PT-203

PT-203 is a preclinical-stage small molecule cancer therapeutic belonging to the xanthine class of compounds developed by p53-Therapeutics. It is designed to bypass mutations or loss of the p53 tumor suppressor gene, which is a common driver of treatment resistance and uncontrolled growth in over 50% of human cancers. As a structural analog of the lead compound CB002, PT-203 acts by inducing an integrated stress response (ISR) that upregulates critical p53-regulated effector genes involved in cell cycle arrest and apoptosis, such as Noxa, PUMA, and p21, in an ATF3/ATF4-dependent manner. This non-canonical pathway activation allows PT-203 to selectively trigger apoptotic cell death and target an S-phase cell cycle checkpoint in p53-deficient or p53-mutated tumor cells without causing toxicity to normal cells.