Here you go, and note at the bottom:

Before filing a marketing application, a developer must have adequate data from two large, controlled clinical trials.

EUA doesn't have to follow that guideline, but just for reference.

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https://www.fda.gov/patients/drug-development...l-research


While preclinical research answers basic questions about a drug’s safety, it is not a substitute for studies of ways the drug will interact with the human body. “Clinical research” refers to studies, or trials, that are done in people. As the developers design the clinical study, they will consider what they want to accomplish for each of the different Clinical Research Phases and begin the Investigational New Drug Process (IND), a process they must go through before clinical research begins.

On this page you will find information on:

Designing Clinical Trials

Clinical Research Phase Studies

The Investigational New Drug Process

Asking for FDA Assistance

FDA IND Review Team

Approval

Designing Clinical Trials

Researchers design clinical trials to answer specific research questions related to a medical product. These trials follow a specific study plan, called a protocol, that is developed by the researcher or manufacturer. Before a clinical trial begins, researchers review prior information about the drug to develop research questions and objectives. Then, they decide:

Who qualifies to participate (selection criteria)

How many people will be part of the study

How long the study will last

Whether there will be a control group and other ways to limit research bias

How the drug will be given to patients and at what dosage

What assessments will be conducted, when, and what data will be collected

How the data will be reviewed and analyzed

Clinical trials follow a typical series from early, small-scale, Phase 1 studies to late-stage, large scale, Phase 3 studies.

What are the Clinical Trial Phases?


Watch this video to learn about the three phases of clinical trials.

Clinical Research Phase Studies



Phase 1



Study Participants: 20 to 100 healthy volunteers or people with the disease/condition.

Length of Study: Several months

Purpose: Safety and dosage



Approximately 70% of drugs move to the next phase



Phase 2



Study Participants: Up to several hundred people with the disease/condition.

Length of Study: Several months to 2 years

Purpose: Efficacy and side effects



Approximately 33% of drugs move to the next phase



Phase 3



Study Participants: 300 to 3,000 volunteers who have the disease or condition

Length of Study: 1 to 4 years

Purpose: Efficacy and monitoring of adverse reactions



Approximately 25-30% of drugs move to the next phase



Phase 4



Study Participants: Several thousand volunteers who have the disease/condition

Purpose: Safety and efficacy





Learn more about Clinical Trials.

The Investigational New Drug Process

Drug developers, or sponsors, must submit an Investigational New Drug (IND) application to FDA before beginning clinical research.

In the IND application, developers must include:

Animal study data and toxicity (side effects that cause great harm) data

Manufacturing information

Clinical protocols (study plans) for studies to be conducted

Data from any prior human research

Information about the investigator

Asking for FDA Assistance

Drug developers are free to ask for help from FDA at any point in the drug development process, including:

Pre-IND application, to review FDA guidance documents and get answers to questions that may help enhance their research

After Phase 2, to obtain guidance on the design of large Phase 3 studies

Any time during the process, to obtain an assessment of the IND application

Even though FDA offers extensive technical assistance, drug developers are not required to take FDA’s suggestions. As long as clinical trials are thoughtfully designed, reflect what developers know about a product, safeguard participants, and otherwise meet Federal standards, FDA allows wide latitude in clinical trial design.

FDA IND Review Team

The review team consists of a group of specialists in different scientific fields. Each member has different responsibilities.

Project Manager: Coordinates the team’s activities throughout the review process, and is the primary contact for the sponsor.

Medical Officer: Reviews all clinical study information and data before, during, and after the trial is complete.

Statistician: Interprets clinical trial designs and data, and works closely with the medical officer to evaluate protocols and safety and efficacy data.

Pharmacologist: Reviews preclinical studies.

Pharmakineticist: Focuses on the drug’s absorption, distribution, metabolism, and excretion processes.Interprets blood-level data at different time intervals from clinical trials, as a way to assess drug dosages and administration schedules.

Chemist: Evaluates a drug’s chemical compounds. Analyzes how a drug was made and its stability, quality control, continuity, the presence of impurities, etc.

Microbiologist: Reviews the data submitted, if the product is an antimicrobial product, to assess response across different classes of microbes.

Approval

The FDA review team has 30 days to review the original IND submission. The process protects volunteers who participate in clinical trials from unreasonable and significant risk in clinical trials. FDA responds to IND applications in one of two ways:

Approval to begin clinical trials.

Clinical hold to delay or stop the investigation. FDA can place a clinical hold for specific reasons, including:

Participants are exposed to unreasonable or significant risk.

Investigators are not qualified.

Materials for the volunteer participants are misleading.

The IND application does not include enough information about the trial’s risks.

A clinical hold is rare; instead, FDA often provides comments intended to improve the quality of a clinical trial. In most cases, if FDA is satisfied that the trial meets Federal standards, the applicant is allowed to proceed with the proposed study.

The developer is responsible for informing the review team about new protocols, as well as serious side effects seen during the trial. This information ensures that the team can monitor the trials carefully for signs of any problems. After the trial ends, researchers must submit study reports.

This process continues until the developer decides to end clinical trials or files a marketing application. Before filing a marketing application, a developer must have adequate data from two large, controlled clinical trials.

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