Boundless Bio Raises Fresh Capital to Boost extrachromosomal DNA Targeting Therapeutic Efforts

On April 28th, Boundless Bio announced the closure of the oversubscribed Series B financing of $105 million. The money will be used to advance multiple therapeutics targeting extrachromosomal DNA (ecDNA), develop companion diagnostics, and expand their pipeline.

Cancers driven by high copy numbers of oncogenes are some of the most aggressive cancers, as the oncogenes promote survival, growth, and resistance. High copy number is correlated to poor prognosis and relapse. However, recent discoveries have changed our view of where those multiple copy numbers are located.

ecDNA are circular pieces of DNA separate from the chromosomes that contain functional genes including oncogenes. ecDNA is normally not present on healthy cells, but almost half of the solid tumors contain them. They have a high protein production rate, can replicate rapidly, and are inherited by daughter cells.

Consequently, they can greatly contribute to the formation of high copy number-driven cancers, providing a powerful tool for cancer survival. Currently, there are no therapeutics targeting gene amplifications or ecDNA.

ecDNA Targeting Therapies

San Diego-based Boundless Bio focuses on developing therapeutics, and diagnostics for ecDNA. Their Spyglass drug discovery platform compares ecDNA tumor models with non-ecDNA driven tumor models. Then using proprietary imaging and molecular tools, they identify novel targets for therapeutics. Spyglass also enables the company to identify patients whose tumors would respond to their therapeutics. So it serves not only as a discovery tool but a diagnostic one as well. Currently, they are currently the only company specializing in the targeting of ecDNA.

Boundless Bio has secured a total of $151.4 million in funding so far. In September 2019, it raised $46.4 million in Series A financing. Its latest Series B round led by RA Capital Management and Nextech Invest also saw participation from current investors and some new ones, namely Fidelity Management & Research Company LLC, Redmile Group, Wellington Management, Surveyor Capital (a Citadel company), PFM Health Sciences, and Logos Capital.

The company intends to utilize the funds to advance multiple ecDNA-directed therapeutic programs into the clinic, and expand its pipeline including its ecDNA Harboring Oncogenes (ECHO) diagnostic platform.

“Boundless Bio has made tremendous progress since launching in 2019. Over the past two years, our team has custom built a platform, called Spyglass, that enables us to interrogate ecDNA in cancer and reveal key therapeutically targetable liabilities in ecDNA-driven, gene amplified tumors. From these efforts, we have discovered and validated three ecDNA-essential targets and have initiated drug discovery against each,” said Zachary Hornby, President, and CEO of Boundless Bio.

“In addition, we are developing the ECHO companion diagnostic assay to identify patients with ecDNA-driven tumors. This financing round and stellar investor syndicate reflects the investment community’s appreciation for the high unmet clinical need of patients with oncogene amplified cancers and the promise of our innovative approach to targeting ecDNA to improve and prolong the lives of these patients.”

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Author

Daniel Ojeda