Boundless Bio is developing therapeutics directed against extrachromosomal DNA (eDNA) to treat the most intractable cancers. ecDNAs are large units of circular DNA that reside within the cell nucleus yet are distinct from the chromosomal DNA. As ecDNAs can encode genes, they provide a mechanism for higher copy numbers of oncogenes, genes that are known to drive aggressive tumor growth and resistance to cancer treatments. Boundless has identified ecDNA as a differentiating feature of cancer cells that does not exist in normal cells. By further characterizing the biology of ecDNAs using their Spyglass platform, Boundless is generating a broad pipeline of ecDNA-directed therapies (ecDTx) to target gene amplified cancers.