BridgeBio Oncology Therapeutics Inc美股招股说明书(2026-01-07版)

63,054,549 Shares of Common Stock by the Selling Securityholders This prospectus supplement no. 2 (this “Prospectus Supplement”) amends and supplements the prospectus dated September10, 2025 (as may besupplemented or amended from time to time, the “Prospectus”), which forms part of our Registration Statement on Form S-1 (Registration StatementNo.333-289940). This Prospectus Supplement is being filed to update and supplement the information included or incorporated by reference in theProspectus with the information contained in the attached Current Report on Form 8-K, filed with the Securities and Exchange Commission (the This Prospectus Supplement updates and supplements the information in the Prospectus and is not complete without, and may not be delivered orutilized except in combination with, the Prospectus, including any amendments or supplements thereto. This Prospectus Supplement should be read inconjunction with the Prospectus, and if there is any inconsistency between the information in the Prospectus and this Prospectus Supplement, you should Our common stock, par value $0.0001 per share (“Common Stock”) is listed on Nasdaq Global Market (“Nasdaq”) under the symbol “BBOT”. OnJanuary6, 2026, the closing price of our Common Stock as reported on Nasdaq was $11.59 per share. We are an “emerging growth company” as that term is defined under the federal securities laws and, as such, are subject to certain reducedpublic company reporting requirements. Investing in our securities involves risks that are described in the “Risk Factors” section beginning on page 10 of theProspectus. Neither the SEC nor any state securities commission has approved or disapproved of the securities to be issued under this prospectus ordetermined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense. The date of this Prospectus Supplement is January7, 2026. UNITED STATESSECURITIES AND EXCHANGE COMMISSION 39-3690783(IRS EmployerIdentification No.) Item 8.01Other Events. On January7, 2026, BridgeBio Oncology Therapeutics, Inc. (the “Company”) issued a press release titled “BBOT Announces New Clinical DataAdvancing Its Portfolio of Three Innovative and Differentiated RAS and PI3KαPipeline Programs.” A copy of the press release is attached as Item 9.01Financial Statements and Exhibits. (d)Exhibits. Exhibit No.Description99.1Press release dated January7, 2026. 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 theundersigned thereunto duly authorized. BRIDGEBIO ONCOLOGY THERAPEUTICS, INC. By:/s/ Eli WallaceName:Eli Wallace Date: January7, 2026 BBOT Announces New Clinical Data Advancing Its Portfolio of Three Innovative and Differentiated RAS and PI3KPipeline Programs •BBO-8520 monotherapy in patients withKRASG12Cnon-small cell lung cancer (NSCLC) showed a 65% objective response rate (ORR)and a 66% 6-month progression-free survival (PFS), with 83% of patients eligible for 6-month follow-up remaining on treatment for ≥6months, alongside a potentially differentiated safety profile. Encouraging early efficacy signals were seen in patients withKRASG12Cand •BBO-8520 in combination with pembrolizumab, at active dose levels, demonstrated promising efficacy data and a distinct, differentiatedsafety profile. A favorable liver safety profile was observed compared with pembrolizumab monotherapy. •BBO-11818 monotherapy demonstrated a partial response (PR) in pancreatic cancer and anti-tumor activity was observed across doselevels and tumor types with tumor reductions at higher dose levels with a generally favorable, differentiated safety profile in doseescalation. •BBO-10203 demonstrated a potentially differentiated safety profile without any observed events of hyperglycemia and without anyenrollment restrictions on baseline HbA1c and glucose levels; combination studies with standard-of-care (SOC) treatments in colorectal •Company webcast to be held today at 8:30 a.m. Eastern Time (ET). SOUTH SAN FRANCISCO, Calif., January7, 2026— BridgeBio Oncology Therapeutics, Inc. (“BBOT”) (Nasdaq: BBOT), a clinical-stagebiopharmaceutical company focused on RAS-pathway malignancies, today announced positive preliminary safety and antitumor data across its threeorally bioavailable, differentiated small molecule RAS and PI3Kprograms. The data updates include BBO-8520, a direct inhibitor targeting both theON and OFF states of KRASG12C; BBO-11818, a panKRAS inhibitor targeting mutantKRASin both the ON and OFF states, and BBO-10203, a “Today’s data underscore the strength of our differentiated precision oncology portfolio targeting RAS and PI3K,” said Eli Wallace, PhD, ChiefExecutive Officer of BBOT. “By focusing on ON biology and leveraging strong chemistry, we are developing highly selective therapies designed to bebetter tolerated and, as a result, deliver greater anti-tumor activity. We are plea