Δ42PD1 Antibody Drug as an Immunotherapy against Cancers and Infections

Hepatocellular carcinoma (HCC) causes over 900,000 new cases yearly worldwide, with >45% in China, driven by chronic HBV/HCV or NAFLD. Standard treatments offer poor 5-year survival (3-11%). Current immune checkpoint inhibitors achieve only ~20% response rates in HCC, creating urgent need for novel targets beyond PD-1/PD-L1.

• Δ42PD1 is an alternatively spliced PD-1 isoform (14-amino-acid deletion in exon 2) expressed on immune cells like γδ T cells; it promotes pro-inflammatory TLR4 signaling without binding PD-L1/L2.
• Specific monoclonal antibody CH101 selectively blocks Δ42PD1, avoiding cross-reactivity with canonical PD-1, enabling reversal of T cell exhaustion and suppression of tumor-promoting inflammation.
• Humanized versions (huCH101) advance toward clinical use, offering a PD-1-independent mechanism for enhanced anti-tumor immunity.

• Addresses low ~20% response rates in HCC immunotherapy by targeting a novel pathway, potentially improving outcomes in non-responders to standard ICB.
• Independent of PD-1/PD-L1 interaction reduces risks of traditional ICB side effects while restoring functional T cell responses.
• High HCC burden in China positions Orimmune for primary market access via partnerships

• Awarded significant funding under HKSAR Government's RAISe+ Scheme for Δ42PD1 antibody development and commercialization against cancers and infections

• Liver cancer (hepatocellular carcinoma, HCC) – primary indication
• Other solid tumors (e.g., nasopharyngeal carcinoma
• Infectious diseases (under R&D)