The illustration below provides more detail on the various steps in the drug development process and the types of studies that are undertaken. 

The Phase I first-in-human studies for both of Nyrada’s drug development programs will be run in Australia.

1. Drug Discovery

• Hundreds of compounds are reviewed to determine those with therapeutic potential
• Further research assesses promising candidates for:
  • How they are absorbed, distributed, metabolised and excreted (ADME)
  • Optimal dosage and how the drug will be administered
  • Potential side effects and toxicity
  • Possible interactions with other commonly administered drugs

2. Preclinical Research

• Preclinical studies evaluate a drug candidate's potential to cause serious harm. Dosing and toxicity levels are determined to inform whether the drug should be tested in humans.
• Two types of preclinical research:
  • In vitro - studies performed outside of living organisms (e.g. petri dish studies)
  • In vivo - studies conducted within a living organism (e.g. animal research models)
• The US Food & Drug Administration (FDA) requires these studies to be performed in accordance with good laboratory practices (GLP) which set minimum requirements for how studies are to be conducted

3. Clinical Research

• This the first time a drug candidate is tested in humans. Clinical trials follow a set protocol in order to answer specific research questions related to the drug's safety, tolerability and efficacy.
• The protocol covers the study's duration, number of subjects and selection criteria, dosing, and data assessment. Trials consist of three phases:
  • Phase I studies assess drug candidate safety and tolerability (~20-100 healthy volunteers)
  • Phase II studies evaluate a drug's efficacy in relation to the target disease/ illness (several hundred volunteers with the target indication)
  • Phase III studies involve ~300-3000 volunteers with target indication to confirm effectiveness, monitor side effects and compare to treatments

Australian Clinical Trials

• The Therapeutic Goods Administration (TGA) regulates the use of therapeutic goods in clinical trials.
• The TGA must be notified before a clinical study commences, however it is the Human Research Ethics Committee (HREC) for the relevant trial site that reviews the scientific validity of the trial design, the balance of risk versus harm of the therapeutic good, ethical acceptability of the trial process, and approves the trial protocol. The HREC is also responsible for monitoring the conduct of the trial.
• The institution or organisation where the trial is run gives the final approval for the conduct of the trial at the site, having due regard to advice from the HREC.

US Clinical Trials

• Drug developers must submit an Investigational New Drug (IND) application to FDA, including animal study data and toxicity, study plans and drug manufacturing information.
• Provided clinical trials are thoughtfully designed, reflect what developers know about a product, safeguard participants, and otherwise meet US Federal standards, FDA allows wide latitude in clinical trial design.
• The FDA review team has 30 days to review the original IND submission before responding.

4. US FDA Drug Review

• If a drug developer has evidence from its early tests and preclinical and clinical research that a drug is safe and effective for its intended use, the company can file a New Drug Application (NDA) to market the drug.
• Typically, this would occur after the completion of Phase III trial.
• Purpose of the NDA is to demonstrate that the drug is safe and effective for its intended use in the target population studies. Preclinical data through to Phase III trial data must be included.
• The FDA review team thoroughly examines all submitted data on the drug and decides whether to approve or not. FDA approval will allow the drug to be marketed and sold in the US.

Source: https://www.fda.gov/patients/learn-about-drug-and-device-approvals/drug-development-process