Lund, Sweden, 1 December 2025 – Alligator Bioscience (Nasdaq Stockholm: ATORX) today announced the publication of a peer-reviewed article in Nature communications, reporting data from the REACtiVe-2 clinical trial. REACtiVe-2 is a Phase 1 dose-escalation study evaluating the safety, tolerability and immunological effects of mitazalimab in combination with the dendritic cell-based vaccine MesoPher, developed by Amphera, in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) following standard of care chemotherapy. The study, conducted at Erasmus Medical Center in Rotterdam, underscores mitazalimab’s ability to activate anti-tumor immunity and support its proposed mode of action, including a reduction of tumor fibrosis, as well as increased T-cell infiltration and activation in the tumor.

Key findings:

• The combination therapy significantly decreased intratumoral collagen content, likely through mitazalimab-mediated macrophage activation and stromal degradation.
• Treated tumors showed a clear rise in intratumoral T cells, indicating improved recruitment and immune access to the tumor.
• The treatment activated central memory CD4+ T cells and triggered immune pathways related to antigen presentation.
• Patients with stable disease after prior chemotherapy achieved a median OS of 12.1 months and a 1-year survival rate of 50%.

“These compelling translational data provide further support for the therapeutic potential of mitazalimab in reshaping the immunosuppressive microenvironment characteristic of pancreatic cancer,” said Søren Bregenholt, CEO of Alligator Bioscience. “Furthermore, the data validates the immunological basis behind mitazalimab’s mechanism of action, thereby reinforcing it’s rational in mPDAC and other solid tumors, in combination with other treatment modalities.

The REACtiVe-2 study has been a part of Alligator’s broader clinical strategy to establish mitazalimab as a immunotherapy in hard-to-treat cancers such as mPDAC. The findings further highlight the synergistic potential of mitazalimab when combined with vaccines and chemotherapy.

The full article is available online via >> this link <<.

For further information, please contact:

Søren Bregenholt, CEO
E-mail: soren.bregenholt@alligatorbioscience.com
Phone: +46 (0) 46 540 82 00

The information was submitted for publication, through the agency of the contact person set out above, at 8:45 a.m. CET on 1 December 2025.

About Alligator Bioscience

Alligator is a clinical-stage biotechnology company developing tumor-directed immuno-oncology antibody drugs focused on the CD40 receptor. This validated approach promotes priming of tumor-specific T cells and reversing the immunosuppressive nature of the tumor microenvironment, with significant potential benefits for cancer patients across multiple types of cancer. The Company’s lead drug candidate mitazalimab is currently ready for Phase 3 development, and has previously presented unprecedented survival data at 24-months follow up in first-line metastatic pancreatic cancer patients in the Phase 2 trial OPTIMIZE-1.

Alligator is listed on Nasdaq Stockholm (ATORX) and headquartered in Lund, Sweden.

For more information, please visit alligatorbioscience.com.

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Alligator Bioscience announces publication of REACtiVe-2 Phase 1 trial data in Nature Communications

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