The Annual Congress of the European Alliance of Associations for Rheumatology (EULAR), one of the world’s top authoritative academic conferences in rheumatology and immunology, is set to kick off shortly. BristarImmunotech will present clinical findings of its universal CD19 STAR-T (YTS109) for severe/refractory autoimmune diseases via an abstract presentation, showcasing the company’s proprietary technological strengths and clinical translational achievements in the field of off-the-shelf allogeneic cellular therapeutics for autoimmune disorders.

Abstract ID: 779

Abstract Title: Safety and Efficacy of Allogeneic anti-CD19 STAR-T cell in Severe/Refractory Autoimmune Diseases: A phase I trial

Category: Phase I Clinical Study | Main Topic: Systemic Lupus Erythematosus | Subtopic: Adult Rheumatology

Collaborative Team: BristarImmunotech & Changhai Hospital, Naval Medical University (led by Professor Huji Xu)

Abstract Link: To be released

Clinical Trial Registration: NCT06379646

Sponsored and led by Professor Huji Xu, a leading domestic expert in rheumatology from Changhai Hospital, Naval Medical University, this prospective Phase I trial explores the clinical application of universal STAR-T across multiple severe autoimmune disease indications.

YTS109 is an allogeneic off-the-shelf CD19 STAR-T product independently developed by BristarImmunotech based on two core proprietary platforms: original STAR-T technology and site-specific genome integration engineering. Leveraging CRISPR/Cas9 gene editing, the product precisely knocks out key genes responsible for allogeneic graft rejection and inserts anti-CD9 STAR transgene into the endogenous TRAC locus to drive physiological TCR-like signal transduction. This design markedly enhances in vivo expansion capacity, tissue infiltration and anti-disease potency, overcoming long-standing bottlenecks of conventional allogeneic CAR-T including severe graft-versus-host disease (GVHD), insufficient cell persistence and poor clinical accessibility. Featuring no patient HLA matching requirement and scalable large-scale manufacturing, YTS10 is broadly applicable to diverse B-cell-driven autoimmune diseases such as lupus nephritis, primary Sjögren’s syndrome and diffuse cutaneous systemic sclerosis, providing an off-the-shelf therapeutic option for critically ill patients lacking standard effective therapies.

The trial enrolled and treated a total of nine patients with intractable severe autoimmune diseases refractory to conventional therapies between April 2024 and April 2025, covering three core disease categories: six cases of lupus nephritis (SLE-LN), one case of primary Sjögren’s syndrome (pSS), and two patients with diffuse cutaneous systemic sclerosis (dcSSc). All subjects received lymphodepletion conditioning with fludarabine plus cyclophosphamide prior to YTS109 infusion. During the whole trial period, investigators continuously monitored in vivo STAR-T kinetics, B-cell depletion and reconstitution, safety parameters as well as predefined clinical endpoints. Upcoming EULAR data will demonstrate differentiated clinical benefits across three disease cohorts alongside a favorable overall safety profile.

Notable Clinical Efficacy

Lupus Nephritis (SLE-LN)

Six patients (2 males, 4 females; aged 23–41 years, disease duration ranging from 2 to 30 years) with median follow-up of 12 months:

• All six patients achieved clinical response meeting SRI-4 criteria;
• Five out of six patients attained LLDAS-defined low disease activity at Month 6 post-treatment;
• Three patients achieved complete normalization of 24-hour urinary protein, obtained DORIS-defined complete remission including full renal remission within 1–2 months, with sustained disease remission exceeding 12 months;
• Post-treatment renal biopsy from five patients confirmed prominent pathological improvement: reduced glomerular cellular infiltration and mesangial expansion, decreased immune complex deposition, and ameliorated tubular/interstitial lesions, indicating substantial renal inflammatory regression and structural repair.

Primary Sjögren’s Syndrome (pSS)

This marks the world’s first publicly reported cellular therapy case for pSS with landmark clinical value:

• The patient reached predefined therapeutic response as early as one month after infusion;
• Marked regression of lymphadenopathy and peripheral neuropathy;
• ESSDAI disease activity score dropped from 24 down to 7, ESSPRI quality-of-life score declined from 7.667 to 3.67 alongside obvious improvement in lacrimal gland secretion function.

Diffuse Cutaneous Systemic Sclerosis (dcSSc)

Two enrolled patients (aged 35–48 years, disease duration 5–20 years, median follow-up 6 months):

• ACR-CRISS scores reached 0.908 and 0.951 respectively;
• EUSTAR-AI scores were 0.252 and 1.504 at six months post-treatment;
• Modified Rodnan Skin Score (mRSS) decreased from 12 to 3 and from 13 to 6 individually, demonstrating significant reversal and improvement of cutaneous fibrosis.

Favourable Safety Profile

• Only three patients developed Grade 1 cytokine release syndrome (CRS);
• No cases of ICANS, GVHD or unexpected serious adverse events were observed throughout treatment;
• Two patients developed mild self-limiting infections that resolved spontaneously without targeted medical intervention, reflecting an overall well-tolerated safety profile.

Clarified Mechanism of Action

Pharmacokinetic data confirmed robust stable in vivo expansion of infused YTS109, leading to profound B-cell depletion followed by orderly physiological reconstitution of naive B lymphocytes. Multi-omics analyses including transcriptomics and proteomics further verified that YTS109 eliminates pathogenic immune clones, suppresses systemic inflammatory signaling pathways, and triggers tissue repair and immune regulatory cascades, ultimately remodeling local renal immune microenvironment and restoring systemic immune homeostasis.

Contact Us

•BD Cooperation: jinming@bristarimmunotech.com

•Clinical Cooperation: zhenghongli@bristarimmunotech.com