BioInvent International AB presents the latest data from a Phase 1/2a trial of its first-in-class anti-tumor necrosis factor receptor 2 (TNFR2) antibody BI-1808 as a single agent, at the Society of Immunotherapy for Cancer (SITC) 38th Annual Meeting in San Diego, California. The poster presentation, entitled "Phase 1/2a Clinical Trial of BI-1808, a Monoclonal Antibody to Tumor Necrosis Factor Receptor 2 (TNFR2) as Single Agent and in Combination with Pembrolizumab" include data from the BI-1808 monotherapy arm of the Phase 1 study and display encouraging results in the form of early efficacy signals. Furthermore, BI-1808 exhibited a favorable safety profile with no dose-limiting toxicity observed in the monotherapy arm and no maximum tolerated dose could be found.

BI-1808 was well tolerated across all dose levels studied. The data strengthens the outlook for the ongoing Phase 2 part of the clinical trial and positions BI-1808 as the best-in-class. BI-1808 administered as single agent induced a robust partial response (PR) in a patient with a gastrointestinal tumor (GIST) who had received 12 previous lines of treatment.

Immune checkpoint inhibitors have previously shown very limited activity in this tumor type. The patient is still receiving BI-1808 treatment, and the most recent scan showed a tumor burden reduced to 48% compared to baseline, with 2/4 target lesions no longer detectable. There are a further 7 cases of stable disease out of 21 evaluable patients and pharmacokinetic/pharmacodynamic data has enabled identification of a wide dose range where complete target coverage can be achieved with a remarkable safety profile.

The title and number of the SITC poster presentation is as follows: Title: Phase 1/2a Clinical Trial of BI-1808, a Monoclonal Antibody to Tumor Necrosis Factor Receptor 2 (TNFR2) as Single Agent and in Combination with Pembrolizumab Number: 757. BI-1808 and the second anti-TNFR2 antibody BI-1910, are part of BioInvent's tumor-associated regulatory T cells (Treg)-targeting program. TNFR2 is particularly upregulated on Tregs of the tumor microenvironment and has been shown to be determinant for tumor growth and survival, representing a new and promising target for cancer immunotherapy.

The dose-escalation, multicenter, first-in-human, consecutive-cohort, open-label trial of BI-1808 is investigating it as a single agent and in combination with MSD's (Merck & Co. Inc., Rahway, NJ., USA) anti-PD-1 therapy KEYTRUDA® (pembrolizumab) in subjects with advanced malignancies, whose disease has progressed after standard therapy. It consists of Phase 1 Parts A and B (dose escalation as single agent and in combination with pembrolizumab, respectively), and Phase 2a Parts A and B (dose expansion cohorts with treatment as single agent and in combination, respectively).

The efficacy of BI-1808 as single agent is currently further explored in an ongoing Phase 2a trial in a larger sample of patients. In addition to the originally planned expansion cohorts in lung cancer, ovarian cancer and cutaneous T cell lymphoma (CTCL), BioInvent plans to enlarge the scope of the signal seeking cohorts to include new cohorts in melanoma and other forms of T cell lymphomas. This is driven by the exciting data observed so far.

Phase 1 data on the combination of BI-1808 with pembrolizumab is due in H1 2024.