BOSTON and ROCKVILLE, Md., March 22, 2021 (GLOBE NEWSWIRE) — Sensei Biotherapeutics, Inc. (Nasdaq: SNSE), a clinical-stage immunotherapy company focused on the discovery and development of next generation therapeutics for cancer, today announced that it will be added to the Russell 2000® Index effective March 22, 2021, as part of its quarterly initial public offering (IPO) additions. The Russell 2000® Index measures the performance of the small cap segment of the U.S. equity market. Membership in the Russell 2000® provides automatic inclusion in the appropriate growth and value style indexes.

The Russell U.S. Indexes are widely used by investment managers and institutional investors for index funds and as benchmarks for active investment strategies. Approximately $9 trillion in assets are benchmarked against Russell U.S. Indexes. Russell U.S. Indexes are part of FTSE Russell, a leading global index provider. For more information about the Russell U.S. Indexes and the Russell Indexes reconstitution, visit the FTSE Russell website.

About Sensei Biotherapeutics

Sensei Biotherapeutics is a clinical-stage biopharmaceutical company focused on the discovery, development and delivery of next generation immunotherapies for the treatment of cancer and infectious diseases. The company has developed a proprietary bacteriophage-based platform, ImmunoPhage™, that enables the rapid generation of immune activating therapeutic agents that fully engage the immune system. Using the ImmunoPhage™ platform, Sensei is developing a library of ImmunoPhage, called Phortress™, 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 ImmunoPhage™ 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, an ImmunoPhage™ 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).

Investor Contact:

Julie Seidel

Stern Investor Relations, Inc.

212-362-1200

Julie.seidel@sternir.com

Media Contact:

Laura Liotta

Sam Brown, Inc.

484-580-6411

Lauraliotta@sambrown.com