Upstream Bio Inc 2025年季度报告

(Mark One) ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF1934 For the quarterly period endedMarch 31,2025OR ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF1934 For the transition period from _________________ to _________________Commission File Number:001-42366 UPSTREAM BIO, INC. (Exact Name of Registrant as Specified in its Charter) 38-4187694(I.R.S. EmployerIdentification No.) Delaware 890 Winter Street,Suite 200Waltham,MA(Address of principal executive offices) 02451(Zip Code) Registrant’s telephone number, including area code: (781)208-2466 Securities registered pursuant to Section 12(b) of the Act: Title of each classTradingSymbol(s)Name of each exchange on which registeredCommon Stock, par value $0.001 per shareUPBThe Nasdaq Global Select Market 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 of1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject tosuch 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 Rule405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required tosubmit 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 an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerginggrowth company” in Rule 12b-2 of the Exchange Act. Accelerated filer☐Smaller reporting company☒Emerging growth company☒ Large accelerated filer☐Non-accelerated filer☒ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying withany 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 May 2, 2025, the registrant had53,793,703shares of common stock, $0.001 par value per share, outstanding. Special Note Regarding Forward-Looking Statements This Quarterly Report on Form 10-Q (“Quarterly Report”) contains express or implied forward-looking statements that are basedon our management’s belief and assumptions and on information currently available to our management. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of theSecurities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended(the “Exchange Act”). These statements relate to future events or our future operational or financial performance, and involveknown and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to bematerially different from any future results, performance or achievements expressed or implied by these forward-lookingstatements. Forward-looking statements in this Quarterly Report include, but are not limited to, statements about: •the initiation, timing, progress, and results of our planned and future clinical trials for verekitug, for the treatment ofsevere asthma, chronic rhinosinusitis with nasal polyps (“CRSwNP”) and chronic obstructive pulmonary disease(“COPD”);•our ability to replicate positive results from earlier preclinical studies or clinical trials conducted by us or third partiesin current or future clinical trials;•our ability to demonstrate that verekitug and any potential future product candidates are safe and effective for theirproposed indications and our expectations around their beneficial characteristics and therapeutic effects;•our ability to advance verekitug and any potential future product candidates through applicable regulatory approvalprocesses, including timing of Investigational New Drug (“IND”) applications and final U.S. Food and DrugAdministration (“FDA”) approval of verekitug or any future product candidate;•our estimates of the number of patients that we will enroll and our ability to initiate, recruit and enroll patients in andconduct and successfully complete our clinical trials at the pace we project;•the implementation of our business model and strategic plans;•our ability to rely on third-party manufacturers and successfully manufacture verekitug for preclinical use, for clinicaltrials and on a larger scale for commercial use, if approved;•our ability to commercialize verekitug, if approved, and obtain favorable pricing and reimbursement;•the size and growth pot