Analytical

Ask the Expert: Accelerating Bioprocess Development Using Shake-Flask Metabolic Activity Data

with Dr. Gernot John of PreSens Precision Sensing GmbH Shake flasks are simple, low-cost devices widely used in screening and media optimization. The most widely measured parameter to determine biomass is optical density (OD). It is typically measured offline because no suitable equipment for broad range biomass measurements in shake flasks has been available. But a new, compact, SFR vario device from PreSens Precision Sensing can be placed under shake flasks to measure four parameters online: pH, O2 saturation, oxygen…

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…

Understanding and Controlling Sources of Process Variation: Risks to Achieving Product Critical Quality Attributes

Biopharmaceuticals include recombinant proteins, vaccines, gene therapies, and drug products derived from stem cell technology. One key characteristic of shared by all biologics is that they tend to be extremely large molecules with complex three-dimensional structures, critical to their functionality. For example, monoclonal antibodies (MAbs) are composed of more than one thousand times larger than a molecule of aspirin (one analogy compares the complexity of a MAb to that of an F16 jet, and the complexity of aspirin to that…

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…

Design of Experiments with Small-Scale Bioreactor Systems: Efficient Bioprocess Development and Optimization

Design of experiments (DoE) is one of the most valuable techniques for organized and efficient planning, execution, and statistical evaluation of experiments. Although a DoE investigation can be completed using several runs in one bioreactor, small-scale bioreactor systems designed for parallel operation (such as the ambr15 or ambr250 systems) provide the optimal basis to economically realize a series of experiments. Because of the multitude of interdependent parameters involved in applications such as cell line development, culture media screening, and the…

Targeting G Protein–Coupled Receptors with Biologics for Therapeutic Use, Part 2

In part 1, we summarized the advances made in new approaches developed to address the challenges of antigen generation for targeting G protein–coupled receptors (GPCRs). We reviewed the antibody and biologics pipeline with progress highlighted by some interesting case studies on new targets (1). Here, we conclude by reviewing progress attained with other biologics. Peptides Targeting G Protein–Coupled Receptors More than 50 peptide-based therapeutic products are commercially available, but very few of them have been derived from recombinant display technology.…

Paired ADCC Reporter Bioassays Enable Differentiation of Antibody Fc Effector Activities via V158 and F158 Variant FcyRIIIa Receptors

Antibody-dependent cell-mediated cytotoxicity (ADCC) contributes to clinical efficacy of a broad range of therapeutic antibodies. FcγRIIIa polymorphism of individual cancer patients are correlated with clinical efficacy of some of these antibody drugs. Classic ADCC cytotoxicity assays rely on primary effector cells, which are highly heterogeneous and variable. To quantitatively measure antibody activity and evaluate the impact of FcγRIIIa polymorphism, we developed a pair of reporter-based ADCC assays using two engineered effector cell lines in Jurkat that stably express an NFAT-RE driven…

Targeting G Protein–Coupled Receptors with Biologics for Therapeutic Use, Part 1

G -protein coupled receptors (GPCRs) represent a target superfamily linked to many disorders across all therapeutic areas. Although this target class has been historically treated by small molecules and peptides, antibodies can offer a number of advantages over such molecules by virtue of their specificity, dosing frequency, and restricted penetration. They also can provide other functional effects specifically mediated by the Fc region (ADCC and CDC) as well as different modalities such as those offered by bispecific and antibody drug…

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…