Identification and characterization of host cell protein product-associated impurities in monoclonal antibody bioprocessing

Tailoring polishing steps for effective removal of polysorbate-degrading host cell proteins in antibody purification

Ensuring the quality and safety of biopharmaceutical products requires the effective separation of monoclonal antibodies (mAbs) from host cell proteins (HCPs). A major challenge in this field is the enzymatic hydrolysis of polysorbates (PS) in drug products. This study addresses this issue by investigating the removal of polysorbate-degrading HCPs during the polishing steps of downstream purification, an area where knowledge about individual HCP behavior is still limited. We investigated the separation of different mAb formats from four individual polysorbate degrading hydrolases (CES1F, CES2C, LPLA2, and PAF-AH) using cation exchange (CEX) and mixed-mode chromatography (MMC) polishing steps. Our research identified a key challenge: The similar elution behavior of mAbs and HCPs during chromatographic separation. To investigate this phenomenon, we performed high-throughput binding screenings for recombinant polysorbate degrading hydrolases and representative mAb candidates on CEX and MMC chromatography resins. We then employed a three-step strategy that also served as a scale-up process, optimizing separation conditions and leading to the successful removal of specific HCPs while maintaining high mAb recovery rates (>96%). This strategy involved the use of surface response models and miniature columns for screening, followed by validation on larger columns using a chromatography system. Our results highlight the critical role of the inherent properties of mAbs for successful separation from HCPs. These results underscore the need to tailor the purification process to leverage the slight differences in binding behavior and elution profiles between mAbs and specific HCPs. This approach lays the foundation for developing more effective strategies for overcoming the challenge of enzymatic polysorbate degradation, paving the way for improved quality and safety in biopharmaceutical products.

Host cell protein networks as a novel co-elution mechanism during protein A chromatography

Host cell proteins (HCPs) are process-related impurities of therapeutic proteins produced in for example, Chinese hamster ovary (CHO) cells. Protein A affinity chromatography is the initial capture step to purify monoclonal antibodies or Fc-based proteins and is most effective for HCP removal. Previously proposed mechanisms that contribute to co-purification of HCPs with the therapeutic protein are either HCP-drug association or leaching from chromatin heteroaggregates. In this study, we analyzed protein A eluates of 23 Fc-based proteins by LC-MS/MS to determine their HCP content. The analysis revealed a high degree of heterogeneity in the number of HCPs identified in the different protein A eluates. Among all identified HCPs, the majority co-eluted with less than three Fc-based proteins indicating a drug-specific co-purification for most HCPs. Only ten HCPs co-purified with over 50% of the 23 Fc-based proteins. A correlation analysis of HCPs identified across multiple protein A eluates revealed their co-elution as HCP groups. Functional annotation and protein interaction analysis confirmed that some HCP groups are associated with protein-protein interaction networks. Here, we propose an additional mechanism for HCP co-elution involving protein-protein interactions within functional networks. Our findings may help to guide cell line development and to refine downstream purification strategies.

Factors affecting product association as a mechanism of host-cell protein persistence in bioprocessing

Product association of host-cell proteins (HCPs) to monoclonal antibodies (mAbs) is widely regarded as a mechanism that can enable HCP persistence through multiple purification steps and even into the final drug substance. Discussion of this mechanism often implies that the existence or extent of persistence is directly related to the strength of binding but actual measurements of the binding affinity of such interactions remain sparse. Two separate avenues of investigation of HCP-mAb binding are reported here. One is the measurement of the affinity of binding of individual, commonly persistent Chinese hamster ovary (CHO) HCPs to each of a set of mAbs, and the other uses quantitative proteomic measurements to assess binding of HCPs in a null CHO harvested cell culture fluid (HCCF) to mAbs produced in the same cell line. The individual HCP measurements show that the binding affinities of individual HCPs to different mAbs can vary appreciably but are rarely very high, with only weak pH dependence. The measurements on the null HCCF allow estimation of individual HCP-mAb affinities; these are typically weaker than those seen in affinity measurements on isolated HCPs. Instead, the extent of binding appears correlated with the initial abundance of individual HCPs in the HCCF and the forms of the HCPs in the solution, i.e., whether HCPs are present as free molecules or as parts of large aggregates. Separate protein A chromatography experiments performed by feeding different fractions of a mAb-containing HCCF obtained by size-exclusion chromatography (SEC) showed clear differences in the number and identity of HCPs found in the protein A eluate. These results indicate a significant role for HCP-mAb association in determining HCP persistence through protein A chromatography, presumably through binding of HCP-mAb complexes to the resin. Overall, the results illustrate the importance of considering more fully the biophysical context of HCP-product association in assessing the factors that may affect the phenomenon and determine its implications. Knowledge of the abundances and the forms of individual or aggregated HCPs in HCCF are particularly significant, emphasizing the integration of upstream and downstream bioprocessing and the importance of understanding the collective properties of HCPs in addition to just the biophysical properties of individual HCPs.

Methods comparison of two-dimensional gel electrophoresis for host cell protein characterization

Two-dimensional electrophoresis (2DE) is a gel-based protein separation method based on size and charge which is commonly used for the characterization of host cell proteins (HCPs) during drug development in biotech and pharmaceutical companies. HCPs are a heterogenous mixture of proteins produced by host cells during a biologics drug manufacturing process. Different gel electrophoresis methods including traditional 2D SDS-PAGE with silver and SYPRO Ruby fluorescent dye staining as well as two-dimensional difference gel electrophoresis (2D-DIGE) were compared for their relative abilities to characterize HCPs. SYPRO Ruby was shown to be more sensitive than silver stain in the traditional 2D gels both with and without product protein present. Silver stain also displayed a significant preference for staining acidic proteins over basic ones while SYPRO Ruby was more consistent in imaging proteins across different isoelectric points. The non-traditional method of 2D-DIGE provides high resolution and reproducibility when comparing samples with similar protein profiles but was limited in imaging HCP spots due to its narrow dynamic range. Overall, 2DE is a powerful tool to separate and characterize HCPs and is optimized by choosing the best stain or method for each specific application. Using a combination of two or more different 2DE staining methods, when possible, provides the most comprehensive coverage to support the characterization of a complex mixture like HCPs. However, in instances where only one staining method can be used, SYPRO Ruby is shown to be the more reliable, more sensitive, and easier to use traditional staining method for most HCP-based applications.

Host cell proteins in monoclonal antibody processing: Control, detection, and removal

Host cell proteins (HCPs) are process-related impurities in a therapeutic protein expressed using cell culture technology. This review presents biopharmaceutical industry trends in terms of both HCPs in the bioprocessing of monoclonal antibodies (mAbs) and the capabilities for HCP clearance by downstream unit operations. A comprehensive assessment of currently implemented and emerging technologies in the manufacturing processes with extensive references was performed. Meta-analyses of published downstream data were conducted to identify trends. Improved analytical methods and understanding of "high-risk" HCPs lead to more robust manufacturing processes and higher-quality therapeutics. The trend of higher cell density cultures leads to both higher mAb expression and higher HCP levels. However, HCP levels can be significantly reduced with improvements in operations, resulting in similar concentrations of approx. 10 ppm HCPs. There are no differences in the performance of HCP clearance between recent enhanced downstream operations and traditional batch processing. This review includes best practices for developing improved processes.

Proteomic analysis of host cell protein fouling during bioreactor harvesting

Chinese hamster ovary (CHO) cells are among the most common cell lines used for therapeutic protein production. Membrane fouling during bioreactor harvesting is a major limitation for the downstream purification of therapeutic proteins. Host cell proteins (HCP) are the most challenging impurities during downstream purification processes. The present work focuses on identification of HCP foulants during CHO bioreactor harvesting using reverse asymmetrical commercial membrane BioOptimal™ MF-SL. In order to investigate foulants and fouling behavior during cell clarification, for the first time a novel backwash process was developed to effectively elute almost all the HCP and DNA from the fouled membrane filter. The isoelectric points (pIs) and molecular weights (MWs) of major HCP in the bioreactor harvest and fouled on the membrane were successfully characterized using two-dimensional gel electrophoresis (2D SDS-PAGE). In addition, a total of 8 HCP were identified using matrix-assisted laser desorption/ionization-mass spectroscopy (MALDI-MS). The majority of these HCP are enzymes or associated with exosomes, both of which can form submicron-sized particles which could lead to the plugging of the filters.

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.

Evaluation of mild pH elution protein A resins for antibodies and Fc-fusion proteins

Protein A affinity chromatography is widely used as a capture step for monoclonal antibodies (mAb) and molecules that possess an Fc-domain, such as fusion proteins and bispecific antibodies. However, the use of low pH (3.0-4.0) to elute the molecule and achieve acceptable yield (>85 %) can lead to product degradation (e.g. fragmentation, aggregation) for molecules sensitive to low pH. In this paper, we describe a comprehensive evaluation of two protein A resins with ligands designed to elute at a milder pH as a result of modified sequences in their Fc and VH3 binding regions. One of the evaluated resins has been made commercially available by Purolite and named Praesto Jetted A50 HipH. Results demonstrated that Jetted A50 HipH could elute the Fc-fusion protein and most mAbs evaluated with an elution pH at or above 4.6. Elution and wash optimization determined run conditions for high recovery (>90 % monomer yield), reduction of high molecular weight (HMW) species (>50 %), and significant host cell protein (HCP) clearance at the mildest elution pH possible. For a pH-stable mAb and a pH-sensitive fusion protein, cell culture material was purified with optimized conditions and demonstrated the mild elution pH resins' ability to purify product with acceptable yield, comparable or better impurity clearance, and significantly milder native eluate pH compared to traditional resins. The benefits of the mild elution pH resins were clearly exemplified for the pH-sensitive protein, where a milder elution buffer and native eluate pH resulted in only 2 % HMW in the eluate that remained stable over 48 h. In contrast, a traditional protein A resin requiring low pH elution led to eluate HMW levels of 8 %, which increased to 16 % over the same hold time. Additionally, these resins have high dynamic binding capacity and allow the use of traditional HCP washes. Therefore, Jetted A50 HipH is an ideal candidate for a platform protein A resin and provides flexibility for pH-sensitive proteins and stable mAbs, while preserving product quality, recovery, and seamless integration into a downstream process.

Identification and characterization of CHO host-cell proteins in monoclonal antibody bioprocessing

Host-cell proteins (HCPs) are the foremost class of process-related impurities to be controlled and removed in downstream processing steps in monoclonal antibody (mAb) manufacturing. However, some HCPs may evade clearance in multiple purification steps and reach the final drug product, potentially threatening drug stability and patient safety. This study extends prior work on HCP characterization and persistence in mAb process streams by using mass spectrometry (MS)-based methods to track HCPs through downstream processing steps for seven mAbs that were generated by five different cell lines. The results show considerable variability in HCP identities in the processing steps but extensive commonality in the identities and quantities of the most abundant HCPs in the harvests for different processes. Analysis of HCP abundance in the harvests shows a likely relationship between abundance and the reproducibility of quantification measurements and suggests that some groups of HCPs may hinder the characterization. Quantitative monitoring of HCPs persisting through purification steps coupled with the findings from the harvest analysis suggest that multiple factors, including HCP abundance and mAb-HCP interactions, can contribute to the persistence of individual HCPs and the identification of groups of common, persistent HCPs in mAb manufacturing.

Application of Formulation Principles to Stability Issues Encountered During Processing, Manufacturing, and Storage of Drug Substance and Drug Product Protein Therapeutics

The field of formulation and stabilization of protein therapeutics has become rather extensive. However, most of the focus has been on stabilization of the final drug product. Yet, proteins experience stress and degradation through the manufacturing process, starting with fermentaition. This review describes how formulation principles can be applied to stabilize biopharmaceutical proteins during bioprocessing and manufacturing, considering each unit operation involved in prepration of the drug substance. In addition, the impact of the container on stabilty is discussed as well.

Analytical characterization of host-cell-protein-rich aggregates in monoclonal antibody solutions

Host-cell proteins (HCPs) and high molecular weight (HMW) species have historically been treated as independent classes of impurities in the downstream processing of monoclonal antibodies (mAbs), but recent indications suggest that they may be partially linked. We have explored this connection with a shotgun proteomic analysis of HMW impurities that were isolated from harvest cell culture fluid (HCCF) and protein A eluate using size-exclusion chromatography (SEC). As part of the proteomic analysis, a cross-digest study was performed in which samples were analyzed using both the standard and native digest techniques to enable a fair comparison between bioprocess pools. This comparison reveals that the HCP profiles of HCCF and protein A eluate overlap substantially more than previous work has suggested, because hundreds of HCPs are conserved in aggregates that may be up to ~50 nm in hydrodynamic radius and that persist through the protein A capture step. Quantitative SWATH proteomics suggests that the majority of the protein A eluate's HCP mass is found in such aggregates, and this is corroborated by ELISA measurements on SEC fractions. The SWATH data also show that intra-aggregate concentrations of individual HCPs are positively correlated between aggregates that were isolated from HCCF and protein A eluate, and species that have generally been considered difficult to remove tend to be more concentrated than their counterparts. These observations support prior hypotheses regarding aggregate-mediated HCP persistence through protein A chromatography and highlight the importance of this persistence mechanism.

Behavior of host-cell-protein-rich aggregates in antibody capture and polishing chromatography

Recent work has shown that aggregates in monoclonal antibody (mAb) solutions may be made up not just of mAb oligomers but can also harbor hundreds of host-cell proteins (HCPs), suggesting that aggregate persistence through downstream purification operations may be related to HCP clearance. We have examined this in a primary analysis of aggregate persistence through processing steps that are typically implemented for HCP reduction, demonstrating that the phenomenon is relevant to depth filtration, protein A chromatography and flow-through anion-exchange (AEX) polishing. Confocal laser scanning microscopy observations show that aggregates compete with the mAb to adsorb specifically in protein A chromatography and that this competitive interaction is integral to the efficacy of protein A washes. Column chromatography reveals that the protein A elution tail can have a relatively high concentration of aggregates, which corroborates analogous observations from recent HCP studies. Similar measurements in flow-through AEX chromatography show that relatively large aggregates that harbor HCPs and that persist into the protein A eluate can be retained to an extent that appears to depend primarily on the resin surface chemistry. The total aggregate mass fraction of both protein A eluate pools (∼ 2.4 - 3.6%) and AEX flow-through fractions (∼ 1.5 - 3.2%) correlates generally with HCP concentrations measured using enzyme-linked immunosorbent assay (ELISA) as well as the number of HCPs that may be identified in proteomic analysis. This suggests that quantification of the aggregate mass fraction may serve as a convenient albeit imperfect surrogate for informing early process development decisions regarding HCP clearance strategies.

Engineering protein A ligands to mitigate antibody loss during high-pH washes in protein A chromatography

Protein A chromatography is a workhorse in monoclonal antibody (mAb) manufacture since it provides effective separation of mAbs from impurities such as host-cell proteins (HCPs) in a single capture step. HCP clearance can be aided by the inclusion of a wash step prior to low-pH elution. Although high-pH washes can be effective in removing additional HCPs from the loaded column, they may also contribute to a reduced mAb yield. In this work we show that this yield loss is reflected in a pH-dependent variation of the equilibrium binding capacity of the protein A resin, which is also observed for the capacity of the Fc fragments alone and therefore not a result of steric interactions involving the Fab fragments in the intact mAbs. We therefore hypothesized that the high-pH wash loss was due to protonation or deprotonation of ionizable residues on the protein A ligand. To evaluate this, we applied a rational protein engineering approach to the Z domain (the Fc-binding component of most commercial protein A ligands) and expressed engineered mutants in E. coli. Biolayer interferometry and affinity chromatography experiments showed that some of the Z domain mutants were able to mitigate wash loss at high pH while maintaining similar binding characteristics at neutral pH. These experiments enabled elucidation of the roles of specific interactions in the Z domain - Fc complex, but more importantly offer a route to ameliorating the disadvantages of high-pH washes in protein A chromatography.

Characterization and implications of host-cell protein aggregates in biopharmaceutical processing

In the production of biopharmaceuticals such as monoclonal antibodies (mAbs) and vaccines, the residual amounts of host-cell proteins (HCPs) are among the critical quality attributes. In addition to overall HCP levels, individual HCPs may elude purification, potentially causing issues in product stability or patient safety. Such HCP persistence has been attributed mainly to biophysical interactions between individual HCPs and the product, resin media, or residual chromatin particles. Based on measurements on process streams from seven mAb processes, we have found that HCPs in aggregates, not necessarily chromatin-derived, may play a significant role in the persistence of many HCPs. Such aggregates may also hinder accurate detection of HCPs using existing proteomics methods. The findings also highlight that certain HCPs may be difficult to remove because of their functional complementarity to the product; specifically, chaperones and other proteins involved in the unfolded protein response (UPR) are disproportionately present in the aggregates. The methods and findings described here expand our understanding of the origins and potential behavior of HCPs in cell-based biopharmaceutical processes and may be instrumental in improving existing techniques for HCP detection and clearance.

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.

Methods for addressing host cell protein impurities in biopharmaceutical product development

The high demand for monoclonal antibody (mAb) therapeutics in recent years has resulted in significant efforts to improve their costly manufacturing process. The high cost of manufacturing mAbs derives mainly from the purification process, which contributes to 50%-80% of the total manufacturing cost. One of the main challenges facing industry at the purification stage is the clearance of host cell proteins (HCPs) that are produced and often co-purified with the desired mAb product. One of the issues HCPs can cause is the degradation of the final mAb protein product. In this review, techniques are considered that can be used at different stages (upstream and downstream) of mAb manufacture to improve HCP clearance. In addition to established techniques, many new approaches for HCP removal are discussed that have the potential to replace current methods for improving HCP reduction and thereby the quality and stability of the final mAb product.

A reflection on the improvement of Chinese Hamster ovary cell-based bioprocesses through advances in proteomic techniques

Chinese hamster ovary (CHO) cells are the preferred mammalian host for the large-scale production of recombinant proteins in the biopharmaceutical industry. Research endeavors have been directed to the optimization of CHO-based bioprocesses to increase protein quantity and quality, often in an empirical manner. To provide a rationale for those achievements, a myriad of CHO proteomic studies has arisen in recent decades. This review gives an overview of significant advances in LC-MS-based proteomics and sheds light on CHO proteomic studies, with a particular focus on CHO cells with superior bioprocessing phenotypes (growth, viability, titer, productivity and cQA), that have exploited novel proteomic or sub-omic techniques. These proteomic findings expand the current knowledge and understanding about the underlying protein clusters, protein regulatory networks and biological pathways governing such phenotypic changes. The proteomic studies, highlighted herein, will help in the targeted modulation of these cell factories to the desired needs.

Impact of IgG subclass on monoclonal antibody developability

IgG-based monoclonal antibody therapeutics, which are mainly IgG1, IgG2, and IgG4 subclasses or related variants, have dominated the biotherapeutics field for decades. Multiple laboratories have reported that the IgG subclasses possess different molecular characteristics that can affect their developability. For example, IgG1, the most popular IgG subclass for therapeutics, is known to have a characteristic degradation pathway related to its hinge fragility. However, there remains a paucity of studies that systematically evaluate the IgG subclasses on manufacturability and long-term stability. We thus conducted a systematic study of 12 mAbs derived from three sets of unrelated variable regions, each cloned into IgG1, an IgG1 variant with diminished effector functions, IgG2, and a stabilized IgG4 variant with further reduced FcγR interaction, to evaluate the impact of IgG subclass on manufacturability and high concentration stability in a common formulation buffer matrix. Our evaluation included Chinese hamster ovary cell productivity, host cell protein removal efficiency, N-linked glycan structure at the conserved N297 Fc position, solution appearance at high concentration, and aggregate growth, fragmentation, charge variant profile change, and post-translational modification upon thermal stress conditions or long-term storage at refrigerated temperature. Our results elucidated molecular attributes that are common to all IgG subclasses, as well as those that are unique to certain Fc domains, providing new insight into the effects of IgG subclass on antibody manufacturability and stability. These learnings can be used to enable a balanced decision on IgG subclass selection for therapeutic antibodies and aid in acceleration of their product development process.

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.

Comprehensive Assessment of Host Cell Protein Expression after Extended Culture and Bioreactor Production of CHO Cell Lines

The biomanufacturing industry is advancing toward continuous processes that will involve longer culture durations and older cell ages. These upstream trends may bring unforeseen challenges for downstream purification due to fluctuations in host cell protein (HCP) levels. To understand the extent of HCP expression instability exhibited by Chinese hamster ovary (CHO) cells over these time scales, an industry-wide consortium collaborated to develop a study to characterize age-dependent changes in HCP levels across 30, 60, and 90 cell doublings, representing a period of approximately 60 days. A monoclonal antibody (mAb)-producing cell line with bulk productivity up to 3 g/L in a bioreactor was aged in parallel with its parental CHO-K1 host. Subsequently, both cell types at each age were cultivated in an automated bioreactor system to generate harvested cell culture fluid (HCCF) for HCP analysis. More than 1,500 HCPs were quantified using complementary proteomic techniques, two-dimensional electrophoresis (2DE) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). While up to 13% of proteins showed variable expression with age, more changes were observed when comparing between the two cell lines with up to 47% of HCPs differentially expressed. A small subset (50 HCPs) with age-dependent expression were previously reported to be problematic as high-risk and/or difficult-to-remove impurities; however, the vast majority of these were down-regulated with age. Our findings suggest that HCP expression changes over this time scale may not be as dramatic and pose as great of a challenge to downstream processing as originally expected but that monitoring of variably expressed problematic HCPs remains critical. This article is protected by copyright. All rights reserved.

Towards continuous mAb purification: clearance of host cell proteins from CHO cell culture harvests via "flow-through affinity chromatography" using peptide-based adsorbents

The growth of advanced analytics in manufacturing monoclonal antibodies (mAb) has highlighted the challenges associated with the clearance of host cell proteins (HCPs). Of special concern is the removal of "persistent" HCPs, including immunogenic and mAb-degrading proteins, that co-elute from the Protein A resin and can escape the polishing steps. Responding to this challenge, we introduced an ensemble of peptide ligands that target the HCPs in Chinese hamster ovary (CHO) cell culture fluids and enable mAb purification via flow-through affinity chromatography. This work describes their integration into LigaGuardTM, an affinity adsorbent featuring an equilibrium binding capacity of ~30 mg of HCPs per mL of resin as well as dynamic capacities up to 16 and 22 mg/mL at 1- and 2-minute residence times, respectively. When evaluated against cell culture harvests with different mAb and HCP titers and properties, LigaGuardTM afforded high HCP clearance, with logarithmic removal values (LRVs) up to 1.5, and mAb yield above 90%. Proteomic analysis of the effluents confirmed the removal of high-risk HCPs, including cathepsins, histones, glutathione-S transferase, and lipoprotein lipases. Finally, combining LigaGuardTM for HCP removal with affinity adsorbents for product capture afforded a global mAb yield of 85%, and HCP and DNA LRVs > 4. This article is protected by copyright. All rights reserved.

Biopharmaceutical Manufacturing: Historical Perspectives and Future Directions

This review describes key milestones related to the production of biopharmaceuticals-therapies manufactured using recombinant DNA technology. The market for biopharmaceuticals has grown significantly since the first biopharmaceutical approval in 1982, and the scientific maturity of the technologies used in their manufacturing processes has grown concomitantly. Early processes relied on established unit operations, with research focused on process scale-up and improved culture productivity. In the early 2000s, changes in regulatory frameworks and the introduction of Quality by Design emphasized the importance of developing manufacturing processes to deliver a desired product quality profile. As a result, companies adopted platform processes and focused on understanding the dynamic interplay between product quality and processing conditions. The consistent and reproducible manufacturing processes of today's biopharmaceutical industry have set high standards for product efficacy, quality, and safety, and as the industry continues to evolve in the coming decade, intensified processing capabilities for an expanded range of therapeutic modalities will likely become routine. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 13 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Toward optimal clearance - A universal affinity based mass spectrometry approach for comprehensive ELISA reagent coverage evaluation and HCP hitchhiker analysis

In the control strategy for process related impurities in biopharmaceuticals the enzyme linked immunosorbent assay (ELISA) is the method of choice for the quantification of host cell proteins (HCP). Besides two dimensional - western blots (2D-WB), the coverage of ELISA antibodies is increasingly evaluated by affinity purification based liquid chromatography-tandem mass spectrometry (AP-MS) methods. However, all these methods face the problem of unspecific binding issues between antibodies and the matrix, involving the application of arbitrarily defined thresholds during data evaluation. To solve this, a new approach (optimized AP-MS) was developed in this study, for which a cleavable linker was conjugated to the ELISA antibodies enabling the subsequent isolation of specifically interacting HCPs. By comparing both approaches in terms of method variability and the number of false positive or negative hits, we could demonstrate that the optimized AP-MS method is very reproducible and superior in the identification of antibody detection gaps, while previously described strategies suffered from over- or underestimating the coverage. As only antibody associated HCPs were identified, we demonstrated that the method is beneficial for hitchhiker analysis. Overall, the method described herein has proven as a powerful tool for reliable coverage determination of ELISA antibodies, without the need to arbitrarily exclude HCPs during the coverage evaluation. This article is protected by copyright. All rights reserved.

Detection and quantitation of host cell proteins in monoclonal antibody drug products using automated sample preparation and data-independent acquisition LC-MS/MS

Ensuring the removal of host cell proteins (HCPs) during downstream processing of recombinant proteins such as monoclonal antibodies (mAbs) remains a challenge. Since residual HCPs might affect product stability or safety, constant monitoring is required to demonstrate their removal to be below the regulatory accepted level of 100 ng/mg. The current standard analytical approach for this procedure is based on ELISA; however, this approach only measures the overall HCP content. Therefore, the use of orthogonal methods, such as liquid chromatography-mass spectrometry (LC-MS), has been established, as it facilitates the quantitation of total HCPs as well as the identification and quantitation of the individual HCPs present. In the present study, a workflow for HCP detection and quantitation using an automated magnetic bead-based sample preparation, in combination with a data-independent acquisition (DIA) LC-MS analysis, was established. Employing the same instrumental setup commonly used for peptide mapping analysis of mAbs allows for its quick and easy implementation into pre-existing workflows, avoiding the need for dedicated instrumentation or personnel. Thereby, quantitation of HCPs over a broad dynamic range was enabled to allow monitoring of problematic HCPs or to track changes upon altered bioprocessing conditions.

•

Reproducible HCP analysis using automated, magnetic bead-based sample preparation.

•

Quick and easy implementation into pre-existing LC-MS peptide mapping workflows.

•

DIA-LC-MS/MS for comprehensive analysis of low abundant HCPs, contaminating peptides without additional sample pretreatment.

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.

Versatile LC-MS-Based Workflow with Robust 0.1 ppm Sensitivity for Identifying Residual HCPs in Biotherapeutic Products

Residual host cell proteins (HCPs) in the drug product can affect product quality, stability, and/or safety. In particular, highly active hydrolytic enzymes at sub-ppm levels can negatively impact the shelf life of drug products but are challenging to identify by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) due to their high dynamic range between HCPs and biotherapeutic proteins. We employed new strategies to address the challenge: (1) native digest at a high protein concentration; (2) sodium deoxycholate added during the reduction step to minimize the inadvertent omission of HCPs observed with native digestion; and (3) solid phase extraction with 50% MeCN elution prior to LC-MS/MS analysis to ensure effective mAb removal. A 50 cm long nanoflow charged surface hybrid column was also packed to allow for higher sample load for increased sensitivity. Our workflow has increased the sensitivity for HCP identification by 10- to 100-fold over previous reports and showed the robustness as low as 0.1 ppm for identifying HCPs (34.5 to 66.2 kDa MW). The method capability was further confirmed by consistently identifying >85% of 48 UPS-1 proteins (0.10 to 1.34 ppm, 6.3 to 82.9 kDa MW) in a monoclonal antibody (mAb) and the largest number (746) of mouse proteins from NIST mAb reported to date by a single analysis. Our work has filled a significant gap in HCP analysis for detecting and demonstrating HCP clearance, in particular, extremely low-level hydrolases in drug process development.

Identification and classification of host cell proteins during biopharmaceutical process development

As significant improvements in volumetric antibody productivity have been achieved by advances in upstream processing over the last decade, and harvest material has become progressively more difficult to recover with these intensified upstream operations, the segregation of upstream and downstream processing has remained largely unchanged. By integrating upstream and downstream process development, product purification issues are given consideration during the optimization of upstream operating conditions, which mitigates the need for extensive and expensive clearance strategies downstream. To investigate the impact of cell culture duration on critical quality attributes, CHO-expressed IgG1 was cultivated in two 2 L bioreactors with samples taken on days 8, 10, 13, 15, and 17. The material was centrifuged, filtered and protein A purified on a 1 ml HiTrap column. Host cell protein (HCP) identification by mass spectrometry (MS) was applied to this system to provide insights into cellular behavior and HCP carryover during protein A purification. It was shown that as cultivation progressed from day 8 to 17 and antibody titer increased, product quality declined due to an increase in post-protein A HCPs (from 72 to 475 peptides detected by MS) and a decrease in product monomer percentage (from 98% to 95.5%). Additionally, the MS data revealed an increase in the abundance of several classes of post-protein A HCPs (e.g., stress response proteins and indicators of cell age), particularly on days 15 and 17 of culture, which were associated with significant increases in total overall HCP levels. This provides new insight into the specific types of HCPs that are retained during mAb purification and may be used to aid process development strategies.

Tracking the Behavior of Monoclonal Antibody Product Quality Attributes Using a Multi-Attribute Method Workflow

The multi-attribute method (MAM) is a liquid chromatography-mass spectrometry based method that is used to directly characterize and monitor many product quality attributes and impurities on biotherapeutics, most commonly at the peptide level. It utilizes high-resolution accurate mass spectral data which are analyzed in an automated fashion. MAM is a promising approach that is intended to replace or supplement several conventional assays with a single LC-MS analysis and can be implemented in a Current Good Manufacturing Practice environment. MAM provides accurate site-specific quantitation information on targeted attributes and the nontargeted new peak detection function allows to detect new peaks as impurities, modifications, or sequence variants when comparing to a reference sample. The high resolution MAM workflow was applied here for three independent case studies. First, to monitor the behavior of monoclonal antibody product quality attributes over the course of a 12-day cell culture experiment providing an insight into the behavior and dynamics of product attributes throughout the process. Second, the workflow was applied to test the purity and identity of a product through analysis of samples spiked with host cell proteins. Third, through the comparison of a drug product and a biosimilar with known sequence variants. The three case studies presented here, clearly demonstrate the robustness and accuracy of the MAM workflow that implies suitability for deployment in the regulated environment.

Analytics of host cell proteins (HCPs): lessons from biopharmaceutical mAb analysis for Gene therapy products

Analytics for host cell protein (HCP) analysis of therapeutic monoclonal antibody preparations have developed enormously. We consider how learnings from this can inform HCP analysis of gene therapy viral vector products. The application of mass spectrometry (MS) approaches for analysis of HCPs in viral vector preparations is being established, although such information remains limited and is yet to be widely applied into process or host cell line development to reduce HCP amounts or risk. As these MS approaches, and the data from them, are applied and become available, the process understanding created will speed process development activity. We describe technologies that have been, or can be, applied to viral vector HCP analysis to aid process development, reduce HCP amounts, identify critical HCPs and thus inform risk assessment and management based on a knowledge of specific HCPs, ultimately delivering safe and efficacious gene therapy products to the clinic.

Rational optimization of a monoclonal antibody improves the aggregation propensity and enhances the CMC properties along the entire pharmaceutical process chain

The discovery of therapeutic monoclonal antibodies (mAbs) primarily focuses on their biological activity favoring the selection of highly potent drug candidates. These candidates, however, may have physical or chemical attributes that lead to unfavorable chemistry, manufacturing, and control (CMC) properties, such as low product titers, conformational and colloidal instabilities, or poor solubility, which can hamper or even prevent development and manufacturing. Hence, there is an urgent need to consider the developability of mAb candidates during lead identification and optimization. This work provides a comprehensive proof of concept study for the significantly improved developability of a mAb variant that was optimized with the help of sophisticated in silico tools relative to its difficult-to-develop parental counterpart. Interestingly, a single amino acid substitution in the variable domain of the light chain resulted in a three-fold increased product titer after stable expression in Chinese hamster ovary cells. Microscopic investigations revealed that wild type mAb-producing cells displayed potential antibody inclusions, while the in silico optimized variant-producing cells showed a rescued phenotype. Notably, the drug substance of the in silico optimized variant contained substantially reduced levels of aggregates and fragments after downstream process purification. Finally, formulation studies unraveled a significantly enhanced colloidal stability of the in silico optimized variant while its folding stability and potency were maintained. This study emphasizes that implementation of bioinformatics early in lead generation and optimization of biotherapeutics reduces failures during subsequent development activities and supports the reduction of project timelines and resources.

Identification and Characterization of Polysorbate-Degrading Enzymes in a Monoclonal Antibody Formulation

Degradation of polysorbate (PS) by hydrolytically active host cell proteins (HCPs) in drug products may impair the protein-stabilizing properties of PS and lead to the formation of particles due to the accumulation of poorly soluble free fatty acids upon long-term storage. The identification of the causative enzymes is challenging due to their low-abundance even when using state-of-the-art instrumentation and workflows. To overcome these challenges, we developed a rigorous enrichment strategy for HCPs, utilizing both Protein A and anti-HCP affinity chromatography, which facilitated the in-depth characterization of the HCP population in a monoclonal antibody formulation prone to PS hydrolysis. Based on the HCPs identified by liquid chromatography coupled to tandem mass spectrometry, a number of enzymes annotated as hydrolases were recombinantly expressed and characterized in terms of polysorbate degradation. Among the selected candidates, Lipoprotein Lipase, Lysosomal Acid Lipase (LIPA) and Palmitoyl-Protein Thioesterase 1 (PPT1) exhibited notable activity towards PS. To our knowledge, this is the first report to identify LIPA and PPT1 as residual HCPs that can contribute to PS degradation in a biological product.

Targeted CHO cell engineering approaches can reduce HCP-related enzymatic degradation and improve mAb product quality

Host cell proteins (HCP) that co-purify with biologics produced in Chinese hamster ovary cells have been shown to impact product quality through proteolytic degradation of recombinant proteins, leading to potential product losses. Several problematic HCPs can remain in the final product even after extensive purification. Each recombinant cell line has a unique HCP profile that can be determined by numerous upstream and downstream factors, including clonal variation and the protein sequence of the expressed therapeutic molecule. Here, we worked with recombinant cell lines with high levels of copurifying HCPs, and showed that in those cell lines even modest downregulation (≤50%) of the difficult to remove HCP Cathepsin D, through stable short hairpin RNA interference or monoallelic deletion of the target gene using CRISPR-Cas9, is sufficient to greatly reduce levels of co-purifying HCP as measured by high throughput targeted LC-MS. This reduction led to improved product quality by reducing fragmentation of the drug product in forced degradation studies to negligible levels. We also show the potential of cell engineering to target other undesired HCPs and relieve the burden on downstream purification.

"High-risk" host cell proteins (HCPs): A multi-company collaborative view

Host cell proteins (HCPs) are process-related impurities that may copurify with biopharmaceutical drug products. Within this class of impurities there are some that are more problematic. These problematic HCPs can be considered high-risk and can include those that are immunogenic, biologically active, or enzymatically active with the potential to degrade either product molecules or excipients used in formulation. Some have been shown to be difficult to remove by purification. Why should the biopharmaceutical industry worry about these high-risk HCPs? What approach could be taken to understand the origin of its copurification and address these high-risk HCPs? To answer these questions, the BioPhorum Development Group HCP Workstream initiated a collaboration among its 26-company team with the goal of industry alignment around high-risk HCPs. The information gathered through literature searches, company experiences, and surveys were used to compile a list of frequently seen problematic/high-risk HCPs. These high-risk HCPs were further classified based on their potential impact into different risk categories. A step-by-step recommendation is provided for establishing a comprehensive control strategy based on risk assessments for monitoring and/or eliminating the known impurity from the process that would be beneficial to the biopharmaceutical industry.

Development of an activated carbon filtration step and high throughput screening method to remove host cell proteins from a recombinant enzyme process

An increasing number of non-mAb recombinant proteins are being developed today. These biotherapeutics provide greater purification challenges where multiple polishing steps may be required to meet final purity specifications or the process steps may require extensive optimization. Recent studies have shown that activated carbon can be employed in downstream purification processes to selectively separate host cell proteins (HCPs) from monoclonal antibodies (mAb). However, the use of activated carbon as a unit operation in a cGMP purification process is relatively new. As such, the goal of this work is to provide guidance on development approaches, insight into operating parameters and solution conditions that can impact HCP removal, as well as further investigate the mechanism of removal by using mass spectrometry. In this work, activated carbon was evaluated to remove HCPs in the downstream purification process of a recombinant enzyme. Impact of process placement, flux (or residence time), and mass loading on HCP removal was investigated. Feasibility of high throughput screening (HTS) using loose activated carbon was assessed to reduce the amount of therapeutic protein needed and enable testing of a larger number of solution conditions. Finally, mass spectrometry was used to determine the population of HCPs removed by activated carbon. Our work demonstrates that activated carbon can be used effectively in downstream processes of biopharmaceuticals to remove HCPs (up to a 3 log₁₀ reduction) and that an HTS format can be implemented to reduce material demands by up to 23x and allow for process optimization of this adsorbent for purification purposes.

Displacement to separate host-cell proteins and aggregates in cation-exchange chromatography of monoclonal antibodies

An efficient and consistent method of monoclonal antibody (mAb) purification can improve process productivity and product consistency. Although protein A chromatography removes most host-cell proteins (HCPs), mAb aggregates and the remaining HCPs are challenging to remove in a typical bind-and-elute cation-exchange chromatography (CEX) polishing step. A variant of the bind-and-elute mode is the displacement mode, which allows strongly binding impurities to be preferentially retained and significantly improves resin utilization. Improved resin utilization renders displacement chromatography particularly suitable in continuous chromatography operations. In this study we demonstrate and exploit sample displacement between a mAb and impurities present at low prevalence (0.002%-1.4%) using different multicolumn designs and recycling. Aggregate displacement depends on the residence time, sample concentration, and solution environment, the latter by enhancing the differences between the binding affinities of the product and the impurities. Displacement among the mAb and low-prevalence HCPs resulted in an effectively bimodal-like distribution of HCPs along the length of a multi-column system, with the mAb separating the relatively more basic group of HCPs from those that are more acidic. Our findings demonstrate that displacement of low-prevalence impurities along multiple CEX columns allows for selective separation of mAb aggregates and HCPs that persist through protein A chromatography.

A comprehensive CHO SWATH-MS spectral library for robust quantitative profiling of 10,000 proteins

Sequential window acquisition of all theoretical fragment-ion spectra (SWATH) is a data-independent acquisition (DIA) strategy that requires a specific spectral library to generate unbiased and consistent quantitative data matrices of all peptides. SWATH-MS is a promising approach for in-depth proteomic profiling of Chinese hamster Ovary (CHO) cell lines, improving mechanistic understanding of process optimization, and real-time monitoring of process parameters in biologics R&D and manufacturing. However, no spectral library for CHO cells is publicly available. Here we present a comprehensive CHO global spectral library to measure the abundance of more than 10,000 proteins consisting of 199,102 identified peptides from a CHO-K1 cell proteome. The robustness, accuracy and consistency of the spectral library were validated for high confidence in protein identification and reproducible quantification in different CHO-derived cell lines, instrumental setups and downstream processing samples. The availability of a comprehensive SWATH CHO global spectral library will facilitate detailed characterization of upstream and downstream processes, as well as quality by design (QbD) in biomanufacturing. The data have been deposited to ProteomeXchange (PXD016047).

Multiplex secretome engineering enhances recombinant protein production and purity

Host cell proteins (HCPs) are process-related impurities generated during biotherapeutic protein production. HCPs can be problematic if they pose a significant metabolic demand, degrade product quality, or contaminate the final product. Here, we present an effort to create a "clean" Chinese hamster ovary (CHO) cell by disrupting multiple genes to eliminate HCPs. Using a model of CHO cell protein secretion, we predict that the elimination of unnecessary HCPs could have a non-negligible impact on protein production. We analyze the HCP content of 6-protein, 11-protein, and 14-protein knockout clones. These cell lines exhibit a substantial reduction in total HCP content (40%-70%). We also observe higher productivity and improved growth characteristics in specific clones. The reduced HCP content facilitates purification of a monoclonal antibody. Thus, substantial improvements can be made in protein titer and purity through large-scale HCP deletion, providing an avenue to increased quality and affordability of high-value biopharmaceuticals.

Biotechnology and Bioprocesses: Their Contribution to Sustainability

Significant advancements in biotechnology have resulted in the development of numerous fundamental bioprocesses, which have consolidated research and development and industrial progress in the field. These bioprocesses are used in medical therapies, diagnostic and immunization procedures, agriculture, food production, biofuel production, and environmental solutions (to address water-, soil-, and air-related problems), among other areas. The present study is a first approach toward the identification of scientific and technological bioprocess trajectories within the framework of sustainability. The method included a literature search (Scopus), a patent search (Patentscope), and a network analysis for the period from 2010 to 2019. Our results highlight the main technological sectors, countries, institutions, and academic publications that carry out work or publish literature related to sustainability and bioprocesses. The network analysis allowed for the identification of thematic clusters associated with sustainability and bioprocesses, revealing different related scientific topics. Our conclusions confirm that biotechnology is firmly positioned as an emerging knowledge area. Its dynamics, development, and outcomes during the study period reflect a substantial number of studies and technologies focused on the creation of knowledge aimed at improving economic development, environmental protection, and social welfare.

A novel approach to evaluate ELISA antibody coverage of host cell proteins-combining ELISA-based immunocapture and mass spectrometry

Monitoring host cell proteins (HCPs) is one of the most important analytical requirements in production of recombinant biopharmaceuticals to ensure product purity and patient safety. Enzyme‐linked immunosorbent assay (ELISA) is the standard method for monitoring HCP clearance. It is important to validate that the critical reagent of an ELISA, the HCP antibody, covers a broad spectrum of the HCPs potentially present in the purified drug substance. Current coverage methods for assessing HCP antibody coverage are based on 2D‐Western blot or immunoaffinity‐purification combined with 2D gel electrophoresis and have several limitations. In the present study, we present a novel coverage method combining ELISA‐based immunocapture with protein identification by liquid chromatography–tandem mass spectrometry (LC–MS/MS): ELISA‐MS. ELISA‐MS is used to accurately determine HCP coverage of an early process sample by three commercially available anti‐Escherichia coli HCP antibodies, evading the limitations of current methods for coverage analysis, and taking advantage of the benefits of MS analysis. The results obtained comprise a list of individual HCPs covered by each HCP antibody. The novel method shows high sensitivity, high reproducibility, and enables tight control of nonspecific binding through inclusion of a species‐specific isotype control antibody. We propose that ELISA‐MS will be a valuable supplement to existing coverage methods or even a replacement. ELISA‐MS will increase the possibility of selecting the best HCP ELISA, thus improving HCP surveillance and resulting in a final HCP profile with the lowest achievable risk. Overall, this will be beneficial to both the pharmaceutical industry and patient safety.