From Selectivity to Translation: Building Confidence in Class B GPCR Drug Discovery

By: Lakshmi Anantharaman & Julia Bautista

Class B GPCRs are playing an increasingly important role in modern drug discovery, particularly in metabolic, endocrine, and obesity-related programs. Their therapeutic promise is significant, but so are the challenges. Structural similarity across receptors and overlapping signaling pathways can make it difficult to assess selectivity, mechanism of action (MoA), and downstream risk with confidence early in development.

The right assay strategy can help address these questions early in discovery.

Step 1: Establish Selectivity with Broad Class B GPCR Profiling

The Peptide Hormone Class B GPCR LeadHunter panel is designed to address key early discovery questions with high-quality dose-response data across peptide hormone receptors.

In a single experiment, researchers can:

• Confirm mechanism of action by identifying receptor activation or inhibition
• Assess selectivity and cross-reactivity across closely related targets like GLP-1R, GIPR, and GCGR
• De-risk off-target effects linked to metabolic or endocrine liabilities
• Accelerate lead optimization with quantitative, robust, high-quality data

This matters in Class B GPCR biology, where even small differences in receptor engagement can lead to significantly different physiological outcomes.

In addition, functional add-on readouts (e.g., GSIS/insulin secretion) can complement panel data, helping teams move beyond receptor profiling alone and better assess biological relevance.

Step 2: Look Beyond Selectivity

Early selectivity profiling is essential, but it answers only part of the question.

Even when a compound shows strong potency and clean selectivity in a human receptor panel, several important questions remain:

• Will this activity translate across species?
• How predictive are my in vivo models?
• Are there species-specific differences that could impact efficacy or safety?

These questions are particularly relevant for GPCR targets, where subtle sequence differences between species can significantly affect ligand binding and signaling.

Step 3: Strengthen Translation with Ortholog Assays

To move from in vitro insight to in vivo relevance, ortholog assays provide an important next step.

Eurofins Discovery’s ortholog in vitro assays are designed to evaluate compound activity across multiple species—including human, mouse, rat, and non-human primates—using comparable assay systems.

This allows researchers to:

• Compare pharmacology across species using aligned assay formats
• Select the most predictive preclinical models
• Identify species-specific differences early
• Strengthen translational confidence before in vivo studies

When paired with human panel data, ortholog results help teams understand how receptor activity may translate from screening into preclinical models, reducing surprises later in development.

Putting It All Together: A Smarter Discovery Workflow

Combining the Peptide Hormone Class B GPCR LeadHunter panel with ortholog follow-up assays creates a streamlined, decision-oriented workflow:

1. Screen broadly across Class B GPCRs to establish selectivity and MoA
2. Prioritize leads based on potency, efficacy, and off-target profile
3. Validate translation using ortholog assays across relevant species
4. Advance with confidence into in vivo studies

This integrated approach helps ensure that the compounds you advance are not only potent, but also biologically relevant, translatable, and better positioned for success.

Why It Matters

In today’s competitive drug discovery landscape, speed matters – but confidence matters more.

By combining comprehensive receptor profiling with translational ortholog data, researchers can:

• Make better decisions earlier
• Reduce late-stage risk
• Improve alignment between in vitro and in vivo results
• Build stronger, more compelling data packages

Explore More

Ready to strengthen your Class B GPCR discovery strategy?

• Explore the Peptide Hormone Class B GPCR LeadHunter panel
• Learn more about ortholog in vitro assays
• Contact our team to design a workflow tailored to your program