Seaport Therapeutics, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

For the quarterly period ended September 30,2026

OR

For the transition period from ______________________ to ______________________

Commission File Number:001-43254

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (617)807-4062

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 October 27, 2026, the registrant had 53,530,550 shares of voting common stock, $0.0001 par value per share, outstanding.

Table of Contents

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Quarterly Report on Form 10-Q contains forward-looking statements about us and our industry that involve substantial risks and uncertainties. All statements other than statements of historical facts contained in this Quarterly Report on Form 10-Q, including statements regarding our future results of operations and financial position, business strategy, product candidates, planned nonclinical studies and clinical trials, results of nonclinical studies, clinical trials, research and development costs, regulatory approvals, commercial strategy, timing and likelihood of success, as well as plans and objectives of management for future operations, are forward-looking statements. These statements involve known and unknown risks, uncertainties, and other important factors that are in some cases beyond our control and may cause our actual results, performance, or achievements to be materially different from any future results, performance, or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “believe,” “estimate,” “predict,” “potential,” or “continue,” or the negative of these terms or other similar expressions. Forward-looking statements contained in this Quarterly Report on Form 10-Q include, but are not limited to, statements about:

• the initiation, timing, progress and results of our current and future clinical trials, nonclinical studies, and research and development programs;

• the timing of announcement of results from clinical trials;

• our ability to successfully complete our clinical trials;

• our ability to advance other product candidates that we may identify and successfully complete any clinical studies, including the manufacture of any such product candidates;

• our ability to quickly leverage programs within our initial target indications and to progress additional programs to further develop our pipeline;

• the prevalence of certain disorders we intend to treat and the size of the market opportunity for our product candidates;

• estimates of the number of patients with certain disorders we intend to treat and the number of patients that we will enroll in our clinical trials;

• the likelihood of our clinical trials demonstrating safety and efficacy of our product candidates;

• the timing of our investigational new drug applications, or INDs, submissions;

• the implementation of our strategic plans for our business, platform, and our programs;

• the scope of protection we are able to establish and maintain for intellectual property rights;

• developments related to our competitors and our industry;

• the success of competing therapies that are or may become available;

• our ability to leverage the clinical, regulatory, and manufacturing advancements to accelerate our clinical trials and approval of product candidates;

• our ability to meet future regulatory standards with respect to our product candidates, if approved;

• our ability to maintain our existing license agreements and identify and enter into future license agreements and collaborations;

• our reliance on third parties to conduct clinical trials of our product candidates;

• our reliance on third parties for the manufacture of our product candidates;

• developments related to our platform;

• regulatory developments in the United States and foreign countries;

• our commercialization, marketing, and manufacturing capabilities;

• our expectations regarding the period during which we will qualify as an emerging growth company under the JOBS Act or a smaller reporting company;

• our ability to attract and retain key scientific and management personnel; and

• our anticipated cash runway, our financial performance, estimates of our expenses, capital requirements, and needs for additional financing.

We have based these forward-looking statements largely on our current expectations and projections about our business, the industry in which we operate and financial trends that we believe may affect our business, financial condition, results of operations and prospects, and these forward-looking statements are not guarantees of future performance or development. These forward-looking statements speak only as of the date of this Quarterly Report on Form 10-Q and are subject to a number of risks, uncertainties and assumptions described in "Risk Factor Summary," “Risk Factors” and elsewhere in this Quarterly Report on Form 10-Q. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. 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, or otherwise. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, collaborations, joint ventures, or investments that we may make or enter into. In addition, statements that “we believe” and similar 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 Quarterly Report on Form 10-Q, 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 unduly rely upon these statements.

You should read this Quarterly Report on Form 10-Q and the documents that we have filed as exhibits to this Quarterly Report on Form 10-Q completely and with the understanding that our actual future results may be materially different from what we expect. The forward-looking statements contained in this Quarterly Report on Form 10-Q are made as of the date of this Quarterly Report on Form 10-Q, and we do not assume any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by applicable law.

This Quarterly Report on Form 10-Q may include industry and market data, which we may obtain from our own internal estimates and research, as well as from industry and general publications and research, surveys, and studies conducted by third parties. Industry publications, studies, and surveys generally state that they have been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information. While we believe that such studies and publications are reliable, we have not independently verified market and industry data from third‑party sources.

Website and Social Media Disclosure

From time to time, we may use our website (www.seaporttx.com), investor and media relations website (investors.seaporttx.com), LinkedIn page (http://www.linkedin.com/company/seaport-therapeutics), Bluesky (https://bsky.app/profile/seaporttx.bsky.social), and X feed (https://x.com/SeaportTx) as channels for the distribution of information. The information we post through these channels may be deemed material. Accordingly, investors should monitor these channels, in addition to following our press releases and subscribing to our email alerts, Securities and Exchange Commission filings and public conference calls and webcasts. The contents of our website and social media channels are not, however, a part of this report.

Risk Factor Summary

Investment in our securities involves risk. You should carefully consider the following summary of what we believe to be the principal risks facing our business, in addition to the risks described more fully in Part II. Item 1A, “Risk Factors” in this Quarterly Report on Form 10-Q and other information included in this report. The risks and uncertainties described below are not the only risks and uncertainties we face. Additional risks and uncertainties not presently known to us or that we presently deem less significant may also impair our business operations.

If any of the following risks occurs, our business, financial condition and results of operations and future growth prospects could be materially and adversely affected, and the actual outcomes of matters as to which forward-looking statements are made in this report could be materially different from those anticipated in such forward-looking statements.

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We are a clinical-stage therapeutics company, have no history of generating commercial revenue, have a history of operating losses and may never achieve or maintain profitability.

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Company management continues to pursue additional financing to support future operations, however such funding may not be available on acceptable terms or at all.

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We are substantially dependent on the success of our drug product candidates, and significant additional research and development and clinical testing will be required before we can potentially seek regulatory approval for or commercialize any of our drug product candidates.

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Our proprietary Glyph™ platform is based on a novel approach that may not result in approvable or marketable products, which exposes us to unforeseen risks and makes it difficult for us to predict the time and cost of product development and potential for regulatory approval.

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Success in nonclinical studies or early clinical trials may not be indicative of results obtained in later trials.

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We have concentrated our research and development efforts on the treatment of disorders of the brain and central nervous system, a field that faces certain challenges in drug development.

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We may conduct clinical trials for our product candidates outside of the United States and the FDA may not accept data from such trials, in which case our development plans may be delayed, which could materially harm our business.

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We may not be successful in our efforts to identify additional drug product candidates. We must prioritize the development of certain drug product candidates, and these decisions may prove to be wrong and may adversely affect our business.

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We expect to expand our organization, and as a result, we may encounter difficulties in managing our growth, and our future growth depends on attracting, hiring and retaining our key personnel and recruiting additional qualified personnel.

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We rely on third parties to assist in conducting our clinical trials and nonclinical studies, manufacture our product candidates and seek to establish collaborations on product development and commercialization plans.

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Our commercial success depends on our ability to obtain, maintain, enforce, and otherwise protect our intellectual property and proprietary technology.

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We are an “emerging growth company” and a “smaller reporting company” and have elected to take advantage of the reduced reporting requirements applicable to emerging growth companies and smaller reporting companies, and we will continue to incur significant costs associated with operating as a public company.