Agenus to Participate in Brain Cancer Vaccine and Immunotherapy Discussion on September 23rd Webcast

Agenus Inc. (NASDAQ: AGEN) today announced that Dr. Garo Armen, chairman and CEO of Agenus, will participate in a webcast, titled “Glioblastoma – Brain Cancer: The Next Generation of Therapies,” being sponsored by ProActive Capital Group on Monday, September 23, 2013 at 12 noon ET. The webcast will feature two medical experts in the field of glioblastoma multiforme (GBM) in a moderated discussion of immunological approaches for the treatment of brain cancer:

• Andrew T. Parsa, MD, PhD, Michael J. Marchese Professor and Chair, Department of Neurological Surgery at Northwestern University School of Medicine
• John A. Boockvar, MD, Professor of Neurological Surgery and Co-director of the Brain and Spinal Tumor Program at the Weill Cornell Brain and Spine Center

The discussion will be moderated by the biotechnology team at Maxim Group, led by Jason Kolbert.

Webcast Information

To access the live audio webcast, please log on through a link located on Agenus’ website www.agenusbio.com/webcast/ and use passcode 40290515. A replay of the webcast will be available approximately one hour after the conclusion of the live event.

About Glioblastoma Multiforme (GBM)

The incidence rates of primary malignant brain and central nervous system cancers have increased over the last three decades.1 The American Cancer Society estimates that more than 23,000 malignant tumors of the brain or spinal cord will be diagnosed during 2013 in the US, and that more than 14,000 people will die from these tumors. 2 GBM is the most common primary malignant brain tumor and accounts for the majority of diagnoses. It has been associated with a particularly poor prognosis, with survival rates at one and five years equaling 33.7% and 4.5%, respectively.3 The current standard of care for patients with newly diagnosed GBM is surgical resection followed by fractionated external beam radiotherapy and systemic temozolomide4 resulting in a median OS of 14.6 months5 based on data from a randomized Phase 3 trial. Although this treatment can prolong survival, it is not curative and the vast majority of patients with GBM experience recurrent disease, with a median time to recurrence of seven months.6 Currently, there is no standard treatment for patients with recurrent GBM, although additional surgery, chemotherapy (i.e., CCNU, temozolomide), bevacizumab, and radiotherapy are used.

About the Prophage Series (HSPPC-96) Cancer Vaccines

The Prophage Series G vaccines are currently being studied in two different settings of GBM: newly diagnosed and recurrent disease. Prophage Series cancer vaccines are autologous therapies derived from cells extracted from the patient’s tumor. As a result, Prophage Series vaccines contain a precise antigenic ‘fingerprint’ of a patient’s particular cancer and are designed to reprogram the body’s immune system to target only cells bearing this fingerprint, reducing the risk that powerful anti-cancer agents will target healthy tissue and cause debilitating side effects often associated with chemotherapy and radiation therapy.

About Agenus

Agenus Inc. is a biotechnology company working to develop treatments for cancers and infectious diseases. The company is focused on immunotherapeutic products based on strong platform technologies with multiple product candidates advancing through the clinic, including several product candidates that have advanced into late-stage clinical trials through corporate partners. Between Agenus and its partners, 23 programs are in clinical development. For more information, please visit www.agenusbio.com, or connect with the company on Facebook, LinkedIn, Twitter and Google+.

Forward-Looking Statement

This press release contains forward-looking statements, including statements regarding up-coming presentations and the potential application of the Company’s technologies and product candidates in the prevention and treatment of diseases. 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 Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission for the period ended June 30, 2013. 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 document, and Agenus undertakes no obligation to update or revise the statements. All forward-looking statements are expressly qualified in their entirety by this cautionary statement. Agenus’ business is subject to substantial risks and uncertainties, including those identified above. When evaluating Agenus’ business and securities, investors should give careful consideration to these risks and uncertainties.

References

1. Maher EA, McKee AC. In: Atlas of diagnostic oncology. 3. Skarin AT, Canellos GP, editor. London: Elsevier Science; 2003. Neoplasms of the central nervous system; pp. 5–10.

2. http://www.cancer.gov/cancertopics/pdq/treatment/adultbrain/HealthProfessional/page1

3. Central Brain Tumor Registry of the United States (CBTRUS) 2010 CBTRUS statistical report: primary brain and central nervous system tumors diagnosed in the United States in 2004-2006. http://www.cbtrus.org/reports/reports.html

4. National Comprehensive Cancer Network clinical practice guidelines in oncology-central nervous system cancers. v.1.2010.

5. Stupp, R., et al., Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med, 2005. 352(10): p. 987-96.

6. Wen PY, DeAngelis LM. Chemotherapy for low-grade gliomas: emerging consensus on its benefits. Neurology. 2007;68(21):1762–1763. doi: 10.1212/01.wnl.0000266866.13748.a9.