Boundless Bio is like:

• Kite Pharma, but pioneering a new class of cancer therapies by targeting ecDNA.
• Vertex Pharmaceuticals, but developing platform-driven therapies for a newly identified root cause of cancer: ecDNA.

• BBI-355: A novel, oral, selective inhibitor of checkpoint kinase 1 (CHK1) currently in Phase 1/2 clinical trials for patients with oncogene amplified cancers.
• BBI-825: A novel, oral, selective inhibitor of ribonucleotide reductase (RNR) currently in Phase 1/2 clinical trials for patients with resistance gene amplifications.
• Third ecDTx Program: A drug discovery program focused on an undrugged kinesin target essential for ecDNA segregation and inheritance during cell division.
• ECHO (ecDNA Diagnostic): A proprietary diagnostic test to detect extrachromosomal DNA (ecDNA) in patient tumor samples by analyzing genomic data from NGS assays.
• Spyglass Platform: A proprietary drug discovery platform used to identify specific, druggable targets essential for ecDNA formation and function in cancer cells.

At its current stage of development, Boundless Bio does not have major customers in the traditional sense, as its products have not yet received regulatory approval and are not commercially available for sale. The company's primary activities involve advancing its drug candidates through preclinical and clinical development.

Upon potential future commercialization of its therapies, Boundless Bio's ultimate customers would be healthcare providers, hospitals, and potentially government health programs or private insurance companies, who would purchase and administer the approved therapies to patients with oncogene amplified cancers.

Zachary Hornby, Chief Executive Officer, President, and Director

Zachary Hornby has served as CEO, President, and a Director at Boundless Bio since May 2019. Prior to joining Boundless Bio, he was the Chief Operating Officer and previously Chief Financial Officer at Ignyta, Inc. At Ignyta, Mr. Hornby oversaw the development of four clinical-stage therapeutics and led the business development process that resulted in Ignyta's acquisition by Roche for $2 billion. He also served in roles of increasing responsibility in business development, marketing, finance, and regulatory affairs at Fate Therapeutics, Halozyme Therapeutics, Neurocrine Biosciences, and Transkaryotic Therapeutics.

David Hinkle, Senior Vice President, Finance & Controller, and Principal Financial and Accounting Officer

David Hinkle assumed the roles of principal financial and accounting officer for Boundless Bio in October 2024, after serving as Senior Vice President, Finance and Controller since June 2021. He has over 25 years of experience in finance and technical accounting. Before joining Boundless Bio, Mr. Hinkle was the Vice President, Finance and Controller at Crinetics Pharmaceuticals. His prior experience also includes similar finance and controller capacities at Ignyta, Receptos, Somaxon Pharmaceuticals, and Digirad, and he began his career at Deloitte.

Dr. Robert Doebele, M.D., Ph.D., Chief Medical Officer

Dr. Robert Doebele was appointed Chief Medical Officer of Boundless Bio in February 2025. He is a co-founder of Rain Oncology, Inc. (acquired by Pathos AI), where he held the positions of Chief Scientific and Medical Officer. Dr. Doebele is recognized for leading research and clinical trials at the University of Colorado, which were instrumental in establishing the TRK inhibitor field.

Chris Hassig, Ph.D., Chief Scientific Officer

Chris Hassig serves as the Chief Scientific Officer for Boundless Bio.

Meredith Wesley, Chief Human Resources Officer

Meredith Wesley holds the position of Chief Human Resources Officer at Boundless Bio, also listed as Senior Vice President, Talent & Culture.

Key Business Risks for Boundless Bio (BOLD)

• Clinical Trial and Regulatory Approval Risk: As a clinical-stage oncology company, Boundless Bio's success is heavily dependent on the ability to successfully develop its investigational drug candidates, BBI-355, BBI-825, and future ecDTx programs, through all phases of clinical trials, demonstrate their safety and efficacy, and obtain regulatory approval from agencies such as the FDA. Failure at any stage of clinical development, including unexpected adverse events, insufficient efficacy, or inability to meet primary endpoints, or delays in regulatory submissions and approvals, would severely impact the company's business prospects and financial viability. The company explicitly states timelines for preliminary data and IND submissions, indicating critical upcoming milestones that carry inherent risks.

• Novel Therapeutic Approach Risk: Boundless Bio is pioneering a new paradigm in cancer therapeutics by targeting extrachromosomal DNA (ecDNA), positioning itself as the "world’s leading ecDNA company." While this offers a potential first-mover advantage, it also introduces significant risk associated with the novelty of the approach. There is inherent uncertainty regarding the broad clinical applicability, efficacy, and safety profile of ecDNA-directed therapies in a larger patient population and over longer periods. The medical community's acceptance and adoption of this novel mechanism of action, compared to established cancer treatments, also present a potential hurdle, which could affect market penetration and commercial success even if the drugs prove effective.

• Competition and Market Acceptance: Despite Boundless Bio's claim of being the first and only company to date to bring an ecDTx into the clinic, the oncology landscape is highly competitive. Existing pharmaceutical and biotechnology companies with greater resources may develop competing therapies, including those targeting ecDNA or alternative mechanisms that address oncogene amplified tumors. Furthermore, the company's proprietary Spyglass platform and ecDNA diagnostic (ECHO) could face competition or challenges in broad adoption, potentially limiting the company's ability to identify and treat patients effectively.

Boundless Bio (BOLD) focuses on developing therapeutics for patients with oncogene amplified tumors, which the company states are observed in more than 14% of cancer patients. The company's main products are its ecDNA-directed therapeutic candidates (ecDTx), including BBI-355 and BBI-825. Boundless Bio also develops an ecDNA diagnostic, ECHO, to identify patients for its ecDTx.

The addressable market for Boundless Bio's ecDTx products is estimated as follows:

• Global Therapeutics Market: The global cancer treatment drugs market was valued at approximately $193.1 billion in 2024. Based on Boundless Bio's focus on a patient population representing more than 14% of cancer patients, their addressable market within global cancer therapeutics is approximately $27.03 billion.
• U.S. Therapeutics Market: The U.S. oncology market was valued at approximately $81.34 billion in 2025. Assuming drug-based therapies constitute roughly 68% of this market, the U.S. cancer treatment drugs market is estimated to be approximately $55.31 billion in 2025. Boundless Bio's addressable market within U.S. cancer therapeutics is approximately $7.74 billion.

For Boundless Bio's ecDNA diagnostic (ECHO), a specific addressable market size is not available from the provided information.

Here are 3-5 expected drivers of future revenue growth for Boundless Bio (BOLD) over the next 2-3 years:

1. Advancement and positive clinical data for BBI-355: The anticipated preliminary clinical proof of concept safety and antitumor activity data of BBI-355 from the POTENTIATE Phase 1/2 clinical trial in the second half of 2024 is a significant driver. Positive results would de-risk the lead asset, potentially attracting strategic partnerships, licensing deals, or further investment, which could lead to milestone payments or funding that contributes to future revenue.
2. Advancement and positive clinical data for BBI-825: The expected preliminary clinical proof of concept safety and antitumor activity data for BBI-825 from the STARMAP Phase 1/2 clinical trial in the second half of 2025 will be another critical driver. Successful outcomes for this second ecDTx would further validate Boundless Bio's platform and pipeline, enhancing its overall value and increasing the potential for future revenue-generating collaborations or accelerated development.
3. Progression of the third ecDTx program into clinical trials: The planned submission of an Investigational New Drug (IND) application in the first half of 2026 for their third ecDTx program, targeting a kinesin essential for ecDNA segregation, is an important pipeline expansion. This advancement signifies continued innovation and adds another potential source of future revenue through successful development, eventual commercialization, or partnerships.
4. Potential commercialization or strategic partnerships for the ECHO ecDNA diagnostic: The development of the ECHO ecDNA diagnostic into a clinical trial assay, which the FDA has deemed a non-significant risk device for patient selection in the POTENTIATE trial, presents a potential revenue opportunity. If this diagnostic is further developed, commercialized independently, or licensed to an in vitro diagnostic company, it could generate revenue from testing services or licensing fees within the specified timeframe.

Share Issuance

• Boundless Bio completed its Initial Public Offering (IPO) on March 28, 2024, offering 6,250,000 shares of common stock at $16.00 per share, resulting in gross proceeds of $100.0 million.
• The company granted underwriters a 30-day option to purchase up to an additional 937,500 shares of common stock at the IPO price.
• As of September 30, 2025, Boundless Bio had 4,369,000 common stock options issued and outstanding for employees and consultants, an increase from 3,818,000 as of December 31, 2024.

Inbound Investments

• In April 2021, Boundless Bio completed an oversubscribed Series B financing round, raising $105 million.
• The company announced a $100 million oversubscribed Series C financing round in May 2023.

Capital Expenditures

• Purchases of property and equipment amounted to $0.5 million in 2025, a decrease from $2.5 million in 2024.
• The reduction in capital expenditures for 2025 was due to lower investment needs following the relocation to a new headquarters in 2024.
• Research and development (R&D) expenses, representing the primary focus of the company's investment in its pipeline, were $44.8 million for the full year 2025 and $55.3 million for the full year 2024.