On November 5, 2025 Alligator Bioscience (Nasdaq Stockholm: ATORX), a clinical-stage biotechnology company developing tumor-directed immuno-oncology antibody drugs, reported the publication of two abstracts accepted for presentation at the Society for Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) 40th Anniversary Annual Meeting, to be held 5–9 November 2025 in National Harbor, MD, USA.
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The mitazalimab abstract presents new data from the OPTIMIZE-1 trial in metastatic pancreatic cancer, further characterizing efficacy, safety, and biomarker responses at two dose levels. These findings strengthen the clinical rationale for selecting the 900 μg/kg dose in the planned Phase 3 study and the exposure-response data further supports mitazalimab contribution to the clinical benefits observed in OPTIMIZE-1. Alligator will also present preclinical data on ATOR-4066, a bispecific antibody targeting CD40 and CEACAM5, demonstrating immune activation and remodeling of the tumor microenvironment.
Mitazalimab presentation details
Title: CD40 agonist mitazalimab + mFOLFIRINOX in patients with metastatic pancreatic ductal adenocarcinoma: dose characterization based on exposure response and biomarker analysis from the OPTIMIZE-1 study
Abstract number: 530
Time: Saturday, 8 November 2025
Presenter: Yago Pico de Coaña, Medical Science Director, Alligator Bioscience
Key findings:
Improved survival outcomes at 6 months:
PFS: 50.8% vs. 38.7%
OS: 89.5% vs. 69.4%
Manageable safety profile: Safety was manageable across both dose levels, with the increased rate of adverse events in the 900 μg/kg group attributed to extended treatment exposure
Biomarker analyses: Greater immune activation at 900 μg/kg, including higher levels of Ki67+ T cells, a marker of actively dividing and proliferating immune cells
Dose selection for Phase 3: Data support 900 μg/kg as the recommended dose for the planned Phase 3 study in metastatic pancreatic cancer
ATOR-4066 presentation details
Title: ATOR-4066, a bispecific antibody targeting CD40 and CEACAM5, induces potent anti-tumor activity that associates with activated intra-tumoral immune cells and disassembly of extracellular tumor matrix
Abstract number: 940
Time: Saturday, 8 November 2025
Presenter: Hampus Andersson, Industrial PhD student, Alligator Bioscience
Key findings:
Localized immune activation: Enhanced dendritic cell and macrophage activation, uptake of tumor antigens, and priming of neoantigen-specific T cells
Potent anti-tumor activity: Superior efficacy compared to CD40 monospecific antibodies in preclinical tumor models
Tumor microenvironment remodeling: Downregulation of extracellular matrix (ECM) organization genes and upregulation of ECM disassembly pathways, correlating with increased immune cell infiltration
"The new OPTIMIZE-1 data provide important validation of mitazalimab’s therapeutic potential in metastatic pancreatic cancer and further strengthen the rationale for the planned Phase 3 study using the 900 μg/kg dose level," said Søren Bregenholt, CEO of Alligator Bioscience. "This is a significant milestone for Alligator as we prepare mitazalimab for late-stage development. In addition, we are pleased to share encouraging preclinical results for ATOR-4066, underscoring the breadth and innovation of our pipeline."
(Press release, Alligator Bioscience, NOV 5, 2025, View Source [SID1234659455])