MB5029

MB5029 is a bispecific fusion protein immuno-oncology drug candidate developed by Must Bio. It combines an anti-PD-1 antibody with an engineered interleukin-2 variant (IL-2v) that lacks IL-2Rα binding and has attenuated IL-2Rγ binding. This design enables selective activation of immune cells within the tumor microenvironment (TME), where PD-1 is overexpressed, while minimizing immune activation in peripheral blood, thereby reducing systemic toxicity. Preclinical studies demonstrate robust anti-tumor efficacy, increased tumor-infiltrating lymphocytes (especially CD8+ T cells), and improved safety compared to conventional IL-2-based therapies or wild-type IL-2 fusions. MB5029 has shown activity in models resistant to immune checkpoint inhibitors and displays favorable pharmacokinetics and tolerability in animal studies[1][2][4][6].