Blood Publishes Promising Results of IASO Bio's Anti-GPRC5D CAR-T RD118 in Relapsed/Refractory Multiple Myeloma

SHANGHAI, NANJING, China and PLEASANTON, Calif., Oct. 22, 2025 /PRNewswire/ -- IASO Biotherapeutics ("IASO Bio"), a biopharmaceutical company focused on the discovery, development, production, and commercialization of novel cell therapies, today announced that the Blood published the latest results of its independently developed fully human anti-GPRC5D CAR-T cell therapy, RD118, for the treatment of relapsed/refractory multiple myeloma (R/R MM). The study demonstrates that RD118 exhibited significant efficacy and a manageable safety profile in heavily pretreated R/R MM patients, offering new therapeutic hope for the patients with a poor prognosis.

The study entitled 'Fully Human anti-GPRC5D CAR T-Cell Therapy RD118 Induces Durable Remissions in Relapsed/Refractory Multiple Myeloma' has been published in Blood. Full text available at: https://doi.org/10.1182/blood.2025030559. This is an open-label, phase 1 dose-escalation and expansion study to evaluate the efficacy and safety of RD118 in the treatment of R/R MM, which was conducted at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, and Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (registered as NCT05759793 and NCT05219721).

A total of eighteen patients received RD118 infusion in this study, including 17 with R/R MM and 1 with a history of primary plasma cell leukemia (pPCL) who had relapsed after achieving complete remission. Among the 18 patients, the median age was 59.5 years, and the median line of prior therapies was 5. High-risk features included double-hit cytogenetics (50%), triple-class refractoriness (50%), penta-class refractoriness (22.2%), and prior anti-BCMA CAR-T therapy (38.9%). Following lymphodepletion with fludarabine and cyclophosphamide, patients received a single infusion of RD118 at one of three dose levels (1.0, 2.0, or 3.0×10⁶ cells/kg) during the dose-escalation phase or 2.0×10⁶ cells/kg in the expansion cohort. At a median follow-up of 17.0 months, results show that:

Efficacy: The overall response rate (ORR) was 94.4%, with 72.2% of patients achieving complete response or stringent complete responses (CR/sCR). Among the seven patients who had received prior BCMA-directed CAR T-cell therapy, the ORR was 85.7%, with 5 patients (71.4%) achieving CR/sCR. All three patients with extramedullary disease and the patient with pPCL achieved sCR and remained in remission at last follow-up. The median progression-free survival (PFS) was 18.2 months, with 12-month PFS and overall survival (OS) rates of 82.1% and 93.3%, respectively.

Safety: Cytokine release syndrome (CRS) occurred in 88.9% of patients, primarily grade 1-2. Only one patient developed grade 3 or higher CRS, which rapidly recovered with intensive management. One patient developed grade 3 immune effector cell–associated neurotoxicity (ICANS) which resolved within 72 hours. No cerebellar toxicities or treatment-related deaths were reported

Conclusion ：Fully human anti-GPRC5D CAR-T therapy RD118 demonstrated a 94.4% ORR and a median PFS of 18.2 months with a manageable safety profile in heavily over pretreated R/R MM, including patients who relapsed after prior anti-BCMA CAR-T therapy.

Professor Mi Jianqing from Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, commented: "Multiple myeloma remains an incurable malignant plasma cell disorder. While anti-BCMA CAR-T therapy has greatly transformed the treatment for relapsed/refractory patients, challenges such as antigen escape often leads to relapse, highlighting the need for novel targets to overcome these limitations. GPRC5D has attracted significant attention due to its high expression, specificity, and independence from BCMA. The current study results have validated its potential: among patients previously treated with anti-BCMA CAR-T therapy, RD118 achieved an 85.7% overall response rate, with 71.4% of patients reaching complete response, demonstrating that GPRC5D is a highly promising novel therapeutic target."

Professor Chunrui Li from Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, commented: "The innovative design of RD118 is the foundation of its outstanding clinical performance. RD118 is a novel GPRC5D-directed CAR-T that incorporates a fully human nanobody (VHH) as its antigen-binding domain. This design provides distinct advantages over conventional scFv, it is expected to lower immunogenicity, and potentially enhanced persistence, offering a new approach to overcome the safety limitations of existing comparable therapies. Meanwhile, the construct also includes a 4-1BB and a CD3ζsignal domains, which support expansion and sustained anti-tumor activity. Together, these features position RD118 as a highly competitive next-generation CAR-T product."

Ms. Jinhua Zhang, Founder, Chairwoman and CEO of IASO Bio, remarked: "We are delighted that the remarkable research results of IASO Bio's independently developed anti-GPRC5D CAR-T product, RD118, for the treatment of R/R MM have been published in the prestigious international journal Blood. This achievement marks another significant milestone for the product following the IND approval from China's NMPA in June 2024. The treatment landscape for multiple myeloma requires continuous innovation, and GPRC5D, alongside BCMA, are represents a crucial therapeutic target in this field. Developed based on our fully human antibody platform, RD118 is designed to provide a new treatment option for patients. It offers renewed hope particularly for those who have relapsed after prior anti-BCMA CAR-T therapy. This publication will further motivate us to advance the clinical development of RD118, with the goal of delivering this innovative therapy to more patients worldwide."

About RD118

RD118 is an autologous T-cell immunotherapy product targeting G protein-coupled receptor class C group 5 member D (GPRC5D). It can identify and eliminate malignant tumor cells expressing GPRC5D. GPRC5D is highly expressed on multiple myeloma cells. However, in normal tissues, its expression is limited to plasma cells and hair follicle cells. Such a feature has made GPRC5D a promising safe and effective target for the treatment of multiple myeloma.

The antigen recognition domain of RD118 is developed from IASO Bio's proprietary fully human single-domain antibody library. It has advantages of high affinity, high specificity, and low immunogenicity. The intracellular domain is a fusion of 4-1BB (CD137) and CD3ζ signaling domains. RD118 has been subjected to extensive development and optimization in terms of antibody screening and structure design. The candidate molecule has demonstrated excellent in vitro cytotoxic activity and in vivo tumor suppression ability. Additionally, it has good expansion capability and persistence in vivo, indicating high development potential.

SOURCE IASO Bio