Boundless Bio is a clinical-stage oncology company developing small molecule drugs designed to target extrachromosomal DNA (ecDNA), a genetic abnormality present in 14–17% of cancer patients that drives aggressive tumor behavior and resistance to standard therapies. The company uses its proprietary Spyglass platform to identify and develop ecDNA-directed therapeutic candidates (ecDTx) that exploit the dependency of ecDNA-amplified cancer cells on this biology, aiming to create synthetic-lethal treatments that kill cancer cells while sparing healthy tissue. With no approved products or revenue to date, the company intends to commercialize its therapies independently or with partners upon regulatory approval, targeting indications including breast cancer and other solid tumors with high ecDNA prevalence.