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Combination of IL-15 and IL-21 robustly augments NK and CD8 T cell activity LA JOLLA, Calif.--(BUSINESS WIRE)-- $EQ -- Equillium Inc. (Nasdaq: EQ), a clinical-stage biotechnology company leveraging a deep understanding of immunobiology to develop novel therapeutics to treat severe autoimmune and inflammatory disorders, today announced that an abstract was accepted for poster presentation at the 39 th Annual Meeting of the Society for Immunotherapy of Cancer. The conference will take place at the George R. Brown Convention Center in Houston, Texas from November 6 to 10, 2024. Title: Interleukin (IL)-15 and IL-21 synergistically enhance NK and CD8+ T cell responses Presenting Author: Phoi Tiet, Senior Research Associate, Equillium, Inc. Abstract Number: 908 Location: Exhibit Halls A & B Date: Saturday, November 9, 2024 The abstract highlights that cytokines are a focus of anti-cancer therapeutic development due to their central role in regulating anti-tumoral immune responses, and that data demonstrates that IL-15 and IL-21 synergistically augment NK and CD8 T cells activities, which further enhanced their proliferation and cytolytic function. With the ability to rescue T cell dysfunction, this cytokine combination could be a promising treatment approach to stimulating anti-tumor immune responses. About Multi-Cytokine Platform and Multi-Cytokine Inhibitors EQ101 & EQ302 Our proprietary multi-cytokine platform generates rationally designed composite peptides that selectively block key cytokines at the shared receptor level targeting pathogenic cytokine redundancies and synergies while preserving non-pathogenic signaling. This approach is expected to avoid the broad immuno-suppression and off-target safety liabilities that may be associated with other therapeutic classes, such as Janus kinase inhibitors. Many immune-mediated diseases are driven by the same combination of dysregulated cytokines, and we believe identifying the key cytokines for these diseases will allow us to target and develop customized treatment strategies for multiple autoimmune and inflammatory diseases. Current platform assets include EQ101, a clinical stage, first-in-class, selective, tri-specific inhibitor of IL-2, IL-9, and IL-15 for intravenous and subcutaneous delivery and EQ302, a preclinical stage, first-in-class, selective, bi-specific inhibitor of IL-15 and IL-21 for oral delivery. About Equillium Equillium is a clinical-stage biotechnology company leveraging a deep understanding of immunobiology to develop novel therapeutics to treat severe autoimmune and inflammatory disorders with high unmet medical need. The company’s pipeline consists of the following novel first-in-class immunomodulatory assets and product platform targeting immuno-inflammatory pathways. EQ101: a selective tri-specific cytokine inhibitor targeting IL-2, IL-9, and IL-15; recently announced positive results from a Phase 2 proof-of-concept clinical study of patients with alopecia areata. EQ302: an orally delivered, selective bi-specific cytokine inhibitor targeting IL-15 and IL-21; currently in pre-clinical development. The multi-cytokine platform: generates rationally designed composite peptides that selectively block key cytokines at the shared receptor level targeting pathogenic cytokine redundancies and synergies while preserving non-pathogenic signaling. Itolizumab: a monoclonal antibody that targets the CD6-ALCAM signaling pathway which plays a central role in the modulation of effector T cells; currently under evaluation in a Phase 3 clinical study of patients with acute graft-versus-host disease (aGVHD) and exhibited positive results in a completed Phase 1b clinical study of patients with lupus/lupus nephritis in April 2024. Equillium acquired rights to itolizumab through an exclusive partnership with Biocon Limited and has entered a strategic partnership with Ono Pharmaceutical Co., Ltd., for the development and commercialization of itolizumab under an option and asset purchase agreement. For more information, visit . Forward Looking Statements Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate”, “believe”, “could”, “continue”, “expect”, “estimate”, “may”, “plan”, “outlook”, “future” and “project” and other similar expressions that predict or indicate future events or trends or that are not statements of historical matters. Because such statements are subject to risks and uncertainties, many of which are outside of Equillium’s control, actual results may differ materially from those expressed or implied by such forward-looking statements. Risks that contribute to the uncertain nature of the forward-looking statements include: Equillium’s ability to execute its plans and strategies; risks related to performing clinical studies; whether the results from clinical studies will validate and support the safety and efficacy of Equillium’s product candidates. These and other risks and uncertainties are described more fully under the caption “Risk Factors” and elsewhere in Equillium’s filings and reports, which may be accessed for free by visiting the Securities and Exchange Commission’s website at and on Equillium’s website under the heading “Investors.” Investors should take such risks into account and should not rely on forward-looking statements when making investment decisions. All forward-looking statements contained in this press release speak only as of the date on which they were made. Equillium undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made, except as required by law. Contacts Investor Contact Michael Moore Vice President, Investor Relations & Corporate Communications 619-302-4431 ir@equilliumbio.com

An oral EQ302 formulation could offer a convenient, bioavailable therapy for patients with inflammatory and autoimmune diseases. Image: Shutterstock/ Busra Ispir. Massachusetts-based biotech Vivtex and Swiss company Equillium have agreed on a research and licensing deal to use Vivtex’s AI-enabled screening platform to optimise the bioavailability of Equillium’s autoimmune therapy, EQ302. The partnership, announced yesterday (16 September), supports EQ302 development as Equillium looks to initiate a Phase I trial in the latter half of 2025. Though the financial specifics of the deal have not been made public, Equillium will have the option to enter into a licensing agreement within which Vivtex could be eligible for royalties and other payments. EQ302 is a peptide which targets interleukins (IL)-15 and IL-21, cytokines active in the pathology of several inflammatory conditions. To maximise bioavailability, Equillium will employ Vivtex’s GI-ORIS (gastrointestinal organic robotic interface system) platform, an AI-enabled technology which uses porcine GI tissue for high-throughput screening. It is the derivate of a previously promising precursor, EQ102, which was in a Phase I trial for coeliac disease but was dropped after Phase II data showed underwhelming bioavailability . As opposed to its parent molecule, administered through subcutaneous injection, EQ302 is an oral formulation. EQ302 is currently in preclinical testing for inflammatory bowel disease, coeliac disease, eosinophilic esophagitis, and skin inflammation. It comprises Equillium’s developmental pipeline along with EQ101, a trispecific cytokine inhibitor in Phase II trials in cancers and alopecia, and itolizumab, a monoclonal antibody targeting the CD6-ALCAM pathway. See Also: Bicara Therapeutics closes $362m IPO in flurry of biotech listing activity MaxCyte and Kamau Therapeutics sign platform license agreement Itolizumab is the company’s most advanced candidate, and is in a Phase III trial (NCT05263999) for acute graft-versus-host disease. GlobalData projects that the drug will generate an annual $180m for Equillium by 2030. GlobalData is the parent company of Pharmaceutical Technology . The agreement caused little movement in Equillium stock. Equillium’s share price stood at $0.87 as the markets closed before the weekend and rose to $0.90 as they opened on 16 September, as per Yahoo Finance . The company has yet to reverse a general decline since a share price high of $19.69 in November 2018. Its market cap is currently valued at $30.47m. Stephen Connelly, CSO of Equillium, underlined the company’s confidence in Vivtex’s platform in a statement on the development. This was reiterated by Maureen Deehan, CEO of Vivtex, who said those involved were, “confident that this partnership will accelerate efforts to offer more effective, accessible, and less burdensome treatment options to patients”, with improved patient compliance stressed as an integral benefit of the oral formulation.

CAMBRIDGE, MA, USA and SCHLIEREN, Switzerland I September 16, 2024 I Vivtex Corporation (“Vivtex” or “the Company”), a biotech company aiming to transform the development of oral biologic therapies for major diseases, announces that it has entered a research and licensing agreement with Equillium, Inc. (“Equillium”), a clinical-stage biotechnology company developing novel therapeutics to treat severe autoimmune and inflammatory disorders. The research collaboration is focused on the application of Vivtex’s unique and proprietary AI-enabled GI-ORIS™ screening and formulation platform technology to develop an optimized oral version of Equillium’s EQ302, a first-in-class bi-specific peptide inhibitor of IL-15 and IL-21 in development for the treatment of gastrointestinal (GI) inflammation. Under the agreement, Equillium has the option to enter into a license agreement under which Vivtex may be eligible for royalties and other payments. No financial terms are disclosed. EQ302 inhibits IL-15 and IL-21, two cytokines important in the pathophysiology of a range of GI disorders, including Inflammatory Bowel Disease (IBD), Celiac Disease and Eosinophilic Esophagitis. An optimized GI-targeted, oral formulation of EQ302 has the potential to revolutionize treatment options for patients suffering with GI disorders by combining a strong anti-inflammatory effect with improved convenience and patient compliance compared to current biologic therapies. Equillium is targeting a first-in-human Phase 1 trial to begin in 2H 2025. With a growing number of biotech and pharma collaborations, Vivtex is emerging as a leader in oral biologics delivery and has successfully delivered on multiple internal and external therapeutic programs. Vivtex’s technology has the ability to improve the oral bioavailability of peptides multiple fold beyond what current technologies can accomplish and is providing peptide drug developers with renewed hope to create oral therapeutics. Maureen Deehan, CEO of Vivtex , commented: “This collaboration with Equillium expands our portfolio of projects and speaks to the strength and potential of our GI-ORIS™ technology. Together, we are redefining what is possible with orally available peptides and are confident that this partnership will accelerate efforts to offer more effective, accessible, and less burdensome treatment options to patients.” “This partnership underscores our confidence in Vivtex’s ability to model complex gastrointestinal environments and provide critical insights to advance the development of EQ302 for oral delivery,” said Stephen Connelly, Chief Scientific Officer at Equillium. ### About Vivtex Corporation Vivtex was launched as a spin out from the labs of Robert Langer (MIT) and Giovanni Traverso (MIT, Harvard Medical School). The company is focused on transforming the market for biologic therapies through the development of novel oral biologics including enhanced, oral versions of existing high-value biologic candidates that can only be administered by injection or infusion. To achieve its mission, Vivtex is leveraging its proprietary and extensively validated AI-enabled high-throughput GI-ORIS™ screening and formulation platform through strategic partnerships and R&D collaborations with biotechnology and pharmaceutical companies. To find out more about Vivtex, please visit our website: www.vivtex.com and LinkedIn . About Equillium Equillium is a clinical-stage biotechnology company leveraging a deep understanding of immunobiology to develop novel therapeutics to treat severe autoimmune and inflammatory disorders with high unmet medical need. The company’s pipeline consists of the following novel first-in-class immunomodulatory assets and product platform targeting immuno-inflammatory pathways. EQ101 is a selective tri-specific cytokine inhibitor targeting IL-2, IL-9, and IL-15 being developed for dermatological conditions, and EQ302 is an orally delivered, selective bi-specific cytokine inhibitor targeting IL-15 and IL-21 being developed for gastrointestinal conditions. The multi-cytokine platform generates rationally designed composite peptides. Itolizumab, a monoclonal antibody that targets the CD6-ALCAM signaling pathway, is in a Phase 3 clinical study of patients with acute graft-versus-host disease (aGVHD) and exhibited positive results in a completed Phase 1b clinical study of patients with lupus/lupus nephritis in April 2024. For more information, visit www.equilliumbio.com . SOURCE: Equillium