XH-07 is an innovative ionizable cationic lipid that forms the backbone of the JCXH-211 lipid nanoparticle (LNP) delivery system. This complex is engineered to encapsulate and deliver self-replicating RNA (srRNA) encoding interleukin-12 (IL-12), a potent immunostimulatory cytokine. The LNP formulation featuring XH-07 exhibits optimal physicochemical properties, such as a mean particle size of approximately 82.12 nm with low polydispersity, and a near-neutral zeta potential around -3.181 mV, which facilitates stable circulation and efficient cellular uptake upon intravenous administration. Upon delivery, the srRNA leverages the host cell's machinery to produce sustained levels of IL-12p70, as demonstrated in B16F10 tumor-bearing mice, where a single dose led to peak cytokine production in sera and tumors. This induced IL-12 expression activates T cells and NK cells, generating a robust antitumor response. In murine models of melanoma and breast cancer, JCXH-211 monotherapy resulted in significant tumor regression and complete responses in some subjects, and it synergized with anti-PD-1 therapy to enhance efficacy. Importantly, the safety profile was acceptable, with transient liver enzyme elevations in mice that normalized quickly, and no significant adverse events in cynomolgus monkeys after repeated dosing, as evidenced by stable clinical observations and pathology tests. Thus, XH-07 is pivotal for enabling the safe and effective delivery of IL-12 encoding RNA, positioning JCXH-211 as a promising cancer immunotherapy.
