Sensei Biotherapeutics Announces Launch of Initial Public Offering

Sensei Biotherapeutics, Inc., a clinical-stage immunotherapy company focused on the discovery and development of next generation therapeutics for cancer, today announced that it has launched an underwritten initial public offering of 5,885,000 shares of its common stock at an anticipated initial public offering price between $16.00 and $18.00 per share pursuant to a registration statement on Form S-1 filed with the U.S. Securities and Exchange Commission (the "SEC"). In addition, Sensei intends to grant the underwriters a 30-day option to purchase up to an additional 882,750 shares of common stock. All of the shares to be sold in the proposed offering will be offered by Sensei. Sensei has applied to list the shares on the Nasdaq Global Market under the symbol "SNSE."

Citigroup, Piper Sandler and Berenberg are acting as joint book-running managers for the offering. Oppenheimer & Co. is acting as the lead manager for the proposed offering. 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 as to the actual size or terms of the offering.

The proposed offering of these securities is being made only by means of a prospectus. A copy of the preliminary prospectus may be obtained from Citigroup Global Markets Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, or by telephone at 800-831-9146 or by email at [email protected]; Piper Sandler & Co., Attention: Prospectus Department, 800 Nicollet Mall, J12S03, Minneapolis, MN 55402, or by telephone at 800-747-3924 or by email at [email protected]; or Berenberg Capital Markets LLC, Attention: Investment Banking, 1251 Avenue of the Americas, 53^rd Floor, New York, NY 10020, or by telephone at 646-949-9000 or by email at [email protected].

Sensei is offering access to roadshow materials to both institutional and retail investors. Interested retail investors can view the management presentation at www.retailroadshow.com/?link=SNSE.

This press release shall not constitute an offer to sell, or the solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Sensei Biotherapeutics

Sensei Biotherapeutics is a clinical-stage biopharmaceutical company focused on the discovery, development and delivery of next generation of immunotherapies for the treatment of cancer and infectious diseases. The company has developed a proprietary bacteriophage-based platform, ImmunoPhagetm, that enables the rapid generation of immune activating therapeutic agents that fully engage the immune system. Using the ImmunoPhagetm platform, Sensei is developing a library of ImmunoPhage, called Phortresstm, to target multiple tumor-associated antigens to create a personalized yet off-the-shelf cocktail approach for treating cancer patients. The platform enables efficient, scalable and cost-effective manufacturing to support all of Sensei's clinical programs. The company's most advanced immunotherapy, SNS-301, a first-in-class ImmunoPhagetm targeting the tumor antigen Aspartyl beta Hydroxylase (ASPH), is currently in a Phase 1/2 clinical trial in patients with advanced Squamous Cell Carcinoma of the Head and Neck. Earlier stage programs include SNS-401, a ImmunoPhagetm cocktail for the treatment of Merkel Cell Carcinoma, and SNS-VISTA, an antibody-based therapeutic targeting an immune checkpoint gene that inhibits anti-tumor immune responses called V-domain Ig suppressor of T cell activation (VISTA).