LUND, Sweden – May 12, 2026
BioInvent International AB announced new Phase 2a clinical data demonstrating that its investigational anti-TNFR2 monoclonal antibody BI-1808 produced strong clinical responses and robust immune activation in patients with advanced cutaneous T-cell lymphoma (CTCL), both as a single agent and in combination with KEYTRUDA® (pembrolizumab). The findings, which will be presented at the 2026 European Hematology Association (EHA) Congress in Stockholm, highlight BI-1808’s potential as a first-in-class immunotherapy targeting the tumor necrosis factor receptor 2 (TNFR2) pathway in difficult-to-treat hematologic cancers. The study demonstrated a 40% objective response rate (ORR) in heavily pretreated CTCL patients receiving BI-1808 monotherapy and a 50% ORR in patients treated with the combination of BI-1808 and pembrolizumab, alongside evidence of significant immune remodeling and durable anti-tumor activity.
BI-1808 Demonstrates Durable Responses in Advanced CTCL
According to BioInvent, the ongoing Phase 2a study enrolled patients with advanced mycosis fungoides (MF) and Sézary syndrome (SS), two aggressive forms of cutaneous T-cell lymphoma associated with poor long-term outcomes and limited treatment options after multiple lines of systemic therapy. Patients in the study had received a median of five prior systemic therapies in mycosis fungoides and three prior therapies in Sézary syndrome, underscoring the highly refractory nature of the population. Despite these challenges, BI-1808 demonstrated meaningful clinical activity across evaluable patients, including one durable complete response in a patient with Sézary syndrome that has remained ongoing for more than two years.
The company stated that multiple confirmed partial responses were also observed across both disease subtypes, with additional patients achieving stable disease. Importantly, the therapy showed encouraging efficacy not only as monotherapy but also when combined with KEYTRUDA®, Merck’s anti-PD-1 checkpoint inhibitor. The combination strategy is supported through an ongoing clinical collaboration agreement between BioInvent and Merck & Co., signed in 2021, to evaluate BI-1808 alongside pembrolizumab across hematologic cancers and solid tumors.
Researchers emphasized that durable responses are especially uncommon in advanced CTCL, where patients frequently relapse after exhausting available therapies. Five-year survival rates for advanced CTCL remain poor, particularly in Sézary syndrome, creating substantial unmet medical need for novel immunotherapies capable of delivering sustained disease control. BioInvent believes the latest findings reinforce TNFR2 as a promising new immuno-oncology target with potential applications extending beyond CTCL into broader oncology indications.
TNFR2 Targeting Drives Potent Immune Activation
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The EHA2026 data also provided important mechanistic insights into how BI-1808 reshapes the tumor immune microenvironment. TNFR2 is highly expressed on regulatory T cells (Tregs) within tumors, where it contributes to immune suppression and tumor survival. BioInvent stated that BI-1808 works by selectively depleting immunosuppressive Tregs while simultaneously reprogramming myeloid cells and enhancing CD8+ T-cell antitumor activity. Correlative analyses from the trial demonstrated significant depletion of Tregs alongside increased infiltration of CD8+ T cells and elevated granzyme B expression in responding patients, indicating enhanced cytotoxic immune activity inside tumor lesions.
Serum biomarker studies further showed rapid and sustained induction of IL-12, supporting a shift away from a tumor-promoting Th2 immune environment toward a more favorable Th1-driven anti-tumor immune response. Researchers also identified early transient skin reactions, referred to as “flares,” characterized by erythema, itching, and skin peeling. Rather than indicating disease progression, these flares were found to correlate with immune activation and CD8+ T-cell infiltration, suggesting they may represent a pharmacodynamic marker of on-target biological activity.
The therapy also demonstrated a favorable safety profile, with most treatment-related adverse events reported as mild to moderate in severity and no unexpected safety signals identified. Only limited Grade 3 adverse events were observed during the study. BioInvent executives stated that the strong balance between efficacy, immune activation, and tolerability supports continued development of BI-1808 as a potentially differentiated immunotherapy for T-cell lymphomas.
BioInvent Strengthens Immuno-Oncology Pipeline
BioInvent stated that the monotherapy arm of the Phase 2a study has already progressed into dose optimization to support future pivotal development planning. The company also highlighted that BI-1808 has received both FDA Fast Track Designation and Orphan Drug Designation for T-cell lymphoma in the United States, as well as Orphan Drug Designation for CTCL in Europe, positioning the program for accelerated regulatory development.
The company’s broader immuno-oncology strategy centers on developing first-in-class immune-modulatory antibodies using its proprietary F.I.R.S.T.™ platform, which identifies novel immune targets and antibody candidates for cancer therapy. In addition to BI-1808, BioInvent is advancing other TNFR2-targeting programs including BI-1910, a differentiated agonist antibody designed to directly stimulate T and natural killer (NK) cells through alternative immune activation mechanisms.
As pharmaceutical companies continue expanding investment in precision immunotherapies and next-generation immune checkpoint strategies, TNFR2-targeted therapies are emerging as a potentially important new area within oncology drug development. BioInvent believes the latest EHA2026 findings strengthen the rationale for TNFR2 blockade as a novel therapeutic strategy capable of overcoming immune suppression and improving clinical outcomes in patients with advanced hematologic malignancies.
Source: BioInvent press release
