JRT39

JRT39 is a first-in-class, synthetic peptide drug candidate developed by Jalon Therapeutics for the treatment of hard-to-treat and refractory cancers. It is derived from the AAC-11 (Anti-Apoptosis Clone-11) protein, a scaffold protein involved in cancer cell survival, adaptation to stress, resistance to therapies, immune evasion, and metastatic potential. JRT39 acts as a molecular decoy inside tumor cells to block interactions between AAC-11 and its protein partners—disrupting essential survival pathways in cancer cells. Additionally, it binds to AAC-11 partners present on tumor cell membranes and induces membranolysis (cell destruction). The drug combines broad tissue distribution and cell permeability typical of small molecules with the specificity and target engagement potency of antibodies. Its mechanisms include inhibition of both PAK1 (p21-activated kinase 1) and API5 (Apoptosis Inhibitor 5), targeting non-oncogene addiction pathways that are vital for malignant phenotypes but not necessary for normal cells. As of June 2025, JRT39 remains in advanced preclinical development with plans for future clinical trials[1][2][3][4][5][6][8][10].