MBX Biosciences, Inc.

There have been no material changes to our risk factors previously disclosed in Part I, Item 1A, “Risk Factors” in our 2025 Annual Report. Our business involves significant risks. Stockholders should carefully consider the risks and uncertainties described in our 2025 Annual Report together with all of the other information contained in this Quarterly Report on Form 10-Q (this "Quarterly Report") and in the other documents that we file with the SEC, including our unaudited condensed financial statements and related notes appearing in this Quarterly Report, before deciding to invest in our common stock. If any of the events or developments described were to occur, our business, prospects, operating results and financial condition could suffer materially, the trading price of our common stock could decline and you could lose all or part of your investment. The risks and uncertainties described are not the only ones we face. Additional risks and uncertainties not presently known to us or that we currently believe to be immaterial may also adversely affect our business.