BioInvent's BI-1808: A New Hope for Cutaneous T Cell Lymphoma?

The 16th Annual T-Cell Lymphoma Forum, held in La Jolla, California, from March 20-22, 2025, was abuzz with anticipation as BioInvent International AB presented groundbreaking data on their lead program, BI-1808. This anti-TNFR2 antibody, a first-in-class drug candidate, has shown promising early efficacy in the treatment of Cutaneous T Cell Lymphoma (CTCL), a rare and often aggressive form of cancer. The data, presented in a poster session, highlighted the potential of BI-1808 as a monotherapy in CTCL, offering new hope to patients who have exhausted standard treatment options.



The poster, titled "Evidence of T reg depletion and Corresponding Early Efficacy after Tumor Necrosis Factor Receptor 2 (TNFR2) Blockade by BI-1808 in Cutaneous T Cell Lymphoma (CTCL) Patients," presented compelling results from the ongoing Phase 2a dose expansion study. Out of four evaluable patients, three showed partial responses (PR) and one had stable disease (SD). All these patients had previously deteriorated after standard treatment, underscoring the unmet medical need in this patient population.

These findings are consistent with and support previous data disclosed by BioInvent. In June 2024, at the American Society of Clinical Oncology (ASCO) conference, BioInvent presented data showing one complete response (CR), one PR, and nine patients with SD in the single-agent arm of the Phase 2a study. The current findings from the T-Cell Lymphoma Forum further validate the potential of BI-1808 as a therapeutic option for CTCL patients.

The safety profile of BI-1808 is another critical aspect that makes it a promising candidate. In the ongoing Phase 1/2a study, BI-1808 has shown excellent tolerability both as a single agent and in combination with pembrolizumab. No Grade 3/4 adverse events related to BI-1808 were observed across the dose range of 25 to 1000 mg. Additionally, the combination therapy with pembrolizumab was well-tolerated, with only two dose-limiting toxicities (DLTs) observed in 19 patients dosed.

The pharmacokinetic profile of BI-1808 is also noteworthy. At doses greater than 675 mg every three weeks, the half-life of BI-1808 was approximately one week, leading to drug accumulation and complete receptor occupancy during the treatment interval. This pharmacokinetic profile ensures that the drug remains effective without causing significant adverse events.

The potential of BI-1808 as a therapeutic option for CTCL and other advanced solid tumors is further supported by its mechanism of action. BI-1808 targets TNFR2, a receptor that is particularly upregulated on regulatory T cells (Tregs) in the tumor microenvironment. By blocking the interaction of TNFR2 with its ligand TNF-α, BI-1808 confers FcγR-dependent depletion of intratumoral Tregs and mediates the expansion of intratumoral CD8+ T cells. This dual action of depleting Tregs and activating CD8+ T cells makes BI-1808 a promising candidate for cancer immunotherapy.

The data presented at the T-Cell Lymphoma Forum, along with the previous findings from the ASCO conference, suggest that BI-1808 could represent a new class of immunomodulatory agents with the potential to improve the efficacy of cancer therapy. However, it is essential to approach these findings with a balanced skepticism. While the early data are promising, the clinical development of BI-1808 is still in its early stages, and further data from the ongoing Phase 2a study are expected by mid-2025.

In conclusion, BioInvent's BI-1808 has shown early efficacy and a favorable safety profile in the treatment of CTCL. The data presented at the T-Cell Lymphoma Forum offer new hope to patients with this rare and aggressive form of cancer. However, it is crucial to await further data from the ongoing clinical trials to fully understand the potential of BI-1808 as a therapeutic option. The biotech industry and patients alike will be watching closely as BioInvent continues to develop this promising drug candidate.