Anbalcabtagene Autoleucel in Relapsed/Refractory CNS Lymphoma

Primary central nervous system lymphoma (PCNSL) and secondary CNS lymphoma (SCNSL) are rare and aggressive subtypes of non-Hodgkin lymphoma (NHL) with poor prognoses in relapsed or refractory cases. Existing salvage therapies provide limited clinical benefit due to low response durability and high relapse rates, underscoring the need for novel therapeutic strategies.

Chimeric antigen receptor T (CAR-T) cell therapy is a form of adoptive cell transfer (ACT) that reprograms T cells to target specific tumor antigens via genetically engineered immunoreceptors. Unlike T-cell receptor (TCR)-based approaches, CAR-T cells recognize tumor-associated antigens independently of HLA presentation.

Anbalcabtagene autoleucel (Anbal-cel) is an investigational autologous anti-CD19 CAR-T cell product, incorporating a CD19-specific scFv, CD8 hinge and transmembrane domains, a 4-1BB co-stimulatory domain, and a CD3-zeta signaling domain. Upon CD19 engagement, Anbal-cel forms an immunological synapse and triggers effector functions, including proliferation, cytokine secretion (e.g., IFN-γ, IL-6, TNF-α, GM-CSF), and cytotoxic activity via perforin/granzyme and death receptor pathways.

Notably, Anbal-cel is engineered to minimize T-cell exhaustion by downregulating immune checkpoint molecules such as PD-1 and TIGIT, which are frequently overexpressed in B-cell lymphoma. This design is anticipated to enhance antitumor efficacy relative to conventional anti-CD19 CAR-T therapies.

This single-arm, open-label pilot study aims to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of Anbal-cel in patients with relapsed or refractory PCNSL and SCNSL. In the prior phase 1/2 study (CRC01-01, NCT04836507), patients with CNS involvement were excluded; this study represents the first clinical evaluation of Anbal-cel in this population.

The study includes a safety lead-in phase involving an initial cohort of three patients receiving the recommended phase 2 dose (RP2D) of 2 × 10⁶ CAR-T cells/kg. A Safety Review Committee (SRC) will assess initial safety data before proceeding with additional enrollment.

To prepare for Anbal-cel infusion, patients will receive a lymphodepletion regimen of fludarabine (30 mg/m²/day) and cyclophosphamide (500 mg/m²/day) on Days -5 to -2. This approach is supported by prior CAR-T studies (e.g., Yescarta®), which demonstrated improved expansion and persistence with acceptable safety profiles.

The **primary objective** is to assess the overall response rate (ORR) using the International Primary CNS Lymphoma Collaborative Group criteria.

• Secondary objectives** include:

• Complete response rate (CRR)
• Time to response (TTR)
• Duration of response (DOR)
• Event-free survival (EFS)
• Progression-free survival (PFS)
• Overall survival (OS)
• Safety and tolerability
• Pharmacokinetics and immune profiling
• Exploratory objectives** include evaluating associations between Anbal-cel expansion, cytokine levels, and immune-related adverse events (e.g., CRS, ICANS), as well as biomarker analyses (e.g., CD19, PD-1, TIGIT, LAG-3, TIM-3 in tumor or CSF) to characterize immune phenotype and gene expression changes linked to response.

All patients will undergo long-term follow-up for 5 years in accordance with gene therapy guidance. Additionally, subjects who provide consent will be enrolled in a separate 15-year long-term safety follow-up protocol. Dose adjustments and WBC thresholds will guide lymphodepletion decisions based on patient condition and clinical safety monitoring.

Inclusion criteria

• Individuals aged 19 years or older who voluntarily agree to participate in this clinical study and provide written consent.
• Patients with recurrent/refractory B-cell lymphoma confirmed histologically according to the 2017 WHO classification, and who meet one of the following conditions:

Primary central nervous system lymphoma (PCNSL) of the DLBCL subtype Secondary central nervous system involvement of DLBCL with no involvement outside the central nervous system

• Patients who failed treatment with a previous regimen that included high-dose methotrexate or patients intolerant to high-dose methotrexate.
• Patients who agree to provide tumor tissue. If a stored tumor tissue sample is available, it can be submitted only if it was collected within 6 months prior to participation in the clinical study and if no systemic anticancer treatment was administered after collection. If the stored tissue sample does not meet these conditions, tumor tissue must be obtained through a core needle biopsy or excisional biopsy during the screening period. If the investigator deems the biopsy to be medically unsafe for the patient, the decision on whether to enroll the patient in the clinical study can be made in consultation with the patient's clinical physician.
• Individuals with an ECOG performance status score of 2 or lower at the time of screening.
• Individuals with appropriate renal and liver function confirmed by laboratory test results:

Total Bilirubin ≤2.0 mg/dL (for individuals with Gilbert-Meulengracht syndrome: total bilirubin ≤3.0 × upper limit of normal (ULN), direct bilirubin ≤1.5 x ULN) Aspartate transaminase (AST) and alanine transaminase (ALT) ≤3 × ULN (if liver metastasis is confirmed: AST, ALT ≤5 × ULN) Serum creatinine ≤1.5 x ULN Estimated glomerular filtration rate (eGFR)* ≥60 mL/min/1.73 m²

*MDRD-GFR (mL/min/1.73 m²) = 186 × (serum creatinine)-1.154 × (age)-0.203 (× 0.742 for females)

• Individuals with appropriate hematologic function confirmed within 2 weeks prior to screening without transfusion, based on the following criteria:

Hemoglobin >8.0 g/dL Absolute neutrophil count (ANC) >1,000/μL Absolute lymphocyte count (ALC) ≥300/μL Platelets ≥50,000/μL

• Individuals who are hemodynamically stable at the time of screening, have no signs of pericardial effusion, and have a left ventricular ejection fraction of 50% or higher based on an echocardiogram (ECHO) or multigated acquisition (MUGA) scan.
• Individuals from whom adequate non-mobilized cells for Anbal-cel manufacturing can be collected through leukapheresis.
• Individuals with an expected survival of 12 weeks or longer.
• Individuals who agree to comply with the scheduled site visits, examination schedules, and assessments as per the protocol during the course of the clinical study, including primary and secondary follow-up visits.
• Women of childbearing potential and men who agree to use appropriate contraception* for at least 12 months after Anbal-cel administration until Anbal-cel is no longer detected in PCR tests. *Hormonal contraception, intrauterine system implants, dual barrier methods (simultaneous use of a diaphragm or cervical cap with a condom and spermicide), sterilization procedures (e.g., vasectomy, bilateral tubal ligation), etc.

Exclusion criteria

• Individuals with a history of allogeneic hematopoietic stem cell transplantation.
• Individuals with the following medical history:

• History of other malignancies, except B-cell non-Hodgkin lymphoma, within 3 years prior to screening (however, individuals with a history of basal cell carcinoma, squamous cell carcinoma of the skin, localized prostate cancer, papillary thyroid cancer, cervical carcinoma in situ, or early-stage gastric cancer may participate if the investigator considers them to be fully cured after successful treatment, even if 3 years have not passed).
• History of unstable angina and/or myocardial infarction within 12 months prior to screening.
• History of thromboembolism, pulmonary embolism, or bleeding diatheses within 6 months prior to screening.
• History of hypoxia, clinically significant pleural effusion, or abnormal electrocardiogram findings within 6 months prior to screening.
• Individuals with the following conditions at the time of screening:

• Known positive for human immunodeficiency virus (HIV).
• Active neurological autoimmune or inflammatory diseases (e.g., Guillain-Barré syndrome, amyotrophic lateral sclerosis).
• Recurrent or symptomatic ventricular tachycardia or atrial fibrillation with rapid ventricular response despite treatment in the 3 months prior to screening.
• Individuals whose disease is rapidly progressing, as determined by the investigator.
• Individuals who have undergone major surgery requiring general anesthesia or respiratory support within 4 weeks prior to screening (however, video-assisted thoracoscopic surgery (VATS) or open-and-closed (ONC) surgery is permissible if conducted within 2 weeks).
• Individuals with severe infections requiring the administration of antibiotics, antifungals, or antivirals at the time of screening or with uncontrolled active infections.
• Individuals who have received or been exposed to other investigational drugs or devices within 4 weeks prior to screening.
• Pregnant or breastfeeding women.
• Individuals with a hypersensitivity to the ingredients of the investigational drug.