Iaso Bio Announces Publication of Phase 1 Clinical Data for RD118, a Fully Human Anti-GPRC5D CAR-T Therapy, in Relapsed/Refractory Multiple Myeloma in Blood Journal

Oct 22, 2025 17:01 CST Updated 17:01

IASO Biotechnology

Cancer Treatment New Drug Developer

On October 22, 2025, IASO Bio announced today that Blood, a top journal in the international hematology field, published the latest clinical research results of its self-developed fully human GPRC5D-targeted CAR-T cell therapy product RD118 for the treatment of relapsed/refractory multiple myeloma (R/R MM).Research data shows that RD118 demonstrates significant efficacy and manageable safety in R/R MM patients who have relapsed after multiple prior treatments, offering new hope for these patients.

The article titled "Fully Human anti-GPRC5D CAR T-Cell Therapy RD118 Induces Durable Remissions in Relapsed/Refractory Multiple Myeloma" was published in Blood (Full text available at: https://doi.org/10.1182/blood.2025030559). This is an open-label, dose-finding phase 1 clinical study aimed at evaluating the safety and efficacy of RD118 in treating R/R MM. The study was conducted at Ruijin Hospital, affiliated with Shanghai Jiao Tong University School of Medicine, and Tongji Hospital, affiliated with Tongji Medical College of Huazhong University of Science and Technology (registered under numbers NCT05759793 and NCT05219721).

This study included 18 patients who received RD118 infusion, including 17 patients with R/R MM and 1 patient with relapsed primary plasma cell leukemia (pPCL) after complete remission. The median age of the 18 patients was 59.5 years, and the median number of prior treatment lines was 5. High-risk features included double-hit cytogenetic abnormalities (50%), triple-refractory status (50%), penta-refractory status (22.2%), and prior CAR-T therapy targeting BCMA (38.9%). After lymphodepletion conditioning, patients received doses of 1.0, 2.0, or 3.0×10 in the dose-escalation phase.⁶cells/kg RD118 cell infusion, or receive 2.0×10 in the expansion phase⁶cells/kg RD118 cell infusion. At a median follow-up of 17.0 months, the study results showed:

Efficacy

The overall response rate (ORR) was as high as 94.4%, with 72.2% of patients achieving complete response or stringent complete response (CR/sCR). Among 7 patients previously treated with BCMA-targeted CAR-T cell therapy, the ORR still reached 85.7%, with 5 cases (71.4%) achieving CR/sCR. All 3 patients with extramedullary disease and 1 patient with pPCL achieved sCR and remained in remission at the last follow-up. The median progression-free survival (PFS) was 18.2 months; the 12-month PFS rate and overall survival (OS) rate were 82.1% and 93.3%, respectively.

Safety

The incidence of cytokine release syndrome (CRS) was 88.9%, mainly grade 1-2, with only one patient experiencing ≥grade 3 CRS, which resolved rapidly after treatment. Only one patient developed grade 3 immune effector cell-associated neurotoxicity syndrome (ICANS), which resolved within 72 hours. No cerebellar toxicity or treatment-related deaths were reported.

Conclusion:The fully human targeted GPRC5D CAR-T cell therapy RD118 demonstrated significantly outstanding efficacy in R/R MM patients who had undergone multiple prior lines of treatment (including those who relapsed after prior targeted BCMA CAR-T therapy), with an overall response rate of 94.4%, a median progression-free survival of 18.2 months, and a manageable safety profile.

Mijian QingProfessor

Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine

Multiple Myeloma Remains an Incurable Malignant Plasma Cell Disease. Despite the revolutionary impact of BCMA-targeted CAR-T therapy for relapsed/refractory patients, issues such as antigen escape can still lead to recurrence, making the search for new targets critical to breaking the deadlock. GPRC5D has garnered significant attention due to its high expression, specificity, and independence from BCMA. The results of this study strongly confirm its potential: among patients previously treated with BCMA-targeted CAR-T therapy, RD118 still achieved an overall response rate of 85.7%, with 71.4% of patients reaching complete remission. This fully demonstrates that GPRC5D is a highly valuable new therapeutic target.

Professor Chunrui Li

Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology

The innovative design of RD118 is the cornerstone of its outstanding clinical performance. It is a novel CAR-T cell therapy targeting GPRC5D, utilizing a fully human nanobody (VHH) as the antigen-binding domain. Compared to traditional single-chain variable fragment (scFv) designs, it has a smaller molecular size, lower immunogenicity, and potentially greater persistence, offering a new approach to overcoming the safety bottlenecks of existing similar therapies. Additionally, the incorporation of the 4-1BB/CD3ζ signaling domain for fine-tuned regulation of T-cell activity and persistence makes it a highly competitive next-generation CAR-T product.

Ms. Zhang Jinhua

Founder, Chairman and Chief Executive Officer of IASO Bio

We are pleased to announce that the outstanding clinical research results of RD118, a CAR-T product targeting GPRC5D independently developed by IASO Bio, have been published in the prestigious international journal *Blood*. This marks another significant milestone following the product’s IND approval by the National Medical Products Administration in June 2024. The treatment landscape for multiple myeloma requires continuous innovation, and GPRC5D has become one of the key targets shaping this landscape, alongside BCMA. RD118 is a CAR-T product developed based on our fully human monoclonal antibody platform, designed to offer patients a new treatment option, especially for those who have relapsed after prior BCMA-targeted CAR-T therapy, providing them with renewed hope. This publication will further motivate us to advance the clinical development of RD118, with the goal of bringing this innovative therapy to more patients worldwide as soon as possible.

About RD118

RD118 is a personalized, autologous infusion gene-modified T-cell immunotherapy product targeting GPRC5D, capable of identifying and eliminating malignant tumor cells expressing GPRC5D. The GPRC5D target is highly expressed in multiple myeloma cells and is only expressed in plasma cells and hair follicle cells in normal tissues, making it an emerging safe and effective target for the treatment of multiple myeloma.

The target recognition domain of RD118 was developed from IASO Bio's proprietary fully human single-domain antibody platform, offering advantages such as high affinity, high specificity, and low immunogenicity. Intracellularly, it incorporates a fusion of the 4-1BB (CD137) and CD3ζ signaling domains. RD118 has undergone extensive development in antibody screening and structural optimization, with the candidate molecule demonstrating excellent in vitro cytotoxic activity and in vivo tumor inhibition capabilities. It also exhibits robust in vivo expansion and persistence, showing strong developmental potential.