contaminant control – BioProcessing Journal

The Impact of Process Closure on Biomanufacturing Risk

“Closed system.” The term itself appears deceptively simple. However, the definition of a closed system, its implementation, and its impact on biomanufacturing has been anything but straightforward.

The journey toward implementing closed systems spans over 20 years. The concept of closed systems was introduced in January 2000 with the draft issue of ICH Q7. Since then, other industry guidance documents emerged, defining and supporting process/system closure as a primary means of risk mitigation to meet the baseline requirement of protecting the product, as defined in cGMP.

Presently, global regulatory agencies recognize three distinct definitions of a closed system. These definitions, found in EU Annex 1, EU Annex 2, and the PIC Annex 2A, all focus on product protection where the product is not exposed to the immediate room environment during manufacturing. This is where the journey begins.

Manufacturing Risk Analysis and Management

closed system contaminant control cost reduction facility design GMP process closure

Design and Performance of Viral Clearance Studies with Tissue-Derived Products

Tissue-derived products are a class of biological materials harvested directly from animal or human tissue, in contrast to recombinant DNA materials grown in cell culture bioreactors. Tissue-derived products are often used for structural purposes and are typically regulated as medical devices. However, when used to treat human patients, tissue-derived products are subject to many of the same concerns as recombinant DNA biotherapeutics, with viral safety being one of them. To address this, the tissue source material must undergo a risk analysis and testing regimen for the presence of viral contaminants. In addition, viral clearance studies must be performed to evaluate whether the purification process is robust enough to remove and/or inactivate viruses that may be present in the starting material.

The goals of viral clearance studies are the same for tissue-derived products and biotherapeutics, but the design and performance of these studies can be quite different because of the diverse nature of the materials. In this article, we will present an overview of viral clearance studies for tissue-derived products based on our experience in performing a large number of such studies. Rather than discussing the issues related to viral clearance in general, our focus will be on the unique challenges that tissue-derived products pose.

Biologics Production Regulatory Risk Analysis and Management

contaminant control purification tissue-derived products viral clearance viral clearance study viral safety

Gamma Irradiation of Animal Serum: General Regulatory Environment and Process Controls

This is the sixth and last in a series of articles describing and demystifying the processes involved in the gamma irradiation of serum. This serum treatment is intended to mitigate the risk of introducing adventitious contaminants into cell cultures. In this article, we discuss the regulatory environment under which gamma irradiation of serum is performed, and provide additional details on best practices for documentation of the irradiation process, selection of the contract irradiator, evaluation of risk versus benefit needed to arrive at the radiation dose range to be used, as well as an understanding of the level of remaining risk following irradiation at that dose range. Gamma irradiation should not be viewed as a means of totally eliminating risk, but rather as a means of reducing the risk of introducing adventitious agents into cell cultures. A balance must be achieved between the desire to eliminate all adventitious contaminants, and the need to retain the desired performance characteristics of the serum, once irradiated…

Regulatory Risk Analysis and Management

adventitious agents animal serum animal-derived raw materials contaminant control gamma irradiation process control

Investigation of an Adventitious Agent Test False Positive Signal in a Plant-Derived Influenza Vaccine

Medicago manufactures influenza vaccine virus-like particles (VLPs) in an unusual production platform consisting of Nicotiana benthamiana plants. During the in vitro adventitious agent test (AAT) of certain Medicago B strain influenza vaccine VLP test samples, positive hemagglutination of guinea pig red blood cells was observed on day 14, but not on day 28. The positive result in the assay was surprising because the production process uses no animal-derived raw materials and contains a viral inactivation step. Plant-associated viruses would not be expected to infect the mammalian cell-based assay. No cytopathic effects or hemadsorption of red blood cells was observed in these AATs. The positive hemagglutination was observed at 2–8°C, but not at 36–38 °C, and only in a few of the six detector cell lines used in the assay. Because this is quite an unusual pattern of responses for an AAT, Medicago and the contract testing lab, Eurofins Lancaster Laboratories (ELLI) investigated the positive responses thoroughly for the presence of an adventitious agent or an alternative explanation not involving a viral contaminant. Investigation results indicated that the hemagglutinating activity associated with the vaccine test sample itself was responsible for the positive hemagglutination response. The positive hemagglutination on day 14 of these AATs was deemed an assay artifact, and preventive actions were taken to prevent recurrence of this type of false positive response…

Biologics Production Regulatory Risk Analysis and Management

adventitious agent test adventitious agents contaminant control false-positive hemagglutination vaccines virus-like particles

Demonstration of Porcine Circovirus Type 2 Inactivation by the Low pH Step of the Trypsin Manufacturing Process Using a New Infectivity Assay

Porcine circoviruses (PCVs) are small (17 nm) non-enveloped viruses with a covalently closed, circular, single-stranded DNA genome. PCV type 1 (PCV-1) and PCV type 2 (PCV-2) belong to the circovirus genus within the Circoviridae family. PCV-1 was originally isolated as a contaminant of porcine kidney (PK15) cells, and although it was found to be widely distributed in domestic swine in both North America and Europe, no correlation to any porcine disease or disorder has been established. PCV-2, however, has been found to be associated with several disease syndromes in pigs. For manufacturers of biologics utilizing porcine tissue or porcine tissue-derived materials, PCVs represent a contamination risk. In fact, an independent academic laboratory detected PCV-1 in a live attenuated rotavirus vaccine using metagenomic analysis and a PCV-1-specific polymerase chain reaction (PCR). While this study did not detect PCV-1 or PCV-2 nucleic acid in rotavirus vaccine from a second manufacturer, subsequent testing by the manufacturer revealed low levels of both PCV-1 and PCV-2 DNA. The source of the PCV nucleic acid contaminating both vaccines was determined to be porcine pancreas-derived trypsin used in the manufacture of the vaccines. The manufacturer of the rotavirus vaccine that was initially found to contain PCV sequences determined that their cell banks and virus seeds were contaminated with the viral sequences. The strong safety record of both vaccines and the benefits of vaccination against rotavirus convinced both the United States Food and Drug Administration (US FDA) and the European Medicines Agency (EMA) to permit their continued use…

Manufacturing

animal-derived raw materials contaminant control infectivity assay porcine tissue-derived materials trypsin viral clearance

Engineering MVM Resistance in CHO Cells

For decades, Chinese hamster ovary (CHO) cells have proven to be indispensable for the biopharmaceutical manufacturing industry, serving as cell factories that reliably produce grams per liter of recombinant proteins with the appropriate post-translational modifications and protein folding. However, one of the challenges of working with mammalian cells is that they are susceptible to viral contamination. Although the adoption of a wide range of risk mitigation strategies has made viral contamination a rare event, staggering costs and a shortage of life-saving medicines can result when these prevention strategies do fail, as demonstrated by a number of high-profile contamination events within the industry…

Manufacturing Risk Analysis and Management

contaminant control gene editing mammalian cell culture mammalian cell line development viral contamination

Identification of Worst-Case Model Viruses for Low and High pH Inactivation

In this paper, we review the efficacy data for low and high pH inactivation of viruses in solutions (i.e., liquid inactivation) and discuss the mechanisms of action and the impact of temperature and treatment time, as these are the primary determinants of inactivation efficacy, besides pH, for different viruses. Only enveloped viruses were considered for low pH inactivation, as the literature concerning low pH inactivation of non-enveloped virus is not extensive and low pH is not considered to be an effective inactivation approach for most non-enveloped viruses. We conclude that for low pH treatment of enveloped viruses, and high pH treatment of both enveloped and non-enveloped viruses, an enteric flavivirus such as bovine viral diarrhea virus represents a worst-case model virus…

Biologics Production

contaminant control pH inactivation purification viral clearance viral inactivation

Gamma Irradiation of Frozen Animal Serum: Dose Mapping for Irradiation Process Validation

The treatment of animal serum by gamma irradiation is performed to mitigate the risk of introducing undesired microorganisms (viruses, mollicutes, or other microbes) into a cell culture. Serum manufacturers and end-users utilize irradiation contractors to perform this process. The irradiation process must be validated, which involves establishing the: (A) minimum dose that achieves the required inactivation of the microorganisms of interest; (B) maximum acceptable dose at which the serum still maintains all of its required functional specifications; and (C) process used by the contract irradiator that allows treatment of the serum product within these defined limits. In the present article, we describe the best practices for qualifying the distribution and magnitude of absorbed dose (performance qualification [PQ] dose-mapping) when serum is gamma irradiated. PQ dose-mapping includes the following: (1) documentation of dose distribution characteristics in defined product load configurations for a specified pathway through the irradiator; (2) assessment of the process capability of the defined product load configurations and irradiation pathway for respecting the dose specification for the serum; and (3) development of a method for routine dose monitoring of the irradiation process with the defined product load configurations and the specified irradiation pathway…

Biologics Production Risk Analysis and Management

animal serum contaminant control dose mapping gamma irradiation process validation

Authentication and Characterization of Animal Cell Lines: The Impact on Research

Propagation and culturing of animal cells is fundamental to biomedical research. Over the past decade, there has been an increased demand for cell lines for usage as both research tools and models by academic and industrial scientists. Cell culture is a critical tool in such areas as cell biology, gene therapy, genomics, transcriptomics and proteomics. The increased demand for cells and cell-based assays has triggered a remarkable boost in cell culture activities, which in turn has lead to a greater incidence of misidentified and contaminated cell cultures…

Research

animal cell line authentication characterization contaminant control microbial contamination morphology

Testing Strategies for Mammalian Cell Banks

Contamination by adventitious agents (bacteria, fungi, mycoplasma, and viruses) represents potential safety risks for biologics produced in mammalian cells. Bacterial and fungal contaminations are usually easy to detect in culture medium due to changes in pH and visual indicators such as color and opacity. Mycoplasma contamination has been detected in 15–35% of cell lines deposited in some cell culture collection. This is because mycoplasma contaminations often cause little changes that can be readily detected by visual inspection. However, bacterial, fungal, and mycoplasma contamination can be more effectively controlled than viral contamination by careful screening of initial parental cell banks, proper environmental monitoring, along with ongoing testing…

Cell & Tissue Banking

contaminant control mammalian cell culture raw materials qualification safety testing viral clearance viral contamination

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