Seaport Therapeutics, Inc.

Revenue

To date, we have not recognized any revenue and do not expect to generate any revenue from the sale of products in the near term, if at all. If our development efforts for our current or potential future product candidates are successful and result in regulatory approval or if we enter into additional license or collaboration agreements with third parties, we may generate revenue in the future from product sales, payments from such license or collaboration agreements, or any combination thereof. However, there can be no assurance as to when we will generate such revenue, if at all.

Operating Expenses

Research and Development Expenses

Research and development, or R&D, expenses consist primarily of costs incurred in connection with the discovery, non-clinical development, and clinical development of our lead product candidates and potential future product candidates. R&D expenses include direct costs specifically attributable to our programs including external fees to conduct certain clinical and non-clinical research and development activities, preclinical and early discovery assets, such as costs paid to contract research and manufacturing organizations, consulting fees, laboratory services and supplies, and costs incurred in connection with the Monash License Agreement, as well as indirect costs that are not directly attributable to a specific program such as personnel related expenses, including stock-based compensation, facility expenses, depreciation, and information technology costs.

We expense research and development costs as incurred. We recognize direct development costs based on an evaluation of the progress to completion of specific tasks using information provided to us by our vendors or our estimate of the level of service that has been performed at each reporting date. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our condensed consolidated financial statements as prepaid or accrued research and development expenses.

Due to the inherently unpredictable nature of preclinical and clinical development, we do not allocate all of our internal research and development expenses on a program-by-program basis as these expenses primarily relate to personnel and other overhead costs that are deployed across multiple programs under development. Our research and development expenses also include external costs, which we do track on a program-by-program basis following the program’s nomination as a product candidate. We began tracking such external costs upon the nomination for GlyphAllo in 2020, GlyphAgo in 2023 and Glyph2BLSD in 2024.

Research and development activities are central to our business model. We expect that our research and development expenses will continue to increase for the foreseeable future as we advance our current and any future product candidates into and through clinical development and as we continue to develop additional product candidates.

General and Administrative Expenses

General and administrative expenses consist of salaries and personnel-related costs, including stock-based compensation expense, for our personnel in executive, business development, legal, finance and accounting, human resources and other administrative functions, consulting fees, facility costs not otherwise included in R&D expenses, fees paid for accounting and tax services, insurance expenses, legal costs consisting of general corporate legal fees and patent legal fees.

We anticipate that our general and administrative expenses will increase in the future as we increase our headcount to support the expansion of our business, particularly in support of development of product candidates and our continued research and clinical development activities. We will also incur significant costs associated with being a public company, including increased accounting, audit, legal, regulatory, compliance, and director and officer insurance costs, as well as expenses related to services associated with maintaining compliance with the requirements of the Nasdaq Stock Market, the Securities and Exchange Commission, and investor relations costs.

Other Income (Expense), Net

Other income (expense), net consists primarily of interest income earned on our investments and cash equivalents, research and development tax credits from the Australian government’s tax incentive program, and realized and unrealized foreign currency gains and losses.

Provision for Income Taxes

Provision for income taxes consists of United States federal and state income taxes in jurisdictions in which we conduct business and foreign income taxes related to our Australian subsidiary. The provision for income taxes is based on our taxable income. Our loss before income taxes is adjusted for permanent and temporary tax differences, primarily related to capitalized non-U.S. research and development expenses, resulting in taxable income or loss. We recorded a full valuation allowance of our U.S. deferred tax asset position as of March 31, 2026 and 2025 as we believe it was more likely than not that we would not be able to utilize our deferred tax assets.