Bioconjugates represent an important and growing class of pharmaceuticals that include PEGylated proteins, vaccines, and antibody-drug conjugates (ADCs) (1–8). Numerous protein conjugation techniques exist (9). Among the more important conjugation chemistries used for protein therapeutics are N-hydroxysuccinimide (NHS), aldehyde, and maleimide (10–13). To date, process development of industrial biopharmaceutical conjugation reactions has largely been empirical in nature. Typically, many experiments testing different reaction parameters are required to identify optimal process conditions. In some instances, nonmechanistic statistical models can be used,…
Analytical
Fine-Tuning ADCs for Best-in-Class Therapeutics
Antibody–drug conjugates (ADCs) use the targeting ability of a monoclonal antibody (MAb) to deliver a highly biologically active drug to diseased cells while sparing healthy cells, creating potent and effective therapies. This emerging class of novel drugs currently focuses almost exclusively on cancer treatment. Two blockbuster ADCs — brentuximab vedotin (Adcetris from Seattle Genetics) for treatment of rare lymphomas and ado-trastuzumab emtansine (Kadcyla from Genentech/ Roche, manufactured by Lonza) for treatment of HER2-positive metastatic breast cancer — have improved treatment…
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…
Automated Mini Bioreactor Technology for Microbial and Mammalian Cell Culture: Flexible Strategy to Optimize Early Process Development of Biologics and Vaccines
The use of mammalian and microbial cells in the production of biologics and vaccines is well established, and the majority of the top 10 drugs are now manufactured in this way. There is a significant and growing pipeline of new biologics (1), which in combination with increased pressure on cost reduction and generic competition from biosimilars (2), means that many biopharmaceutical companies are looking for ways to improve productivity in their development laboratories to ensure that upstream processes are efficient…
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…
Consistently Superior Cell Growth: Achieved with New Polyethylene Film Formulation
During the past decade, single-use bioprocessing bags and bioreactors have gained a significant foothold in the biopharmaceutical industry because they offer a number of advantages over traditional stainless steel equipment, especially for clinical production, multiproduct facilities, and emerging economies. At the same time, some companies are concerned that plastic materials might release potentially toxic substances that could affect cell growth and product titers (1). In a worst-case scenario, they could even compromise drug safety when a company uses disposable bags…
Verification of New Flexsafe STR Single-Use Bioreactor Bags: Using a CHO Fed-Batch Monoclonal Antibody Production Process at 1,000-L Scale
In the past decade, single-use bioreactors have gained wide acceptance for biomanufacturing. The biopharmaceutical industry is increasingly interested in performing modern production processes in single-use facilities. That trend is driven by the time and cost benefits of single-use technologies, as well as the enhanced manufacturing flexibility they offer (1). With single-use bioreactors increasingly used in late-phase clinical trials and commercial production, their quality, reliability, and assurance of supply becomes more critical. Many industry experts consider process control of film and…
Pressure Decay Method for Postinstallation Single-Use Bioreactor Bag Testing
Single-use technology is well accepted today, and manufacturers’ quality assurance programs ensure leak-free single-use bags upon delivery. But what about risks involved with installation and other handling errors? Operator training and implementation of suitable standard operating procedures (SOPs) are mandatory, but should they be the only ways to mitigate the risk of failures? In addition, more companies are advocating the use of ballroom concepts (1) for the manufacture of biopharmaceutical drug substances and drug products. However, how do you prove…
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…
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.…