#409 ‒ Inside modern drug development: the science, economics, and regulatory hurdles behind bringing new medicines to patients | Lloyd Klickstein, M.D., Ph.D.
September 28, 2026
AI Summary
5 min readInside Modern Drug Development: The Science, Economics, and Regulatory Hurdles
Dr. Lloyd Klickstein, a physician-scientist and rheumatologist who spent over two decades in drug development at Novartis and later as CEO of Versanis Bio, walks through the entire lifecycle of bringing a new medicine to patients—using the muscle-building antibody bimagrumab as a case study. The conversation reveals why drug development takes so long, costs billions, and so often fails, while clarifying how scientists actually decide which diseases to pursue and how they navigate the regulatory system.
How Drug Discovery Actually Begins
Klickstein starts not with molecules or targets, but with patients and unmet medical needs. He distinguishes between two broad categories: incremental improvements (a statin that works slightly better or can be taken less frequently) and quantum leaps (treating conditions that may not even have diagnostic codes yet). The pharmaceutical industry has a strong bias toward the former because it carries less uncertainty.
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What you'll learn
- 1 (03:12) **Background & The Drug Developer’s Mindset** - Lloyd Klickstein describes his path from physician-scientist at Harvard/Brigham to Novartis, where he helped pioneer translational medicine in industry.
- 2 (10:59) **The Problem of Frailty as a Medical Indication** - Lloyd frames sarcopenia/frailty as a critical target, noting that nursing-home-bound frail elderly patients had a three-year mortality rate approaching 90%.
- 3 (12:27) **Drug Formats: Small Molecules, Biologics, and Patents** - Lloyd breaks down the major drug classes: small molecules (chemicals), biologics (antibodies, peptides), gene therapies, and devices.
- 4 (21:56) **Agnostic vs. Format-Driven Drug Design** - Lloyd explains that big companies are format-agnostic, but the choice of small molecule vs. biologic is driven by the target’s biology and the patient population.
- 5 (37:01) **The Biology of Myostatin and the Discovery of Bimagrumab** - Lloyd details the discovery of the myostatin pathway and why blocking it leads to muscle growth in animals.
- 6 (48:58) **Why an Antibody (Biologic) Was the Right Choice** - Lloyd explains the biophysical reason for choosing an antibody over a small molecule: the ligand-receptor interaction is extremely “sticky” (low nanomolar), so the inhibitor must be even “stickier” (low picomolar), which is nearly impossible for a small molecule.
- 7 (63:02) **Preclinical Testing and Toxicology** - Lloyd walks through the transition from mouse to primate studies, focusing on the critical question of cardiac hypertrophy.
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Show Notes
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Lloyd B. Klickstein is a physician-scientist who has spent more than 20 years at the intersection of drug discovery, healthy aging, and preventive medicine. Drawing on his experience in academic medicine, translational research, and biotechnology, Lloyd walks through the full arc of modern drug development. He explains how scientists identify an unmet medical need and decide which diseases and therapeutic targets are worth pursuing. From there, he takes us through the process of engineering a drug, testing it in animals, and navigating clinical trials and regulatory approval. Using bimagrumab as a case study, Lloyd explains the rationale for targeting myostatin and activin signaling to increase muscle mass and strength and describes how the antibody was engineered and screened. He then walks through what was learned from early clinical trials. Unexpected effects on fat mass and type 2 diabetes helped reshape bimagrumab's development as a potential treatment for obesity, including its use in combination with semaglutide. Along the way, Peter and Lloyd explore the differences among drug modalities, including biologics and small-molecule therapeutics. They discuss the roles of patents and capital allocation in drug development, along with the requirements for IND submission and GMP manufacturing. They also examine why developing a new drug takes so long and costs so much, and why identifying failures early is critical. At the end of the episode, the conversation turns to mTOR inhibition and geroprotection, as well as Lloyd's current work on a novel pharmacologic approach to cancer prevention. This episode provides a rare behind-the-scenes look at how new medicines are actually created and the scientific, regulatory, and economic decisions that determine which ideas ultimately make it to patients.
We discuss:
- Lloyd's path from academic medicine to translational drug development [3:15];
- Drug modalities, patents, and the economics of innovation [11:30];
- Choosing sarcopenia as a target for drug development, and confronting the problem of measuring falls [23:00];
- The rationale for bimagrumab: improving muscle mass and strength by targeting myostatin and activin signaling (and why fo
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