoietic stem cell transplantation.

Laboratory values at screening meeting all of the following:

Serum creatinine ≤2.5 × upper limit of normal (ULN). Oxygen saturation ≥90% at baseline. Total bilirubin ≤3 × ULN. ALT and AST ≤3 × ULN. Adequate venous access for mononuclear cell collection and no contraindications to leukapheresis.

Female participants of childbearing potential must have a negative high-sensitivity serum pregnancy test (β-hCG) at screening and before the first dose of fludarabine/cyclophosphamide. Male and female participants of childbearing potential must agree to use effective contraception from informed consent through at least 36 months after CD7-CAR-T infusion.

After review by the investigator team, the overall benefit of trial participation is judged to outweigh potential risks.

Ability to understand and sign informed consent, and willingness to comply with study procedures and restrictions.

Exclusion Criteria:

History of or treatment for other malignancies within 5 years prior to screening, except adequately treated cervical carcinoma in situ, basal or squamous cell skin cancer, curatively treated localized prostate cancer, or ductal carcinoma in situ.

Severe systemic diseases, including:

NYHA class III or IV congestive heart failure. Stroke, myocardial infarction, or hemodynamically unstable arrhythmia within 6 months prior to consent.

Left ventricular ejection fraction (LVEF) <50% by echocardiography. Severe or uncontrolled concomitant illness within 14 days prior to consent, including active infection.

Pregnant or breastfeeding women. Positive serology for HIV. Positive for hepatitis B surface antigen or detectable HBV DNA. Positive for hepatitis C antibody with detectable HCV RNA. Positive syphilis serology (TP-Ab and RPR). Positive CMV DNA.

History of life-threatening hypersensitivity to CD7-CAR-T cells or any excipients (including DMSO), or known hypersensitivity to biologics such as antibodies or cytokines.

Contraindications to fludarabine or cyclophosphamide therapy. History of alcohol dependence, substance abuse, or psychiatric disorders that may interfere with study compliance.

Any other condition that, in the opinion of the investigator, makes the participant unsuitable for the study.

Adult patients (≥18 years) with refractory or relapsed severe aplastic anemia (SAA) after standard immunosuppressive therapy, or ineligible for/allogeneic hematopoietic stem cell transplantation. Participants must have ECOG 0-1, life expectancy ≥3 months, suitable venous access for leukapheresis, and meet basic lab criteria. Key exclusions include active infections, severe cardiovascular disease, recent malignancy, pregnancy/breastfeeding, or known HIV, HBV, or HCV infection.