AltruBio Unveils ALTB-268 In Vivo Data at 9th FIMSA 2024 Congress

AltruBio Inc., a clinical-stage biotechnology firm focused on developing innovative immune checkpoint enhancers for immunological and inflammatory diseases, has announced encouraging in-vivo proof-of-concept results for their leading candidate, ALTB-268. The data was presented at the 9th Federation of Immunological Societies of Asia-Oceania (FIMSA) 2024 Congress, held in Taipei from October 23-27, 2024.

The new findings validate the therapeutic potential of ALTB-268, evidencing its anti-inflammatory effects in a non-clinical disease model and reinforcing its advancement in clinical trials for ulcerative colitis (UC). ALTB-268 demonstrated significant efficacy in an acute colitis hPSGL-1 mouse model, showcasing its ability to act as an immune checkpoint enhancer by modulating T cell effector functions and restoring immune system balance.

Dr. Judy Chou, President and CEO of AltruBio, expressed optimism about the data, stating, "We are pleased to continue building evidence of ALTB-268’s potential to treat T-cell-mediated inflammatory diseases through its unique mechanism of action targeting the PSGL-1 pathway. The anti-inflammatory effects observed in the acute colitis mouse model further support ALTB-268’s clinical advancement for UC. We look forward to sharing data from the ongoing Phase 2a trial in UC in the second half of 2025 and demonstrating how its distinct mechanism of action may translate into clinical potential. With its novel immune checkpoint enhancement and subcutaneous administration, ALTB-268 could transform the treatment landscape for UC and other immunological and inflammatory diseases with unmet needs."

The poster session, titled "ALTB-268, A PSGL-1 Agonistic Antibody, Demonstrates Anti-Inflammatory Effect in an Acute Colitis Model Established in Human PSGL-1 Knock-in Mice," was presented by Dr. Evelyn Chiang. Key highlights from the data included:

1. ALTB-268 inhibited human T cell activation both in-vitro and in-vivo, confirming its mechanism of action.
2. In a dextran sodium sulfate (DSS)-induced colitis hPSGL-1 mice model, ALTB-268 significantly reduced disease severity. This was evidenced by a decrease in the disease activity index (DAI) score, colon weight/length ratio, and histological damage, alongside a reduction in inflammatory cytokines and leukocyte infiltration in the colon.
3. An intact leukocyte migration observed in hPSGL-1 knock-in mice suggests that these newly generated mice provide a valuable animal model for mechanism of action and translational studies for anti-hPSGL-1 monoclonal antibodies and Fc-fusion proteins.

ALTB-268 is a subcutaneously administered, tetravalent agonist antibody that targets PSGL-1, a critical immune checkpoint regulator. It functions as an immune checkpoint enhancer (ICE), preferentially downregulating chronically activated late-stage T effector cells, leading to their exhaustion and/or apoptosis. This unique mechanism is akin to AltruBio’s bivalent, intravenously administered ICE, ALTB-168, which has shown promising Phase 2 results in various conditions, including ulcerative colitis, psoriasis, psoriatic arthritis, and steroid-refractory/ treatment-refractory acute graft-versus-host disease (SR/TR-aGvHD).

Currently, ALTB-268 is being evaluated in a Phase 2a exploratory biomarker study for biologics-refractory ulcerative colitis patients, with a randomized global Phase 2b study planned to begin in the first half of 2025. Both studies aim to assess clinical remission and endoscopic improvement.

With the potential for broad indication expansion due to its T-cell modulation capabilities, ALTB-268 represents a promising "pipeline-in-a-product" for addressing multiple immunological and inflammatory diseases. AltruBio is led by a team of experts with successful track records in drug development and commercialization, committed to delivering safer, more effective, and durable biologic treatments to improve patient outcomes.