iTeos Announces New Data for its Anti-TIGIT Antibody, EOS-448, at the American Society of Hematology Annual Meeting and TIGIT Therapies Digital Summit 2021

• Data from preclinical studies in collaboration with Fred Hutchinson Cancer Research Center will be presented at ASH and provide strong rationale for use of EOS-448 as a single agent and in combination with an immunomodulatory drug in patients with multiple myeloma
• Preclinical data shared at TIGIT Therapies Digital Summit highlight evidence for multifaceted mechanism of action of EOS-448

CAMBRIDGE, Mass. and GOSSELIES, Belgium, Dec. 09, 2021 (GLOBE NEWSWIRE) -- iTeos Therapeutics, Inc. (Nasdaq: ITOS), a clinical-stage biopharmaceutical company pioneering the discovery and development of a new generation of highly differentiated immuno-oncology therapeutics for patients, today announced the presentation of new preclinical data for its anti-TIGIT monoclonal antibody, EOS-448, at the 63rd American Society of Hematology (ASH) Annual Meeting & Exposition and the TIGIT Therapies Digital Summit 2021.

“The data we presented this week at the TIGIT Therapies Digital Summit provide further evidence of the multifaceted mechanism of our high affinity, potent anti-TIGIT monoclonal antibody, EOS-448. We presented preclinical data showing activation of immune stimulatory cells is dependent on activating via FcγR, and also show clinically that this activation is translating to depletion of immunosuppressive cells. Furthermore, the upcoming data presentations at ASH demonstrate the synergistic effect of combining an FcγR active anti-TIGIT antibody with an IMiD in a preclinical model of multiple myeloma and provide strong rationale for our ongoing Phase 1/2 trial in this difficult to treat cancer,” said Michel Detheux, Ph.D., president and chief executive officer of iTeos. “These results underscore our enthusiasm for EOS-448 as a potential therapy capable of harnessing the immune system to help improve outcomes for patients with advanced, aggressive cancers. We look forward to progressing our clinical development plan in 2022 in both multiple myeloma and solid tumors with several combinations.” 

ASH 2021:

The Combination of Anti-Tigit and Lenalidomide Promotes Synergistic Myeloma-Specific Immunity after ASCT
Presented by: Simone A. Minnie, Ph.D., Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA
Abstract #: 154087

Preclinical data demonstrating the efficacy of a mouse surrogate EOS-448 as a single agent and in combination with an immunomodulatory imide drug (IMiD) in a preclinical model of multiple myeloma was presented by our collaborator at the Fred Hutchinson Cancer Research Center. The Fc-enabled anti-TIGIT monoclonal antibody elicited effective control of multiple myeloma disease progression, while an Fc-disabled version was inactive, indicating the importance of engaging the FcγR. Furthermore, the Fc-enabled anti-TIGIT antibody demonstrated synergistic activity when combined with an IMiD, a class of drugs that has previously shown clinical activity in multiple myeloma.

TIG-007: Study of EOS884448/GSK4428859A Alone, and in Combination with Iberdomide with or without Dexamethasone, in Participants with Relapsed or Refractory Multiple Myeloma
Presented by: Philippe Moreau, M.D., Hematology Department, Nantes University Hospital, Nantes, France
Abstract #: 152395

The presentation highlighted TIG-007, an ongoing open-label, multicenter, dose-escalation/expansion Phase 1/2 trial evaluating the safety, tolerability, and preliminary activity of EOS-448 as monotherapy and in combination with Bristol Myers Squibb’s IMiD, iberdomide, with or without dexamethasone, in adults with relapsed or refractory multiple myeloma. The preclinical data presented from the preclinical model of multiple myeloma provide a strong rationale for combining TIGIT inhibition with immunomodulatory drugs to prevent the progression of myeloma, and previous studies have shown notable clinical activity and acceptable tolerability with iberdomide in combination with dexamethasone or other antimyeloma agents in heavily pre-treated patients with relapsed or refractory multiple myeloma. The study aims to assess the therapeutic opportunity of EOS-448 alone or in combination with iberdomide, with or without dexamethasone to amplify myeloma-specific T cell anti-tumor responses in patients with difficult-to-treat relapsed or refractory multiple myeloma.

TIGIT Therapies Digital Summit 2021:

Targeting TIGIT: Which cell populations are modulated by FcγR engagement?
Presented by: Gregory Driessens, Ph.D., Senior Director, Project Head, iTeos Therapeutics

The presentation featured both preclinical and clinical evidence for the multifaceted mechanism of action of EOS-448, including activation of T cells, modulation of antigen-presenting cells and depletion of regulatory T cells (Tregs) and terminally exhausted T cells. Preclinical data demonstrated that FcγR engagement activated professional antigen-presenting cells either alone or synergistically with anti-PD1, both in the tumor and within the tumor draining lymph node. This effect was only evident when using a fully functional anti-TIGIT antibody, providing support for the design of EOS-448 as an IgG1 antibody. An update on the pharmacodynamic effect of EOS-448 in the blood of treated patients from the Phase 1 trial showed strong depletion of Tregs, an increase in the CD8/Treg ratio and a transient increase in proliferation (as assessed by the Ki67 marker), in line with previous observations with pembrolizumab.

About iTeos Therapeutics, Inc.
iTeos Therapeutics is a clinical-stage biopharmaceutical company pioneering the discovery and development of a new generation of highly differentiated immuno-oncology therapeutics for patients. iTeos Therapeutics leverages its deep understanding of tumor immunology and immunosuppressive pathways to design novel product candidates with the potential to fully restore the immune response against cancer. The Company’s innovative pipeline includes two clinical-stage programs targeting novel, validated immuno-oncology pathways designed with optimized pharmacologic properties for improved clinical outcomes. The first antibody product candidate, EOS-448, is a high affinity, potent, anti-TIGIT antibody with a functional Fc domain, designed to enhance the anti-tumor response through a multifaceted immune modulatory mechanism, currently progressing in multiple indications in collaboration with GSK. The Company is also advancing inupadenant, a next-generation adenosine A2A receptor antagonist tailored to overcome cancer immunosuppression into proof-of concept trials in several indications following encouraging single-agent activity in Phase 1. iTeos Therapeutics is headquartered in Cambridge, MA with a research center in Gosselies, Belgium.

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Forward-Looking Statements
This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995 and other federal securities laws. Any statements that are not statements of historical fact may be deemed to be forward-looking statements. Words such as “believe,” “anticipate,” “plan,” “expect,” “will,” “may,” “intend,” “prepare,” “look,” “potential,” “possible” and similar expressions are intended to identify forward-looking statements. These forward-looking statements include statements relating to the potential benefits of our product candidates, including EOS-448’s potential to harness the immune system to help improve outcomes for patients with advanced and aggressive cancers, and our plan to progress our EOS-448 clinical development plan in 2022 in both multiple myeloma and solid tumors with several combinations.

These forward-looking statements involve risks and uncertainties, many of which are beyond iTeos’ control. Actual results could materially differ from those stated or implied by these forward-looking statements as a result of such risks and uncertainties. Known risk factors include the following: success in preclinical testing and early clinical trials does not ensure that later clinical trials will be successful, and early results from a clinical trial do not necessarily predict final results; the data for our product candidates may not be sufficient for obtaining regulatory approval; iTeos may not be able to execute on its business plans, including meeting its expected or planned regulatory milestones and timelines, research and clinical development plans, and bringing its product candidates to market, for various reasons, some of which may be outside of iTeos’ control, including possible limitations of company financial and other resources, manufacturing limitations that may not be anticipated or resolved for in a timely manner, regulatory, court or agency decisions such as decisions by the United States Patent and Trademark Office with respect to patents that cover our product candidates and the impact of the COVID-19 pandemic; and those risks identified under the heading “Risk Factors” in iTeos’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2021 filed with the Securities and Exchange Commission (SEC) as well as other SEC filings made by the Company which you are encouraged to review.

Any of the foregoing risks could materially and adversely affect iTeos’ business, results of operations and the trading price of iTeos’ common stock. We caution investors not to place considerable reliance on the forward-looking statements contained in this press release. iTeos does not undertake any obligation to publicly update its forward-looking statements based on events or circumstances after the date hereof.

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