Excyte Received U.S. FDA IND Clearance for YK012 — World’s First TCE Bispecific Antibody to Treat Primary Membranous Nephropathy
Key Highlights
- YK012 is the world’s first TCE that advanced into clinic studies for pMN and now received IND clearance in the US to evaluate safety and efficacy
- Data from current China pMN trial showed promising efficacy and safety data to date
- Milder T cell activation than Blincyto and Target cell-dependent T cell activation
- Multiple CR observed in ongoing r/r NHL and r/r ALL Phase Ib/II2 trials
BEIJING, September 29, 2025 --, Excyte Biopharma Ltd. (hereinafter referred to as “Excyte”) announced that its in-house developed innovative bispecific antibody YK012, targeting CD19/CD3, has officially received Investigational New Drug (IND) clearance from the U.S. Food and Drug Administration (FDA) for the treatment of primary membranous nephropathy (pMN). It is the world’s first T-cell engager (TCE) bispecific antibody drug approved for clinical trials for this indication, representing a simultaneous breakthrough in China’s proprietary bispecific antibody technology for autoimmune diseases in both China and the U.S. Earlier in 2025, Excyte received IND approval in China for pMN and has been enrolling patients since May 2025. Excyte is simultaneously conducting clinical trials of YK012 in hematologic malignancies.
Addressing Treatment Challenges in pMN: A Globally Pioneering "B-Cell Reset" Mechanism
Primary membranous nephropathy is a chronic autoimmune kidney disease characterized by the deposition of immune complexes in the glomerular basement membrane. It is a leading cause of nephrotic syndrome in adults and can result in progressive renal impairment. Current treatments are limited by delayed onset, poor efficacy, and safety concerns, underscoring the urgent need for novel therapeutic approaches. YK012 employs a unique "B-cell reset" mechanism that targets the CD19 antigen on B cells and the CD3 receptor on T cells, activating T cells mildly only in the presence of target cells to precisely eliminate B cells.
Clinical and preclinical data demonstrate three core advantages of YK012:
Long half-life, supporting once-weekly intravenous administration;
Favorable safety and tolerability, with CRS and ICANS limited to Grade ≤2;
High expression levels exceeding 5000 mg/L, providing a strong foundation for industrialization.
China-U.S. Synergy Accelerates Development, Targeting a Multibillion-Dollar Autoimmune Market
The development of YK012 leverages Excyte’s dual-center strategy, comprising its Beijing headquarters and U.S. wholly-owned subsidiary, Excyte LLC. Following this FDA IND approval, the company will progressively initiate international multicenter clinical studies. These efforts will complement data from the ongoing multicenter trial in China led by Professor Zhao Minghui of Peking University First Hospital, accelerating global development progress.
Excyte Co-founder Qingwu Meng stated, “The expansion of YK012 from hematologic malignancies to autoimmune applications fully demonstrates the cross-disciplinary potential of the FIST bispecific antibody platform. Mechanistically, this drug is suited for dozens of autoimmune diseases, including pMN and systemic lupus erythematosus (SLE), and is poised to achieve global competitiveness as a 'one drug, multiple indications' therapy.”
Co-founder Qing’an Yuan pointed out, “Nephrology is a key strategic focus for our company, with primary membranous nephropathy, IgA nephropathy, and lupus nephritis among our high-priority areas. The FDA’s IND approval for YK012 is a major milestone for both Excyte and patients with primary membranous nephropathy. We remain committed to advancing this innovative therapy to address the pressing need for safer and more effective treatment options.”
YK012 has already obtained patent protection in multiple countries, including China and Japan, and has attracted several partnership inquiries in overseas BD discussions, reflecting initial international recognition of its global commercial value.
Regarding clinical progress, the Phase Ia trial of YK012 for pMN has been successfully initiated, with dosing completed in three cohorts. Preliminary data indicate favorable safety and tolerability, and two patients have achieved partial remission(PR), demonstrating promising early efficacy signals. Meanwhile, the Phase Ib/II clinical trial of YK012 for systemic lupus erythematosus (SLE) in China has also completed the administration of the study drug to the first cohort of patients. The first patient achieved comprehensive improvement in symptoms and met the criteria for Lupus Low Disease Activity State (LLDAS).
The drug has also delivered excellent results in oncology, consistently demonstrating robust efficacy and safety in relapsed/refractory non-Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL).
Industry Milestone: TCE Bispecific Antibody Pioneers New Frontier in Autoimmune Treatment
While global TCE bispecific R&D has largely focused on oncology, YK012 stands out as a representative TCE drug entering autoimmune therapeutics. Its “low toxicity and long-acting” profile breaks through the safety barriers of traditional immunotherapies. With clinical advances in autoimmune indications such as pMN, YK012 is expected to become the first bispecific blockbuster drug covering both oncology and autoimmune diseases, unlocking a global market worth over $100 billion.
In parallel, Excyte is advancing the development of its second bispecific antibody, YKST02 (BCMA/CD3). The company has formally submitted a pre-IND application in China for IgA nephropathy. In the field of multiple myeloma treatment, YKST02 has already demonstrated considerable efficacy, particularly in patients with extramedullary tumors.
Notably, the combination of YKST02 and YK012 can target the full spectrum of B-cell development stages, further expanding the treatment landscape across autoimmune and oncology fields.
About YK012
YK012 is a T-cell engaging bispecific antibody targeting both CD19 and CD3, activating T-cell immunity via CD3 while targeting CD19. It is developed from Excyte’s proprietary FIST platform. In December 2024, YK012 obtained Clinical Trial Approval Notice (No. CXSL2400727) from China's National Medical Products Administration (NMPA) and was registered on ClinicalTrials.gov (NCT06982729). Earlier this year, Excyte also secured clinical trial approval for systemic lupus erythematosus (SLE), with Professor Xiaofeng Zeng from Peking Union Medical College Hospital serving as Principal Investigator. YK012 has also been investigated in oncology indications such as NHL and ALL.
About Excyte
Excyte Ltd. was co-founded by biotech industry veterans with decades of antibody engineering experiences. The company has also established a U.S.-based wholly-owned subsidiary, Excyte LLC, forming a dual-engine drug R&D hub spanning China and the U.S. Excyte is dedicated to developing innovative bispecific antibody drugs for hematologic cancers, multiple myeloma, solid tumors, autoimmune diseases, and other conditions. Excyte’s FIST platform and next generation assets possess features such as long-acting, low-toxicity, and high-yield technological innovations. For more information, please visit https://www.iExcyte.com/
Business Development Contact
Ying Liu, liuying@iExcyte.com