Cation Exchange Flow-Through Purification for ADC vHMWS Reduction
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Solution Overview
Problem
The purification of antibody drug conjugates (ADCs) using cation-exchange chromatography in flow-through mode is challenging due to the risk of protein aggregation, particularly very high molecular weight species (vHMWS), which can lead to immunogenicity and require stringent control of the Drug-to-Antibody Ratio (DAR) and drug load distribution, while existing methods like Bind-Elute and Overload Chromatography face limitations in yield and facility fit, and High-throughput Screening is not suitable for handling cytotoxic compounds.
Innovation Solution
A method involving a first purification of the antibody intermediate using cation exchange chromatography followed by a second purification of the crude ADC in flow-through mode with specific conditions for load density, buffer species, pH, and conductivity to reduce vHMWS concentration by at least 85% without altering critical quality attributes, using resins like POROS 50HS, POROS XS, and SPFF, and leveraging High-throughput Screening to determine binding behavior for optimal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Bind-Elute chromatography is used for ADC purification, then product purity is improved, but column load density is reduced and facility footprint increases
Solution Approach 1:
The patent inverts the traditional Bind-Elute approach by using Flow-Through mode where the antibody intermediate binds to the cation exchange column and impurities flow through, or alternatively where the ADC flows through while aggregates bind. This inversion allows high load density operation while achieving purity through selective binding behavior at elevated pH conditions specific to ADCs.
2Productivity
If Flow-Through chromatography is used for ADC purification, then column load density is improved, but aggregate removal efficiency may be reduced
Solution Approach 1:
The patent exploits parameter changes by operating at elevated pH conditions (typically pH 7.0-9.0) that are specific to ADC stability requirements. At these elevated pH values, the binding behavior of aggregates versus monomeric ADC changes significantly on cation exchange resins, enabling selective retention of aggregates while ADC flows through, or vice versa, achieving both high load density and effective aggregate removal.
3Productivity
If High-throughput Screening is used for method development, then screening efficiency is improved, but safety risks increase due to cytotoxic compound handling
Solution Approach 1:
The patent extracts the cytotoxic drug component from the screening process by using the antibody intermediate (without drug conjugation) for High-Throughput Screening of chromatography conditions. The screened conditions are then validated with the actual ADC in reduced-scale experiments, eliminating the need for large-scale handling of cytotoxic compounds during method development while still achieving efficient condition optimization.
4Productivity
If reaction conditions for ADC formation are used, then conjugation efficiency is improved, but protein aggregation increases
Solution Approach 1:
The patent applies preliminary purification of the antibody intermediate using cation exchange chromatography before conjugation to remove potential aggregating impurities. Additionally, a post-conjugation Flow-Through purification step is implemented that specifically targets and removes aggregates formed during the conjugation reaction, allowing the use of efficient conjugation conditions while controlling aggregate levels in the final product.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces vHMWS to less than 0.1% in the ADC, maintains high yields, and does not change the critical quality attributes of the ADC product, providing a robust and cost-effective purification step for ADCs.
Implementation Method 1
performing a second purification of the crude preparation with cation exchange chromatography material in flow-through mode
Data Source
AI summary
The present invention relates to a method of developing purification processes for antibody drug conjugates using cation-exchange chromatography in flow-through mode leveraging the purification conditions of the antibody intermediate without a change to the critical quality attributes (CQA) of the ADC.