BOLD

Boundless Bio, Inc. is a clinical-stage oncology company developing precision therapies that target extrachromosomal DNA (ecDNA), a recently discovered mechanism driving aggressive cancers. Headquartered in San Diego, California, Boundless Bio has pioneered understanding of how ecDNA—circular pieces of DNA separate from chromosomes—drives oncogene amplification and tumor evolution, leading to treatment resistance and poor outcomes. The company's approach represents a fundamentally new way to treat cancer by targeting this distinct form of genetic material found in approximately 15% of all cancers and up to 30% of certain aggressive tumor types. Boundless Bio's lead program is BBI-355, a first-in-class small molecule inhibitor designed to target ecDNA biology and oncogene function. The company has identified that ecDNA not only amplifies oncogenes like EGFR, MYC, and others to extremely high levels, but also makes these genes more accessible and transcriptionally active compared to chromosomal DNA. BBI-355 is designed to exploit these unique properties, selectively affecting ecDNA-driven cancers while potentially sparing normal cells. The company is conducting clinical trials in multiple ecDNA-positive cancer types including glioblastoma, colorectal cancer, and other solid tumors. The discovery of ecDNA's role in cancer represents a paradigm shift in understanding tumor genetics and evolution. Traditional targeted therapies often fail in ecDNA-driven cancers because the extreme oncogene amplification on ecDNA overwhelms inhibition, and ecDNA's structure enables rapid evolution and resistance. Boundless Bio's platform includes proprietary methods for detecting and characterizing ecDNA in patient tumors, enabling precision patient selection. The company has secured significant funding and partnerships based on the innovative science underlying its approach. Success depends on demonstrating clinical efficacy in ecDNA-positive cancers, establishing ecDNA testing as part of clinical workflows, completing regulatory pathways, and potentially expanding into additional ecDNA-driven tumor types. Boundless Bio addresses a novel cancer mechanism with potential to impact thousands of patients whose tumors harbor this aggressive genetic feature.