Andrew J. Reason, SGS M-Scan Europe
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Representatives from leading contract research organizations (CROs) weigh in on key challenges tied to the biopharmaceutical
R&D, including issues regarding bioequivalence, platform technologies, process analytics, and more. Particpating in the BioPharm International roundtable are: Nancy Gillett, PhD, corporate executive vice-president and president of Global Preclinical Services at Charles
River Laboratories; Jon S. Kauffman, PhD, director of Biopharmaceutical Services and Analytical Method Development/Validation
at Lancaster Laboratories; Alan Breau, PhD, vice-president of Scientific Affairs–Analytical Sciences at MPI Research; Fiona
Greer, Global Director of BioPharm Services Development, SGS M-Scan; and Andrew J. Reason, Group Manager, SGS M-Scan Europe.
ANALYTICAL CHALLENGES
BioPharm: Biologics are clearly more complex to develop and characterize than small-molecule drug products. What would you say are
the key unique challenges associated with biopharmaceutical development and testing?
Nancy Gillett, Charles River Laboratories
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Gillett (Charles River): Choice of models is key. Products need to be screened for the intended human activity against targets from one to several
models. In addition, they need to be tested for a loss of potency. This testing requires varied technologies for binding and
activity assessment–early staging of these tests is important for reducing costs and avoiding unnecessary studies.
Immune reactions on the part of the model to human protein, cell, or gene-based treatments can be complex and are required
not only to detect antibodies to drug, but also to interpret toxicology results. Occasionally, this comparison of kinetic,
biomarker, and immune-reaction assessments reveal that a drug's toxicity is due to immune reactions. In such a case, the drug
can be freed from an "alert" and continued through development without interruption. Without the bioanalytical assays and
careful scientific review of assay results, however, a drug program might be terminated for the wrong reasons.
Jon S. Kauffman, Lancaster Laboratories
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Kauffman (Lancaster Labs): One unique challenge is the vast array of testing required to fully characterize a biologic. Assays can range from simple
pH measurements to peptide mapping to cell-based potency assays. In some instances, orthogonal techniques are also required.
Therefore, the contract laboratory needs to have state-of-the-art equipment and staff with specific skill sets and expertise.
Further, the laboratory needs to have redundancy of high-end equipment and specialized capabilities to be able to support
multiple projects on short timelines.
Another challenge is that the process, not just product, must be characterized and understood. Potential contaminants are
not just synthetic chemicals like those found in small-molecule manufacturing. Testing for more complex organisms, such as
adventitious viruses, bacteria, yeast, fungi and mycoplasma, along with a wide array of antibiotics, and other additives,
may need to be performed.
Alan Breau, MPI Research
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Breau (MPI): I see three key challenges: handling, analysis, and disposition. Unlike small molecules, biological drug candidates require
ordered secondary and tertiary structures to exert their desired activity, making their storage and handling much more complicated.
For example, vigorous mixing of a small-molecule solution usually is not a problem; yet a similar procedure would likely denature
a biologic drug, which could compromise its potency.
Assay development for small molecules usually consists of test article analysis using components and instruments that are
generally available, such as extraction cartridges, high-performance liquid chromatography (HPLC) columns, and liquid chromatography/mass
spectrometry (LC/MS) systems. Because most biologics are analyzed by immunoassay methods, specific reagents must be developed
for a particular biologic. This requires time to produce novel, well-characterized reagents, as well as assay development
time, which can lengthen the time needed to complete the full analysis of the studies required to file for product registration.
However, in preclinical species, it may be possible to use readily-available antibodies that bind to the constant region (Fc)
on a humanized monoclonal antibody (mAb) candidate for immunoassay detection, thus eliminating the need for reagent development.
Ultimately, the sponsor and CRO must work together to define and fulfill the reagent requirements at the onset of a project
to mutually understand the sequence of developmental activities required to meet project timeline expectations.
Finally, with rare exceptions, small molecules undergo absorption, metabolism, and excretion after administration, using well-defined
enzymatic and physiological pathways. The development and regulatory paradigm to evaluate small molecule disposition has been
well studied and characterized. The disposition of biologics, on the other hand, is typically not well characterized during
development.
Biologics must be assessed for the potential to develop neutralizing antibodies. There is no appropriate surrogate to assess
the clinical development of neutralizing antibodies, which can be critical for endogenous biologic replacement therapy. The
development of neutralizing antibodies to an endogenous protein can produce auto-immunity against a key physiological process.
The sponsor and CRO therefore must develop a well-designed plan to assess neutralizing antibodies in nonhuman primates and
in the clinic, as this is an important component of biologics development, especially when the biologic is meant to serve
as a replacement therapy for an endogenous compound.
Fiona Greer, SGS M-Scan
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Greer (SGS): Undoubtedly, the main issues associated with biopharmaceutical products have to do with the fact that these products are
'manufactured' in living systems. In addition to being larger and more complex, biologic products are invariably a mixture
of closely related proteins with the potential for a large variety of post-translational modifications which are not predictable
from the gene sequence. Thus, key challenges include: how to develop a process that will consistently yield a product of defined
quality; how to develop sensitive and robust analytical tests to characterize primary and higher order structure of the molecule,
including degradents and impurities; and how to predict or detect highly undesirable immunogenicity. These analytical studies
are crucial to better predict how the compound will work and enable support of clinical-trial design.
Another challenge tied to biologics analytical testing is the development and validation of robust and reliable potency assays.
Among potency assays, cell-based assays are probably the most adequate predictive as they allow the measurement of the drug's
efficacy in an in-vitro model. However, due to the intrinsic biological variability of cell and the complexity of cellular signaling pathways, it
can be difficult to define the correct read-out for an assay. The choice of the right cellular model, biomarker, or physiological
activity are important parameters that require expertise and specific technologies, such as flow-cytometry or multiplexing
capabilities.
