Rapid, Autonomous Lot-to-Lot Comparability of Monoclonal Antibodies with the Calypso

Significance of the Topic

Ensuring the purity and lot-to-lot consistency of monoclonal antibodies is fundamental in biopharmaceutical development. Traditional SEC-MALS provides accurate molecular weight profiles but can introduce sample dilution, non-specific interactions, and shear-induced artifacts. Direct batch-mode MALS offers an orthogonal confirmation but is often labor-intensive and requires large sample volumes. An automated system promises rapid, reproducible comparability studies with minimal hands-on time and material consumption.

Aims and Overview of the Study

This study demonstrates the use of the Calypso automated composition gradient system to perform rapid, autonomous batch MALS comparisons of two production lots of a monoclonal antibody. The goal is to validate that automated batch-mode measurements match conventional SEC-MALS results, confirming sample integrity without size-exclusion artifacts.

Used Instrumentation

• Calypso Composition Gradient System (Wyatt Technology)
• miniDAWN TREOS multi-angle light scattering detector
• T-rEX differential refractive index detector
• ASTRA6 and Calypso software for data acquisition and analysis

Methodology

Two lots of mAb1 were diluted from stock to ~0.8 mg/mL in filtered phosphate-buffered saline (PBS, pH 6.8). The Calypso system employed three pumps: one for each lot and a buffer pump for baseline restoration. Each lot underwent five-step concentration gradients (0.6–0.2 mg/mL in 0.1 mg/mL decrements), with 90 s data acquisition delays after each 20 µL injection. Filter housings with 5 µm frits prevented particulates without altering sample composition. Light scattering and refractive index signals were recorded simultaneously and analyzed in the dilute limit to yield absolute molar mass.

Main Results and Discussion

A strong linear correlation between 90° light scattering and differential RI signals confirmed monodispersity across concentrations. Calculated average molar masses were 150.2 ± 2.0 kDa and 149.0 ± 1.7 kDa for lots 1 and 2, respectively. These values closely match the 151.5 kDa measured by SEC-MALS, indicating negligible column-induced artifacts. Automated runs consumed under 7 mL of diluted protein per lot and completed in under 90 minutes.

Benefits and Practical Applications of the Method

• Significant reduction in hands-on experimental time and operator workload
• Lower sample consumption compared to manual batch MALS or SEC-MALS
• Rapid, reproducible lot-to-lot comparability without SEC column interactions
• Scalable workflow for biopharmaceutical development and quality control

Future Trends and Potential Applications

Opportunities include integrating inline buffer exchange, expanding to other biologics (e.g., protein aggregates, fusion proteins), and adapting high-throughput screening for formulation optimization. Advances in automation and data analytics will further streamline molecular characterization in regulated environments.

Conclusion

The Calypso automated composition gradient system enables rapid, low-volume batch MALS analyses that agree with SEC-MALS results. This approach enhances efficiency in purity assessment and lot-to-lot comparability of monoclonal antibodies, supporting accelerated biopharmaceutical development.