Analytical

Development of a Novel Host-Cell Protein Assay: Supporting the Physcomitrella patens Expression System

Host-cell proteins (HCPs) constitute an inevitable impurity of biopharmaceutical products originating from recombinant-cell culture. HCPs are a heterogeneous mix of different proteins, their specific characteristics depending on the kind of organism used as an expression platform, on the “destination” of the expressed recombinant product (extra- or intracellular), and on the corresponding purification approach (1–3). Contamination of a final drug substance with residual HCPs could lead to immunogenic reactions in some patients who receive the drug product (DP). So a reliable…

The Case for a Standardized Assay to Test Suitability of Single-Use Systems in Cell Culture Applications

Increased commercial use of single-use systems (SUS) for large-scale biopharmaceutical production creates the need for consensus on industry best practices and standards for materials in SUS components. End users and suppliers are beginning to develop a shared vision of industry needs in such areas (1, 2). For example, highly visible efforts to harmonize extractables testing include contributions from groups such as the BioPhorum Operations Group (BPOG), Bio-Process Systems Alliance (BPSA), Parenteral Drug Association (PDA), ASTM, and ISPE. In addition to…

Accelerating Biologic and Biosimilar Drug Development: Ready-to-Use, Cell-Based Assays for Potency and Lot-Release Testing

With the drug industry’s expanding emphasis on biologics, the need for robust cell-based assays has grown at all stages of development. Requirements for efficacy, quality, and potency testing often demand a complex set of bioassays and/or cell-based assays for new therapeutics or biosimilars. Developers of the latter have found this need for cell-based assays to be particularly challenging. Commercially available, ready-to-use cell-based assays provide a robust functional response from specific therapeutic targets. They can significantly shorten assay development time while…

Primary and Higher-Order Structural Characterization Strategy for Biosimilarity Assessment

The development pathway of a biosimilar is unlike that of a novel biotherapeutic. Many regulatory authorities reference a stepwise approach to establishing biosimilarity. Analytical requirements are greatly increased before a product enters clinical testing. Enhanced analytical efforts entail physical, chemical, and biological characterization of a biosimilar product compared with an originator reference product. Strategies at this early stage must include intensive characterization of multiple batches to determine variability of quality attributes. Here I address some issues involved in meeting regulatory…

Special Report on Assays, Test Methods, and Comparability: The CMC Strategy Forum Series, Part 4, Introduction

The CMC Strategy Forums focus on relevant chemistry, manufacturing, and controls (CMC) issues throughout the life cycle of a therapeutic and thereby foster collaborative technical and regulatory interaction. Forum chairs share information with regulatory agencies to help them merge good scientific and regulatory practices. Outcomes of the forum meetings are published in BioProcess International and on the CASSS website (www.casss.org). This process is meant to help ensure that biopharmaceutical products manufactured with advancing technologies in a regulated environment will continue…

Special Report on Assays, Test Methods, and Comparability The CMC Strategy Forum Series, Part 4, The Role of Higher-Order Structure in Defining Biopharmaceutical Quality

Cosponsored by CASSS (an International Separation Science Society) and the US FDA, the 17th CMC Strategy Forum was designed to explore the relationships between higher-order molecular structure and quality of therapeutic proteins and peptides, vaccines, and blood-derived products. Understanding those relationships is important to defining and controlling the critical quality attributes (CQAs) of biopharmaceutical products. The forum program highlighted the current state of the art for analytical tools used to monitor higher-order structure. Case studies demonstrating the effects of changes…

Special Report on Assays, Test Methods, and Comparability The CMC Strategy Forum Series, Part 4, The Roles of Bioactivity Assays in Lot Release and Stability Testing

A January 2007 CMC Strategy Forum on the roles of bioactivity assays in lot release and stability testing was held in Washington, DC (1). Its purpose was to promote an understanding of the design and utility of bioassays throughout product development and to delineate the conditions under which surrogate assays could be used to determine product potency. Topics of discussion included appropriate assay selection at each stage of product development, the potential use of binding assays for potency testing, and…

Quantitative Risk Assessment of Bioaccumulation Attributable to Extractables and Leachables in Cellular Immunotherapy Biomanufacturing

Precious patient samples, contamination concerns, and limited product purification options have compelled manufacturers of cellular immunotherapies (iTx) such as chimeric antigen receptor T cells (CAR-T) and T-cell receptor (TCR) technologies toward the disposables industry. Such companies are implementing single-use technologies (SUTs) almost exclusively (1). But despite the dominance of disposable bioprocess platforms and their extraordinary growth in the iTx marketplace, researchers have made limited efforts to understand the perennial and critical bioprocessing risks of leachables and extractables. Here we outline…

Experiences with a Benchtop-Scale Glass Bioreactor: Engineering Data and Cultivation Results

Animal cell lines (the dominant expression systems in biopharmaceutical production processes) are mostly cultivated in stirred bioreactors (1). Although such bioreactors are widely accepted and applicable over a wide range of scales, engineering data for these systems are still lacking. Nevertheless, studies have shown that the correct choice of key parameters (e.g., power input, tip speed, mixing time, and oxygen mass transfer) can influence the growth of animal cell cultures (2). Therefore, detailed characterization is essential. It enables reliable scaling…

Identification and Quantification of Heat-Shock Protein 70: A Major Host-Cell Protein Contaminant from HEK Host Cells

Recombinant therapeutic proteins are commonly produced by cell lines such as Chinese hamster ovary (CHO), human embryonic kidney (HEK) 293, murine myeloma (NS0), and Escherichia coli bacterial cells. Host-cell proteins (HCPs) are indigenous proteins produced by those expression hosts and considered to be process-related impurities generated from the cell culture process (1). HCPs are potentially harmful and immunogenic to patients, and they can compromise the stability of protein drugs (2–4). For those reasons, HCPs must be consistently removed or reduced…