Potency testing is defined in 21 CFR Part 600.3(s) as “the specific ability or capacity of the product, as indicated by appropriate laboratory tests or by adequately controlled clinical data obtained through the administration of the product in the manner intended, to effect a given result†(1). Potency measurement is especially important for complex products such as cellular therapies (CTs). It is considered an essential aspect of the quality-control system for a CT drug substance and drug product. It is…
Product Characterization
Recommendations for Cell Banks Used in GXP Assays
Cells and cell-derived reagents form the basis of an operationally challenging class of test methods used in execution of product potency testing (stability and lot release), assessments of pharmacokinetic/ pharmacodynamic (PK/PD) profiles, detection of antidrug antibodies (ADAs) or neutralizing antibodies (NAB), and characterization and comparability testing of biopharmaceutical products. Frequently, cell-based assays provide the only measurement of the tertiary/quaternary structure of each batch of product at the time of lot release and during stability testing to assist in determining product…
Imaged Capillary Isoelectric Focusing for Charge-Variant Analysis of Biopharmaceuticals
Analyzing charge variants of therapeutic proteins is critical for characterizing and monitoring quality attributes of antibodies. Charge variants include deamidation, formation of N-terminal pyroglutamate, aggregation, isomerization, sialylated glycans, antibody fragmentation, and glycation at the lysine residues. In some cases, such changes affect binding, biological activity, patient safety, and shelf life. The biopharmaceutical industry relies on tools such as ion-exchange chromatography (IEC), isoelectric-focusing gel electrophoresis (IEF), and capillary equivalents such as capillary isoelectric focusing (CIEF) and imaged CIEF (iCIEF)…
Uniting Small Molecule and Biologic Drug Perspectives
Cosponsored by CASSS (an international separation science society) and the US Food and Drug Administration (FDA), the January 2010 CMC Strategy Forum explored antibody–drug conjugates (ADCs), which are monoclonal antibodies (MAbs) coupled to cytotoxic agents. The ADC platform of products is being used more and more for clinical evaluation in oncology. More than a dozen companies are developing several types, including products conjugated with calicheamicin, auristatins, and maytansinoids. Such products use the specificity of a MAb to deliver…
Comparing H1N1 Virus Quantification with a Unique Flow Cytometer and Quantitative PCR
A novel influenza A (H1N1) virus was discovered in Mexico in early 2009 (1). Infections from this strain led to declaration of a pandemic midyear, with about 61 million patients and 13,000 deaths reported by the US Centers for Disease Control (2). Although the pandemic officially ended in August 2010 (3), vaccines are still in demand to protect people against the H1N1 strain that is now expected to circulate seasonally for years to come. To best respond to…
Glycosylation of Therapeutic Proteins
ACMC Strategy Forum held in Washington, DC, on Sunday 28 January 2007, focused on two topics related to protein structure and function. First, analytical techniques used in the glycan analysis characterization included recent advances and correlations among the various tools. And second, current understanding glycosylation’s functional relevance to therapeutic proteins was discussed in the context of its effects on biological activity, pharmacokinetics, and Fc effector functions (for monoclonal antibodies, MAbs). Progress has been made in the field of…
Risk Mitigation Through Improved Process Predictability
Unexpected events — whether catastrophic like the oil leak in the Gulf of Mexico or a disruptive supply chain shortage — can change the future of a company. To prevent such difficulties or at least minimize their impact, life sciences companies spend millions of dollars on daily analysis of enterprise-wide risks. Whereas supply chain and logistics are traditionally a focus of risk analysis teams, manufacturing and quality teams are now charged with improving process predictability. Through process understanding, that not…
Protein Conjugates
Methods and Materials Thanks to vendors large and small — such as Invitrogen (www.invitrogen.com), ProteoChem (www.proteochem.com), Sigma Aldrich (www.sigmaaldrich.com), Soltec Ventures (www.soltecventures.com), and Thermo Scientific Pierce (www.piercenet.com) — bioconjugation chemistry is a field of many options. For example, amine coupling of lysine amino-acid residues typically involves amine-reactive succinimidyl esters. Sulfhydryl coupling of cysteine residues uses a sulfhydryl-reactive maleimide. Photochemically initiated free-radical reactions offer broader reactivity. Most processes couple small molecules to proteins or proteins to one another (e.g., antibodies…
Protein Therapeutics and Aggregates Characterized By Photon Correlation Spectroscopy
New biological entities (NBEs, therapeutic proteins such as interferons or antibodies) are much more complex than new chemical entities (NCEs), the classic “chemical†active ingredients. First, they are much larger. The average molecular weight of antibodies is ~150,000 g/mol. Second, most NBEs contain three-dimensional structural elements — with the protein secondary and tertiary structure being the most prominent, but quaternary structures are also known for some. The 3D structures are essential for correct bioactivity (1), but they are…
Microanalytical Techniques for Identifying Nonprotein Contaminants in Biologics
Proteins can aggregate at any point during pharmaceutical manufacturing. Regulatory agencies pay special attention to aggregates that can enhance immune responses and cause adverse clinical effects and those that can compromise the safety and efficacy of a drug product. Biopharmaceutical companies have stringent quality control (QC) procedures in place to ensure that their final products are free of contaminants and defects, including protein aggregates. Trained QC inspectors, however, can typically see product defects or particulate material only as small as…