Boundless Bio doses first patient in BBI-825 trial

Boundless Bio announced that the first patient has been dosed with BBI-825 in a first-in-human, Phase 1/2 clinical trial for patients with locally advanced or metastatic cancer with resistance gene amplifications. ecDNA are a key driver of high copy number amplification in cancer, and Boundless has validated multiple drug targets that are essential for ecDNA function in cancer cells. BBI-825, the company’s second ecDNA-directed therapy to enter clinical trials, is a novel, selective, oral small molecule inhibitor of ribonucleotide reductase, a rate-limiting enzyme responsible for the de novo synthesis of deoxyribonucleotides, the building blocks of DNA. Boundless has identified an essential role for RNR in ecDNA assembly and repair and in the survival of certain oncogene amplified cancer cells.