Case Report | Preliminary Clinical Data of CARsgen's Allogeneic BCMA CAR-T Product CT0596 for the Treatment of Primary Plasma Cell Leukemia

SHANGHAI, Oct. 19, 2025 /PRNewswire/ -- Primary plasma cell leukemia (pPCL) is a rare and highly aggressive plasma cell malignancy, often associated with complex genetic abnormalities. There is currently no standard treatment regimens, and conventional therapies for multiple myeloma are typically used. While targeted agents and autologous hematopoietic stem cell transplantation can slightly extend the overall survival of pPCL patients to 1.5–3 years, relapsed/refractory pPCL after multiple lines of therapy presents a significant clinical challenge due to the extremely limited treatment options and rapid disease progression, making it difficult to re-induce remission with existing therapies.

CT0596 is an allogeneic BCMA-targeted CAR-T therapy developed using CARsgen's proprietary THANK-u Plus™ platform. It is currently being evaluated in investigator-initiated trials for plasma cell malignancy. As of the data cutoff date (Oct 17, 2025), two patients with relapsed/refractory pPCL had been enrolled. Details are as follows:

pPCL-01:

A 62-year-old male with IgG-λ type experienced poor disease control and rapid progression despite previous autologous hematopoietic stem cell transplantation and treatment with triple classes of drugs (proteasome inhibitor, immunomodulatory agent, and CD38 monoclonal antibody). By the screening period, his serum free light chain level had reached 10,374.86 mg/L. The patient underwent two CAR-T cell infusions approximately two months apart: he first received low-dose lymphodepletion and a relatively lower dose of CAR-T cells per protocol, then followed one cycle of bridge therapy. About one month after the failure of bridge therapy, he received a second CAR-T cell infusion. Following this infusion, he developed Grade 2 CRS, Grade 4 cytopenia, and a lung infection, but recovered after supportive treatment including tocilizumab, corticosteroids, autologous stem cell infusion, and anti-infective therapy. CAR-T cells expanded robustly, with a peak copy number (Cmax) of 161,971 copies/μg gDNA, and copy numbers remained at 10³ by Week 8. Efficacy assessments at both Week 4 and Week 8 post-infusion showed stringent complete response (sCR), and bone marrow minimal residual disease (MRD) was negative (< 10⁻⁶) at Week 4.

pPCL-02:

A 70-year-old male with κ light chain had previously been treated with triple classes of drugs (proteasome inhibitor, immunomodulatory agent, and CD38 monoclonal antibody). The patient developed Grade 1 CRS, Grade 4 neutropenia, and thrombocytopenia following lymphodepletion and CAR-T cell infusion. The CRS and cytopenias were resolved after treatment with tocilizumab and other supportive measures. CAR-T cells expanded robustly, with a Cmax of 151,654 copies/μg gDNA. The patient achieved sCR at the Week 4, Week 8, and Week 12 assessments post-infusion, with bone marrow MRD negative (< 10⁻⁶) at both Week 4 and Week 12.

Based on the current findings, CT0596 has exhibited robust and rapid efficacy in heavily pretreated patients with rapidly progressive relapsed/refractory pPCL. Both pPCL patients achieved sCR following CT0596 infusion, with peak CAR-T cell copy numbers exceeding 10⁵ copies/μg gDNA. Aside from expected CAR-T-associated toxicities such as CRS and hematologic adverse events, no significant organ toxicities were observed, indicating a manageable safety profile. These results lend strong support to the continued investigation of CT0596 across a broader spectrum of plasma cell neoplasms.

About CT0596

CT0596 is an allogeneic BCMA-targeted CAR-T therapy developed using CARsgen's proprietary THANK-u Plus™ platform. It is currently being evaluated in investigator-initiated trials for relapsed/refractory multiple myeloma (R/R MM) or plasma cell leukemia (PCL). CT0596 demonstrated preliminary favorable tolerability and encouraging efficacy signals. Further investigation is planned in additional plasma cell malignancies and autoimmune diseases mediated by autoreactive plasma cells. The company anticipates submitting an Investigational New Drug (IND) application in the second half of 2025.

About CARsgen Therapeutics Holdings Limited

CARsgen is a biopharmaceutical company focusing on developing innovative CAR T-cell therapies to address the unmet clinical needs including but not limited to hematologic malignancies, solid tumors and autoimmune diseases. CARsgen has established end-to-end capabilities for CAR T-cell research and development covering target discovery, preclinical research, product clinical development, and commercial-scale production. CARsgen has developed novel in-house technologies and a product pipeline with global rights to address challenges faced by existing CAR T-cell therapies. Efforts include improving safety profile, enhancing the efficacy in treating solid tumors, and reducing treatment costs, etc. CARsgen's mission is to be a global biopharmaceutical leader that provides innovative and differentiated cell therapies for patients worldwide and makes cancer and other diseases curable.

Forward-looking Statements

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SOURCE CARsgen Therapeutics