Rein Therapeutics, Inc.

We require substantial additional capital to finance our operations. If we are unable to raise such capital when needed, or on acceptable terms, we may be forced to delay, reduce and/or eliminate one or more of our clinical and research and development programs, future commercialization efforts or other operations.

As of September 30, 2025, we had cash and cash equivalents of $4.0 million. Based on our current operating plan, we believe that our existing cash and cash equivalents as of September 30, 2025, together with the proceeds received by us pursuant to the PPA in October 2025, will be sufficient to enable us to fund our operating expenses and capital expenditure requirements only into December 2025. As a result, we will need additional capital to fund our operations, which we may obtain from additional equity or debt financings, strategic collaborations, licensing arrangements or other sources. If we are unable to obtain sufficient funding on terms acceptable to us, on a timely basis or at all, we may be forced to delay, reduce or eliminate some or all of our research and development programs, product portfolio expansion or future commercialization efforts, which could adversely affect our business prospects, or we may be unable to continue operations.

We believe that our working capital as of September 30, 2025, together with the proceeds received by us pursuant to the PPA in October 2025, lack of revenue and recurring net losses raise substantial doubt about our ability to continue as a going concern.

For a discussion of our other risk factors, see “Part I, Item 1A-Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC on April 7, 2025.

You should carefully consider the risks included in our Annual Report on Form 10-K, together with all of the other information in this Quarterly Report on Form 10-Q, including our unaudited condensed consolidated financial statements and the related notes included elsewhere in this Quarterly Report on Form 10-Q. The occurrence of any single risk or any combination of risks could materially and adversely affect our business, financial condition, results of operations, cash flows and the trading price of our common stock.