Bispecific antibodies (BsAb) can recognize two different antigenic epitopes. This feature of dual specificity opens up a broad range of applications, involving redirecting immune cells to tumor cells, blocking two distinct signaling pathways simultaneously, dual targeting of diverse disease mediators, and delivering useful loads to targeted sites. Recently, BsAb has been reported to constitute a newly robust class of therapeutic proteins. Its stability, high solubility, and resistance to stress have attracted more attention to the development of clinical drugs. Here, based on the classical system of developability assessment, Creative Biolabs has established a mature platform for BsAb which consist of a suite of in silico tools, protein structure expertise, and experimental protocols. Our developability assessment strategies have been devised to identify early problems during process development related to stability and solubility that are insufficient to reach expected dosing or sensitivity to stress conditions.
Developability assessment is a wide term covering the evaluation of promising candidates’ drug-like manufacturability, physicochemical properties, and safety profile. It is essential to carry out the assessment as soon as possible before the clinically early-stage development to pick up the candidate with the most stable characteristics. The results can minimally reduce the risk of costly late-stage failures for the industry, hopefully, supply reliable antibody molecules for fundamental research, and potentially deliver safer drugs treating different diseases.
Fig.1 Developability workflow for numerous candidates. (Jarasch, 2015)
From a development point, an ideal protein drug can be generated with high yields and high quality through a standard bioprocessing platform. This candidate demonstrates consistent manufacturability, low product heterogeneity, and is stable over a long time in a liquid formulation. It does not show unqualified signs of fragmentation, aggregation, chemical degradation, and potency loss. In practice, many therapeutic proteins are not optimal in each of the aspects mentioned above. Accordingly, the latent weaknesses should be determined timely in the early generation so that either an alternative candidate can be considered or a re-engineering step will be operated before further activities. Usually, the traits of desired molecular depend to a certain extent on project-specific demands, such as a long-acting dosage or a high-concentration formulation is envisioned.
BsAb can be expressed in prokaryotic, mammalian, yeast, and cell-free systems. We are able to compare multiple expression platforms to achieve product high yield and quality.
Stability (thermostability, half-life, aggregation, etc.), viscosity, and solubility should be evaluated during BsAb drug development. Many BsAbs are different from their parental Abs, it is recommended to determine the BsAb properties as well as the parental ones. And the conventional techniques used to character protein properties can also be well-used.
Fig.2 Impaired stability of an example IgG1 mAb containing a free Cys in CDR H2. (Jarasch, 2015)
Chemical modifications bring in variability during storage and influence in vivo and in vitro binding behaviors. We perform the evaluation including isomerization, deamidation, oxidation of tryptophan and methionine residues, as well as succinimide formation of aspartate and asparagine residues.
This scheme analyzes chemical degradation pathways, post-translational modifications (e.g. oxidation, glycosylation, and deamidation) and some physical stability issues (e.g. BsAb aggregation).
In addition to in vitro properties, suitable in vivo properties are also necessary for good BsAb candidates. Basically, this part usually refers to the in vivo half-life characterization, which can be determined by serum stability and pharmacokinetic studies in rodent and cynomolgus monkeys.
The developability assessment deliverables contain integrative reports highlighting the predictions and analyses from the services listed above. If there are high-risk issues identified in the initial assessment, our experts have an extensive range of antibodies design and protein engineering capabilities that make it possible to improve the structure, bioactivity and the yield of interested BsAb.
High-end biophysical characterization tools and techniques capable of predicting the late-stage behavior of underlying therapeutic antibody proteins, particularly BsAb, are becoming increasingly accessible. Creative Biolabs introduces a selected range of commonly used services to characterize the properties of bispecific antibodies at the beginning of development. Remarkably, there are several conspicuous features and advantages of our assessment technologies as below.
Developability is regarded as an assessment of the suitability of a bispecific antibody to be successfully developed into functional studies and effective therapies. In contrast with safety and efficacy assessments, a number of technical obstacles actually can be evaluated early during development programs. Using predictive methods or tools to figure out problems like these could help decrease the probability of failure in later stages and bridge the gap between discovery and development. To identify technical challenges, Creative Biolabs has devised a full set of developability assays and applied these strategies to a variety of BsAb currently in our pipeline. Aided by us, early quality control and risk assessment of biophysical parameters assist clients in preventing hinders in later phases of antibody development, thereby, reduce costs and save time.
Table.1 Example methods for developability assessment. (Jarasch, 2015)
What’s more, Creative Biolabs has years of experience to offer comprehensive bispecific antibody services, such as BsAb Design, BsAb Engineering, BsAb Manufacturing, and BsAb Analysis, tailored to customers’ exact needs. If you don’t find related BsAb services, please contact us by e-mail or phone with your particular requirements.
1. Jarasch, A.; et al. Developability assessment during the selection of novel therapeutic antibodies. J Pharm Sci. 2015, 104(6): 1885-1898.
2. Jennie R. Lill and Sandoval. W. Characterization of the bispecific molecule. Analytical Characterization of Biotherapeutics. 2017: 180-190.