Newsletter #18

Screening with KinExA

In the fast-paced world of biotherapeutics development, identifying high-affinity candidates early can make or break your pipeline. Imagine screening up to 60 binding pairs in just 24 hours with unmatched precision—helping to identify ultra-tight binders that other technologies simply can’t handle.

Where Does KinExA Screening Fit into Your Workflow?

High-throughput screening with SPR or BLI platforms evaluates thousands of binding pairs to identify the top ~100 strongest binders. When affinities approach the limit of detection, the KinExA Single Point Screen efficiently narrows the field to the top 10 candidates. The full KinExA analysis then provides the most precise solution-phase data, including accurate K_d, k_on/k_off, activity, and non-specific binding—free of surface artifacts.

How KinExA Screening Delivers Superior Results

KinExA operates on a powerful principle: true equilibrium measurements in solution phase, free from surface artifacts that limit methods like SPR or BLI. Here’s the streamlined process:

• Prepare two samples per Constant Binding Partner (CBP): a baseline (Sig100) with CBP alone and an Inhibited sample where CBP is pre-incubated with the binding partner.
• Run non-specific binding (NSB) controls to ensure accuracy.
• Use the intuitive KinExA Pro software to calculate the Screening Ratio: ((Inhibited Signal − NSB) / (Sig100 − NSB)). Lower ratios spotlight tighter binders.
• Optimize with tools like the Theory Curve for ideal concentrations.

This approach allows seamless integration with high-throughput platforms for comprehensive ranking. No more guesswork; just reliable, data-driven decisions.

Key Benefits That Drive Your Success

• Unrivaled Accuracy: Measures affinities down to picomolar and femtomolar levels—perfect for today’s ultra-high-affinity candidates that challenge traditional biosensors.
• Speed and Efficiency: Rank up to 60 candidates in a single day, freeing up resources for deeper characterization.
• Cost Savings: Reduce assay variability and reagent use with precise, equilibrium-based screening, minimizing false positives and downstream failures.
• Flexibility: Easily adapts to your workflow, whether standalone or paired with LSA, SPR, or BLI for hybrid screening.
• Proven Reliability: Backed by over 30 years of innovation, ensuring consistent results in real-world applications.

Real-World Applications

KinExA Screening is already in use and delivering for clients. Consider these compelling examples from recent peer-reviewed studies:

• In antibody screening against soluble cytokines, a panel of 10 candidates was rapidly ranked using single-point inhibition, revealing top performers with exceptional affinity (Kielczewska et al., 2022).
• For SARS-CoV-2 receptor-binding domain antibodies, KinExA evaluated 48 samples and correlated strongly with SPR-based methods, consistently yielding tighter K_d values and reliable rank-ordering—even in single-point mode (Erasmus et al., 2023).
• In the Alntibody competition (Erasmus et al., 2024).

To support the successful implementation of this exciting new feature, current users may require training and updates to software. Please contact your Sapidyne representative or email info@sapidyne.com to discuss the details of screening with your KinExA 4000.

For new customers, comprehensive screening training is included following instrument purchase.

In addition, Sapidyne Instruments provides expert screening and full characterization services through our Contract Research Organization (CRO) laboratory located in Boise, Idaho, or Hannover, Germany.

We invite you to reach out with any questions or to schedule your training session. Our team is ready to assist you in unlocking the full potential of KinExA technology.

Publication Spotlight

Generation and preclinical assessment of depemokimab, an enhanced IL-5 antagonist monoclonal antibody

A recent study from researchers at GSK published in Heliyon presents the development and preclinical evaluation of depemokimab (GSK3511294), a next-generation monoclonal antibody targeting interleukin-5 (IL-5). Designed for the treatment of severe eosinophilic asthma and related eosinophilic diseases, depemokimab features enhanced binding affinity and a significantly extended half-life compared to earlier anti-IL-5 therapies like mepolizumab. These improvements enable dosing every six months, offering a more convenient and potentially more effective option for long-term disease management.

A key aspect of the study was the precise measurement of depemokimab’s binding affinity (K_D) to human IL-5 at 25°C. Conventional surface-based techniques, such as Biacore, proved insufficient for this purpose. The antibody’s exceptionally high affinity pushed beyond the reliable quantification range of those methods, introducing measurement artifacts and limiting accuracy.

To overcome this challenge, the researchers turned to KinExA. KinExA operates in true solution phase, allowing equilibrium binding measurements without the complications of surface immobilization. In the experiments, low concentrations of antibody (50 pM or 300 pM) were equilibrated with a range of IL-5 concentrations. Free antibody was then captured on IL-5-coated beads and quantified, providing a highly accurate determination of the dissociation constant.

The results showed depemokimab bound IL-5 with a K_D of 10 pM (95% confidence interval: 1–32 pM)—more than 10-fold tighter than mepolizumab’s K_D of 123 pM (measured by Biacore). This strong affinity data confirmed the effectiveness of the antibody’s affinity maturation process and supported its superior performance in preclinical potency assessments.

For teams working on high-affinity biologics, these findings highlight the value of KinExA when characterizing very tight interactions that challenge other platforms. If your current KinExA instrument is available, this approach offers a reliable way to generate precise affinity data for your own candidates. For those considering new instrumentation, KinExA provides a proven solution for advancing antibody engineering and supporting robust preclinical development.

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