#409 ‒ Inside modern drug development: the science, economics, and regulatory hurdles behind bringing new medicines to patients | Lloyd Klickstein, M.D., Ph.D.

What It Covers

Lloyd Klickstein, physician-scientist and drug developer with 20+ years at Novartis and multiple biotech companies, traces the complete arc of modern drug development using bimagrumab as a case study — covering target identification, antibody discovery, clinical trial design, FDA regulatory pathways, patent strategy, and why muscle-preserving therapies may reshape metabolic disease treatment.

Key Questions Answered

• •Drug Discovery Starting Point: Begin with unmet clinical need, not available technology. Klickstein's team at Novartis catalogued roughly 7,000 unrecognized clinical indications, grouped them into buckets — healthy aging, fibrotic disease, renal disease, ENT — and systematically identified where no therapy existed. This patient-first framework, rather than a molecule-first approach, generated dozens of projects including bimagrumab, and represents the highest-value path for society even though it carries greater regulatory and commercial risk than incremental improvements on existing drugs.
• •Patent Strategy and Exclusivity Windows: A drug patent runs 20 years from filing, but because IND-enabling studies, clinical trials, and approval consume most of that window, manufacturers realistically capture only 10–15 years of commercial exclusivity. Companies like AbbVie extended Humira's protection by staggering patents on composition of matter, formulation, salts, auto-injector, dosing route, and manufacturing process. Understanding this layered strategy explains why branded biologics remain expensive long after the original compound patent expires and why biosimilar entry is delayed.
• •Small Molecule vs. Biologic Selection: The choice of drug format follows the biology of the target. Myostatin and activin bind their receptors at low nanomolar to high picomolar affinity, meaning any blocker must achieve even tighter binding — a requirement small molecules cannot reliably meet. Therapeutic antibodies, produced via phage display recombinant DNA technology rather than mouse immunization, can reach that affinity threshold. Format selection should be locked early because it determines manufacturing complexity, dosing route, patient suitability, and the entire downstream regulatory and commercial strategy.
• •Bimagrumab Efficacy Gap Between Species: Bimagrumab produces 20–30% skeletal muscle mass increases in rodents but only 4–8% in humans, with eight percent representing the absolute ceiling observed. This gap exists because myostatin alone drives most inhibitory signaling in mice, while humans rely on myostatin plus activin A together — which is why blocking the ActRII receptor rather than myostatin alone was the correct mechanistic choice. The human mass gains did not reliably translate to strength improvements without resistance training, mirroring results seen with IGF-1 agonists and SARMs.
• •Protein Nutrition Amplifies Bimagrumab Response: A Novartis study tested bimagrumab across three protein-calorie intake levels — half, full, and 1.2 times the recommended daily amount. Muscle accrual scaled directly with protein intake, and bimagrumab prevented muscle loss even in the protein-restricted group. This suggests human response to ActRII blockade is substrate-limited, meaning amino acid availability caps hypertrophy independent of drug dose. The practical implication: any muscle-building therapeutic likely requires concurrent protein intake of at least 1.2 g/kg, and higher intakes were never tested but may yield greater gains.
• •Phase One Patient Selection Framework: Use a one-in-100,000 annual risk threshold — equivalent to the US lightning strike probability — to decide between healthy volunteers and patient populations in first-in-human studies. If projected serious adverse event risk exceeds that threshold, enroll patients who stand to benefit so a risk-benefit argument can be made. Dose escalation should use sentinel patients sequentially rather than dosing multiple subjects simultaneously, a lesson formalized after the 2006 TGN1412 CD28 agonist trial in which six healthy volunteers were dosed concurrently and experienced life-threatening cytokine release syndrome.
• •Gray-Market Peptides Carry Compounding Risks: Peptides sold online as research compounds — including those marketed as GLP-1 analogs or BPC-157 — lack GMP certification, meaning purity, potency, sterility, and actual identity are unverified. GMP manufacturing involves separate certified facilities for drug substance, formulation, packaging, and distribution, each subject to regulatory inspection. BPC-157 carries additional red flags: it is not encoded in the human genome, has no identified receptor, has no known mechanism of action, and all published data originate from a single investigator whose findings have not been independently reproduced.