IL-5 CAR-T therapy for refractory or relapsed eosinophilic leukemia

The Safety and Efficay Investigation of IL-5 CAR-T Cell Therapy for Patients With Refractory/Relapsed Eosinophilic Leukemia

We will test whether IL-5 CAR-T cells can help adults with CD125-positive refractory or relapsed eosinophilic leukemia.

Quick facts

• Phase: Phase 1
• Study type: Interventional
• Enrollment: 20 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Zhejiang University (Academic / other)
• Drugs / interventions: imatinib, chemotherapy, CAR-T
• Locations: 1 site (Hangzhou, Zhejiang)
• Trial ID: NCT07257640 on ClinicalTrials.gov

What this trial studies

This open-label, single-arm Phase 1 study delivers an experimental CAR-T cell product that uses full-length human IL-5 fused to CD8α hinge/transmembrane, 4-1BB co-stimulatory, and CD3ζ signaling domains to target CD125 (IL-5Rα) on leukemic blasts. Eligible adults with ≥50% CD125-positive blasts receive lymphodepleting preconditioning followed by a single infusion of IL-5 CAR-T cells and intensive monitoring for adverse events. The primary focus is safety and initial anti-leukemia activity, while secondary endpoints include CAR-T expansion, persistence, and cytokine/kinetic profiling. Patients will undergo scheduled clinical and laboratory follow-up to record responses, toxicities, and CAR-T cell behavior.

Who should consider this trial

Good fit: Adults (≥18 years) with refractory or relapsed eosinophilic leukemia whose blasts express CD125 on at least 50% of cells and who meet required organ-function and performance criteria are the intended candidates.

Not a fit: Patients whose leukemic cells lack CD125 expression, who have inadequate heart or liver function, or who have a very limited life expectancy are unlikely to benefit from this therapy.

Why it matters

Potential benefit: If successful, this targeted CAR-T approach could induce remissions in patients whose eosinophilic leukemia has failed standard treatments.

How similar studies have performed: While CAR-T therapies have shown high response rates in other blood cancers, using IL-5 as a CAR to target CD125 in eosinophilic leukemia is novel and largely unproven.

Eligibility criteria

Inclusion Criteria:

* 1.Male or female patients aged ≥18 years;
* 2.Diagnosis of eosinophilic leukemia (EL) established according to the WHO 2022 diagnostic criteria;
* 3.Interleukin-5 receptor α (IL-5Rα, CD125) is expressed on ≥50% of leukemic blasts.
* 4.Meet any of the following criteria for refractory/relapsed eosinophilic leukemia:
* a) Inadequate response to standard therapy: failure to achieve complete remission (CR) after standard treatments (e.g., imatinib, corticosteroids, interferon-α, chemotherapy, etc.);
* b) Disease progression/relapse within 6 months after achieving remission;
* 5.Serum total bilirubin ≤1.5 × the upper limit of normal (ULN), and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤3 × ULN;
* 6.Left ventricular ejection fraction (LVEF) \>50% as assessed by echocardiography;
* 7.Peripheral oxygen saturation (SpO₂) ≥92% on room air (without supplemental oxygen);
* 8.Estimated life expectancy \>3 months;
* 9.Eastern Cooperative Oncology Group (ECOG) performance status 0-1;
* 10.Women and men of childbearing potential must agree to use appropriate, effective contraception prior to study entry, throughout the study period, and for 6 months after cell infusion (the safety of this therapy for unborn children is unknown and may pose potential risks);
* 11.Patients who are willing to participate in this study and who are able to understand and voluntarily sign the written informed consent form.

Exclusion Criteria:

* 1.History of epilepsy or other central nervous system (CNS) disorders;
* 2.Presence of any of the following:Hepatitis B surface antigen (HBsAg)-positive; Any of HBeAg, HBeAb, or HBcAb positive and detectable hepatitis B virus (HBV) DNA in peripheral blood above the lower limit of detection; Hepatitis C virus (HCV) antibody-positive; Human immunodeficiency virus (HIV) antibody-positive; Positive serologic test for syphilis;
* 3.History of QT interval prolongation or severe cardiac disease;
* 4.Presence of uncontrolled active infection;
* 5.Any condition that, in the opinion of the investigator, may increase the risk to the subject or interfere with the interpretation of the study results.

Where this trial is running

Hangzhou, Zhejiang

• The first affiliated hospital of medical college of zhejiang university — Hangzhou, Zhejiang, China (Recruiting)

Study contacts

• Principal investigator: He Huang, MD — First Affiliated Hospital of Zhejiang University
• Study coordinator: Songmin Ying, MD

Conditions Hematologic Diseases; Neoplasms; IL-5 CAR-T; Eosinophil