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1.
Biotechnol Prog ; 40(2): e3414, 2024.
Article in English | MEDLINE | ID: mdl-38013652

ABSTRACT

The N-mAb case study was produced by the National Institute for Innovation in Manufacturing Biopharmaceuticals (NIIMBL) to support teaching and learning for both industry and regulators around adoption of advanced manufacturing process technologies such as integrated continuous bioprocesses (ICB) for monoclonal antibodies (mAbs). N-mAb presents the evolution of an integrated control strategy, from early clinical through process validation and commercial manufacturing with a focus on elements that are unique to ICB. The entire N-mAb case study is quite comprehensive, therefore this publication presents a summary of the chapter on managing deviations from a state of control in real time. This topic is of critical importance to ICB and is also applicable to batch processes operated at a rapid cadence.


Subject(s)
Biological Products , Technology, Pharmaceutical , Antibodies, Monoclonal
2.
Biologicals ; 62: 8-15, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31668854

ABSTRACT

The case study described in this paper was developed for the purpose of training for a better understanding of principles relating especially to a comprehensive evaluation of multiple quality attributes as outlined in the WHO guidelines on evaluation of similar biotherapeutic products. It is also to emphasize the importance of an understanding of the critical quality attributes and a risk assessment of the impact on clinical performance. It was prepared to mimic a real situation in which regulators need to evaluate the differences in quality attributes known to have potential impact on clinical activity. Erythropoietin has been identified as one of the important glycosylated therapeutic proteins and a good example to illustrate how structural characteristics would affect product efficacy and safety. The case study illustrates biosimilarity assessment of a candidate of erythropoietin biosimilar and the important quality attributes that need to be considered in order to understand the importance of structure-function relationships as they contribute to the stepwise evaluation of biosimilarity. This paper reflects the outcomes of the case study exercise and discussion from two WHO implementation workshops held in Ghana (September 2015) and Denmark (July 2017).


Subject(s)
Biosimilar Pharmaceuticals/standards , Biosimilar Pharmaceuticals/therapeutic use , Drug Approval , Erythropoietin/standards , Erythropoietin/therapeutic use , Humans , Quality Control
3.
J Pharm Sci ; 107(6): 1512-1520, 2018 06.
Article in English | MEDLINE | ID: mdl-29408510

ABSTRACT

Comparability studies used to assess a proposed manufacturing change for a biological product include sensitive analytical studies to confirm there are no significant differences in structural or functional attributes that may contribute to clinically meaningful changes in efficacy or safety. When a proposed change is relatively complex or when clinically relevant differences between the product before and after the change cannot be ruled out based on analytical studies, nonclinical and clinical bridging studies are generally required to confirm overall comparability. In this study, we report findings from a comparability assessment of epoetin alfa before and after a proposed manufacturing process change. Although differences in glycosylation attributes were observed, these were initially believed to be irrelevant to the product's pharmacology. This assumption was initially supported via nonclinical and clinical pharmacology studies, but a clinically meaningful difference in potency was ultimately observed in a phase 3 clinical study conducted in a sensitive patient population using a sensitive study design. These results indicate that the nonclinical assessments of structure-function relationships were insufficiently sensitive to identify clinically relevant differences resulting from differences in the glycosylation profile. This case study highlights important findings that may be relevant in the development of biosimilar epoetin alfa products.


Subject(s)
Anemia/drug therapy , Epoetin Alfa/therapeutic use , Hematinics/therapeutic use , Renal Insufficiency, Chronic/drug therapy , Anemia/complications , Animals , Biosimilar Pharmaceuticals/chemistry , Biosimilar Pharmaceuticals/pharmacokinetics , Biosimilar Pharmaceuticals/pharmacology , Biosimilar Pharmaceuticals/therapeutic use , Drug Approval , Epoetin Alfa/chemistry , Epoetin Alfa/pharmacokinetics , Epoetin Alfa/pharmacology , Glycosylation , Hematinics/chemistry , Hematinics/pharmacokinetics , Hematinics/pharmacology , Humans , Mice , Mice, SCID , Recombinant Proteins/chemistry , Recombinant Proteins/pharmacokinetics , Recombinant Proteins/pharmacology , Recombinant Proteins/therapeutic use , Renal Insufficiency, Chronic/complications , Research Design , Structure-Activity Relationship
4.
Drug Saf ; 39(11): 1117-1127, 2016 11.
Article in English | MEDLINE | ID: mdl-27638657

ABSTRACT

INTRODUCTION: The under-reporting of adverse drug events (ADEs) is an international health concern. A number of studies have assessed the root causes but, to our knowledge, little information exists relating under-reporting to practices and systems used for the recording and tracking of drug-related adverse event observations in ambulatory settings, institutional settings, and retail pharmacies. OBJECTIVES: Our objective was to explore the process for reporting ADEs in US hospitals, ambulatory settings, and retail pharmacies; to explore gaps and inconsistencies in the reporting process; and to identify the causes of under-reporting ADEs in these settings. METHODS: The Tufts Center for the Study of Drug Development (Tufts CSDD) interviewed 11 thought leaders and conducted a survey between May and August 2014 among US-based healthcare providers (HCPs) in diverse settings to assess their experiences with, and processes for, reporting ADEs. RESULTS: A total of 123 individuals completed the survey (42 % were pharmacists; 27 % were nurses; 15 % were physicians; and 16 % were classified as 'other'). HCPs indicated that the main reasons for under-reporting were difficulty in determining the cause of the ADE, given that most patients receive multiple therapies simultaneously (66 % of respondents); that HCPs lack sufficient time to report ADEs (63 % of respondents); poor integration of ADE-reporting systems (53 % of respondents); and uncertainty about reporting procedures (52 % of respondents). DISCUSSION: The results of this pilot study identify that key factors contributing to the under-reporting of ADEs relate to a lack of standardized process, a lack of training and education, and a lack of integrated health information technologies.


Subject(s)
Adverse Drug Reaction Reporting Systems , Attitude of Health Personnel , Hospitals , Humans , Nurses , Pharmacies , Pharmacists , Physicians , Pilot Projects , Private Practice , Surveys and Questionnaires , United States
5.
Nephrol News Issues ; 29(12): 46-8, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26677596

ABSTRACT

U.S. regulations require biosimilars to be highly similar to their reference product and demonstrate no clinically meaningful differences in safety, purity, or potency. For biosimilars of erythropoiesis-stimulating agents (ESAs), this standard is challenging--structural differences are likely, and their effect on safety and efficacy cannot be predicted from analytical studies. Thus, clinical trials should compare hemoglobin, dose, and immunogenicity endpoints.


Subject(s)
Biosimilar Pharmaceuticals , Clinical Trials as Topic/methods , Hematinics , Guidelines as Topic , Humans , Research Design
6.
BioDrugs ; 29(6): 365-72, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26581551

ABSTRACT

Biosimilars are required to be similar or highly similar in structure to their biologic reference product but are neither expected nor required to contain identical active substances. For example, glycosylated biosimilars approved to date demonstrate quantitative and qualitative structural differences from their reference product and exemplify the latitude of variations permitted for biosimilars. Although differences between a candidate biosimilar and its reference product will be evaluated for differential clinical effects during biosimilarity assessment, it is unlikely that potential differences between any two indirectly related biosimilars will be formally evaluated. Furthermore, biosimilar pathways permit variations in pharmaceutical attributes, clinical development approaches, and regulatory outcomes, resulting in further diversity of attributes among approved biosimilars. Because biosimilars may vary across the ranges of structural and functional acceptance criteria, they should not be treated like multisource, generic drugs.


Subject(s)
Biosimilar Pharmaceuticals/chemical synthesis , Drug Design , Drug Discovery/methods , Animals , Biosimilar Pharmaceuticals/economics , Biosimilar Pharmaceuticals/metabolism , Drug Approval/methods , Drug Discovery/economics , Drug Discovery/legislation & jurisprudence , Drugs, Generic/chemical synthesis , Drugs, Generic/economics , Drugs, Generic/metabolism , Epoetin Alfa/chemical synthesis , Epoetin Alfa/economics , Epoetin Alfa/metabolism , Humans
7.
BioDrugs ; 29(5): 309-21, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26419971

ABSTRACT

In 2015, five or more biosimilars may be approved in the USA. Because no two biologic medicines are identical, postapproval safety monitoring will be critical to detect potential differences in safety signals between a biosimilar, its reference product, and other biosimilars. Postapproval safety monitoring in the USA uses two signal detection systems: spontaneous reporting systems (SRSs) and active surveillance (AS) systems. Both depend on accurate identification of the specific product(s) dispensed or administered to patients, which may be compromised when products from multiple manufacturers share common drug nomenclature or coding. Product identification can present challenges across different healthcare settings, including inpatient and ambulatory care. Common oral-dosage drugs are predominantly dispensed directly to patients by pharmacists, whereas most injectable drugs, including biologics, are administered to patients by healthcare professionals in outpatient clinics or hospitals. Thus, the effectiveness of SRS and AS mechanisms in both pharmacy and medical channels must be given greater consideration as biotechnology matures. In this article, we describe these systems and their limitations. We identify challenges and opportunities for product-specific safety surveillance of biologics in both the pharmacy and medical settings and provide recommendations to improve biologic safety surveillance under the current and future systems envisioned in the Drug Quality and Security Act. As biosimilars are integrated into existing pharmacovigilance systems, distinguishable nonproprietary names and codes for all biologics, as well as other opportunities to improve traceability (e.g., increased use of barcodes), must be considered to ensure patient safety and confidence in this new class of drugs.


Subject(s)
Adverse Drug Reaction Reporting Systems , Biosimilar Pharmaceuticals , Pharmacovigilance , Humans , United States
8.
AAPS J ; 17(4): 1011-8, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25840884

ABSTRACT

On September 16 and 17, 2014, the Food and Drug Administration (FDA) and Product Quality Research Institute (PQRI) inaugurated their Conference on Evolving Product Quality. The Conference is conceived as an annual forum in which scientists from regulatory agencies, industry, and academia may exchange viewpoints and work together to advance pharmaceutical quality. This Conference Summary Report highlights key topics of this conference, including (1) risk-based approaches to pharmaceutical development, manufacturing, regulatory assessment, and post-approval changes; (2) FDA-proposed quality metrics for products, facilities, and quality management systems; (3) performance-based quality assessment and clinically relevant specifications; (4) recent developments and implementation of continuous manufacturing processes, question-based review, and European Medicines Agency (EMA)-FDA pilot for Quality-by-Design (QbD) applications; and (5) breakthrough therapies, biosimilars, and international harmonization, focusing on ICH M7 and Q3D guidelines. The second FDA/PQRI conference on advancing product quality is planned for October 5-7, 2015.


Subject(s)
Drug Design , Pharmaceutical Preparations/standards , Drug Approval , Humans , Quality Control , United States , United States Food and Drug Administration
9.
Expert Opin Drug Saf ; 14(3): 349-60, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25557261

ABSTRACT

OBJECTIVE: This retrospective analysis assessed the capability of active and passive safety surveillance systems to track product-specific safety events in the USA for branded and generic enoxaparin, a complex injectable subject to immune-related and other adverse events (AEs). METHODS: Analysis of heparin-induced thrombocytopenia (HIT) incidence was performed on benefit claims for commercial and Medicare supplemental-insured individuals newly treated with enoxaparin under pharmacy benefit (1 January 2009 - 30 June 2012). Additionally, spontaneous reports from the FDA AE Reporting System were reviewed to identify incidence and attribution of enoxaparin-related reports to specific manufacturers. RESULTS: Specific, dispensed products were identifiable from National Drug Codes only in pharmacy-benefit databases, permitting sensitive comparison of HIT incidence in nearly a third of patients treated with brand or generic enoxaparin. After originator medicine's loss of exclusivity, only 5% of spontaneous reports were processed by generic manufacturers; reports attributable to specific generics were approximately ninefold lower than expected based on market share. CONCLUSIONS: Claims data were useful for active surveillance of enoxaparin generics dispensed under pharmacy benefits but not for products administered under medical benefits. These findings suggest that the current spontaneous reporting system will not distinguish product-specific safety signals for products distributed by multiple manufacturers, including biosimilars.


Subject(s)
Biosimilar Pharmaceuticals/adverse effects , Drugs, Generic/adverse effects , Enoxaparin/adverse effects , Thrombocytopenia/chemically induced , Adverse Drug Reaction Reporting Systems , Anticoagulants/administration & dosage , Anticoagulants/adverse effects , Biosimilar Pharmaceuticals/administration & dosage , Drugs, Generic/administration & dosage , Enoxaparin/administration & dosage , Female , Humans , Incidence , Male , Product Surveillance, Postmarketing/methods , Retrospective Studies , Thrombocytopenia/epidemiology , United States/epidemiology
10.
Ther Innov Regul Sci ; 49(5): 706-716, 2015 Sep.
Article in English | MEDLINE | ID: mdl-30227042

ABSTRACT

BACKGROUND: As of 2014, the US FDA was considering policy options to promote accurate attribution of adverse events for biosimilars. In order to assess the identification and traceability of biologics from multiple sources, Tufts University's Center for the Study of Drug Development conducted a study reviewing the current FDA Adverse Event Reporting System (FAERS) for reports related to insulin and growth hormone products. METHODS: For this study, all primary suspect reports that were received by FAERS for human growth hormone (hGH) and human insulin between the fourth quarter of 2005 and the third quarter of 2013 were extracted and analyzed. RESULTS: The rates of "accurate" brand (ie, identifiable) drug names were generally high, with a higher incidence for hGH drugs than for insulin drugs (92% of hGH primary suspect reports vs 84% of insulin primary suspect reports). Lot number completion rates were generally low, with a higher incidence for insulin drugs than for hGH drugs (37% of insulin primary suspect reports vs 13% of hGH primary suspect reports). There were 13.5% of insulin reports that could not be linked to manufacturers, while 7.5% of hGH reports could not be linked to a manufacturer. CONCLUSIONS: The completion and accuracy rates of FAERS data on biologics observed in this study are consistent with those observed in earlier studies and suggest that traceability in adverse event reports can be improved through more consistent use of brand names or other product specific identifiers and through more frequent inclusion of lot numbers.

11.
BioDrugs ; 28(4): 363-72, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24567263

ABSTRACT

Biological medicines (biologics) are produced in living cells and purified in complex, multi-step processes. Compared with chemically synthesized small-molecule drugs, biologics are more sensitive to changes in manufacturing conditions. Process and product consistency should be founded on rigorous design and control of manufacturing processes, but consistency is ultimately ensured through robust quality systems. Even a minor change in any component of a quality system could lead to product drift, evolution, and divergence, which may impact the quality, safety, efficacy, and/or interchangeability of biologics. Unintended or unexplained deviations in manufacturing processes can lead to excursions in product attributes (i.e., drift). Well-managed quality systems can help detect and mitigate drift. Occasionally, quality attributes could shift outside of established acceptable ranges as the result of a known manufacturing change (defined here as evolution). Such changes should be studied extensively for effects on product safety and efficacy. With the advent of biosimilars, similar biologics will be produced by multiple manufacturers with different quality systems. Different patterns of product drift and evolution could contribute, over time, to clinically meaningful differences among biologics, including among originator products across regions and among originator products and biosimilar products, a process defined here as divergence. Manufacturers and policymakers can minimize the potential impact of divergence by establishing robust pharmacovigilance systems; requiring distinguishable names for all biologics, including both originator products and biosimilars; adhering to high standards for designations of interchangeability; and ensuring that patient medical records accurately reflect the specific biologic dispensed, especially if the biologic could be sourced from multiple manufacturers.


Subject(s)
Biological Products/supply & distribution , Biosimilar Pharmaceuticals/supply & distribution , Drug Industry/methods , Biological Products/adverse effects , Biological Products/standards , Biosimilar Pharmaceuticals/adverse effects , Biosimilar Pharmaceuticals/standards , Drug Industry/standards , Humans , Pharmacovigilance
12.
Expert Rev Clin Pharmacol ; 7(2): 151-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24386902

ABSTRACT

Shortages of small-molecule injectable drugs have captured the attention of patients, healthcare providers, regulators and policy makers in recent years. While these shortages have several causes, non-compliance with current good manufacturing practice and subsequent shutdowns of manufacturing facilities have played a central role. Sterile injectable drugs are particularly susceptible to manufacturing quality disruptions because of their sensitivity to contamination. Biologics are subject to the same fill-finish contamination risk as sterile injectables, but their active ingredients are also sensitive to subtle changes in the manufacturing process and to storage and handling of their final dosage forms. Originator biologics will lose market exclusivity in the years ahead as patents expire and as competitors develop biosimilar products. The availability of therapeutic alternatives may provide opportunities to reduce costs and increase patient access, but this should not come at the expense of critical investments in the manufacturing of these complex and sensitive products.


Subject(s)
Biological Products/supply & distribution , Biosimilar Pharmaceuticals/supply & distribution , Drug Industry/standards , Biological Products/administration & dosage , Biological Products/standards , Biosimilar Pharmaceuticals/administration & dosage , Biosimilar Pharmaceuticals/standards , Drug Contamination , Health Services Accessibility , Humans , Injections , Sterilization
13.
BioDrugs ; 27(4): 305-16, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23529766

ABSTRACT

The manufacturing of biologic medicines (biologics) requires robust process and facility design, rigorous regulatory compliance, and a well-trained workforce. Because of the complex attributes of biologics and their sensitivity to production and handling conditions, manufacturing of these medicines also requires a high-reliability manufacturing organization. As required by regulators, such an organization must monitor the state-of-control for the manufacturing process. A high-reliability organization also invests in an experienced and fully engaged technical support staff and fosters a management culture that rewards in-depth analysis of unexpected results, robust risk assessments, and timely and effective implementation of mitigation measures. Such a combination of infrastructure, technology, human capital, management, and a science-based operations culture does not occur without a strong organizational and financial commitment. These attributes of a high-reliability biologics manufacturer are difficult to achieve and may be differentiating factors as the supply of biologics diversifies in future years.


Subject(s)
Accident Prevention , Biological Factors/biosynthesis , Biological Products/metabolism , Risk Management , Biological Factors/adverse effects , Biological Factors/analysis , Biological Factors/chemistry , Biological Products/adverse effects , Biological Products/analysis , Biological Products/chemistry , Biotechnology/trends , Chemistry, Pharmaceutical , Drug Contamination/prevention & control , Drug Industry/trends , Drug Packaging , Drug Stability , Guideline Adherence , Guidelines as Topic , Humans , Quality Control , Reproducibility of Results , Risk Assessment , United States , United States Food and Drug Administration , Workforce
14.
Curr Med Res Opin ; 28(6): 1053-8, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22519391

ABSTRACT

BACKGROUND: Healthcare providers use recombinant biologics such as monoclonal antibodies to treat a variety of serious illnesses. Manufacturing of approved biotechnology products is complex, and the quality of the resulting biologic is dependent on careful control of process inputs and operating conditions. Biosimilars, which are similar but not identical to innovator biologics, are entering regulatory evaluation, approval, and marketing in regions with biosimilar approval pathways. SCOPE AND FINDINGS: This article describes the evaluation and potential impact of manufacturing process changes and biosimilar product development, and explores the similarities and distinctions between the two. Regulatory agencies generally require a comparability exercise following a manufacturing process change. This comparability is focused primarily on analytical characterization of the approved product before and after the manufacturing process change, with non-clinical and clinical confirmation required when determined necessary. When developing a biosimilar, the manufacturer does not have access to key information including the innovator manufacturer's cell line, cell culture conditions, purification procedures, and fill and finish processes. Further, the biosimilar manufacturer does not have access to information about the innovator manufacturer's product development history, including knowledge about the quality attributes of lots used in non-clinical and clinical development. We define the biosimilar manufacturer's lack of information as the knowledge gap. As a result, a biosimilarity exercise to compare a biosimilar to an approved innovator biologic requires a rigorous evaluation to ensure the safety and efficacy of the biosimilar. CONCLUSION: Given the knowledge gap under which biosimilars are developed, data to establish biosimilarity should go beyond a simple comparability exercise.


Subject(s)
Biosimilar Pharmaceuticals/therapeutic use , Health Personnel , Practice Patterns, Physicians' , Therapeutic Equivalency , Biological Products/therapeutic use , Drug Approval , Europe , Humans , Models, Biological
15.
MAbs ; 3(3): 318-25, 2011.
Article in English | MEDLINE | ID: mdl-21512318

ABSTRACT

In the European Union, biosimilar products have been approved since 2006 under an abbreviated pathway that leverages their similarity to an existing "reference" biological product. The products approved to date are based on recombinant versions of endogenous proteins with well-understood structures and pharmacology, but complicated safety and immunogenicity profiles. The period during the 2000s that included the first reviews, approvals, sale and use of biosimilars, is referred to herein as "Biosimilars 1.0." Over the next several years, a new and advanced tranche of biosimilars will be developed for complex reference products, including medicines used in the treatment of cancer and autoimmune diseases. A global market for biosimilars is developing, and this may well foreshadow the beginning of the second era of product development. This Biosimilars 2.0 period will likely be characterized by the development of complex products, global harmonization of standards, and the increasing demand for long-term monitoring of pharmaceuticals. The products developed in this period should exhibit high levels of fidelity to the reference products and should be rigorously evaluated in analytical, non-clinical and clinical comparisons. Additionally, Biosimilars 2.0 manufacturers should strive for transparency in their labels and take proactive strides to be accountable to providers and patients for the quality of their products. An important opportunity now exists for the healthcare community, industry and regulators to work in partnership to outline the appropriate standards for these products to facilitate increased access while meeting patients' needs.


Subject(s)
Biological Products/standards , Drug Approval/methods , Legislation, Drug/standards , Biological Products/therapeutic use , Drug Approval/organization & administration , Drug Industry/legislation & jurisprudence , Drug Industry/standards , Drug Monitoring/standards , Drug Therapy/standards , European Union , Humans
16.
Food Drug Law J ; 65(4): 819-37, ii-iii, 2010.
Article in English | MEDLINE | ID: mdl-24479248

ABSTRACT

On March 23, 2010, President Barack Obama signed into law the Patient Protection and Affordable Care Act, which contains the Biologics Price Competition and Innovation Act. Biosimilars have an important role in the United States health care system, and this new law creates an abbreviated approval pathway for biosimilar products in the U.S. A biosimilar is a biologic product demonstrated to be highly similar to an approved innovator biologic product ("reference product"). While the law provides general information on the standards to demonstrate biosimilarity, Congress has authorized the FDA to define the scientific standards and content of biosimilar applications. There is an increasing global interest in the development of biosimilar products, and several regulatory authorities around the world, as well as the World Health Organization (WHO), have established regulatory guidelines for the approval of biosimilars. The scientific standards and requirements in the biosimilar guidelines of the WHO and other health authorities, including the European Union, Canada, Japan, and South Africa, are reviewed in this paper. The similarities as well as the differences among the policies adopted by these regulatory authorities may provide the FDA valuable information as the agency develops its standards and approaches for the approval of biosimilars in the U.S. At the same time, while establishing such approaches, the FDA has the opportunity to demonstrate leadership in addressing significant safety and other issues related to multi-source biologics and biosimilars that remain a global challenge.


Subject(s)
Biosimilar Pharmaceuticals/standards , Drug Approval/legislation & jurisprudence , Internationality , Drug Labeling/standards , Humans
17.
Biotechnol Bioeng ; 99(1): 201-13, 2008 Jan 01.
Article in English | MEDLINE | ID: mdl-17570711

ABSTRACT

Recombinant human erythropoietin (rHuEPO) produced in a human kidney fibrosarcoma cell line, HT1080, was used as a model to study the effects of sodium butyrate (SB) on protein glycosylation. Treatment with 2 mM SB resulted in complex changes with respect to sugar nucleotide pools including an increase in UDP-Gal and a decrease in UDP-GlcNac. In addition, polylactosamine structures present on rHuEPO increased after SB treatment. To determine if these phenotypic changes correlated with changes in mRNA abundance, we profiled mRNA levels over a 24-h period in the presence or absence of SB using oligonucleotide microarrays. By filtering our data through a functional glycomics gene list associated with the processes of glycan degradation, glycan synthesis, and sugar nucleotide synthesis and transport we identified 26 genes with significantly altered mRNA levels. We were able to correlate the changes in message in six of these genes with measurable phenotypic changes within our system including: neu1, b3gnt6, siat4b, b3gnt1, slc17a5, and galt. Interestingly, for the two genes: cmas and gale, our measurable phenotypic changes did not correlate with changes in mRNA expression. These data demonstrate both the utility and pit falls of coupling biochemical analysis with high throughput oligonucleotide microarrays to predict how changes in cell culture environments will impact glycoprotein oligosaccharide content.


Subject(s)
Butyrates/administration & dosage , Erythropoietin/metabolism , Fibrosarcoma/metabolism , Models, Biological , Protein Engineering/methods , Cell Line, Tumor , Computer Simulation , Dose-Response Relationship, Drug , Erythropoietin/genetics , Fibrosarcoma/genetics , Gene Expression Regulation, Neoplastic/drug effects , Glycosylation/drug effects , Humans , Neoplasm Proteins/metabolism , Recombinant Proteins
18.
Biotechnol Bioeng ; 96(3): 538-49, 2007 Feb 15.
Article in English | MEDLINE | ID: mdl-16937399

ABSTRACT

The manufacture of secreted proteins is complicated by the need for both high levels of expression and appropriate processing of the nascent polypeptide. For glycoproteins, such as erythropoietin (EPO), posttranslational processing involves the addition of oligosaccharide chains. We initially noted that a subset of the amino acids present in the cell culture media had become depleted by cellular metabolism during the last harvest cycle in our batch fed system and hypothesized that by supplementing these nutrients we would improve EPO yields. By increasing the concentration of these amino acids we increased recombinant human erythropoietin (rHuEPO) biosynthesis in the last harvest cycle as expected but, surprisingly, we also observed a large increase in the amount of rHuEPO with a relatively low sialic acid content. To understand the nature of this process we isolated and characterized the lower sialylated rHuEPO pool. Decreased sialylation correlated with an increase in N-linked carbohydrates missing terminal galactose moieties, suggesting that beta-1,4-galactosyltransferase may be rate limiting in our system. To test this hypothesis we supplemented our cultures with varying concentrations of manganese (Mn(2+)), a cofactor for beta-1,4-galactosyltransferase. Consistent with our hypothesis we found that Mn(2+) addition improved galactosylation and greatly reduced the amount of rHuEPO in the lower sialylated fraction. Additionally, we found that Mn(2+) addition increased carbohydrate site occupancy and narrowed carbohydrate branching to bi-antennary structures in these lower sialylated pools. Surprisingly Mn(2+) only had this effect late in the culture process. These data indicate that the addition of Mn(2+) has complex effects on stressed batch fed cultures.


Subject(s)
Amino Acids/pharmacology , Coenzymes/pharmacology , Erythropoietin/metabolism , Manganese/pharmacology , N-Acetyllactosamine Synthase/metabolism , Protein Modification, Translational/genetics , Animals , CHO Cells , Cell Culture Techniques/methods , Cricetinae , Cricetulus , Glycosylation/drug effects , Humans , Recombinant Proteins
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