SAN FRANCISCO, June 15, 2023 (GLOBE NEWSWIRE) -- AltruBio Inc. (“AltruBio” or “the Company”), a clinical stage biotech company dedicated to the development of novel therapeutics for the treatment of immunological diseases with high unmet medical needs, today announced that the company will be giving an oral presentation on its immune checkpoint enhancer (ICE), ALTB-268, as well as feature a poster on ICE ALTB-168 at the 2023 Federation of Clinical Immunology Societies (FOCIS) Annual Meeting, which is being held June 20-23, 2023 in Boston, Massachusetts. “We’re pleased to share some of the foundational work that continue to support the advancement of our novel ICEs in development to restore immune balance by downregulating T cell effector function for the treatment of human inflammatory diseases," said David Lin, M.D. Ph.D., Vice President of Research of AltruBio. “Our mission is to bring safer, more durable biologic treatments to improve the lives of patients, and we believe selective inhibition or depletion of activated T cells by leveraging an agonistic pathway of the immune checkpoint protein PSGL-1 is a promising therapeutic approach. We look forward to sharing further progress as we continue to evaluate our ICEs in clinical trials.” Oral PresentationSession: Mechanisms of AutoimmunityTitle: ALTB-268, a tetravalent anti-PSGL-1 antibody derived from ALTB-168, shows enhanced potency in treating T cell mediated inflammatory diseases allowing for subcutaneous administration.Presenter: Yu-Chin Lin, MSc, Senior Scientist, AltruBioOral presentation: Wednesday June 21, 2023, 4:30-4:45 pm ESTPoster Presentation: Wednesday June 21, 2023, 6:15-7:30 pm EST Poster Number: W201 Yu-Chin Lin will discuss in vitro and in vivo data on AltruBio’s second anti-P-selectin glycoprotein ligand 1 (PSGL-1) agonist, ALTB-268, which demonstrates enhanced potency and excellent bioavailability, enabling its formulation for subcutaneous (sc) delivery. ALTB-268 is engineered to be a tetravalent version of its predecessor ALTB-168 and has a similar mechanism of action. Data highlights include: ALTB-268, a tetravalent version of ALTB-168 demonstrated greater than 10-fold higher potency in in vitro T cell activation inhibition assays compared to ALTB-168.When compared in a human-mouse trans-vivo delayed type hypersensitivity (DTH) study as well as in a non-human primate (NHP) DTH study, greater than 3-fold higher potency was observed for ALTB-268.Increased potency is likely related to differences in stoichiometry and increased avidity rather than increased affinity, as a single ALTB-268 molecule can bind to more PSGL-1 compared to a single ALTB-168 molecule, while similar affinity for both ALTB-168 and ALTB-268 was measured by surface plasmon resonance or ELISA.A similar safety profile as ALTB-168 was observed for ALTB-268 in NHP toxicology assessments, with a NOAEL of 120 mg/kg in a definitive 28-day weekly repeat-dose toxicity study, and a bioavailability of 70% by sc route. Poster PresentationSession: Exhibit & Poster Opening ReceptionTitle: ALTB-168, an Immune Checkpoint Enhancer (ICE) targeting P-selectin glycoprotein-1 (PSGL-1), is effective in treating T-cell mediated inflammatory diseasesPresenter: Evelyn Chiang, Ph.D., Principal Scientist, AltruBioPoster Presentation: Tuesday, June 20, 2023, 6:00 p.m. – 7:45 p.m. ESTPoster Number: Tu221 The preclinical data will highlight a new role for PSGL-1 as a novel immune checkpoint regulator that modulates T cell homeostasis. The poster presents data demonstrating that PSGL-1 is upregulated in activated T cells compared to naïve T cells, providing rationale for AltruBio’s first anti-PSGL-1 agonistic antibody, ALTB-168, to act as an ICE to downregulate early T cell receptor mediated signaling, T cell proliferation and cytokine secretion, which is independent of the migration function of PSGL-1 as ALTB-168 does not interfere with the binding of P-selectin to PSGL-1. Data highlights: ALTB-168 treatment in a pre-clinical graft-versus-host disease (GvHD) model resulted in increased population of apoptotic CD3 T cells, reduced severity of GvHD and prolonged survival of mice.In a trans-vivo DTH study where human peripheral blood mononuclear cells (PBMCs), previously sensitized with tetanus toxoid (TT), were implanted in the mouse footpad together with TT, the induration of the mouse footpad was reduced by ALTB-168 in a dose-dependent manner.DTH studies performed in NHP also showed that ALTB-168 inhibited skin induration as well as the inflammation of the lesion site.ALTB-168 treatment does not impact the development of T cell dependent antibody production, suggesting a marginal impact in primary T cells and represents a significant safety advantage in clinical development.To date more than 200 subjects have been treated with ALTB-168 and no significant adverse events have been reported.ALTB-168 has been clinically validated for safety, tolerability, and efficacy in treating inflammatory diseases including Psoriasis, Psoriatic Arthritis, Ulcerative Colitis and acute GVHD. About AltruBio Inc.AltruBio is a privately held biotechnology company headquartered in San Francisco that is focused on developing novel therapeutics for the treatment of immunological diseases with high unmet medical needs. The company has leveraged its deep understanding of the role PSGL-1 plays as an immune checkpoint regulator protein to develop a platform for T-cell mediated immunological diseases. Its first-generation molecule, ALTB-168, a PSGL-1 agonist antibody serving as an immune checkpoint enhancer (ICE), has achieved proof of mechanism in four autoimmune and inflammatory diseases, including ulcerative colitis, psoriatic arthritis, psoriasis and steroid refractory acute graft-versus-host disease (SR-aGVHD). The next-generation ICE, ALTB-268, is a tetravalent version of ALTB-168 and has demonstrated higher potency via the same mechanism, making it suitable for subcutaneous administration. ALTB-268 is now being evaluated in a Phase 1 clinical trial before advancing towards clinical studies in multiple autoimmune and inflammatory disorders with the initiation in ulcerative colitis. Note on Forward-Looking StatementsStatements made in this news release that are not historical facts are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as expects, believes, intends, and similar expressions are intended to identify forward-looking statements. Actual results may differ materially from those projected in any forward-looking statement. Specifically, there are a number of important factors that could cause actual results to differ materially from those anticipated, such as the Company's ability to raise additional capital, and risks related to the Company's ability to initiate, and enroll patients in, planned clinical trials. You should not place undue reliance on any forward-looking statements. The Company assumes no obligation to update any forward-looking statements as a result of new information, future events or developments, except as required by law. Contacts AltruBio Inc: +1-415-655-6603 info@altrubio.com Media Contact:Luke ShiploLifeSci Communicationslshiplo@lifescicomms.com