BOLD

EX-99.1

2 bold-ex99_1.htm

EX-99.1

EX-99.1

Exhibit 99.1

Boundless Bio Reports First Quarter 2026

Financial Results and Business Highlights

Enrollment proceeding in KOMODO-1 first-in-human clinical trial of BBI-940

$93 million in cash provides runway through expected clinical proof-of-concept

readout for KOMODO-1

SAN DIEGO, May 8, 2026 – Boundless Bio (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 financial results and business highlights for the fiscal quarter ended March 31, 2026.

“We are encouraged by the progress of the KOMODO-1 trial," said Zachary Hornby, President and Chief Executive Officer of Boundless Bio. “We continue to expand the body of evidence supporting BBI-940’s kinesin degradation mechanism, with our recent AACR poster demonstrating anti-tumor activity and tumor regression across multiple ecDNA+ cancer models. These findings further strengthen our confidence in the therapeutic potential of BBI-940 as we advance the program through a first-in-human clinical trial.”

Business Highlights and Upcoming Milestones

BBI-940 Novel Kinesin Degrader Clinical Program

• Enrollment is ongoing in KOMODO-1 (Kinesin Oral Molecular Degrader for Oncology-1), a first-in-human clinical trial of BBI-940 in patients with estrogen receptor positive and human epidermal growth factor receptor 2 negative (ER+/HER2-) breast cancer who have progressed following treatment with a cyclin-dependent kinase 4 and/or 6 (CDK4/6) inhibitor plus endocrine therapy, as well as patients with triple-negative breast cancer luminal androgen receptor subtype (TNBC-LAR).

• Initial safety and efficacy clinical proof-of-concept data are expected within the Company’s existing cash runway timeline.

Validating Kinesin Degradation Data Presented at 2026 AACR Annual Meeting

• In vitro and in vivo study data were presented at the American Association for Cancer Research (AACR) Annual Meeting 2026, which demonstrated that genetic depletion and pharmacologic degradation of a novel kinesin (Kinesin) cause ecDNA mis-segregation, ecDNA reduction, and reduced viability of ecDNA positive (ecDNA+) cancer cells.

• Further, selective degradation of Kinesin in a panel of tumor cell lines demonstrated sensitivity across multiple tumor types, including 32% of breast cancer cell lines, including those positive for ecDNA and FGFR1 gain. This molecularly defined subgroup for Kinesin degradation sensitivity was further validated in vivo with demonstrated monotherapy tumor regressions in an ecDNA+ TNBC-LAR model, and significant antitumor activity as monotherapy and in combination with fulvestrant in an ecDNA+/FGFR1+ ER+ breast cancer model.

First Quarter 2026 Financial Results

• Cash Position: Cash, cash equivalents, and short-term investments totaled $92.8 million as of March 31, 2026. The Company expects its cash to fund operations into the second half of 2028.

• Research and Development (R&D) Expenses: R&D expenses were $9.7 million for the first quarter of 2026 compared to $12.1 million for the same period in 2025.

• General and Administrative (G&A) Expenses: G&A expenses were $4.7 million for the first quarter of 2026 compared to $5.2 million for the same period in 2025.

• Net Loss: Net loss totaled $13.6 million for the first quarter of 2026 compared to $15.8 million for the same period in 2025.

About Boundless Bio

Boundless Bio is a clinical-stage oncology company dedicated to unlocking a new paradigm in cancer therapeutics that addresses the significant unmet need in patients with oncogene amplified tumors. Boundless Bio’s research focuses on extrachromosomal DNA (ecDNA), a root cause of oncogene amplification observed in 14% to 17% of cancer patients. Boundless Bio is developing BBI-940, a potentially first-in-class, oral, selective Kinesin degrader as an ecDNA-directed therapeutic candidate (ecDTx). Boundless Bio is headquartered in San Diego, California.

For more information, visit https://boundlessbio.com/and follow us on LinkedIn and X.

Forward-Looking Statements

Boundless Bio, Inc. (the Company) cautions you that statements contained in this press release that are not a description of historical facts are forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “would,” “target,” or “will” or the negative of these terms or other similar expressions. Forward-looking statements are based on the Company’s current beliefs and expectations and include but are not limited to statements regarding: plans to continue enrollment in and advance the KOMODO-1 trial through initial clinical proof-of-concept data; the expected timing of an initial clinical proof-of-conce

8-K

0001782303false00017823032026-03-032026-03-03

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 03, 2026

Boundless Bio, Inc. (Exact Name of Registrant as Specified in Its Charter)

Delaware

001-41989

83-0751369

(State or Other Jurisdiction of Incorporation)

(Commission File Number)

(IRS Employer Identification No.)

10955 Alexandria Way, Suite 100,

San Diego, California

92121

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s Telephone Number, Including Area Code: (858) 766-9912

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock, par value $0.0001 per share

BOLD

Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company ☒ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition. On March 9, 2026, Boundless Bio, Inc. (the Company) issued a press release announcing its financial results for the fourth quarter and full year ended December 31, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. In accordance with General Instruction B.2 of Form 8-K, the information in this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the Exchange Act), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof and regardless of any general incorporation by reference language in any such filing, unless the Company specifically states in such filing that such information, or a portion thereof, is to be considered “filed” rather than furnished or incorporated by reference therein. Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangement of Certain Officers. Effective March 3, 2026, Christine Brennan, Ph.D. notified the Company of her resignation from the Board of Directors of the Company. Dr. Brennan’s resignation was made in connection with her assuming a new role at Johnson & Johnson Development Corporation, and was not the result of any disagreement with the Company, including on any matter relating to its operations, policies or practices. Item 9.01 Financial Statements and Exhibits. (d) Exhibits.

Exhibit Number

Description

99.1

Press Release Issued on March 9, 2026

104

Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

BOUNDLESS BIO, INC.

Date:

March 9, 2026

By:

/s/ Jessica Oien

Name: Jessica Oien Title: Chief Legal Officer and Corporate Secretary

8-K

0001782303false00017823032025-11-052025-11-05

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 05, 2025

Boundless Bio, Inc. (Exact Name of Registrant as Specified in Its Charter)

Delaware

001-41989

83-0751369

(State or Other Jurisdiction of Incorporation)

(Commission File Number)

(IRS Employer Identification No.)

10955 Alexandria Way, Suite 100,

San Diego, California

92121

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s Telephone Number, Including Area Code: (858) 766-9912

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock, par value $0.0001 per share

BOLD

Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company ☒ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition. On November 5, 2025, Boundless Bio, Inc. (the Company) issued a press release announcing its financial results for the quarter ended September 30, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. In accordance with General Instruction B.2 of Form 8-K, the information in this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the Exchange Act), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof and regardless of any general incorporation by reference language in any such filing, unless the Company specifically states in such filing that such information, or a portion thereof, is to be considered “filed” rather than furnished or incorporated by reference therein. Item 9.01 Financial Statements and Exhibits. (d) Exhibits.

Exhibit Number

Description

99.1

Press Release Issued on November 5, 2025

104

Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

BOUNDLESS BIO, INC.

Date:

November 5, 2025

By:

/s/ Jessica Oien

Name: Jessica Oien Title: Chief Legal Officer and Corporate Secretary