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 1934during 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 requirementsfor 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 ofRegulation 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, a smaller reporting company, or anemerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” inRule 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 orrevised 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 May 4, 2026, the registrant had 75,389,375 shares of common stock, $0.00001 par value per share, outstanding, comprising 61,902,733 shares ofvoting common stock, $0.00001 par value per share, and 13,486,642 shares of non-voting common stock, $0.00001 par value per share. APOGEE THERAPEUTICS, INC.TABLE OF CONTENTS PagePART IFINANCIAL INFORMATION1Item 1.Condensed Consolidated Financial Statements (Unaudited)1Condensed Consolidated Balance Sheets as of March 31, 2026 and December 31, 20251Condensed Consolidated Statement of Operations for the Three Months Ended March 31, 2026 and 20252Condensed Consolidated Statement of Comprehensive Loss for the Three Months Ended March 31, 2026 and20253Condensed Consolidated Statement of Stockholders’ Equity for the Three Months Ended March 31, 2026 and20254Condensed Consolidated Statement of Cash Flows for the Three Months Ended March 31, 2026 and 20256Notes to the Unaudited Interim Condensed Consolidated Financial Statements7Item 2.Management’s Discussion and Analysis of Financial Condition and Results of Operations24Item 3.Quantitative and Qualitative Disclosures About Market Risk37Item 4.Controls and Procedures37PART IIOTHER INFORMATION38Item 1.Legal Proceedings38Item 1A.Risk Factors38Item 2.Unregistered Sales of Equity Securities and Use of Proceeds69Item 3.Defaults Upon Senior Securities70Item 4.Mine Safety Disclosures70Item 5.Other Information70Item 6.Exhibits71Signatures72 SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS This Quarterly Report on Form 10-Q (this “Quarterly Report”) contains “forward-looking statements” within the meaning ofthe federal securities laws, which statements are subject to substantial risks and uncertainties and are based on current expectations,estimates, forecasts and assumptions. All statements other than statements of historical fact included in this Quarterly Report,including statements concerning our plans, objectives, goals, strategies, future events, future revenues or performance, capitalrequirements or financing needs, capital expenditures, commitments, preclinical studies, clinical trials, plans or intentions relatingto product candidates, expected markets and business trends, and other statements, including without limitation, those discussedunder the sections titled “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results ofOperations”, are forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “may,”“might,” “will,” “would,” “shall,” “objective,” “intend,” “target,” “should,” “could,” “can,” “expect,” “anticipate,” “believe,”“design,” “estimate,” “forecast,” “predict,” “potential,” “plan,” “seek,” or “continue” or the negative of these terms and similarexpressions intended to identify forward-looking statements. Forward-looking statements reflect our current views with respect tofuture events. Given the significant risks and uncertainties, you should not place undue reliance on these forward-lookingstatements. There are a number of risks, uncertainties and other factors that could cause our actual results to differ materially from theforward-looking statements expressed or implied in this Quarterly Report. Such risks, uncertainties and other factors include,among others, the following: •our plans to develop and commercialize our programs for the treatment of atopic dermatitis, asthma, eosinophilicesophagitis, chronic obstructive pulmonary disease, and related inflammatory and immunology indications with highunmet need;•our ability to obtain funding for our operations, inc