Accelerating pre-CLD developability assessments

Human cell render

The process of cell line development in the production of biologic therapies is laborious and time consuming. Candidate clones must meet a variety of requirements including high productivity and stable expression, while maintaining high product quality. Moreover, selected clones must be amenable to scale-up, and fulfil a variety of standard requirements (e.g. monoclonal identity and free of contaminants). Here we describe ValitaTiter, a screening tool that leverages high throughput IgG quantification and superior usability to facilitate pre-cell line development (CLD) developability assessment workflows. When run prior to lead candidate selection, the assay can provide increased transfection and productivity characterisation to optimise pool selection, before commitment to expensive CLD projects.


Drug discovery for new biologic therapeutics is a costly and heavily time consuming process [1, 2]. In order to avoid the inevitable spiralling costs that accompany the high attrition rates during preclinical and clinical development, strategies that identify failure early and cheaply are of paramount importance to the biopharma industry [2,3]. In an effort to ‘de-risk’ the process, new focus is being placed on upstream strategies that asses the feasibility of molecules to successfully progress from lead generation, through development, to commercial product [4,5].

So-called developability assessments encompass a variety of analytical approaches employed to increase the quality of leads with respect their biophysical characteristics and manufacturability in early-stage development [4,5] . In mAb production for example, where traditional emphasis has been placed on a molecule’s affinity and functionality; a developability assessment aims to more comprehensively evaluate characteristics including expression yield, and propensity for protein self-interaction or aggregation, to reduce chance of product failure in downstream processes [5].

Valita®Titer for HT pool selection analytics

In CLD, developability stage assays are therefore intended to run prior to lead selection in order to provide increased up-front clone characterisation that can allow removal of candidates with poor productivity or suboptimal transfection performance. Following host cell culture, transfection and pool selection, the stages encompassing cell line development – screening, single cell cloning, media development, bioreactor process development – all demand considerable optimisation, time and resources [1]. Pool screening is therefore critical to select clones that produce high titers, facilitate quick recovery of product, and are scalable to high-capacity culture processes.

The ValitaTiter assay is an analytic solution optimally suited for HTP assessment of transfection efficiency and stable IgG expression in cell lines; that facilitates the early elimination of undesirable clones before commitment to the CLD process (Figure 1). Based on a novel application of fluorescence polarisation (FP) technology, the assay relies on a signal that is robust to cellular contamination and requires minimal sample volume, making it ideal for employment during mini-pool screening approaches. The additional critical features of the assay, available in 96- or 384-well format, are the rapid turnaround time (<15 min for plate prep and analysis of 96 samples, based on manual preparation) and a homogenous, platform agnostic layout, which aides reliable analysis and is amenable to automated workflows.

Overview of pre-CLD process steps

Figure 1: Overview of pre-CLD process steps, incorporating ValitaTiter for HT pool ranking based on IgG expression. Following (1) vector optimisation and (2) host cell culture and transfection, (3) rapid clone production assessment is conducted in either 96- or 384-well format with no pre-purifcation before (4) single cell cloning.  

[1] Ho C, Tong, Y & Yang Y (2013). Generation of monoclonal antibody-producing mammalian cell lines. Pharm. Bioprocess. 1(1), 71–87

[2] Pérez A, Sormanni P, Andersen S, Sakhnini S, Rodriguez-Leon I, Bjelke J, Gajhede A, De Maria L, Otzen D, Vendruscolo, M & Lorenzen N (2019). In vitro and in silico assessment of the developability of a designed monoclonal antibody library, mAbs, 11:2, 388 400, DOI: 10.1080/19420862.2018.1556082

[3] Kim Y, Han, S.K., Yoon, S. et al (2020).  Rich production media as a platform for CHO cell line development. AMB Expr 10, 93

[4] Jesús Zurdo Pharm (2013). Developability assessment as an early de-risking tool for biopharmaceutical development Bioprocess. 1(1), 29–50

[5] Bailly M, Mieczkowski C, Juan V, et al. Predicting Antibody Developability Profiles Through Early Stage Discovery Screening. MAbs. 2020;12(1):1743053. doi:10.1080/19420862.2020.1743053

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