Model-Informed Drug Development of the Masked Anti-PD-L1 Antibody CX-072

Area of Science:

• Immunology
• Pharmacology
• Biotechnology

Background:

• CX-072 is a novel anti-PD-L1 Probody therapeutic designed for tumor-specific activation.
• Tumor microenvironment proteases activate CX-072, minimizing off-target effects in healthy tissues.

Purpose of the Study:

• To report the model-informed drug development of CX-072.
• To establish pharmacokinetic and exposure-response relationships for CX-072.
• To support dose selection for further clinical evaluation.

Main Methods:

• Quantitative systems pharmacology (QSP) modeling to predict Probody therapeutic (Pb-Tx) behavior.
• Analysis of preliminary human pharmacokinetic (PK) data from single-dose studies.
• Population PK (POPPK) analysis incorporating antidrug antibody (ADA) effects.
• Exposure-response analyses to assess safety and efficacy relationships.

Main Results:

• QSP model predicted target receptor occupancy based on masked CX-072 trough levels.
• Preliminary PK data aligned with QSP predictions, showing CX-072 circulating as intact drug.
• POPPK analysis estimated intact CX-072 clearance and volume of distribution.
• No statistically significant exposure-response relationships were found for adverse events or efficacy measures.
• Simulations indicated a fixed 800 mg dose every two weeks would achieve target trough levels in most patients, irrespective of ADA status.

Conclusions:

• Model-informed drug development successfully guided the clinical translation of CX-072.
• CX-072 exhibits predictable pharmacokinetics, with a fixed dose regimen being suitable for Phase II studies.
• The fixed 800 mg dose is supported for further clinical evaluation, demonstrating potential efficacy independent of ADA presence.