REIN THERAPEUTICS, INC.

30,000,000 Shares of Common Stock

We are selling 30,000,000 shares of our common stock at an assumed public offering price of $1.66 per share, the last reported sale price of our common stock as reported on The Nasdaq Capital Market on April 24, 2026. The actual public offering price per share of common stock will be determined between us and the underwriters at the time of pricing and may be at a discount to this assumed offering price. Therefore, the assumed public offering price used throughout this prospectus may not be indicative of the final offering price.

Our common stock is listed on the Nasdaq Capital Market under the symbol "RNTX." On April 24, 2026, the last reported sale price of our common stock on the Nasdaq Capital Market was $1.66 per share.