Abogen's mRNA-Encoded T-Cell Engager ABO2203 Shows Promise in B-Cell Lymphoma with Superior Safety Profile
核心洞察
Abogen (搜索)'s ABO2203, an mRNA-encoded CD3 (搜索)×CD19 (搜索) bispecific T-cell engager, demonstrated exceptional safety with no cytokine release syndrome (搜索) observed in first-in-human trial for relapsed/refractory B-cell non-Hodgkin lymphoma (搜索).
The therapy showed dose-dependent efficacy with objective response rates reaching 100% in the high-dose cohort and complete responses observed across both aggressive and indolent lymphoma subtypes.
ABO2203's sustained pharmacokinetic profile contrasts with protein-based T-cell engagers, potentially offering improved tolerability and extended dosing intervals while maintaining anti-tumor efficacy.
Abogen (搜索) announced preliminary clinical results from the first-in-human study of ABO2203, a lipid nanoparticle-formulated mRNA drug candidate encoding a CD3 (搜索)×CD19 (搜索) bispecific T-cell engager, in patients with relapsed/refractory B-cell non-Hodgkin lymphoma (搜索). The data were presented at the AACR Annual Meeting 2026 in San Diego by Professor Li Wang of Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine.
ABO2203 is designed to enable in vivo T-cell engager expression via mRNA technology, with the goal of mitigating cytokine release syndrome (搜索) while maintaining robust clinical efficacy. The approach addresses a critical safety challenge in T-cell engager therapies, as nearly all marketed protein-based T-cell engagers carry black-box warnings for cytokine release syndrome.
Addressing Critical Safety Limitations
Current protein-based T-cell engager therapies face significant safety challenges, with Grade 2 cytokine release syndrome (搜索) occurring on average in 13%-22% of patients despite step-up dosing strategies. Some cases require hospitalization or ICU admission, and drug development typically requires 2-3 years for dose-finding to determine appropriate step-up dosing regimens.
These safety concerns become even more pronounced when considering T-cell engager applications in autoimmune diseases (搜索), where patients often exhibit heightened immune responsiveness and lower tolerance for adverse events. In chronic, generally non-life-threatening autoimmune conditions, cytokine release syndrome (搜索)-related risks present significant clinical barriers, particularly in outpatient settings.
Clinical Trial Results
The first-in-human trial of ABO2203 in relapsed/refractory B-cell non-Hodgkin lymphoma (搜索) is a dose-escalation and expansion study. The presentation included data from nine patients in the dose-escalation stage who had received a median of four prior lines of therapy and all had failed prior CD20 (搜索)-targeted therapy. ABO2203 was administered subcutaneously across dose levels ranging from 3 μg to 1,920 μg, with the maximum tolerated dose not yet reached.
Safety Profile
ABO2203 demonstrated exceptional tolerability across all evaluated dose levels. No dose-limiting toxicities, cytokine release syndrome (搜索), or immune cell-associated neurotoxicity syndrome were observed. Liver enzyme elevations were limited to Grade 1 and occurred at low incidence. The most common adverse event was Grade 1-2 pyrexia, without clinically significant changes in oxygen saturation or blood pressure. Grade 3/4 events were infrequent and primarily hematologic, with no unexpected safety signals beyond those associated with the T-cell engager class or non-Hodgkin lymphoma.
Pharmacokinetic Advantages
T-cell engager expression was detected across all three dose cohorts, with a gradual time to peak concentration after each administration (Tmax = 5.5 days) and a half-life of 7.9 days. These findings support an initial once-weekly dosing regimen, with potential to extend dosing intervals to every two weeks following response, and possibly every three to four weeks thereafter.
In contrast to the "pulse-like" pharmacokinetic profile of protein-based T-cell engagers, the mRNA-expressed T-cell engager demonstrated a flatter and more sustained exposure profile. Compared with a protein T-cell engager of identical amino acid sequence (P4107 (搜索)), which reached peak levels and was eliminated rapidly, ABO2203 exhibited a delayed peak T-cell engager concentration and prolonged half-life. The lower peak concentration may help mitigate cytokine release, while sustained mRNA expression may contribute to more durable anti-tumor efficacy than P4107.
Efficacy Results
Based on Lugano 2014 criteria, objective response rates were dose-dependent across cohorts, reaching 33%, 67%, and 100% in the low-, medium-, and high-dose groups, respectively. Complete metabolic responses were observed in both the medium- and high-dose cohorts, with a 100% complete response rate achieved in the high-dose cohort as updated by Professor Li Wang. Responses were seen across both aggressive (DLBCL (搜索)) and indolent (FL, MCL, MZL) lymphomas, with a 100% objective response rate in follicular lymphoma (搜索).
Market Context and Commercial Potential
The results provide initial clinical proof of concept for mRNA-encoded T-cell engager therapeutics, demonstrating a superior safety profile, favorable pharmacodynamics, and encouraging efficacy in B-cell non-Hodgkin lymphoma. The data also suggest potential applications in autoimmune diseases (搜索), as ABO2203's ability to effectively deplete B cells within lymph nodes may address a well-recognized limitation of conventional CD19 (搜索)/CD20 (搜索) monoclonal antibodies and existing T-cell engagers in these indications.
The results come amid growing momentum in the T-cell engager field. Since late 2024, the sector has seen increased deal activity, including Merck (搜索)'s $1.3 billion acquisition of CN201 (CD3 (搜索)/CD19 (搜索)) and GSK's $300 million upfront licensing of Chimagen (搜索)'s trispecific T-cell engager. More recently, Gilead announced a $1.675 billion upfront acquisition of Ouro Medicines (搜索) and its CD3/BCMA (搜索) bispecific asset, CM336/OM336 (搜索) in March. With the global T-cell engager market projected to reach $121 billion by 2035 according to Frost & Sullivan, ABO2203 represents a promising asset in this rapidly expanding category.
Abogen (搜索) is a clinical-stage biotechnology company founded in 2019, dedicated to developing novel medicines based on RNA technologies. The company has established integrated in-house capabilities spanning the full mRNA development lifecycle, including protein engineering, mRNA sequence design and synthesis, lipid nanoparticle delivery, formulation, and large-scale manufacturing.