This Phase 2, multicenter, open-label study is evaluating CK0801 for the treatment of aplastic anemia in adults with persistent transfusion dependence after at least one prior line of therapy or intolerance to standard-of-care treatment. CK0801 is an allogeneic cord blood-derived regulatory T-cell therapy administered intravenously. The study is designed to assess safety and clinical activity, including hematologic response, transfusion independence, duration of response, survival outcomes, and patient-reported outcomes. Exploratory assessments include immune reconstitution, biomarkers, pharmacokinetics, immunogenicity, and donor-specific antibodies. The primary endpoint is overall response at Day 180.

Aplastic anemia is a rare, life-threatening bone marrow failure disorder caused by immune-mediated destruction of hematopoietic stem and progenitor cells. Regulatory T cells (Tregs), which help maintain immune homeostasis, are decreased and functionally impaired in aplastic anemia. CK0801 is an allogeneic cord blood-derived Treg cell therapy being studied as a potential treatment to restore immune balance and improve hematopoiesis. Prior clinical experience described in the protocol showed a favorable safety profile and early signs of activity, including reduced transfusion requirements in patients with bone marrow failure.

This Phase 2, multicenter, open-label, single-agent study will evaluate the safety and efficacy of intravenous CK0801 in adults with aplastic anemia who remain transfusion dependent after at least one prior line of therapy or who are intolerant to standard-of-care treatment. A total of 12 participants are planned. CK0801 will be administered as a weight-based intravenous infusion, with protocol-defined premedication before treatment.

The primary endpoint is overall response at Day 180. Secondary endpoints include response at Days 28, 56, 100, and 365, time to best response, time to transfusion independence, duration of transfusion independence, immunosuppression-free survival, overall survival, progression-free survival, clonal evolution, patient-reported outcomes, and safety. Exploratory endpoints include donor-specific antibodies, immunosuppressive medication discontinuation, cytokine and biomarker changes, pharmacokinetics, immunogenicity, and immune reconstitution.

Enrollment will proceed using Simon's two-stage design. In Stage 1, 6 participants will be enrolled. If predefined activity criteria are met, the study will proceed to Stage 2 and enroll 6 additional participants, for a total of 12 participants. Participants will undergo protocol-defined clinical, laboratory, disease, safety, and correlative assessments. The overall study duration is expected to be approximately 24 months.

Inclusion Criteria:

• Age 18 years or older
• Diagnosis of aplastic anemia
• Transfusion dependent after at least one prior line of treatment, or intolerance to standard-of-care treatment
• Female subjects of childbearing potential must have a negative urine or serum pregnancy test
• Agrees to comply with all protocol-required procedures, including study-related assessments, visits, and long-term follow-up
• Willing and able to provide written informed consent

Exclusion Criteria:

• Known HIV seropositivity
• Uncontrolled infection not responding to appropriate antimicrobial agents after 7 days of therapy; the Protocol PI is the final arbiter of eligibility
• Uncontrolled intercurrent illness that, in the opinion of the investigator, would place the subject at greater risk of severe toxicity and/or impair the activity of CK0801
• Pregnant or breastfeeding
• Unable to provide consent or, in the opinion of the investigator, unlikely to fully comply with protocol requirements