Bispecific Targeting of PD-1 and PD-L1 Enhances T-cell Activation and Antitumor Immunity

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• The programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) pathway is a key coinhibitory mechanism that suppresses T-cell-mediated immunity.
• Current immunotherapies targeting this pathway often utilize monospecific antibodies, which may have limitations in efficacy.

Purpose of the Study:

• To investigate the potential of a bispecific antibody, LY3434172, designed to simultaneously target both PD-1 and PD-L1.
• To evaluate if this cotargeting strategy enhances antitumor activity compared to monospecific antibodies.

Main Methods:

• Development of LY3434172, a bispecific IgG1 monoclonal antibody with ablated Fc effector function, targeting human PD-1 and PD-L1.
• In vitro assessment of T-cell activation in response to LY3434172 compared to parent antibodies.
• In vivo evaluation of LY3434172's antitumor efficacy in mouse models engrafted with human immune cells.

Main Results:

• LY3434172 demonstrated complete inhibition of PD-1 pathway inhibitory receptor-ligand interactions.
• In vitro studies showed enhanced functional T-cell activation with LY3434172 compared to combination or monotherapy with parent antibodies.
• LY3434172 induced potent and dramatic antitumor activity in preclinical models, outperforming individual antibodies or their combination.

Conclusions:

• LY3434172 exhibits enhanced immunomodulatory properties through dual blockade of PD-1 and PD-L1.
• These preclinical findings support LY3434172 as a novel bispecific cancer immunotherapy with improved antitumor immune response.
• Further clinical evaluation of LY3434172 is warranted for its potential in cancer treatment.