Use of Biochemical Assays in Early-Stage Drug Discovery and Screening

Reliable analytical methodologies are critical in early-stage drug discovery and development. Biochemical assays are foundational technologies for identifying promising drug candidates and advancing them to subsequent stages of preclinical and clinical studies. Biochemical assays are robust analytical tools that evaluate enzymatic activities, protein-protein binding events, and molecular interactions vital for compound screening and target validation.

So what is biochemical analysis? Biochemical analysis is the systematic determination of biomolecules and their interactions to evaluate therapeutic potential and the mechanism of drug action. Today, specialized Biomarker Services are supporting early discovery studies through target engagement assessment and analytical characterization. This article explores Biochemical Assay methodologies, applications, and services for early-stage drug discovery programs.

The Role of Biochemical Assays in Early-Stage Drug Discovery and Development

A drug product may take around 15 years and cost nearly $1 billion to reach the market. After the initial identification, optimization, validation, and efficacy testing, around 3 to 6 years are required to test the efficacy and safety of the drug in an animal model. Even after such elaborate initiatives, one-third of the drug compounds fail at the first clinical trial stages, and half of them may demonstrate toxicity in humans. This failure is mainly due to the assumption that the drug candidate tested in animal models will be safe in humans.

The remaining failed drug products may fail due to inefficiency seen during later stages of clinical trials. Hence, drug developers are increasingly focused on testing the efficacy and safety of drug candidates early during drug development. These early studies using human cells and in vitro assays offer an ideal approach to accelerate drug discovery and save time and resources.

Assays are methods that evaluate the effectiveness and safety of drug candidates on desired molecular or biochemical targets. This approach is also known as hit discovery. After identifying and validating the target, drug developers develop assays for efficient optimization of drug compounds. Most importantly, the assay should be economical, biologically relevant, and support high-throughput screening. 

Assay development is one of the primary stages of drug development. This development step focuses on creating assay systems to evaluate effects on desired processes, including biochemical and cellular systems. High-throughput screening allows genetic or pharmacological testing through automated machines and sensitive detectors. This process identifies compounds with therapeutic functions or properties relevant to human health or different diseases. These identified compounds are further evaluated and optimized for their use in development programs as therapeutic candidates. Some of the most common assay types employed in drug discovery and development include cell-based assays, biochemical assays, and in silico assays.

Biochemical Assays

Biochemical assays can test the inhibitory activity or binding activity of the drug candidate with the receptor molecule or target enzyme. They are commonly employed in early screening stages to assess receptor targets or enzymes in a cell-free and controlled environment. Biochemical Assays are known for their reliability, simplicity, and consistency compared to complex cell-based assays. Some key techniques include:

• Enzyme inhibition assays: these assays evaluate the compounds’ ability to inhibit enzyme activity.

• Receptor binding assays: these systems can detect ligand binding to intracellular receptors or cell surfaces and characterize specificity and affinity.

• Fluorescence-based assays: these assays employ fluorescent tags or ligands to visualize molecular interactions in real-time. These assays include Forster resonance energy transfer, time-resolved FRET, or fluorescence polarization assays, offering automation capabilities and high sensitivity.

• Radiometric assays: these methods employ radioactive isotope labels to detect receptor or enzymatic activity with enhanced sensitivity. Although they have been historically used in drug development, their applications have declined because of safety risks, challenges in disposal, and regulatory constraints. 

• High-performance liquid chromatography: this technique can assess proteolytic action and can also screen inhibitors to some degree.

• Surface plasmon resonance techniques: this method studies the interaction between a compound and its target protein.

The success of a drug discovery program begins with the identification and validation of disease-associated molecular targets. Biochemical assays to identify targets are employed to show that modulating a specific enzyme, receptor, or protein generates a therapeutic benefit. These assay formats offer a reproducible and controlled environment to confine molecular interactions and measure binding, activity, or inhibition, without the need for complex whole-cell systems.

Must Read: How to Choose the Right Biochemical Assay for Your Experiment?

However, inadequate method validation at this discovery stage is one of the primary reasons for failure in subsequent stages of clinical trials. This failure is often due to unforeseen toxicity or lack of efficacy. On the other hand, successful clinical trials are guided through confirmed target engagement, enough exposure at the site of action, and robust evidence of the desired drug effect.

Conclusion

Biochemical assays are fundamental analytical platforms for pharmaceutical innovations and early-stage drug discovery programs. They are critical in reducing development costs and accelerating drug development programs. Hence, a comprehensive understanding of what biochemical analysis is enhances discovery studies, while specialized biomarker services support program execution. Comprehending the potential of biochemical assays in advancing therapeutic solutions and driving pharmaceutical innovation will remain essential for unmet medical needs.