ERX-315

ERX-315 is a novel small molecule drug developed to treat advanced solid tumors, with a particular focus on endocrine therapy-resistant breast cancers driven by mutant estrogen receptor alpha (ERα). The compound was identified from a screen of over 2,000 oligo-benzamides and demonstrates potent anti-proliferative activity against both wild-type and mutant ERα-driven breast cancer cells. Mechanistically, ERX-315 acts as a modulator of lysosomal acid lipase (LIPA), inducing catastrophic levels of endoplasmic reticulum (ER) stress in cancer cells. This leads to shutdown of de novo protein synthesis and triggers apoptotic cell death specifically in tumor cells while sparing normal tissues. Preclinical studies have shown that the drug is non-toxic in animal models and has an excellent therapeutic window. Formulations for both intravenous and oral administration have been developed with favorable pharmacokinetic properties. As of mid-2025, ERX-315 is being evaluated in Phase 1 clinical trials for patients with advanced solid tumors who have failed standard therapies[2][3][4][5][9].