Analytical

Antibody–Drug Conjugates: Fast-Track Development from Gene to Product

In the fight against cancer, antibody–drug conjugates (ADCs) represent an increasingly important therapeutic approach. These biopharmaceuticals are designed to maximize the therapeutic index of cytotoxic small-molecule drugs through their selective delivery to tumor cells while leaving normal, healthy cells untouched. Structurally, an ADC is a monoclonal antibody (MAb) conjugated by a chemical linker to a potent cytotoxic drug. Conceptually, the MAb serves as the delivery component, targeting a specific tumor antigen that ideally is not expressed (or is expressed at…

Antibody Higher Order Structure Stability: Polymorphism Revealed By Protein Conformational Array

For protein therapeutics and other biologics, the importance of the molecule’s structure to its efficacy and safety is well established (1–5). In particular, their tertiary and quaternary structures play very important roles in product quality and have been monitored extensively in comparability studies (6–12). However, because of both the large molecular size and rotational property of amino acid α carbons, a protein can assume an enormous number of different conformations (13). For antibody-based biologics such as monoclonal antibodies (MAbs), fusion…

A Stirred, Single-Use, Small-Scale Process Development System: Evaluation for Microbial Cultivation

Mammalian and microbial protein production platforms have been used for over 30 years to produce a number of successful biologic drugs, including monoclonal antibodies (MAbs), recombinant proteins, and therapeutic enzymes (1). Most biologics are produced by mammalian cell lines, with Chinese hamster ovary (CHO) cells being the most widely used. However, microbial cells also are used to express recombinant therapeutic proteins, and almost 30% of currently approved biologics are produced by Escherichia coli bacteria (2). With worldwide biologics sales >56…

Particulate Contamination in Single-Use Systems: Challenges of Detection, Measurement, and Continuous Improvement

Patients receiving particulate contamination through parenteral delivery of biopharmaceuticals presents a significant potential health risk. However, the severity of that risk often is unclear. It depends on the route of administration, dosage volume administered, particle properties and amount received, and the ultimate fate of particles within a patient’s body (1). The appearance of particulate contamination also can be a visible indicator of product quality. Consequently, when such contamination is discovered within biopharmaceutical manufacturing operations, often it triggers costly investigations and…

Recent Advances in Endotoxin Removal: An Upgrade to a Traditional Method and a New Adsorption Chemistry

Endotoxin contamination has been the bane of the bioprocessing industry since its inception. Endotoxins are everywhere: They are toxic and/or interfere with every type of therapeutic, diagnostic, and research product; they are indestructible within the limits of product tolerance; and they are difficult to remove (1–4). Beyond that, they interact with various biological species in ways that prevent accurate measurement (5, 6). Managing these issues has been a focus of the industry for at least half a century, yet it…

Viral Vector Particle Integrity and Purity Analyses in Early Process Development

Gene therapy is the transfer of genetic material to a patient’s cells to achieve a therapeutic effect. Therapeutic DNA typically is delivered using a viral vector system, and adenoviruses have been used for this purpose for over 20 years (1–3). Within the past 10 years or so, lentiviruses have shown promise in clinical trials (1–3), and adenoassociated viruses (AAVs) have been used in the first approved gene therapies in the Western world (4). The number of gene therapy applications based…

Development of a Host-Cell Protein Platform Assay for a Chinese Hamster Ovary Cell Line

The Chinese hamster ovary (CHO) cell line is the most prevalent biopharmaceutical expression system and has been proven safe for commercial production of protein therapeutics (1). However, even after multiple purification steps, biopharmaceuticals contain residual host-cell protein (HCP) impurities that pose a potential safety risk to patients (2). Health authorities demand close monitoring of HCP impurities and require sensitive analytical methods with high coverage: the ability to detect a broad range of HCP impurities (3, 4). Polyclonal sandwich immunoassays are…

Moving DSC Downstream: Exploiting Differential Scanning Calorimetry As a Process Development Tool

The primary goal of biopharmaceutical process development is to determine what steps and conditions will maximize and optimize yields of purified product in the most reproducible, robust, and cost-efficient way. Characterized by high batch-to-batch comparability minimizing economic losses associated with batch failures, success relies on a thorough understanding of a given biological drug. Determining how its activity and stability are affected by processing and how to mitigate and control associated risks is advocated by a quality by design (QbD) approach.…

Development Approaches to Adenoassociated Virus Production

After many years of development, gene therapy is beginning to deliver on its promises in the clinic, in some cases with spectacular outputs. Those clinical successes also have led to an influx of funding and engagement from large pharmaceutical companies, thereby bringing the required financial support and expertise for late-stage clinical developments and product commercialization. Although many initial studies were confined to small patient groups and focused on a range of rare monogenetic diseases, new approaches to gene editing have…

Controlling Glycosylation in Fusion Protein Manufacturing to Generate Potent Biobetters

The pipelines of pharmaceutical companies are full of biological drugs. Many of them are innovative therapeutic proteins, but a growing number represent biosimilars and biobetters (Figure 1) (1). Biobetters typically are defined as being “based on innovative biologics but with improved properties” (2). Their development benefits from known therapeutic approaches and mechanisms of action resulting in low risk, fast paths to the clinic and thus lower costs. Superiority is achieved through extended half-life (t1/2), improved efficacy, and reduced immunogenicity or…