New Clinical Responses for AGEN1181 Presented at AACR

• 7 objective responses observed to date in multiple tumor types
• New responses reported in patients with melanoma and ovarian cancer
• Benefit seen in patients typically unresponsive to I-O agents

LEXINGTON, Mass., April 10, 2021 (GLOBE NEWSWIRE) — Agenus (NASDAQ: AGEN), an immuno-oncology company with an extensive pipeline of checkpoint antibodies, cell therapies, adjuvants, and vaccines designed to activate immune response to cancers and infections, today presented new clinical data on AGEN1181, its next-generation anti-CTLA-4 antibody, at the American Association for Cancer Research (AACR) Annual Meeting from April 10 – 15, 2021.

“The preclinical and translational data in conjunction with our updated clinical data with AGEN1181 alone or in combination with our PD-1, balstilimab, continue to strongly support and differentiate our next-generation CTLA-4 antibody,” said Steven O’Day, MD, Chief Medical Officer of Agenus. “AGEN1181 is showing activity in patients with tumors which typically do not respond to first-generation CTLA-4 and PD-1 antibodies. Equally important, the safety data continues to show no immune mediated hypophysitis, pneumonitis, or hepatitis to date. Given the efficacy and favorable safety profile, we have expanded AGEN1181 into Phase 2 in colorectal cancer patients as a first step in our efforts to expand to additional important cancer indications.”

In two separate presentations at AACR, Agenus showcased the optimal performance of AGEN1181 in relevant models. In addition, as the clinical data matures, additional responses as well as a conversion from a partial response to a complete response, have been observed. The new data announced today include the following clinical responses:

• New partial response in the first melanoma patient treated (monotherapy)
• New conversion to complete response in ovarian cancer patient (AGEN1181 plus balstilimab)
• Partial response in microsatellite stable (MSS) colorectal cancer patient (AGEN1181 plus balstilimab)
• Partial response in PD-L1(-) ovarian cancer patient (AGEN1181 plus balstilimab)
• Partial response in MSS colorectal cancer patient (AGEN1181 plus balstilimab)
• Complete response in PD-L1(-) MSS endometrial cancer patient (monotherapy)
• Complete response by PET in PD-L1(-) MSS endometrial cancer patient (AGEN1181 plus balstilimab)

Presentation Details:
E-poster presentations were made available on the conference platform on April 10 at 8:30am ET. Posters with accompanying audio will be available for viewing to meeting registrants until June 21.

Session: PO.IM02.10 – Therapeutic Antibodies, Including Engineered Antibodies
Poster title: Fc-enhanced anti-CTLA-4 antibody, AGEN1181: New mechanistic insights for potent antitumor immunity and combination potential in treatment-resistant solid tumors
Abstract number: 1878
Presenting author: Antoine Tanne, PhD

Session: PO.IM02.05 – Immune Monitoring / Clinical Correlates
Poster title: Characterization of the pharmacodynamic activity of AGEN1181, an Fc-enhanced CTLA-4 antibody, alone and in combination with the PD-1 antibody balstilimab
Abstract number: 1677
Presenting author: Irina Shapiro, PhD

In addition, Dr. Steven O’Day, Chief Medical Officer, Dr. Dhan Chand, Scientific Director, Head of Drug Discovery, and Dr. Jennifer Buell, President and COO, at Agenus, will participate in a webcast hosted by Dr. Matt Phipps of William Blair on Saturday, April 10, 2021 at 10:30 a.m. ET.

Registration for the webinar can be done in advance at https://williamblair.zoom.us/webinar/register/WN_4tTw7GEFQPC2qC4B3TzrfQ.

A replay will be available after the call on the Events & Presentations page of the Agenus website at https://investor.agenusbio.com/events-and-presentations.

About Agenus
Agenus is a clinical-stage immuno-oncology company focused on the discovery and development of therapies that engage the body’s immune system to fight cancer. The Company’s vision is to expand the patient populations benefiting from cancer immunotherapy by pursuing combination approaches that leverage a broad repertoire of antibody therapeutics, adoptive cell therapies (through its AgenTus Therapeutics subsidiary), and proprietary cancer vaccine platforms. The Company is equipped with a suite of antibody discovery platforms and a state-of-the-art GMP manufacturing facility with the capacity to support clinical programs. Agenus is headquartered in Lexington, MA. For more information, please visit www.agenusbio.com and our Twitter handle @agenus_bio. Information that may be important to investors will be routinely posted on our website and Twitter.

Forward-Looking Statements
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 therapeutic potential of AGEN1181 alone and in combination with other agents, as well as the potential to use such therapies in additional cancer indications. 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.

Contact
Agenus Investor Relations
Jan Medina, CFA
Agenus
781-674-4490
Jan.Medina@agenusbio.com

Agenus Media Relations
Kimberly Ha
KKH Advisors
917-291-5744
kimberly.ha@kkhadvisors.com