QA/QC

Building a Robust Biological Assay for Potency Measurement

Potency is a critical quality attribute of a biological product and is often determined by a biological assay (also called bioassay or biopotency assay). Specifically, potency is the biological activity or capacity of a product directly linked to its clinical efficacy. Potency tests are performed as part of product release, comparability studies, and stability testing. Nonbiological methods — which measure a product’s molecular or biochemical characteristics (e.g., ligand-binding assay) — have gained interest as replacements for often troublesome bioassays. Even…

Evaluating Freeze–Thaw Processes in Biopharmaceutical Development – Small-Scale Study Designs

Regulations mandate that biopharmaceutical product quality be controlled throughout manufacturing, storage, transportation, and delivery to patients (1). Operations often include freezing and thawing of a bulk drug substance, dilution of that purified substance to a target concentration, filtration, filling into a selected container–closure system, additional processing (e.g., lyophilization), inspection, packaging, storage, transport, and delivery (2). Freezing is a common processing step used to maintain stability and quality of a drug substance during development and production of biopharmaceutical products. It is…

Unwanted Immunogenicity: From Risk Assessment to Risk Management

Although vaccines and immunotherapies are designed to engage the human immune system in fighting disease, unwanted immunogenicity can be a major problem for protein-based therapeutics. Some patients produce antidrug antibodies (ADAs), which might lead to drug inactivation or adverse effects. Even human and humanized proteins have proven to be surprisingly immunogenic in some cases, suggesting that immune tolerance requires careful consideration in biologic product design. In rushing to deliver new drugs to market, some biotherapeutics developers have overlooked factors that…

Sterilization Effects on Elastomer Characteristics and Functionality in Parenteral Delivery Systems

To drive efficiencies in producing parenteral drug products, manufacturers are using containers and closure components that are received sterile and ready to be introduced into filling lines. The effects of sterilization on the properties of ready-to-use (RU) components must be assessed to ensure proper processing techniques and suitability over the components’ intended shelf lives. Sterile-drug manufacturers must determine the best sterilization method for components based on their respective drug products and processes. Critical areas of risk include potential changes related…

Replacing Reverse-Phase Chromatography for Mass Spectrometry: Is Salt-Free Size-Exclusion Chromatography Ready?

Protein mass is often determined using ultraperformance liquid chromatography (UPLC) coupled with electrospray-ionization mass spectrometry (UPLC/ ESI MS or simply LC-MS). A UPLC system equipped with an ultraviolet (UV) detector serves as an assisting vehicle to deliver purified and separated protein molecules to the mass analyzer. Reserved-phase chromatography (RPC) is the most common chemistry chosen to serve this purpose. For sample purification, not only does RP-UPLC use salt-free mobile phases that are amenable to MS, but it also can efficiently…

Preuse, Poststerilization Filter Integrity Testing for Single-Use and Stainless-Steel Installations

According to current European Union good manufacturing practice (EU GMP), integrity testing of sterilizing-grade product filters should be performed preuse poststerilization (PUPSIT) and immediately after use. In addition, PDA’s Technical Report 26 states that preuse integrity tests are preferably performed after filter sterilization. Performing an integrity test of an already sterilized product filter in-line requires wetting the filter while maintaining the downstream side sterile. The test gas must also be evacuted on the downstream side throughout testing maintaining sterility. The…

Predicting Aggregation Propensity and Monitoring Aggregates in ADCs

Antibody–drug conjugates (ADCs) are monoclonal antibodies coupled to cytotoxic agents with stable linkers. ADCs travel to target cells, where the antibody binds to its antigen expressed on the cell surface. Upon binding, the full ADC can be internalized by a process called receptor-mediated endocytosis. That process is followed by lysosomal degradation of ADC complexes, which ultimately leads to release of the cytotoxic agent and apoptosis of the target cell. Drugs used in ADCs can be up to a thousand times…

Fed-Batch Cell Culture Process Development: Implementing a Novel Nutrient Additive for a Robust, High-Titer, Scalable Process

The fed-batch culture of Chinese hamster ovary (CHO) cells has become well established as the primary method of manufacturing therapeutic recombinant protein products for various disease indications. Fed-batch process-development approaches focus on supporting high–cell-density cultures that are crucial to achieving high product titers but lead to proportionately high nutritional demands. Exhaustion of key nutrients negatively affects cell growth and ability to produce recombinant proteins. To counter that problem, concentrated feeds are added to the culture. Such feeds tend to be…

Higher-Order Structure Comparability: Case Studies of Biosimilar Monoclonal Antibodies

Great successes for monoclonal antibody (MAb)–based biologics over the past decade have provided many valuable options for patients combating some of the most serious diseases in the world, including cancer and autoimmune diseases. MAbs and antibody–drug conjugates (ADCs) are among the fastest growing biologic segments in development, with hundreds of candidates currently under clinical study. Meanwhile, society is facing the challenge of increasingly higher costs in healthcare including the cost of pharmaceuticals. With an aging population in many parts of…

Site-Specific Characterization of Glycosylation on Protein Drugs

A large proportion of biotherapeutic products are glycoproteins. These include erythropoietin and other cytokines, antibodies, glycosyltransferases, and glycosidases, which together generate billions of dollars in sales worldwide. Such drugs are inherently complex. As new treatments emerge and biosimilars are evaluated, the need to better understand their molecular structures is more acute than ever. Therapeutic glycoproteins are typically produced as recombinant products in cell culture systems. Glycosylation is of major importance during development of these drugs because their glycan chains markedly…