Episode Summary

Potent in vitro hits often fail in vivo—Martin Marro details how robust assay choice and pathway deconvolution can revive GPCR drug discovery programs.

Listeners will learn practical approaches to assay development for GPCR drug discovery, the pitfalls of calcium readouts, and how identifying pathway bias impacts translational success. Dr. Marro shares his experience bridging in vitro–in vivo gaps, refining selection flowcharts, and leveraging pharmacology research to drive clinical candidates. His strategic perspective is rooted in years of leading multimodal discovery teams in pharma and biotech.

Key Takeaways

• Assay selection critically shapes the trajectory from hit to clinic.
• Calcium and IP1 assays may not predict in vivo efficacy for all Gq-coupled receptor targets
• Alternative pathway analysis may be essential for mechanism elucidation.
• Persistence in probing beyond standard readouts can rescue high-profile discovery programs.
• Team structure and collaborative problem-solving are pivotal in resolving translational bottlenecks.

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About the Guest

Dr. Martin Marro leads the Cell Pharmacology group in the DOCTA division at Lilly’s Seaport Innovation Center in Boston, MA. Trained as a pharmacologist, Dr. Marro has accumulated over 20 years of experience spanning large pharmaceutical firms—including GSK, Novartis, and Lilly—and innovative biotech such as Tectonic Therapeutic. He holds deep expertise in early drug discovery across small molecules, peptides, and antibody therapeutics for metabolic, cardiovascular, and gastrointestinal diseases.

Dr. Marro’s research has been central to the discovery and characterization of multiple clinical candidates, with a focus on GPCR target validation, receptor pharmacology, and translational assay strategies. He played a key role in patenting and developing novel fatty acid-conjugated GLP-1 receptor agonists. Driven by the challenge of translating robust in vitro science into clinical proof-of-concept, Dr. Marro’s leadership continues to impact the field of GPCR drug discovery.

Keywords: gpcr podcast, assay development, pharmacology research.

GPCR tools don’t move the field forward unless researchers can actually use them. This episode breaks down how collaboration turns probes into progress.

Summary

In the final episode of this series, David Hodson, Johannes Broichhagen, and Maria Majellaro unpack how academic labs and Celtarys Research partnered to scale fluorescent probes, improve assay development, and support gpcr drug discovery. The conversation spans receptor internalization, fluorescence assays, tech transfer realities, and why tool availability—not just invention—drives translational pharmacology research.

Key takeaways

• Why accessibility defines the real impact of GPCR tools

• How industry enables scalable assay development

• Lessons from receptor internalization studies in complex tissues

• What makes academia–industry collaborations actually work

Read more here: https://www.ecosystem.drgpcr.com/dr-gpcr-podcast/scaling-glp-1-receptor-tools-through-academia–industry-collaboration

Chemical probes are reshaping how we map GLP-1R in real time — revealing receptor pools antibodies can’t reliably capture.

This is Episode 2 of a 3-part GPCR tool-development series created in partnership with Celtarys Research.

Summary:

Dr. Johannes Broichhagen aka JB breaks down the design logic behind fluorophore-linked peptides, assay trade-offs, and what true receptor internalization looks like in live tissue. A concise masterclass in assay development and GPCR drug discovery.

What you’ll learn:

• Why antibody variability pushed JB toward chemical probe engineering

• The design logic behind Luxendin-based fluorescent tools — and how structure guides function

• What “good assay development” looks like when cells, tissue, and probe behavior collide

• Behind-the-scenes stories from the collaboration with David Hodson

• Why parallelized experiments matter for reproducibility and signal quality

• How small-molecule probes outperform antibodies in live-cell and tissue imaging

• The surprising breakthroughs that shifted JB’s entire research trajectory

• Future directions: multi-color GPCR mapping, AI-guided ligand design, and in vivo chemical biology

Dr GPCR Links & Resources:

• Dr. GPCR Ecosystem: https://www.ecosystem.drgpcr.com/

• Membership & Pricing: https://www.ecosystem.drgpcr.com/university-pricing• Weekly News: https://www.ecosystem.drgpcr.com/gpcr-weekly-news