Upstream Bio Files 8-K

TL;DR

Upstream Bio filed a routine 8-K, no major news.

AI Summary

Upstream Bio, Inc. filed an 8-K on September 2, 2025, to report on other events and financial statements. The filing does not contain specific details about material events, acquisitions, or financial performance beyond its routine reporting nature.

Why It Matters

This 8-K filing indicates routine corporate reporting by Upstream Bio, Inc. without disclosing specific material events that would typically impact its stock price.

Risk Assessment

Risk Level: low — The filing is a standard 8-K for other events and financial statements, lacking any specific material disclosures that would indicate increased risk.

Key Players & Entities

• Upstream Bio, Inc. (company) — Registrant
• September 02, 2025 (date) — Date of earliest event reported
• 001-42366 (other) — Commission file number
• 38-4187694 (other) — IRS employer identification no.
• 890 Winter Street Suite 200 (address) — Principal executive offices
• Waltham, Massachusetts (location) — Principal executive offices location
• 02451 (zip_code) — Principal executive offices zip code
• (781) 208-2466 (phone_number) — Registrant's telephone number

FAQ

Key Financial Figures

• $0.001 — nge on which registered Common Stock, $0.001 par value per share UPB The Nasdaq

Filing Documents

• upb-20250902.htm (8-K) — 55KB
• upb-ex99_1.htm (EX-99.1) — 33KB
• upb-ex99_2.htm (EX-99.2) — 1KB
• upb-ex99_2.pdf (EX-99.2) — 1472KB
• 0002022626-25-000005.txt ( ) — 2141KB
• upb-20250902.xsd (EX-101.SCH) — 26KB
• upb-20250902_htm.xml (XML) — 5KB

01 Regulation FD Disclosure

Item 7.01 Regulation FD Disclosure. On September 2, 2025, Upstream Bio, Inc. (the "Company" or "Upstream Bio") issued a press release titled "Upstream Bio Reports Positive Top-Line Results from the Phase 2 VIBRANT Trial of Verekitug for the Treatment of Chronic Rhinosinusitis with Nasal Polyps (CRSwNP)." A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K. Also, on September 2, 2025, the Company hosted a webcast to discuss top-line data from the Phase 2 VIBRANT trial of verekitug in CRSwNP. A copy of the presentation from the webcast is available on the Investors section of the Company's website at https://investors.upstreambio.com and is furnished as Exhibit 99.2 to this Current Report on Form 8-K The information under this Item 7.01, including Exhibit 99.1 and Exhibit 99.2 hereto, is being furnished herewith and shall not be deemed "filed" for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall such information be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended (the "Securities Act"), or the Exchange Act, except as expressly set forth by specific reference in such filing. Item8.01 Other Events. On September 2, 2025, the Company released top-line data from the Phase 2, global, randomized, double-blind, placebo-controlled, parallel group VIBRANT trial (NCT06164704) that evaluated the efficacy and safety of verekitug over 24 weeks in 81 adults with CRSwNP. Participants received either 100 mg of verekitug or placebo subcutaneously every 12 weeks for 24 weeks. The primary endpoint was change in endoscopic nasal polyp score at Week 24, a primary endpoint that has been used in several registrational trials for other biologic treatments for CRSwNP. Secondary endpoints included: nasal congestion score, sinus opacification, difficulty with sense of smell, total sympt

Forward-Looking Statements

Forward-Looking Statements This Current Report on Form 8-K contains "forward-looking statements" within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. These statements may be identified by words such as "aims," "anticipates," "believes," "continue," "could," "estimates," "expects," "forecasts," "goal," "intends," "may," "plans," "possible," "potential," "predict," "project," "seeks," "should," "target," "will" and variations of these words or similar expressions. Any statements in this Current Report on Form 8-K that are not statements of historical fact may be deemed to be forward-looking statements. These forward-looking statements include, without limitation, express or implied statements regarding the future clinical development of verekitug for the treatment of CRSwNP and expectations for the dosing, safety, tolerability and clinical benefit of verekitug in CRSwNP and additional indications. Any forward-looking statements are based on management's current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. Risks that contribute to the uncertain nature of the forward-looking statements include: Upstream Bio's ability to advance verekitug through clinical development, and to obtain regulatory approval of and ultimately commercialize verekitug on the expected timeline, if at all; the initiation, timing, progress and results of clinical trials; the Company's ability to fund its development activities and achieve development goals; the Company's dependence on third parties to conduct clinical trials and manufacture verekitug, and commercialize verekitug, if approved; the Company's ability to attract, hire and retain key personnel, and protect its intellectual property; the Company's financial condition and need for substantial additional funds in order to

01 Financial Statements and Exhibits

Item 9.01 Financial Statements and Exhibits. (d) Exhibits 99.1 Press Release issued by Upstream Bio, Inc. on September 2, 2025, furnished herewith. 99.2 Corporate presentation of Upstream Bio, Inc., furnished herewith. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Upstream Bio, Inc. Date: September 2, 2025 By: /s/ E. Rand Sutherland E. Rand Sutherland, M.D. Chief Executive Officer

View Full Filing

View this 8-K filing on SEC EDGAR