Fapon Biopharma Publishes Pioneering Research in Cell Reports Medicine on FP008, an anti-PD 1 X IL-10M Fusion Protein for Cancer Immunotherapy

DONGGUAN, China, Dec. 23, 2025 /PRNewswire/ — Fapon Biopharma, a biotech in developing therapeutic biologics including cytokine-antibody fusion proteins and T-cell engagers, announced the publication of pioneering research on FP008, a novel fusion protein in Cell Reports Medicine. The peer-reviewed article details the preclinical and translational validation of FP008 (anti-PD-1 × IL-10M). This first-in-class bifunctional fusion protein is designed to address a fundamental limitation in cancer immunotherapy: the inability to reactivate terminally exhausted T cells within tumors.

Interleukin-10 (IL-10) has shown potential to directly activate and expand exhausted CD8⁺ T cells, but its clinical application has been constrained by dose-limiting hematological toxicities. Fapon’s research team addressed this limitation by engineering IL-10 into a monomeric form (IL-10M). As reported, the engineered IL-10M demonstrated a significant reduction in toxicity. The innovative “cis-delivery” mechanism enabled targeted enrichment of IL-10M onto PD-1-positive exhausted CD8⁺ T cells within the tumor micro-environment. This approach mitigates systemic toxicity while potentially enhancing anti-tumor immune responses.

The study demonstrated FP008’s robust anti-tumor activity across multiple mouse tumor models, including those resistant to anti-PD-1 therapy. FP008 reversed terminal exhaustion of CD8⁺ T cells and restored their functional capacity through localized activation, minimizing systemic exposure.

In comprehensive GLP toxicology studies in cynomolgus monkeys, FP008 exhibited a favorable safety profile at doses up to 10 mg/kg, with no significant hematological adverse events observed. The data supported that this approach has the potential to overcome prior clinical limitations of IL-10-based therapies.

FP008 has cleared an Investigational New Drug (IND) application with the U.S. FDA and China NMPA. Phase I clinical trial is currently ongoing with readout expected later this year. FP008 represents a novel therapeutic strategy for patients with advanced solid tumors refractory to or relapsed from PD-1/PD-L1 checkpoint inhibitors.

Reference: Gu et al., Cell Reports Medicine(2025). “An innovative engineered IL-10 monomer strengthens T cell-mediated anti-tumor responses through anti-PD-1 cis-delivery.” DOI: doi.org/10.1016/j.xcrm.2025.102515 

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About Fapon Biopharma

Fapon Biopharma specializes in discovering and developing biologics for cancer treatment, autoimmune diseases and other diseases where there are unmet medical needs. Leveraging cutting-edge technologies, we have built advanced drug discovery platforms, including an antibody discovery platform based on the globally leading mammalian cell display technology, a platform for generating IL-10M fusion proteins, a TCE platform based on cross-species CD3 nanobody of human and monkey. With a differentiated pipeline of leading drug candidates, we have established capabilities that cover the entire drug development process from drug discovery, preclinical research, Chemistry, Manufacturing and Controls (CMC) to early clinical development. Committed to innovation, we strive to deliver safer, more efficacious, affordable, and accessible biologics for everyone.

For more information about FP008 and partnership opportunities, please visit our website (https://en.faponbiopharma.com/) or contact our Business Development team at BiopharmaBD@fapon.com

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