7. Introduction
The introduction of a clinical study report places one study in the development of the medicine: what is already known, what remains uncertain, how the study's critical features answer that uncertainty, and which guidance and regulatory discussions lie behind the protocol.
What the introduction is for
Section 7 explains why this particular study belongs in the development of the medicine. Before reading the procedures and results, the reader needs to understand the problem the study addresses and the contribution it is meant to make.
For a medicine whose earlier studies suggest that it may lower blood pressure, a further study might examine whether a particular dose helps adults whose blood pressure remains inadequately controlled with existing treatment. The introduction connects those facts: what is already known, what remains uncertain, and why the next study has this purpose, population, treatment, and duration.
The introduction provides enough context to make the later sections meaningful while leaving each of them room to do its own job: Section 8 states the study's objectives, Section 9 describes and explains the plan in detail, and Sections 10–12 show what happens to participants and what the study finds.
What Section 7 asks for
ICH E3 asks for a brief statement of no more than one page that places the study in the development of the test drug or investigational product and relates the study's critical features to that development.
The study's place in the development programme
A development programme is the collection of investigations used to understand a medicine and support decisions about its use. One study contributes a particular piece of that evidence. It may explore a dose, assess an intended benefit, examine safety over a longer period, or address a defined uncertainty.
The investigational product's development context explains how the present study relates to the evidence available when it is planned. The introduction gives the relevant background and connects it to the study; it does not need an exhaustive history of the product. Selecting directly relevant background helps keep the introduction focused.
For example, knowing that earlier work identifies a promising dose helps explain why this trial investigates that dose. Knowing that longer treatment remains insufficiently studied helps explain a longer observation period.
The introductory story therefore moves through three questions:
- What relevant information is already available?
- What question or uncertainty gives this study a purpose?
- How do the study's critical features address that purpose?
The three questions are a writing structure, not an additional E3 checklist.
The study's critical features
E3 names the following examples of critical features. In the introduction, their role is to explain how the study fits the programme; detailed procedures belong in the investigational plan.
| Feature | Everyday question | What the terminology means |
|---|---|---|
| Rationale | Why is this study worth doing? | The reasoning that justifies the investigation |
| Aims | What does the study seek to learn? | Connects the objectives to the development need |
| Target population | Who is the study intended to investigate? | The group defined by relevant characteristics, such as disease, severity, or previous treatment |
| Treatment | What is being investigated? | The product or intervention and relevant features of how it is used |
| Duration | Why this amount of time? | The treatment or observation period relevant to the study's purpose |
| Primary endpoints | What main measurements answer the question? | Connects the main outcomes to the development need |
The objective-to-endpoint connection in Section 8 links the development need to a measurable answer. The introduction gives enough of that connection to explain why the study exists.
The introduction can mention the main endpoint without explaining every calculation. Similarly, it can identify adults with persistent symptoms as the target population without reproducing every entry criterion. The entry criteria introduced in the synopsis receive fuller treatment in Section 9.3.
The connection matters as much as the description. “Treatment lasts 12 weeks” states a feature. Explaining how that period serves the developmental question makes the feature intelligible. The report uses the documented rationale; it does not invent an explanation from the results.
Guidance and regulatory discussions
Regulatory authorities evaluate and oversee medicines within their jurisdictions. The sponsor may discuss the protocol with them during development.
E3 asks the introduction to identify or describe:
- Guidelines followed when developing the protocol.
- Agreements between the sponsor/company and regulatory authorities that are relevant to this study.
- Relevant meetings between those parties.
A guideline might influence the type of outcome measured or the study duration. A regulatory discussion might address whether a proposed design answers a particular development question. The introduction identifies the relevant guidance or interaction and makes its connection to the study understandable.
In practice, a clear description names the guideline and applicable version, or the authority, date, subject, and relevant outcome of a meeting when these details are available. E3 Section 7 requires identification or description; it does not prescribe those exact fields as a separate template.
A discussion is not an agreement. A meeting can contain advice, questions, or unresolved issues. Calling it an agreement is appropriate only when the supporting record establishes an agreement. A study-specific agreement does not itself mean that the medicine is approved.
An example introduction
ABC-123 is an investigational medicine in development for hypertension. Earlier clinical evidence supports investigation of the selected dose in adults whose blood pressure remains inadequately controlled with existing treatment. This study evaluates its effect over 12 weeks. The primary endpoint is the change from baseline in systolic blood pressure at Week 12. The population, treatment period, and endpoint address the programme's need to characterise benefit during sustained treatment. Protocol development follows the applicable disease-specific guidance; the relevant guidance and study-specific regulatory discussions are identified here.
The example illustrates the progression, not wording to copy into a real CSR. A real introduction supports the earlier-evidence claims, specifies the applicable guidance, and describes actual regulatory interactions.