Boundless Bio, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

For the quarterly period ended June 30,2026

OR

For the transition period from _______________ to ____________

Commission File Number:001-41989

BOUNDLESS BIO, INC.

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code:(858) 766-9912

Former name, former address and former fiscal year, if changed since last report: N/A

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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.☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes☐ No☒

As of August 5, 2026, the registrant had 22,747,985 shares of common stock, $0.0001 par value per share, outstanding.

Table of Contents

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS AND MARKET AND INDUSTRY DATA

This Quarterly Report on Form 10-Q contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the Securities Act), and Section 21E of the Securities Exchange Act of 1934, as amended (the Exchange Act). All statements other than statements of historical facts contained in this Quarterly Report are forward-looking statements, including statements regarding the completion of the Merger (as defined in this Quarterly Report) and our ability to satisfy the conditions to the closing of the Merger, including required stockholder approvals and any required regulatory and governmental consents, our future results of operations and financial position, our business strategy, research and development plans, the anticipated timing, costs, design, and conduct of any clinical trials and preclinical studies for our extrachromosomal DNA (ecDNA) directed therapeutic candidate (ecDTx), our use of the net proceeds from the initial public offering (IPO) of our common stock, the period over which we estimate our cash position will be sufficient to fund our operations, the sufficiency of our cash position to fund achievement of any milestones, the expected benefits of portfolio prioritizations, the timing and likelihood of success, plans, and objectives of management for future operations, the potential to enter into strategic collaborations, the timing of expected clinical data readout for our ecDTx, the potential safety and therapeutic benefits of our ecDTx, the potential addressable patient populations for our ecDTx, the potential to identify additional development opportunities for our ecDTx or expand our therapeutic pipeline, the timing and likelihood of regulatory submissions, filings and approvals for our ecDTx, expected regulatory approval pathways for our ecDTx, our ability to commercialize our ecDTx, if approved, the pricing and reimbursement of our ecDTx, if approved, potential competition for our ecDTx, our intellectual property and other market exclusivity strategies, our intent regarding any strategic collaborations, licenses, or similar arrangements and the potential benefits of any such arrangements.

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. Our forward-looking statements are only predictions. We have based our forward-looking statements largely on our current expectations and projections about future events and financial and other trends that we believe may affect our business, financial condition, and results of operations based upon information available to us as of the date of this report. Such information may be limited or incomplete. These forward-looking statements speak only as of the date of this report and are subject to several risks, uncertainties, and assumptions, including, without limitation:

•

Failure to complete, or delays in completing, the potential Merger with Serapha Bio, Inc. could materially and adversely affect our results of operations, business, financial results and/ or common stock price;

•

If the conditions to the Merger are not satisfied or waived, the Merger may not occur;

•

The amount of the anticipated cash dividend in connection with the Merger may change based on the timing to complete the Merger, changes in operating expense levels and other factors;

•

The Exchange Ratio (as defined in the Merger Agreement) for the Merger will not change or otherwise be adjusted based on the market price of our common stock;

•

Our stockholders may not realize a benefit from the Merger commensurate with the ownership dilution they will experience in connection with the Merger;

•

Certain provisions of the Merger Agreement may discourage third parties from submitting competing proposals, including proposals that may be superior to the transactions contemplated by the Merger Agreement;

•

The proposed reverse stock split as part of the Merger transaction may not increase the combined company’s stock price over the long-term;

•

We have a limited operating history, have incurred significant operating losses since our inception and expect to incur significant losses for the foreseeable future. We may never generate any revenue or become profitable or, if we achieve profitability, we may not be able to sustain it;

•

If we continue to develop any ecDTx, we will require substantial additional capital to finance our operations, and a failure to obtain this necessary capital when needed on acceptable terms, or at all, could force us to delay, limit, reduce or terminate any ecDTx development programs, commercialization efforts, or other operations;

•

If we continue to develop any ecDTx and are unable to successfully develop, obtain regulatory approval, and ultimately commercialize any current or future ecDTx, or experience significant delays in doing so, our business will be materially harmed;

•

Our approach to treating cancer with oncogene amplifications by developing ecDTx directed against ecDNA is novel and unproven, and we do not know whether we will be able to develop any products of commercial value, or if competing approaches will limit the commercial value of our ecDTx;

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•

Clinical and preclinical development involves a lengthy and expensive process with uncertain timelines and outcomes, and the results of preclinical studies and early clinical trials are not necessarily predictive of future results. Our ecDTx have not achieved sufficiently favorable clinical results to date and may not achieve favorable results in any future clinical trials or preclinical studies or receive regulatory approval on a timely basis, if at all;

•

If we continue to develop any ecDTx, any difficulties or delays in the commencement or completion, or the termination or suspension, of any clinical trials or preclinical studies could result in increased costs to us, delay or limit our ability to generate revenue, or adversely affect our commercial prospects;

•

Use of our ecDTx could be associated with side effects, adverse events, or other properties or safety risks, which could delay or preclude regulatory approval, cause us to suspend or discontinue clinical trials, cause us to abandon an ecDTx, limit the commercial profile of an approved label, or result in other significant negative consequences that could severely harm our business, financial condition, results of operations, and prospects;

•

If we are unable to successfully identify predictive biomarkers to identify patient populations most likely to benefit from our ecDTx, or develop a diagnostic to enable patient selection for our ecDTx, or if we experience significant delays in doing so, we may not realize the full commercial potential of our ecDTx;

•

If we continue to develop any ecDTx, interim, topline, and preliminary data from our clinical trials and preclinical studies that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data;

•

We rely on third parties to conduct our clinical trials and preclinical studies, to manufacture our ecDTx, and to package, label, ship, store, and distribute our ecDTx, and for ecDNA diagnostic development, and these third parties may not perform satisfactorily or at an acceptable cost, which could delay, prevent, or impair our development or commercialization efforts;

•

Disruptions or changes at the U.S. Food and Drug Administration (FDA), the SEC, and other government agencies, including due to government shutdowns, other funding shortages, policy changes, leadership changes, layoffs or significant personnel turnover, or public health concerns could impede development and potential marketing approval of our ecDTx and our ability to raise capital;

•

We face significant competition from entities that have developed or may develop product candidates for cancer, including companies developing novel treatments and technology platforms. If our competitors develop and commercialize their product candidates more rapidly than we do, or their technologies or their product candidates are more effective, safer, or less expensive than our ecDTx, our business and our ability to develop and successfully commercialize ecDTx may be adversely affected;

•

Current and future healthcare reform legislation or regulation may increase the difficulty and cost for us to obtain coverage for and commercialize our ecDTx and may adversely affect the prices we may set;

•

We may engage in strategic transactions that could impact our liquidity, increase our expenses, and divert management’s attention from other business priorities;

•

If we are unable to obtain, maintain, defend, and enforce patent or other intellectual property protection for our ecDTx, ecDNA diagnostic, or technology, or if the scope of the patent or other intellectual property protection obtained is not sufficiently broad, our competitors or other third parties could develop and commercialize products similar or identical to ours, and our ability to successfully commercialize our ecDTx may be adversely affected;

•

Our information technology systems, or those of any of our service providers, may fail or suffer security incidents and other disruptions, which could result in a material disruption of our ecDTx development programs, compromise sensitive information related to our business, or prevent us from accessing critical information, potentially exposing us to liability or otherwise adversely affecting our business;

•

The trading volume and price of our common stock have been and may continue to be highly volatile, and purchasers of our common stock could incur substantial losses;

•

If we fail in the future to satisfy the continued listing requirements of Nasdaq, Nasdaq may take steps to delist our common stock; and

•

Macroeconomic and geopolitical events and conditions outside of our control, including market volatility, high interest rates, inflation, tariffs, and other trade barriers, retaliatory measures taken by foreign countries, slowed economic growth or recession, uncertainty with respect to the federal budget and debt ceiling, potential or prolonged government shutdowns, liquidity concerns at financial institutions, supply chain disruptions, military conflicts, and other geopolitical events and instability in market and economic conditions may have serious adverse consequences on our business, financial condition, results of operations, and stock price.

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You should carefully read all of the risk factors described in Part II, Item 1A, “Risk Factors,” of this Quarterly Report and Part I, Item 1A, “Risk Factors,” of our Annual Report on Form 10-K for the year ended December 31, 2025 filed with the U.S. Securities and Exchange Commission (SEC) on March 9, 2026 (our 2025 10-K) for a detailed description of material risks and uncertainties we face. The events and circumstances reflected in our forward-looking statements may not be achieved or occur, and our actual results, performance, or achievements could differ materially from those expressed or implied by our forward-looking statements. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond our control, you should not place undue reliance on any forward-looking statement. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances, or otherwise. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

In addition, statements that “we believe” and similarly qualified statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this report, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and you are cautioned not to rely unduly upon them.

This report may contain estimates and other statistical data made by independent parties and by us relating to potential market opportunity and other data about our industry and competitive position. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. Projections, assumptions and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk, and are subject to change based on various factors, including those discussed in Part I, Item 1A, “Risk Factors,” of our 2025 10-K. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties or by us.

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