Boundless Bio Announces Pricing of Initial Public Offering

Boundless Bio, Inc. (Nasdaq: BOLD), a clinical stage oncology company interrogating extrachromosomal DNA (ecDNA) biology to deliver transformative therapies to patients with previously intractable oncogene amplified cancers, today announced the pricing of its initial public offering of 6,250,000 shares of its common stock at an initial public offering price of $16.00 per share. All of the shares are being offered by Boundless Bio. The gross proceeds from the offering, before deducting underwriting discounts and commissions and other offering expenses, are expected to be $100.0 million. Boundless Bio's common stock is expected to begin trading on the Nasdaq Global Select Market on March 28, 2024 under the ticker symbol "BOLD." The offering is expected to close on April 2, 2024, subject to the satisfaction of customary closing conditions. In addition, Boundless Bio has granted the underwriters a 30-day option to purchase up to an additional 937,500 shares of common stock at the initial public offering price, less underwriting discounts and commissions.

Goldman Sachs & Co. LLC, Leerink Partners, Piper Sandler and Guggenheim Securities are acting as joint book-running managers for the offering.

A registration statement relating to the offering has been filed with the Securities and Exchange Commission and was declared effective on March 27, 2024. The offering is being made only by means of a prospectus. When available, copies of the final prospectus may be obtained from Goldman Sachs & Co. LLC, Attention: Prospectus Department, 200 West Street, New York, NY 10282, by telephone at (866) 471-2526, or by email at [email protected]; Leerink Partners LLC, Attention: Syndicate Department, 53 State Street, 40th Floor, Boston, MA 02109, by telephone at (800) 808-7525, ext. 6105, or by email at [email protected]; Piper Sandler & Co., Attention: Prospectus Department, 800 Nicollet Mall, J12S03 Minneapolis, MN 55402, by telephone at (800) 747-3924, or by email at [email protected]; or Guggenheim Securities, LLC, Attention: Equity Syndicate Department, 330 Madison Avenue, 8th Floor, New York, NY 10017, by telephone at (212) 518-9544, or by email at [email protected].

This press release shall not constitute an offer to sell or a solicitation of an offer to buy these securities, nor shall there be any offer or sale of these securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or jurisdiction.

About Boundless Bio

Boundless Bio is a clinical-stage oncology company dedicated to unlocking a new paradigm in cancer therapeutics to address the significant unmet need of patients with oncogene amplified tumors by targeting extrachromosomal DNA (ecDNA), a root cause of oncogene amplification and observed in more than 14% of cancer patients. Boundless Bio is developing the first ecDNA-directed therapy (ecDTx), BBI-355, which is an oral inhibitor of checkpoint kinase 1 (CHK1) and is being evaluated in a Phase 1/2 clinical trial in patients with oncogene amplified cancers. Boundless Bio's second ecDTx, BBI-825, is an oral inhibitor of ribonucleotide reductase (RNR) and recently entered a Phase 1/2 clinical trial in cancer patients with resistance gene amplifications. Leveraging its Spyglass platform, Boundless Bio has additional programs advancing through preclinical development and discovery. Boundless Bio is headquartered in San Diego, CA.