Future Directions for HX-MS in Formulation Development and Similarity Assessment
Kent Simmons:
Welcome, everyone, to this Cambridge Healthtech Institute podcast, which is presented in conjunction with the preparations for the 13th annual PEGS Boston, which will be held May 1st through the 5th, 2017, at the Seaport World Trade Center in Boston.
I'm Kent Simmons. I'm a program director with CHI, and with me today is Dr. David Weis, an associate professor in the departments of Chemistry and Pharmaceutical Chemistry at the University of Kansas. His lab focuses on the applications of hydrogen exchange mass spectrometry to protein-protein and protein solvent interactions, and the development of new data analysis methods.
At PEGS, Dr. Weis is speaking in the Biophysical Analysis of Biotherapeutics meeting, where he will give a presentation on the topic Hydrogen Exchange Mass Spectrometry in Formulation Development and Similarity Assessment. Thanks for joining us today, Dr. Weis.
David Weis:
My pleasure.
Kent Simmons:
Maybe as a starting point, could you explain a little bit about the fundamental basis of hydrogen exchange mass spectrometry?
David Weis:
Sure, Kent. We measure the rate at which hydrogen exchanges with deuterium when a protein is placed in heavy water, or D2O. Now this exchange can be most readily measured by either NMR or mass spectrometry. Now the rate is very sensitive to the degree of structure within the protein, so by comparing a protein under different conditions, for example, we may draw conclusions about the effect, or lack of effect, that these different conditions have on the protein. These effects can then be mapped to either individual residues, or short linear segments within the protein.
Kent Simmons:
Thinking about the pharmaceutical and biotech industries, how is this being applied in those research groups?
David Weis:
The spanning role of hydrogen exchange, or HXMS, in industry has mostly been driven by interest in epitope mapping, and in particular, the cases of conformational epitopes. There are already really very good peptide-based methods, such as alanine-scanning, to map linear epitopes, but mapping conformational epitopes requires the use of a high-resolution structural technique like NMR or X-ray crystallography. And in this space, HXMS has proven very effective at providing medium-resolution mapping of epitopes, but at a throughput that's much greater than can be achieved with either NMR or X-ray crystallography methods.
Kent Simmons:
Thinking for a minute about some of the topics you're presenting at PEGS, can you tell us a bit about the roles that HXMS can play in comparability analysis?
David Weis:
To date, hydrogen exchange mass spec has not been widely employed in this area, but I think it has enormous potential. The reason is because HXMS measurements are sensitive to changes in the higher order structure of proteins, but I think it's only a matter of time until this method is widely employed to measure a structural fingerprints of a reference material for use in comparability and similarity context.
One of the big questions right now is the limit of detection for observing subtle changes in that higher order structure, and one of the things I'm going to feature in my talks at the PEGS conference will be a new analytical framework for getting at this critical issue.
Kent Simmons:
And does this method also have application in formulation development?
David Weis:
Yes Kent, absolutely. You know, after more than a century of study, there's still so much that we don't understand about the interactions between proteins, solvents, co-solvents, and solutes. And this is a major problem for formulators of biologics, since we don't fully understand how additives put into the formulation can affect the protein stability. To really get at this problem, though, requires structurally [inaudible 00:03:40] resolved measurements on large proteins in solution, and that toolbox is pretty small.
In my talk at the PEGS conference, I will show how we have found that hydrogen exchange mass spec measurements of NAbs formulated with different additives can reveal important behaviors like the destabilization of aggregation hot spots.
Kent Simmons:
How are you seeing this technology evolving over time, as both companies and academic labs are using this methodology?
David Weis:
For many years, HXMS suffered from a poor reputation. It was time-consuming, labor-intensive, and not reproducible. Robotic automation has substantially improved a number of these characteristics, and because of that increased data quality, increased acceptance has followed. The hardware is now commercialized by several vendors, and it seems like we've reached a point where every major pharma has dedicated resources to using this technique. The one area that I think still needs improvements is the informatics. The informatics are getting better, but there's still room for a lot of development in this area.
Kent Simmons:
This is very helpful insight into this new area of technology, Dr. Weis. I think, as I've talked to people in the industry over past years, I'm hearing more and more about the application of this in different companies, and the need in those companies to develop internal expertise to support that, so I think both this podcast and your talk at PEGS are going to be very useful in this community.
I'd like to thank everyone for listening today. This has been an interview with Dr. David Weis. He is an associate professor in the departments of Chemistry and Pharmaceutical Chemistry at the University of Kansas. Dr. Weis is speaking in the PEGS Biophysical Analysis of Biotherapeutics meeting, where he will give a presentation on the topic Hydrogen Exchange Mass Spectrometry in Formulation Development and Similarity Assessment.
Dr. Weis, I'd like to thank you for your time today. Thank you very much for joining us.
David Weis:
You're very welcome, Kent. It's been a pleasure.
Kent Simmons:
All right, well I'll look forward to seeing you in a few weeks in Boston. For those listening, if you'd like to register for PEGS, or learn more about the more than 350 scientific presentations at the event, please visit the PEGS website at pegsummit.com. This has been another Cambridge Healthtech Institute podcast. I'm Kent Simmons, and thank you for listening.