Interviews with Speakers
Post-Translational Modifications: Interviews with speakers
Q: What do you regard as the greatest challenge in post-translational modifications?
A1. Detecting and quantifying low level of PTMs
A2. The impact of PTMs on safety of the biologicals and safety control strategy in manufacturing bioprocess
A3. Understanding how to deal with heterogeneity in and between batches of therapeutics that result from variations in PTMs
A4. Assessing if the difference between expression systems is important
A5. Identification of all unwanted/varying posttranslational modification within the product
A6. Detection of PTMs that lead to heterogeneity within a protein pool and in the worst case to inactivation of the product.
A7. Methods characterizing PTMs are getting more and more important since they are able to identify product candidates containing labile chemical degradation hotspots or product variants resulting from amino acid substitutions in early product development. Furthermore they are necessary for characterization of the carbohydrate profile of glycoengineered antibodies.
A8. Glycosylation
A9. Mixed disulfide bond identification and low level modification characterization. Also fast and high throughput detection and quantification of PTMs (i.e., glycosylation)
A10. Not knowing necessarily which PTMs to look for.
A11. Having effective methods to detect PTMs early in product development and how to control PTMs during development.
A12. The greatest challenge for me is to explain the changes seen in PTMs and to translate these changes to the process, to work out what is causing them, and how to remedy it.
A13. The control and prediction of PTMs at an early stage of product development and development of appropriate analytical tools for detailed characterisation of different types of biotherapeutics.
Q. What do you regard as new and exciting in the field?
A1. Advances in various software tools that allow comparison of different data files
A2. The scientific understanding of the root cause and impact of PTMs on quality
A3. I really appreciate that more and more people now focus on QbD approaches when developing new products. This is the right way.
A4. The ability to characterize in more detail the carbohydrate profile of recombinant produced monoclonal antibodies that lead to increased effector function.
A5. Advances in Mass Spec as a method for quantification
A6. The increasingly improved analytical methods for PTM characterization (electron transfer dissociation for S-S mapping, and more accurate mass determination)
A7. Mass spectrometry based approaches - methods that can search for modifications that are not expected
A8. The emerging field of biosimilars is exciting and I am looking forward to companies bringing more and more biosimilars to the market. PTM will play certainly significant role in this.
A9. More powerful mass-spec based methods for detailed characterisation, glycosylation engineering, more predictive antibody loop (CDR) modelling, faster production of crystal structures.
All of these topics will be addressed at the event by means of industry case studies.
PTMs: the talks the speakers are looking forward to.
When asked “Which sessions are you looking forward to the most at this event and why?” speakers gave the following answers:
1. USP standards for the characterization of post-translational modifications. This may help to make data from different companies comparable.
2. Alistair Kippen's talk on ’Assessment of deamidation sites in antibody products' - because it's an important subject that I want to learn about.
3. Do it Earlier, Save Big Later! - Chemical Stability Stress Test for Therapeutic mAb Lead Candidates by Boyan Zhang. Why? First, I like case studies and second, I am myself very keen on and interested in early assessment of instability.
4. I am very keen to see how the current regulatory view is interpreted by other companies.
5. “High Resolution Glycan Analyses of Monoclonal Antibodies”, by Hansjoerg Toll in which he will compare different methods for glycan analyses and “Analytical Characterization of PTMs to Support Formulation Decisions”, by Jun Ouyang which will describe methods for characterization of PTMs during formulation development.
6. Determination of the A-Fucosylation Distribution within an Antibody Preparation by Christiane Jaeger, Head of Process Biochemistry at F. Hoffmann-La Roche
7. FDA Expectations Regarding Comparability throughout the Product Life-Cycle. I am very interested in the talks presented by the health authorities because the biopharma industry must understand the rational and the scope of their requirements.
8. Distribution of free sulfhydryls and high throughput glycan screening.
9. All talks! Presentations from Jun Ouyang and Boyan Zhang (Genentech), Josef Vlasak (Merck) of key interest within similar scope to our own research.
PTMs: recent publications from our speakers:
- Designing biobetter monoclonal antibody therapeutics by glycoengineering. Morgan, C., & Fernandes, D. International Pharmaceutical Industry (Autumn 2009, pp,38-44, IPI Media.
- link: http://issuu.com/mark123/docs/ipi_-_autumn_2009
- Two-dimensional liquid chromatographic methods to examine phenylboronate interactions with recombinant antibodies. Zhang, B., Mathewson, S., & Chen, H. J. Chromatogr. A, 2009, 1216, 5676-5686.
- Unveiling a Glycation Hotspot in a Recombinant Humanized Monoclonal Antibody Zhang, B., Yang,Y., Yuk, I., Pai, R., McKay, P., Eigenbrot, C., Dennis, M., V. Katta, V. & Francissen, K. Anal. Chem., 2008, 80, 2379-2390.
- Evidence for Trisulfide Bonds in a Recombinant Variant of a Human IgG2 Monoclonal Antibody. Pristatsky, P., Cohen, S.L., Krantz, D., Acevedo, J., Ionescu, R. & Vlasak, J. Anal Chem. 2009 Jul 10.
- Identification and characterization of asparagine deamidation in the light chain CDR1 of a humanized IgG1 antibody. Vlasak J, Bussat MC, Wang S, Wagner-Rousset E, Schaefer M, Klinguer-Hamour C, Kirchmeier M, Corvaïa N, Ionescu R, Beck A. Anal Biochem. 2009 Sep 15;392(2):145-54. Epub 2009 Jun 2.PMID: 19497295
- Impact of methionine oxidation on the binding of human IgG1 to Fc Rn and Fc gamma receptors. Bertolotti-Ciarlet, A., Wang, W., Lownes, R., Pristatsky, P., Fang, Y., McKelvey, T., Li, Y., Drummond, J., Prueksaritanont, T., & Vlasak, J. Mol Immunol. 2009 May;46(8-9):1878-82.