Agenus to Host Research and Development Day on May 14, 2015

Agenus Inc. (NASDAQ: AGEN), today announced additional details for the Company’s upcoming analyst and institutional investor meeting to be held on Thursday, May 14, 2015, from 4:30 to 6:30 PM Eastern Time in New York City. The event will provide an overview of the Company’s proprietary and partnered pipeline, including its antibody platforms and checkpoint modulator programs, its heat shock protein-based vaccine platform and its saponin-based vaccine adjuvant platform. Management will also provide an update on its strategic alliances, including those with Incyte and Merck, and its recent strategic acquisition, all within the framework of its overall corporate strategy.

The event will be moderated by Garo Armen, Ph.D., the Company’s Chief Executive Officer, and Robert Stein, M.D., Ph.D., the Company’s Chief Scientific Officer, and will include presentations by key opinion leaders in immuno-oncology, followed by an in depth panel discussion and a question and answer session.

Presenters will include:

• Charles Drake, M.D., Ph.D., Co-Director at the Prostate Cancer Multidisciplinary Clinic and Associate Professor of Oncology, Urology, and Immunology at the Johns Hopkins School of Medicine. Dr. Drake is a leading authority on checkpoint modulators and will address recent progress, as well as key challenges and opportunities in the immuno-oncology field involving both antibody and vaccine therapeutics.

• Orin Bloch, M.D., Khatib Professor of Neurological Surgery at Northwestern University Feinberg School of Medicine. Dr. Bloch is a leading authority on brain cancer, and was a senior investigator in the Phase 2 study of Agenus’ Prophage vaccine in newly diagnosed glioblastoma multiforme (GBM). He will present an overview of the treatment landscape in GBM, as well as a summary of the most recent data on Prophage.

A live webcast will be accessible from the Company’s website at www.agenusbio.com/webcast/. Portions of the event will be available for replay on the company’s website.

About Agenus

Agenus is an immunology company developing a series of Checkpoint Modulators for the treatment of patients with cancer, infectious diseases, and other immune disorders, heat shock protein (HSP)-based vaccines, and immune adjuvants. These programs are supported by three separate technology platforms. Agenus’ internal and partnered checkpoint modulator programs target GITR, OX40, CTLA-4, LAG-3, TIM-3, PD-1 and other undisclosed programs. The company’s proprietary discovery engine Retrocyte DisplayTM is used to generate fully human and humanized therapeutic antibody drug candidates. The Retrocyte Display platform uses a high-throughput approach incorporating IgG format human antibody libraries expressed in mammalian B-lineage cells. Agenus recently acquired a powerful yeast antibody display platform termed SECANT, developed by Celexion, LLC. SECANT allows rapid generation of soluble, full-length human antibodies. SECANT and Agenus’ mammalian antibody display platform have complementary strengths and further bolster Agenus' abilities to generate and optimize fully human monoclonal antibodies. Agenus’ heat shock protein-based vaccines have completed Phase 2 studies in newly diagnosed glioblastoma multiforme, and in the treatment of herpes simplex viral infection; the heat shock protein-based vaccine platform can generate personalized as well as off the shelf products. The company’s QS-21 Stimulon® adjuvant platform is extensively partnered with GlaxoSmithKline and with Janssen Sciences Ireland UC and includes several candidates in Phase 2 trials, as well as shingles and malaria vaccines which have successfully completed Phase 3 clinical trials. For more information, please visit www.agenusbio.com, or connect with the company on Facebook, LinkedIn, Twitter and Google+; information that may be important to investors will be routinely posted in these locations.

Forward-Looking Statement

This press release contains forward-looking statements that are made pursuant to the safe harbor provisions of the federal securities laws, including statements regarding the Company’s upcoming analyst and institutional investor meeting. These forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially. These risks and uncertainties include, among others, the factors described under the Risk Factors section of our most recent Quarterly Report on Form 10-Q or annual report on Form 10-K filed with the Securities and Exchange Commission. Agenus cautions investors not to place considerable reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this press release, and Agenus undertakes no obligation to update or revise the statements, other than to the extent required by law. All forward-looking statements are expressly qualified in their entirety by this cautionary statement.