MCHM3001 · From Molecules to Therapeutics
Drug Development: Economics, Clinical Trials & Regulation
Lectures 18, 21 and 23 of MCHM3001 cover the back end of the pipeline: the economics of drug development (cost, attrition, Eroom's law), how clinical trials are designed and phased, and what a regulator such as the TGA requires — the ICH guidelines and the Common Technical Document. The examinable core includes the trial phases, the CTD modules, and the exposure-ratio safety-margin calculation. This directly informs the assessed group TGA presentation and the final.
What this chapter covers
- 01Development economics: ~6.5 yr discovery/preclinical + ~7 yr clinical; clinical approval success ~11%; capitalised cost ~US$2.6 bn per drug
- 02Eroom's law: FDA approvals per $bn R&D halve roughly every 9 years since 1950, and its causes
- 03Orphan drugs (US Orphan Drug Act 1983, <200,000 patients) and the niche-buster shift; intellectual property and the patent cliff
- 04Clinical trials: safety, efficacy and quality; controls, randomisation and blinding (single vs double); NHMRC/TGA/HREC governance
- 05Trial phases: Phase 0 microdose, Phase I safety/PK (20–80 healthy), Phase II efficacy, Phase III confirmatory, Phase IV post-marketing
- 06Regulators (TGA/EMA/FDA) and ICH harmonisation in four categories: Quality, Safety, Efficacy, Multidisciplinary
- 07The Common Technical Document (CTD) five modules (M1 admin, M2 summaries, M3 quality, M4 non-clinical, M5 clinical); PI and CMI
- 08Exposure ratio ER = AUC_animal/AUC_human at the NOAEL for safety margins; first-in-human dosing (NOAEL, MABEL)
Exposure ratio and a first-in-human safety margin
- +1State the definition: the exposure ratio is ER = AUC_animal / AUC_human, both taken at the relevant doses (animal NOAEL vs proposed human dose).
- +1Substitute: ER = 45,000 / 3,000.
- +1Evaluate: ER = 15. The animal was safely exposed to 15 times the AUC the human dose is expected to produce.
- +1Interpret and place it: an ER of 15 (>1, and comfortably so) indicates a reasonable safety margin between the human exposure and the level shown to cause no adverse effect in animals. These non-clinical toxicology study reports populate CTD Module 4 (M4) of the TGA submission and underpin the first-in-human dose rationale.
Key terms
- Eroom's law
- The observation (Moore's law spelled backwards) that the number of new drugs approved per billion dollars of R&D has roughly halved every nine years since 1950 — drug discovery getting slower and costlier over time.
- Clinical-trial phases
- Phase 0 (exploratory microdose), Phase I (safety/PK in ~20–80 healthy volunteers), Phase II (efficacy and more safety in patients), Phase III (large confirmatory trial vs standard care), Phase IV (post-marketing surveillance).
- Blinding
- Concealing treatment allocation to remove bias: single-blind hides it from participants, double-blind from both participants and researchers; paired with randomisation and adequate sample size.
- ICH guidelines
- International harmonised guidance in four categories — Quality (Q), Safety (S), Efficacy (E) and Multidisciplinary (M, e.g. M4 = the CTD) — that regulators such as the TGA, EMA and FDA follow.
- Common Technical Document (CTD)
- The five-module submission dossier: M1 region-specific admin, M2 summaries/overviews, M3 quality (CMC), M4 non-clinical study reports, M5 clinical study reports.
- Exposure ratio (ER)
- ER = AUC_animal / AUC_human at the NOAEL; a ratio comfortably above 1 indicates a safety margin between the no-adverse-effect animal exposure and the intended human exposure.
Drug Development: Economics, Clinical Trials & Regulation FAQ
What are the phases of a clinical trial?
Phase 0 is an optional exploratory microdose to check pharmacokinetics. Phase I tests safety, tolerability and dose in a small number (about 20–80) of usually healthy volunteers. Phase II looks for efficacy and more safety in several hundred patients. Phase III is a large confirmatory trial (hundreds to thousands) comparing the drug against standard care to support approval. Phase IV is post-marketing surveillance for long-term safety and new indications.
What is the Common Technical Document and why does it matter for the TGA?
The CTD is the standardised five-module structure in which a sponsor submits a drug to a regulator like the TGA: Module 1 is region-specific administrative material, Module 2 is summaries, Module 3 is quality/CMC data, Module 4 is the non-clinical (toxicology and pharmacology) study reports, and Module 5 is the clinical study reports. Because it is harmonised through ICH, the same dossier structure serves the TGA, EMA and FDA, which is central to the assessed group TGA presentation.
What does an exposure ratio tell you about safety?
It compares how much drug exposure (AUC) the animals safely tolerated at the no-observed-adverse-effect level with how much the intended human dose is expected to produce: ER = AUC_animal/AUC_human. A ratio well above 1 means there is a margin between the human exposure and the level shown to be harmless in animals, which supports the first-in-human dose. A ratio near or below 1 would signal an unacceptably thin safety margin.
Can AI help me with the economics, trials and regulation material?
Yes. Sia can drill the clinical-trial phases and the CTD modules, explain Eroom's law and drug-development economics, and compute an exposure ratio and interpret it as a safety margin. It explains the concepts and checks your reasoning; it does not do the graded TGA presentation or exam for you, and University of Sydney academic-integrity rules apply.
Exam move
This chapter rewards structured recall, so build three lists you can reproduce cold: the clinical-trial phases (0 through IV, with who is enrolled and what each tests), the CTD five modules (M1 admin through M5 clinical), and the ICH four categories (Q, S, E, M). Attach the economics headlines — roughly 11% clinical success, ~US$2.6 bn per drug, and Eroom's law with its causes — as quick context marks. Practise the exposure-ratio calculation (animal over human at NOAEL) and remember it feeds CTD Module 4. Because the group TGA presentation is assessed, rehearse the submission story end to end. When the modules or phases slip, ask Sia to quiz you as flashcards.
Working through Drug Development: Economics, Clinical Trials & Regulation in MCHM3001? Sia is AskSia’s AI Chemistry tutor — ask any MCHM3001 Drug Development: Economics, Clinical Trials & Regulation question and get a clear, step-by-step explanation grounded in how MCHM3001 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.
