LUND, Sweden, June 11, 2026
BioInvent International AB presented new clinical data from its ongoing Phase 2a study evaluating BI-1808, a novel anti-TNFR2 monoclonal antibody, in patients with advanced cutaneous T-cell lymphoma (CTCL). The results, presented at the European Hematology Association (EHA) 2026 Congress, demonstrated meaningful clinical responses and immune activation both as a single agent and in combination with KEYTRUDA® (pembrolizumab) in a heavily pretreated patient population with limited treatment options.
BI-1808 Monotherapy Demonstrates Durable Responses
In the monotherapy cohort, 20 patients with advanced CTCL received BI-1808 at 1000 mg every three weeks. Among the 15 evaluable patients, the therapy achieved a 40% objective response rate (ORR), including five confirmed partial responses across both mycosis fungoides (MF) and Sézary syndrome (SS) subtypes. Notably, one patient with Sézary syndrome achieved a complete response that has remained ongoing for approximately two years. An additional eight patients achieved stable disease, resulting in a 93% disease control rate (DCR). Two patients with peripheral T-cell lymphoma were also evaluable, with one partial response and one stable disease observed.
Combination with KEYTRUDA Shows Enhanced Activity
In the combination arm, nine patients received BI-1808 together with pembrolizumab. The cohort represented a heavily pretreated population with a median of six prior systemic therapies and no prior anti-PD-1 exposure. Among the eight evaluable patients, four achieved partial responses and two achieved stable disease, resulting in a 50% ORR and a 75% DCR. Investigators noted that the lower disease control rate compared with monotherapy likely reflects the smaller sample size and more heavily pretreated nature of the combination cohort.
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Immune Activation Supports Mechanism of Action
Translational analyses provided evidence that BI-1808 is activating anti-tumor immunity through TNFR2 blockade. The study demonstrated sustained depletion of CD4-positive regulatory T cells, increased serum levels of IL-12, CXCL11, and CCL19, and enhanced infiltration of CD8-positive T cells into tumors. These findings support BI-1808’s proposed mechanism of selectively targeting TNFR2 to deplete immunosuppressive Tregs and reprogram the tumor microenvironment, potentially leading to durable anti-tumor immune responses.
Favorable Safety Profile Supports Continued Development
BI-1808 was reported to be very well tolerated as a single agent, with the most common treatment-related adverse events including fatigue, transient cutaneous flares, and hypertension. The combination with pembrolizumab was also generally well tolerated, with fatigue, chills, pyrexia, and infusion-related reactions being the most frequently reported adverse events. BioInvent noted that the favorable tolerability profile has allowed some patients to remain on treatment long term.
BioInvent emphasized that the results strengthen the rationale for TNFR2 as a therapeutic target in CTCL and support further development of BI-1808 as both a monotherapy and combination immunotherapy approach. The program has already received FDA Fast Track Designation and Orphan Drug Designation for CTCL, as well as a positive opinion from the European Medicines Agency for orphan designation, reflecting the significant unmet need in this rare lymphoma.
Source: BioInvent, press release
