JMB2403

JMB2403 (also known as 2403T62) is a tri-specific antibody designed for cancer immunotherapy. It consists of a potent anti-PD-1 IgG fused to weak agonistic nanobodies targeting the IL-2/15Rβ (CD122) and the common γ chain (CD132). This design enables the drug to block the PD-1/PD-L1 axis while simultaneously providing IL-2 receptor signaling specifically to activated PD-1+ T cells (cis-activation). By avoiding binding to IL-2Rα (CD25), JMB2403 minimizes the activation of regulatory T cells (Tregs) and reduces the risk of IL-2-related toxicities such as vascular leak syndrome. In preclinical models of melanoma and lung cancer, JMB2403 demonstrated superior anti-tumor efficacy compared to standard PD-1 inhibitors and clinical-stage PD-1-IL2 fusion proteins.