The value of a good bioprocessing industry conference would not be complete without presentations on the most up-to-date information about the current technologies and research in the fastest growing segments of the field. Thanks to their promising therapeutic outlooks in areas such as cancer, antibody–drug conjugates (ADCs) have created a growing number of novel biologics candidates in various phases of clinical trials. Issues associated with their scale-up, processing, and characterization remain, however. Meanwhile, novel analytical technologies have been developed to help manufacturers in areas such as process validation, quality by design (QbD), and characterization. Such analytical tools are facilitating manufacturers in the processing of vaccines, another rapidly growing area of the industry.

AUDIENCE: PROCESS DEVELOPMENT, REGULATORY, ANALYTICAL, FACILITY DESIGN
KEYWORDS: QBD, ANTIBODIES, CHARACTERIZATION, CELL LINES, BIOASSAYS, RISK MITIGATION, CHARACTERIZATION
TAKE-AWAY: Get up-to-date on the biotechnology industry’s current processing and development “hot topics” with specialty sessions.

Antibody–Drug Conjugate Development and Production

Although the first ADC investigational new drug (IND) filing was submitted nearly 20 years ago, only two ADCs have been approved (Mylotarg in 2000, Wyeth; and Adcetris 2011, Seattle Genetics). Nonetheless, ADCs are at the forefront of therapeutic development for the biotechnology industry. Some experts believe they are poised to become the next major therapies, as evidenced by a steadily increasing clinical-phase pipeline of ADC candidates. All day Tuesday, conference presentations will be dedicated to the latest development case studies, process strategies, and regulatory considerations for ADCs.

Fred Jacobson of Genentech, Inc.starts by delivering the keynote address on “Getting Trastuzumab Emtansine (T-DM1) from the Lab-Bench to the Pharmacy.” In June 2012, the company announced positive results from its pivotal phase 3 trial of the targeted investigational breast cancer drug. Trastuzumab emtansine is an ADC studied in HER2-positive cancers. It is composed of the antibody trastuzumab and the chemotherapy DM1 attached to one another using a stable linker. According to a company release, the drug binds to HER2-positive cancer cells, and “is thought to block out-of-control signals that make the cancer grow while also calling on the body’s immune system to attack the cancer cells. Once trastuzumab emtansine is absorbed into those cancer cells, it is designed to destroy them by releasing the DM1.”

Researchers at ImmunoGen have been working on antibody–maytansinoid conjugates, which have antibody binding activity and cytotoxic activity from the conjugated maytansinoid. As the company’s Gillian Payne points out, “Some conjugates have additional activities such as ADCC, CDC, and inherent apoptosis-inducing activity from the antibody.” She will provide case-study examples of such conjugates having various activities and discuss proposals for release, stability, and characterization testing.

Marjorie A. Shapiro of the US FDA’s Division of Monoclonal Antibodies will discuss regulatory considerations for the manufacture, characterization, and quality assurance of ADCs. Improvements in the conjugation chemistry have led to ADCs with improved serum stability. Using new and improved analytical methods, scientists can now characterize more precisely novel ADC candidates. Shapiro’s presentation will focus on the regulatory approach to ADCs from the drug and biologics review perspectives.

Specialty Focus Sessions

Tuesday, 9 October 2012 8:00 AM – 3:15 PM Antibody Drug Conjugate Development and Production 8:00–11:45 AM Analytical Technologies for Biopharmaceutical Development Thursday, 11 October 2012 8:00 AM – 3:45PM Vaccine and Complex Biologics Development and Production

The International Conference on Harmonisation of Technical Requirements for the Registration of Pharmaceuticals for Human Use (ICH) recommends that new drug applications include information about the characterization of impurities and degradants for biologics. ADC characterization provides unique analytical challenge because such impurities and degradants can come from the protein, linker, or the drug– linker combination. Stanley Kwok of Seattle Genetics will discuss characterization of stress-related degradants in ADC formulation development. He will present his company’s strategies on the generation and characterization of such degradants for both monoclonal antibodies (MAbs) and ADCs during formulation development.

Scale-up and transfer of a conjugated process can be challenging. Deborah Meshulam of ImmunoGen, Inc. will focus on how her company develops conjugates consisting of a proprietary derivative of the cytotoxic agent maytansine attached to tumor-targeting antibodies. “The conjugation process is complex, involving development and transfer of both small and large molecules,” she says. “Key process parameters can be identified and controlled, thus minimizing uncertainty in the transfer and scale-up effort.”

Manufacturing future ADCs will require facilities that can provide flexibility in design and capacity. “Given that ADC technology is still evolving, collaboration with customers early and often in the facility design phase is essential to define requirements,” explains Bill Seaton of SAFC, a contract manufacturer of ADCs. In addition, a robust design must also meet current good manufacturing practices (CGMP) quality requirements and safety aspects, especially for highly potent compounds. Seaton will talk about equipment technologies and instrumentation that all process flexibility.

Analytical Technologies for Biopharmaceutical Development

The growing interest in better characterization and testing methods, as well as interest in implementing QbD-like monitoring and control has driven advances in analytical technologies. Tuesday morning, a specialty track will focus on current analysis methods for process validation, data management, and testing.

Product development relies on comprehensive characterization methods. “Advances in process design coupled with orthogonal analytical technologies enhance understanding of process consistency and product quality,” says Nadine M. Ritter of Biologics Consulting Group. Characterization methods show “continuity
” through appropriate comparability studies conducted in all phases of development as well as postmarket comparability studies for process improvements. With a growing number of biosimilars set to enter the market, manufacturers need to adopt analytical characterization strategies to assess product similarity. Ritter’s presentation will illustrate those strategies as well as “comparability paradigms” for those applications, including emerging analytical tools for characterization and common mistakes made in comparability studies.

QbD principles aim to provide improved understanding of process steps that influence final product quality. Such principles can also be applied to analytical development to minimize method variation and increase method robustness. Marc Thorsteinsson of Merck and Co. will describe examples of assay target profiles, risk analysis, selection of assay design space, and design of experiments.

In 2011, FDA released its long-awaited guidance on process validation, which includes discussion of process-related impurities. NMR methods can be used to detect and qualify such impurities in complex solutions. Ken Skidmore of Genentech, Inc. says that detecting a broad range of process impurities in proteins containing process pools is problematic because of interference from protein, buffer components, and water. “Using a CPMG sequence to attenuate protein signals, we are able use NMR as a general method to quantify organic impurities in protein-based biopharmaceutical products.” His presentation will focus on the approach for both expected and unexpected impurities.

Analytical testing for possible impurities related to extractables and leachables is required for license application. However, as Helmut Schneider of Human Genome Sciences points out, such testing can be difficult if biotech companies lack infrastructure and experience. He will describe his company’s testing of container–closure materials, including risk assessment for contact materials used in the manufacturing and filling processes. Assessment studies used a combination of external services and a buildup of internal capabilities.

Later, Kristine M. Kearns of Merck and Co. will describe automated analytics, data reduction, and data management. The company had to meet the demands of numerous samples and large amounts of data produced in the company’s automated analytical laboratories. “We have developed, and are evolving, a work stream for sample submission and tracking, analytical quality, and data management that requires less ‘hand-on’ time to allow analysts to focus more time in the labs,” she says.

In the final presentation of the analytical technologies track, Rajesh Krishnamurthy of Zyngenia will discuss preliminary characterization of zybodies, a novel class of multispecific antibodies. “Zybodies consist of short molecular recognition domains fused to the termini of MAbs,” he explains. Krishnamurthy will cover their expected attributes and behavior and the analytical approaches used to monitor them. He will also compare them to MAbs and other bispecific molecules.

Vaccine and Complex Biologics Development and Production

Thanks to new research and development funding from both private and public government sources, the biopharmaceutical industry is in the midst of a growth in vaccine development. A specialty focus session on Thursday will cover current areas of investigation in vaccines, including the need to increase understanding process performance and minimize risks.

Sue Behrens of Merck’s manufacturing division kicks off the sessions by reviewing the complex operations involved in vaccine production. “Process performance depends on biological variability, difficult to characterize raw materials, and limitations of analytical tools,” she explains. Risk mitigation includes process monitoring and six sigma programs to identify and correct potential defects. As manufacturers become aware of capacity bottlenecks and options for scheduling adjustments, they will be able to develop lean operations.

Protein Sciences Corporation (PSC) has developed a high-density fermentation processes for its FluBlok recombinant influenza vaccine. The process reduces or eliminates the difficulties associated with traditional embryonated-egg methods. Jamal Meghrous of PSC explains that “to achieve rapid commercial production of influenza vaccines, the use of a cell-based platform becomes unavoidable.” PSC uses the baculovirus expression vector system to produce recombinant hemagglutinin (rHA) for its influenza vaccine. His talk will focus on his company’s approach to develop a simple, low-cost, and scalable process for vaccine manufacturing in a short time frame.

Accurate risk assessment for residual host-cell DNA in biologics is vital for product quality. “It is theoretically possible that the residual DNA could transmit oncogenes and infectious agents to product recipients, and induce oncogenic or infective events,” explains Harry Yang of MedImmune. His presentation will describe a probabilistic model for estimating risk associated with residual host-cell DNA. The model takes account of enzyme inactivation.

Later, Tracy TreDenick of BioTechLogic and William Turner of Dynavax Technologies will focus on late-stage CMC challenges associated with vaccines containing oligonucleotide/adjuvants. Their talk will include information gained from hands-on experience and will describe associated regulatory issues.

Vaccines manufacturers are working with regulators to appropriately apply QbD approaches to vaccine development and control. As Timothy Schofield of Arlenda USA observes, “Many companies, however, have realized the value of these enhanced methods in developing a robust manufacturing process and in helping to ensure product quality through a carefully established control strategy.” His talk will review QbD approaches to ensure that vaccine manufacturers supply an ample supply of quality vaccines to the market.

Mass spectrometry (MS) has long been an essential analytical tool for vaccine development. As Van M. Hoang of Merck points out, MS can be used during early stage development to measure levels of key protein antigens in complex vaccine candidates before availability of critical immunoreagents. It can also be used for in-depth characterization of vaccines, including monitoring functional groups and identifying protein post-translational modifications. Hoang will discuss advances in MS techniques for vaccine development.

Author Details
Maribel Rios is managing editor of BioProcess International. Quotes not otherwise attributed are from presentation abstracts.