Process Development of Site-Specific Antibody-Drug Conjugates

Area of Science:

• Biotechnology
• Pharmaceutical Sciences
• Chemical Biology

Background:

• Antibody-drug conjugates (ADCs) leverage monoclonal antibodies for targeted delivery of cytotoxic payloads.
• Conjugation strategy is critical for ADC quality, manufacturability, and risk management.
• Site-specific conjugation methods (e.g., engineered cysteines, ncAAs, enzyme-mediated) enhance product homogeneity and control drug-to-antibody ratio (DAR).

Purpose of the Study:

• To present a practical framework for process development and characterization of site-specific ADCs.
• To emphasize the integrated nature of upstream, downstream, and conjugation processes for ADC manufacturing.
• To guide the transition from early-phase to late-stage development considering process understanding and regulatory expectations.

Main Methods:

• Treating upstream, recovery, downstream, conjugation, and purification as an integrated system.
• Applying analytical strategies to link process parameters with critical quality attributes (CQAs).
• Considering process intensification, advanced analytics, and process analytical technologies (PAT).

Main Results:

• Variability in any process stage can impact the final drug substance conjugate's performance and quality.
• Analytical strategies are essential for monitoring DAR distribution, aggregation, and impurities.
• Early development decisions and process knowledge are foundational for commercial manufacturing.

Conclusions:

• Integrated process development and robust analytical characterization are key for successful site-specific ADC manufacturing.
• Defining control strategies and increasing process understanding are crucial for regulatory compliance and scale-up.
• Process intensification and advanced analytics, including PAT, can optimize ADC production and ensure commercial viability.