Degradation of Polysorbate 20 by Sialate O-Acetylesterase in Monoclonal Antibody Formulations

Identification of Acyl-Protein Thioesterase-1 as a Polysorbate-Degrading Host Cell Protein in a Monoclonal Antibody Formulation Using Activity-Based Protein Profiling

Polysorbate (PS) degradation in monoclonal antibody (mAb) formulations poses a significant challenge in the biopharmaceutical industry. PS maintains protein stability during drug product's shelf life but is vulnerable to breakdown by low-abundance residual host cell proteins (HCPs), particularly hydrolytic enzymes such as lipases and esterases. In this study, we used activity-based protein profiling (ABPP) coupled with mass spectrometry to identify acyl-protein thioesterase-1 (APT-1) as a polysorbate-degrading HCP in one case of mAb formulation with stability problems. We validated the role of APT1 by matching the polysorbate degradation fingerprint in the mAb formulation with that of a recombinant APT1 protein. Furthermore, we found an agreement between APT1 levels and PS degradation rates in the mAb formulation, and we successfully halted PS degradation using APT1-specific inhibitors ML348 and ML211. APT1 was found to co-purify with a specific mAb via hitchhiking mechanism. Our work provides a streamlined approach to identifying critical HCPs in PS degradation, supporting quality-by-design principles in pharmaceutical development.

A simple and sensitive differential digestion method to analyze adeno-associated virus residual host cell proteins by LC-MS

Many methods using liquid chromatography-mass spectrometry (LC-MS) have been established for identifying residual host cell proteins (HCPs) to aid in the process development and quality control of therapeutic proteins. However, the use of MS-based techniques for adeno-associated virus (AAV) is still in its infancy, with few methods reported and minimal information available on potentially problematic HCPs. In this study, we developed a highly sensitive and effective differential digestion method to profile residual HCPs in AAV. Unlike direct digestion, which completely digests both AAV and HCPs, our differential digestion method takes advantage of AAV's unique characteristics to maintain the integrity of AAV while preferentially digesting HCPs under denaturing and reducing conditions. This differential digestion method requires only several micrograms of sample and significantly enhances the identification of HCPs. Furthermore, this method can be applied to all five different AAV serotypes for comprehensive HCP profiling. Our work fills a gap in AAV HCP analysis by providing a sensitive and robust strategy for detecting, monitoring, and measuring HCPs.

Analysis of Host Cell Proteins in AAV Products with ProteoMiner Protein Enrichment Technology

Despite substantial efforts to detect host cell proteins (HCPs) in antibody drugs, information regarding HCPs in gene therapy products remains limited and has not been widely integrated into the host cell engineering or purification processes. Most methods that have successfully detected HCPs in antibody drugs are not applicable to gene therapy products, except for the ProteoMiner enrichment method. Here, we demonstrate that ProteoMiner beads effectively enrich HCPs in adeno-associated virus (AAV) products and simultaneously remove the detergent Pluronic F-68 without a loss of low-abundance HCPs. Following optimization of this technique, there was up to a 34-fold increase in the enrichment of HCPs compared to direct digestion. Moreover, the detection limit was significantly lowered with the ability to detect HCPs at levels as low as 0.1 ng/mL after ProteoMiner treatment. This approach holds promise in AAV HCP analysis and may be adaptable to other gene therapy products. The findings from this study provide valuable insights into HCPs in AAV products and may facilitate process development and host cell line optimization. The high sensitivity of this approach also facilitates detection of critical low-abundance HCPs, thereby contributing to risk assessment of their impact on the safety and quality of the AAV-based gene therapy products.

Oxidation of polysorbates - An underestimated degradation pathway?

To ensure the stability of biologicals over their entire shelf-life, non-ionic surface-active compounds (surfactants) are added to protect biologics from denaturation and particle formation. In this context, polysorbate 20 and 80 are the most used detergents. Despite their benefits of low toxicity and high biocompatibility, specific factors are influencing the intrinsic stability of polysorbates, leading to degradation, loss in efficacy, or even particle formation. Polysorbate degradation can be categorized into chemical or enzymatic hydrolysis and oxidation. Under pharmaceutical relevant conditions, hydrolysis is commonly originated from host cell proteins, whereas oxidative degradation may be caused by multiple factors such as light, presence of residual metal traces, peroxides, or temperature, which can be introduced upon manufacturing or could be already present in the raw materials. In this review, we provide an overview of the current knowledge on polysorbates with a focus on oxidative degradation. Subsequently, degradation products and key characteristics of oxidative-mediated polysorbate degradation in respect of different types and grades are summarized, followed by an extensive comparison between polysorbate 20 and 80. A better understanding of the radical-induced oxidative PS degradation pathway could support specific mitigation strategies. Finally, buffer conditions, various stressors, as well as appropriate mitigation strategies, reagents, and alternative stabilizers are discussed. Prior manufacturing, careful consideration and a meticulous risk-benefit analysis are highly recommended in terms of polysorbate qualities, buffers, storage conditions, as well as mitigation strategies.

Recent applications of quantitative mass spectrometry in biopharmaceutical process development and manufacturing

Biopharmaceutical products have seen rapid growth over the past few decades and continue to dominate the global pharmaceutical market. Aligning with the quality by design (QbD) framework and realization, recent advances in liquid chromatography-mass spectrometry (LC-MS) instrumentation and related techniques have enhanced biopharmaceutical characterization capabilities and have supported an increased development of biopharmaceutical products. Beyond its routine qualitative characterization, the quantitative feature of LC-MS has unique applications in biopharmaceutical process development and manufacturing. This review describes the recent applications and implications of the advancement of quantitative MS methods in biopharmaceutical process development, and characterization of biopharmaceutical product, product-related variants, and process-related impurities. We also provide insights on the emerging applications of quantitative MS in the lifecycle of biopharmaceutical product development including quality control in the Good Manufacturing Practice (GMP) environment and process analytical technology (PAT) practices during process development and manufacturing. Through collaboration with instrument and software vendors and regulatory agencies, we envision broader adoption of phase-appropriate quantitative MS-based methods for the analysis of biopharmaceutical products, which in turn has the potential to enable manufacture of higher quality products for patients.

Comparative Stability Study of Polysorbate 20 and Polysorbate 80 Related to Oxidative Degradation

The surfactants polysorbate 20 (PS20) and polysorbate 80 (PS80) are utilized to stabilize protein drugs. However, concerns have been raised regarding the degradation of PSs in biologics and the potential impact on product quality. Oxidation has been identified as a prevalent degradation mechanism under pharmaceutically relevant conditions. So far, a systematic stability comparison of both PSs under pharmaceutically relevant conditions has not been conducted and little is known about the dependence of oxidation on PS concentration. Here, we conducted a comparative stability study to investigate (i) the different oxidative degradation propensities between PS20 and PS80 and (ii) the impact of PS concentration on oxidative degradation. PS20 and PS80 in concentrations ranging from 0.1 mg⋅mL-1 to raw material were stored at 5, 25, and 40 °C for 48 weeks in acetate buffer pH 5.5 and water, respectively. We observed a temperature-dependent oxidative degradation of the PSs with strong (40 °C), moderate (25 °C), and weak/no degradation (5 °C). Especially at elevated temperatures such as 40 °C, fast oxidative PS degradation processes were detected. In this case study, a stronger degradation and earlier onset of oxidation was observed for PS80 in comparison to PS20, detected via the fluorescence micelle assay. Additionally, degradation was found to be strongly dependent on PS concentration, with significantly less oxidative processes at higher PS concentrations. Iron impurities, oxygen in the vial headspaces, and the pH values of the formulations were identified as the main contributing factors to accelerate PS oxidation.

Low-Abundance Protein Enrichment for Medical Applications: The Involvement of Combinatorial Peptide Library Technique

The discovery of low- and very low-abundance proteins in medical applications is considered a key success factor in various important domains. To reach this category of proteins, it is essential to adopt procedures consisting of the selective enrichment of species that are present at extremely low concentrations. In the past few years pathways towards this objective have been proposed. In this review, a general landscape of the enrichment technology situation is made first with the presentation and the use of combinatorial peptide libraries. Then, a description of this peculiar technology for the identification of early-stage biomarkers for well-known pathologies with concrete examples is given. In another field of medical applications, the determination of host cell protein traces potentially present in recombinant therapeutic proteins, such as antibodies, is discussed along with their potentially deleterious effects on the health of patients on the one hand, and on the stability of these biodrugs on the other hand. Various additional applications of medical interest are disclosed for biological fluids investigations where the target proteins are present at very low concentrations (e.g., protein allergens).

A fast and sensitive high-throughput assay to assess polysorbate-degrading hydrolytic activity in biopharmaceuticals

Hydrolysis of polysorbate in biopharmaceutical products has been ascribed to the enzymatic activity from trace levels of residual host cell proteins. In recent years, significant efforts to identify the causative enzymes typically used elaborate, material-intensive and time-consuming approaches. Therefore, the lack of fast and sensitive assays to monitor their activity remains a major bottleneck for supporting process optimization and troubleshooting activities where time and sample throughput are crucial constraints. To address this bottleneck, we developed a novel Electrochemiluminescence-based Polysorbase Activity (EPA) assay to measure hydrolytic activities in biotherapeutics throughout the drug substance manufacturing process. By combining the favorable features of an in-house designed surrogate substrate with a well-established detection platform, the method yields fast (∼36 h turnaround time) and highly sensitive readouts compatible with high-throughput testing. The assay capability for detecting substrate conversion in a precise and reliable manner was demonstrated by extensive qualification studies and by employing a number of recombinant hydrolases associated with polysorbate hydrolysis. In addition, high assay sensitivity and wide applicability were confirmed for in-process pool samples of three different antibody products by performing a head-to-head comparison between this method and an established liquid chromatography - mass spectrometry based assay for the quantification of free fatty acids. Overall, our results suggest that this new approach is well-suited to resolve differences in hydrolytic activity through all stages of purification.

Ultrasensitive Quantification Method for Understanding Biologically Relevant Concentrations of Host Cell Proteins in Therapeutics

Certain host cell proteins (HCPs) in biotherapeutic drugs may be detrimental to drug product quality even when they are present at the subppm level. Therefore, an analytical method that can reliably quantify trace amounts of HCPs is desirable. This study demonstrates a novel strategy to quantify HCPs present at subppm levels with ProteoMiner enrichment coupled with limited digestion followed by targeted analysis with nano-liquid chromatography-parallel reaction monitoring. The method can achieve LLOQ values as low as 0.06 ppm, with an accuracy of 85%-111% of the theoretical value, and inter-run and intrarun precision within 12% and 25%, respectively. The approach was applied to the quantification of five high-risk HCPs in drug products. The results indicated that 2.5 ppm lysosomal acid lipase, 0.14 ppm liver carboxylesterase, 1.8 ppm palmitoyl-protein thioesterase 1, and 1 ppm cathepsin D affected the stability of drug products, whereas drug products could safely contain 1.5 ppm lipoprotein lipase, 0.1 ppm lysosomal acid lipase, or 0.3 ppm cathepsin D. In combination with lipase activity analysis, the accurate quantification of lipases/esterases in drug products enables better understanding and comparison of the enzymatic activity of polysorbate degradation from endogenous proteins.

Characterization of Recombinantly-Expressed Hydrolytic Enzymes from Chinese Hamster Ovary Cells: Identification of Host Cell Proteins that Degrade Polysorbate

Enzymatic hydrolysis of polysorbate in drug products is a major challenge for the biopharmaceutical industry. Polysorbate hydrolysis caused by host cell proteins (HCPs) co-purified during bioprocessing can reduce the protective effects of the surfactant for the active pharmaceutical ingredient and cause the accumulation of low-solubility degradation products over the long-term storage. The identities of such HCPs are elusive due to their extremely low concentrations after the efficient purification processes of most biopharmaceuticals. In this work, 20 enzymes-selected for their known or putative hydrolytic activity and potential to degrade polysorbate-were recombinantly expressed, purified, and characterized via orthogonal methods. First, these recombinant HCPs were assessed for hydrolytic activity against a fluorogenic esterase substrate in a recently-developed, high-throughput assay. Second, these HCPs were screened for hydrolytic activity against polysorbate in a representative mAb formulation. Third, HCPs that displayed hydrolytic activities in the first two assays were subjected to more detailed characterization of their enzyme kinetics against polysorbates. Finally, these HCPs were evaluated for substrate specificity towards different sub-species of polysorbates. This work provides critical new insights for targeted LC-MS/MS approaches for identification of relevant polysorbate-degrading enzymes and supports improvements to remove such HCPs, including knockouts or targeted removal during purification.

Characterization of radicals in polysorbate 80 using electron paramagnetic resonance (EPR) spectroscopy and spin trapping

Polysorbates are an important class of nonionic surfactants that are widely used to stabilize biopharmaceuticals. The degradation of polysorbate 20 and 80 and the related particle formation in biologics are heavily discussed in the pharmaceutical community. Although a lot of experimental effort was spent in the detailed study of potential degradation pathways, the underlying mechanisms are only sparsely understood. Besides enzymatic hydrolysis, another proposed mechanism is associated with radical-induced (auto)oxidation of polysorbates. To characterize the types and the origin of the involved radicals and their propagation in bulk material as well as in diluted polysorbate 80 solutions, we applied electron paramagnetic resonance (EPR) spectroscopy using a spin trapping approach. The prerequisite for a meaningful experiment using spin traps is an understanding of the trapping rate, which is an interplay of (i) the presence of the spin trap at the scene of action, (ii) the specific reactivity of the selected spin trap with a certain radical as well as (iii) the stability of the formed spin adducts (a slow decay rate). We discuss whether and to which extent these criteria are fulfilled regarding the identification of different radical classes that might be involved in polysorbate oxidative degradation processes. The ratio of different radicals for different scenarios was determined for various polysorbate 80 quality grades in bulk material and in aqueous solution, showing differences in the ratio of present radicals. Possible correlations between the radical content and product parameters such as the quality grade, the manufacturing date, the manufacturer, the initial peroxide content according to the certificate of analysis of polysorbate 80 are discussed.

Alternative Excipients for Protein Stabilization in Protein Therapeutics: Overcoming the Limitations of Polysorbates

Given their safety and efficiency in protecting protein integrity, polysorbates (PSs) have been the most widely used excipients for the stabilization of protein therapeutics for years. In recent decades, however, there have been numerous reports about visible or sub-visible particles in PS-containing biotherapeutic products, which is a major quality concern for parenteral drugs. Alternative excipients that are safe for parenteral administration, efficient in protecting different protein drugs against various stress conditions, effective in protein stabilization in high-concentrated liquid formulations, stable under the storage conditions for the duration of the product's shelf-life, and compatible with other formulation components and the primary packaging are highly sought after. The aim of this paper is to review potential alternative excipients from different families, including surfactants, carbohydrate- and amino acid-based excipients, synthetic amphiphilic polymers, and ionic liquids that enable protein stabilization. For each category, important characteristics such as the ability to stabilize proteins against thermal and mechanical stresses, current knowledge related to the safety profile for parenteral administration, potential interactions with other formulation components, and primary packaging are debated. Based on the provided information and the detailed discussion thereof, this paper may pave the way for the identification or development of efficient excipients for biotherapeutic protein stabilization.

Formulation mitigations for particle formation induced by enzymatic hydrolysis of polysorbate 20 in protein-based drug products: insights from a full-factorial longitudinal study

Hydrolytic degradation of the polysorbate 20 (PS20) surfactant in protein-based liquid formulations releases free fatty acids (FFAs), which can accumulate to form particles in drug products during real-time (long-term) storage. To identify formulation conditions that mitigate the risk of particle formation, we conducted a longitudinal study using purified recombinant monoclonal antibody (mAb) formulated in 24 conditions. In this real-time stability study at 5 °C, three key formulation parameters—mAb concentration, initial PS20 concentration, and pH—were varied across representative ranges in a full-factorial design. A longitudinal regression analysis was used to evaluate the effects of these parameters and their interactions on PS20 degradation (via measurements of PS20, FFAs, and PS20 ester distribution) and on particle formation (via visible particle observations and subvisible particle counts). The time-dependent onset of visible particles trended with the rise in subvisible particle counts and FFA levels and fall in PS20 concentration. In the ranges studied here, lower mAb concentration and higher initial PS20 concentration delayed the onset of particles, whereas pH had a negligible effect. These observations were consistent with the general trends predicted by our previously published FFA solubility model. Taken together, these findings highlight the complex relationships between formulation parameters, PS20 degradation, and particle formation.

Industry Perspective on the Use and Characterization of Polysorbates for Biopharmaceutical Products Part 2: Survey Report on Control Strategy Preparing for the Future

Polysorbate (PS) 20 and 80 are the main surfactants used to stabilize biopharmaceutical products. Industry practices on various aspects of PS based on a confidential survey and following discussions by 16 globally acting major biotechnology companies is presented in two publications. Part 1 summarizes the current practice and use of PS during manufacture in addition to aspects like current understanding of the (in)stability of PS, the routine QC testing and control of PS, and selected regulatory aspects of PS.¹ The current part 2 of the survey focusses on understanding, monitoring, prediction, and mitigation of PS degradation pathways in order to propose an effective control strategy. The results of the survey and extensive cross-company discussions are put into relation with currently available scientific literature.

Ultrasensitive method for profiling host cell proteins by coupling limited digestion to ProteoMiner technology

Host cell proteins (HCPs) are process-related impurities that remain in therapeutic protein -at trace levels. HCPs must be closely monitored because they may be detrimental to drug product quality. Liquid chromatography coupled to mass spectrometry (LC-MS) is a powerful tool for detecting individual HCPs; however, HCP-derived peptides can be four to ten orders of magnitude less abundant than therapeutic protein-derived peptides in drug products, thus posing a major challenge in LC-MS detection. We previously demonstrated that low abundant HCPs can be enriched several hundreds fold through ProteoMiner. This study further improved the degree of enrichment by coupling limited digestion to ProteoMiner technology (PMLD). HCPs with low abundance were enriched 7694-fold, thus enabling detection of HCPs at concentrations as low as 0.002 ppm. A total of 850 HCPs were detected with high confidence from a NIST monoclonal antibody preparation, a number 40% higher than previously reported.

Analysis of Host Cell Proteins in Monoclonal Antibody Therapeutics Through Size Exclusion Chromatography

PURPOSE

Host cell proteins (HCPs) are impurities derived from expression systems during the manufacturing of biotherapeutics. Even trace amounts of certain HCPs can potentially compromise product safety and quality. Therefore, comprehensive analytical characterization is necessary. In particular, understanding how each HCP co-purifies with the biotherapeutics throughout the purification process would help guide process development to avoid further contamination.

METHODS

We developed a new strategy based on size exclusion chromatography (SEC) fractionation followed by mass spectrometry (MS) analysis to study HCPs.

RESULTS

Through an optimized experimental procedure, HCPs were effectively separated from monoclonal antibody (mAb) drug substances via SEC fractionation and sensitively detected with MS. Many HCPs were enriched in the high molecular weight fraction, thus indicating the formation of HCP-mAb complexes. SEC separation under mild denaturing conditions was demonstrated to disrupt weak interactions between certain HCPs and mAbs. The binding profiles of HCPs to mAbs were further characterized through comparison of the relative abundance of HCPs in each fraction under either native or mild denaturing SEC conditions.

CONCLUSIONS

This new method not only achieves improved identification of HCPs in biotherapeutic drug substances but also offers an effective means to evaluate the binding properties between biotherapeutics and a wide range of HCPs.

Host cell protein identification in monoclonal antibody high molecular weight species

High molecular weight (HMW) species are product-related variants that may impact therapeutic product safety and efficacy. Therefore, HMW species and aggregates are considered critical quality attributes and their levels should be closely monitored and controlled during drug development, commercial manufacturing, and shelf-life storage period for therapeutic monoclonal antibody drug products. Various biophysical and analytical methods have been developed to characterize the HMW species to understand their mechanisms of formation and assess potential product risk. However, host cell protein (HCP) analysis has seldom been conducted to characterize the impurities in aggregates. In this work, HCP analysis of enriched HMW species and drug substance (DS) from five different monoclonal antibodies (mAbs) was performed. More HCPs are identified in the enriched HMW than in the DS, thus demonstrating a potential interaction between HCPs and HMW. Certain HCPs, including commonly detected HCPs and problematic HCPs, were enriched in HMW fractions. Especially, the most abundant HCP from mAb1, CC motif chemokine, was 46 times more abundant in enriched HMW than DS. The enriched HMW was further fractionated into enriched dimers and enriched very HMW (vHMW) fractions. The CC motif chemokine was found to interact mainly with mAb1 dimer species rather than vHMW fraction. Removing the HMW species from mAb1 significantly decreased the CC motif chemokine level in the final mAb1 DS. Our findings demonstrate that some HCPs are more preferentially bound to HMW species and this finding may provide a new opportunity for removing HCPs in downstream purification steps.

Beovu, but not Lucentis impairs the function of the barrier formed by retinal endothelial cells in vitro

Because rare, but severe adverse effects, i.e. retinal vasculitis or retinal vein occlusion, have been observed after repetitive intravitreal injections of VEGF-A-binding single-chain variable fragment brolucizumab (Beovu), we investigated its possible impact on the barrier formed by immortalized bovine retinal endothelial cells (iBREC) in comparison to that of the VEGF-A-binding Fab fragment ranibizumab (Lucentis). As a measure of stability of the barrier formed by a confluent monolayer of iBREC, we determined the cell index over seven days by continuous electric cell-substrate impedance measurements: Beovu but not Lucentis indeed significantly lowered the cell index, evident about 1.5 days after its addition, pointing to barrier impairment. Early after addition of Beovu, amounts of the integrins α5 and β1-subunits of the fibronectin receptor-had changed in opposite ways, suggesting an effect on cell adhesion due to hindered dimer formation. After exposure for eight days to Beovu, levels of claudin-1-an essential part of the iBREC barrier-were significantly lower, less claudin-1 was located at the plasma membrane after exposure to the VEGF-A antagonist for five days. Beovu did not induce secretion of inflammatory cytokines or VEGF-A. Interestingly, polysorbate-80-component of Beovu-but not polysorbate-20-in Lucentis-slightly, but significantly lowered the cell index, also associated with reduced claudin-1 expression. In summary, our results indicate that Beovu changes the behavior of retinal endothelial cells, thus providing an alternative "non-immunological" explanation for the most relevant of observed side effects.

The Characterization of Polysorbate

Polysorbates (PSs), including PS20 and PS80, are non-ionic surfactants widely used in the pharmaceutical industry to enhance drug solubility and stability. Despite their wide application, PSs are prone to degradation by either hydrolysis or oxidation in drug formulations during storage; therefore, a PS characterization method assessing protein products is needed for stability testing and for understanding the degradation pathway. In this article, we detail our protocol for sample preparation for forced degradation study and our instrumentation setup for PS profiling and quantitation in protein samples. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Sample preparation for forced degradation of polysorbate in protein samples Basic Protocol 2: Two-dimensional liquid chromatography coupled with charged aerosol detector or mass spectrometry to analyze polysorbate degradation.

Activity-Based Protein Profiling Probe for the Detection of Enzymes Catalyzing Polysorbate Degradation

Polysorbates are nonionic surfactants that have been widely used in biotherapeutic formulations to prevent protein aggregation and denaturation. However, polysorbates are subject to degradation after prolonged storage if certain lipases are present in the biotherapeutic product. Because the degradation of polysorbates compromises the shelf life of biotherapeutics and leads to the formation of undesirable products such as protein aggregates and subvisible particles, it is important to identify the active enzymes that catalyze polysorbate hydrolysis. In this study, we developed a novel fluorophosphonate activity-based protein profiling (ABPP) probe (termed the REGN probe), which mimics the structure of polysorbate and targets lipases catalyzing polysorbate degradation. We demonstrated that the REGN probe could enrich certain lipases from Chinese hamster ovary (CHO) cell lysate by more than 100-fold compared with direct tryptic digestion. Furthermore, we found that the REGN probe had higher lipase enrichment efficiency than commercially available ABPP probes including fluorophosphonate-biotin (FP-biotin) and FP-desthiobiotin. Remarkably, the REGN probe can enrich several lipases that cannot be labeled by commercial probes, such as lysosomal acid lipase and cytosolic phospholipase A2. Additionally, we showed that lipases with abundances as low as 0.08 ppm in drug substances were detected by the REGN probe enrichment and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Collectively, we have developed a novel ABPP probe with higher enrichment efficiency and broader coverage for lipases compared with commercial probes, and this probe can be used to detect the trace level of lipases in biotherapeutic products and to facilitate their development and manufacturing.

The measurement and control of high-risk host cell proteins for polysorbate degradation in biologics formulation

Nonionic surfactant polysorbates, including PS-80 and PS-20, are commonly used in the formulation of biotherapeutic products for both preventing surface adsorption and acting as stabilizer against protein aggregation. Trace levels of residual host cell proteins (HCPs) with lipase or esterase enzymatic activity have been shown to degrade polysorbates in biologics formulation. The measurement and control of these low abundance, high-risk HCPs for polysorbate degradation are an industry-wide challenge to achieve desired shelf life of biopharmaceuticals in liquid formulation, especially for high-concentration formulation product development. Here, we reviewed the challenges, recent advances, and future opportunities of analytical method development, risk assessment, and control strategies for polysorbate degradation during formulation development with a focus on enzymatic degradation. Continued efforts to advance our understanding of polysorbate degradation in biologics formulation will help develop high-quality medicines for patients.

Identification of the specific causes of polysorbate 20 degradation in monoclonal antibody formulations containing multiple lipases

PURPOSE

Polysorbates (PS) are excipients used in the biotech industry to stabilize monoclonal antibody (mAb) protein products. However, PS in drug product formulations can be degraded during storage and lead to particle formation because of the limited solubility of the free fatty acids released through the enzymatic hydrolysis of PS-a process driven by residual host cell proteins, especially lipases, that are co-purified with the drugs. When multiple lipases are present, it is very difficult to know the cause for PS degradation. In this study, we aim to determine the cause of PS degradation from two lipases, lysosomal acid lipase (LAL) and lipoprotein lipase (LPL).

METHODS

PS degradation pattern of the drug product was compared with those induced by recombinant lipases. Correlations between the concentration of LPL or LAL and PS20 loss were compared. Specific inhibitors, LAL inhibitor lalistat2 and LPL inhibitor GSK264220A, were used to differentiate their degradation of PS in the drug products.

RESULTS

The complete inhibition of PS20 degradation by lalistat2 suggested that LAL, rather than LPL, was responsible for the PS20 degradation. In addition, LAL was more strongly correlated than LPL with the percentage of PS20 degradation. No PS20 degradation was observed for several mAbs containing similar levels of LPL (0.5-1.5 ppm) in the absence of LAL, suggesting that LPL concentrations below 1.5 ppm does not degrade PS20 in drug products.

CONCLUSIONS

LAL was determined to be the cause of the PS20 degradation. This study provides a practical strategy to determine the root cause of PS degradation.