MIT CAACB Risk Assessment Case Study: Assessing Virus Cross-Contamination Risk between Two Simultaneous Processes in an Open Biomanufacturing Facility.

Some members of MIT's Consortium on Adventitious Agent Contamination in Biomanufacturing (CAACB) previously published content on the "Quality Risk Management in the Context of Viral Contamination", which described tools, procedures, and methodologies for assessing and managing the risk of a potential virus contamination in cell culture processes. To address the growing industry interest in moving manufacturing toward open ballrooms with functionally closed systems and to demonstrate how the ideas of risk management can be leveraged to perform a risk assessment, CAACB conducted a case study exercise of these new manufacturing modalities. In the case study exercise, a cross-functional team composed of personnel from many of CAACB's industry membership collaboratively assessed the risks of viral cross-contamination between a human and non-human host cell system in an open manufacturing facility. This open manufacturing facility had no walls to provide architectural separation of two processes occurring simultaneously, specifically a recombinant protein perfusion cell culture process using the human cell line, HEK-293 (Process 1) and a downstream postviral filtration unit operation (Process 2) of a recombinant protein produced in CHO cells. This viral risk assessment focused on cross-contamination of the Process 2 filtration unit operation after the Process 1 perfusion bioreactor was contaminated with a virus that went undetected. The workflow for quality risk management that is recommended by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) was followed, which included identifying and mapping the manufacturing process, defining the risk question, risk evaluation, and risk control. The case study includes a completed Failure Mode and Effects Analysis (FMEA) to provide descriptions of the specific risks and corresponding recommended risk reduction actions.

Biopharmaceutical Industry Approaches to Facility Segregation for Viral Safety: An Effort from the Consortium on Adventitious Agent Contamination in Biomanufacturing.

Appropriate segregation within manufacturing facilities is required by regulators and utilized by manufacturers to ensure that the final product has not been contaminated with (a) adventitious viruses, (b) another pre-/postviral clearance fraction of the same product, or (c) another product processed in the same facility. However, there is no consensus on what constitutes appropriate facility segregation to minimize these risks. In part, this is due to the fact that a wide variety of manufacturing facilities and operational practices exist, including single-product and multiproduct manufacturing, using traditional segregation strategies with separate rooms for specific operations that may use stainless steel or disposable equipment to more modern ballroom-style operations that use mostly disposable equipment (i.e., pre- and postviral clearance manufacturing operations are not physically segregated by walls). Further, consensus is lacking around basic definitions and approaches related to facility segregation. For example, given that several unit operations provide assurance of virus clearance during downstream processing, how does one define pre- and postviral clearance and at which point(s) should a viral segregation barrier be introduced? What is a "functionally closed" system? How can interventions be conducted so that the system remains functionally closed? How can functionally closed systems be used to adequately isolate a product stream and ensure its safety? To address these issues, the member companies of the Consortium on Adventitious Agent Contamination in Biomanufacturing (CAACB) have conducted a facility segregation project with the following goals: define "pre- and postviral clearance zones" and "pre- and postviral clearance materials"; define "functionally closed" manufacturing systems; and identify an array of facility segregation approaches that are used for the safe and effective production of recombinant biologics as well as plasma products. This article reflects the current thinking from this collaborative endeavor.LAY ABSTRACT: Operations in biopharmaceutical manufacturing are segregated to ensure that the final product has not been contaminated with adventitious viruses, another fraction of the same product, or with another product from within the same facility. Yet there is no consensus understanding of what appropriate facility segregation looks like. There are a wide variety of manufacturing facilities and operational practices. There are existing facilities with separate rooms and more modern approaches that use disposable equipment in an open ballroom without walls. There is also no agreement on basic definitions and approaches related to facility segregation approaches. For example, many would like to claim that their manufacturing process is functionally closed, yet exactly how a functionally closed system may be defined is not clear. To address this, the member companies of the Consortium on Adventitious Agent Contamination in Biomanufacturing (CAACB) have conducted a project with the goal of defining important manufacturing terms relevant to designing an appropriately segregated facility and identifying different facility segregation approaches that are used for the safe and effective production of recombinant biologics as well as plasma products.

Role of solvation barriers in protein kinetic stability.

The stability of several protein systems of interest has been shown to have a kinetic basis. Besides the obvious biotechnological implications, the general interest of understanding protein kinetic stability is emphasized by the fact that some emerging molecular approaches to the inhibition of amyloidogenesis focus on the increase of the kinetic stability of protein native states. Lipases are among the most important industrial enzymes. Here, we have studied the thermal denaturation of the wild-type form, four single-mutant variants and two highly stable, multiple-mutant variants of lipase from Thermomyces lanuginosa. In all cases, thermal denaturation was irreversible, kinetically controlled and conformed to the two-state irreversible model. This result supports that the novel molecular-dynamics-focused, directed-evolution approach involved in the preparation of the highly stable variants is successful likely because it addresses kinetic stability and, in particular, because heated molecular dynamics simulations possibly identify regions of disrupted native interactions in the transition state for irreversible denaturation. Furthermore, we find very large mutation effects on activation enthalpy and entropy, which were not accompanied by similarly large changes in kinetic urea m-value. From this we are led to conclude that these mutation effects are associated to some structural feature of the transition state for the irreversible denaturation process that is not linked to large changes in solvent accessibility. Recent computational studies have suggested the existence of solvation/desolvation barriers in at least some protein folding/unfolding processes. We thus propose that a solvation barrier (arising from the asynchrony between breaking of internal contacts and water penetration) may contribute to the kinetic stability of lipase from T. lanuginosa (and, possibly, to the kinetic stability of other proteins as well).