Marker Therapeutics, Inc. (Nasdaq: MRKR), a clinical-stage immuno-oncology company specializing in the development of next-generation T cell-based immunotherapies for the treatment of hematological malignancies and solid tumor indications, today announced that it has commenced an underwritten public offering of shares of its common stock. In addition, Marker expects to grant the underwriters a 30-day option to purchase additional shares of its common stock. All of the shares to be sold in the offering are to be sold by Marker. The offering is subject to market and other conditions, and there can be no assurance as to whether or when the offering may be completed, or the actual size or terms of the offering.

Piper Sandler & Co. is acting as the sole active book-running manager for the offering.

The proposed offering is being made pursuant to a shelf registration statement, including a base prospectus, filed by Marker that was declared effective by the Securities and Exchange Commission ("SEC") on June 25, 2019. The offering will be made only by means of a written prospectus and prospectus supplement that form a part of the registration statement. An electronic copy of the preliminary prospectus supplement and accompanying prospectus relating to the offering will be available on the website of the SEC at www.sec.gov. Copies of the preliminary prospectus supplement, when available, and the accompanying prospectus relating to the offering may be obtained by contacting Piper Sandler & Co., Attention: Prospectus Department, 800 Nicollet Mall, J12S03, Minneapolis, Minnesota 55402, by telephone at (800) 747-3924 or by email at [email protected]. The final terms of the offering will be disclosed in a final prospectus supplement to be filed with the SEC.