Clearance of solvents and small molecule impurities in antibody drug conjugates via ultrafiltration and diafiltration operation

Abstract

Ultrafiltration and diafiltration (UF/DF) processes by tangential flow filtration (TFF) are frequently used for removal of solvents and small molecule impurities and for buffer exchange for biopharmaceutical products. Antibody-drug conjugates (ADCs) as an important class of biological therapeutics, carry unique solvents and small molecule impurities into the final UF/DF step as compared to standard antibody preparation. The production process of ADCs involves multiple chemical steps, for example, reduction and conjugation. The clearance of these solvents and small molecules by UF/DF, specifically the DF step, has been assessed and described herein. The rates of clearance for all the impurities in this study are close to the ideal clearance with no apparent interaction with either the protein or the TFF membrane and system. The effect of process variables during DF, such as pH, temperature, membrane loading, transmembrane pressure, and cross flow rate, has also been evaluated and found to have minimal impact on the clearance rate. These results demonstrate efficient clearance of solvents and small molecule impurities related to the ADC process by the DF process and provide a general data package to facilitate risk assessments based on the sieving factors and program specific needs.

Determination of Purge Factors for Use in Oligonucleotide Control Strategies

“…Overall, the range of purge factor values was unexpectedly wide, ranging from ∼50 to 6000 (see the Experimental Section for details) and may warrant additional study. A recent report on the clearance of small molecules impurities in antibody–drug conjugate during a DF process reported purge values close to theoretical prediction (sieving coefficient of 1) but with a 30 kDa MWCO membrane. , Under ideal conditions, the purge of a small molecule after 5 CV would be between ∼150 and 1100 at 7 CV, but the measured purge values for compounds such as pyridine or acrylonitrile are lower than expected. Note that the purge observed with 5 DVs was of the same order of magnitude as that observed with 7 DVs.…”

A Review of Tangential Flow Filtration: Process Development and Applications in the Pharmaceutical Industry

“…188 An important distinction has been noted that ADC synthesis introduces new solvents and chemical impurities compared to mAb processes, which impact the purification, and TFF processes. 189 However, Gates and co-workers found that many impurities could be sufficiently removed using ultrafiltration and diafiltration steps with minimal effect from process parameters such as TMP, cross-flow rate, pH, and temperature. 189 A couple of studies demonstrate the use of TFF in gram-scale production for the solvent exchange and purification of some ADCs.…”

“…They combine mAbs that target certain tumor antigens with small-molecule cytotoxic drugs via a linker to produce effective site-specific cancer therapies. − TFF is already used commonly for mAb purification, buffer exchange, and concentration and has also been utilized for larger-scale process development for ADCs . An important distinction has been noted that ADC synthesis introduces new solvents and chemical impurities compared to mAb processes, which impact the purification, and TFF processes . However, Gates and co-workers found that many impurities could be sufficiently removed using ultrafiltration and diafiltration steps with minimal effect from process parameters such as TMP, cross-flow rate, pH, and temperature .…”

Current approaches for the purification of antibody–drug conjugates

“…TFF is a simple and robust purification method to achieve high recovery of ADCs (typically greater than 90%) [28]. In 2019, Liao and co-workers reported the technical assessment of the DF step, showing that the clearance rates for small molecular impurities including solvents and TCEP-related byproducts are minimally affected by pH, temperature, membrane loading, transmembrane pressure, and the cross-flow rate [33]. These studies warrant technical guidance for the process development community working on relevant biopharmaceutics.…”