Navigating different types of Clinical Study Reports (CSR) for optimal reporting of trial results

Clinical Study Reports (CSR) are integrated reports of clinical studies for therapeutic, prophylactic, or diagnostic agents conducted in human subjects and the most crucial documents resulting from clinical trials.

CSRs are used for the following purposes:

• Addressing legal* and regulatory** requirements.
• Help inform Sponsor decisions regarding the clinical strategy plan of their medicinal product.
• Advocating marketing authorisation (as part of the Common Technical Document, Module 5).
• Supporting labelling information and promotional materials.

The main points discussed in a CSR are:

• The choice of critical design features of the study.
• The study plan, methodology, and conduct.
• Data on participating subjects, efficacy, safety, and/or pharmacokinetics/pharmacodynamics (PK/PD), depending on study objectives.

Successful CSR completion requires information from the clinical trial protocol, statistical analysis plan/report, tables, listings, and figures obtained after statistical data analysis. Useful additional documents are the study reference manual, Investigator’s Brochure, imaging and/or operational manuals, depending on the trial.

Considering the recently released FDA pilot program to publish information from CSRs for transparency purposes, choosing the correct CSR type is of utmost relevance.

There are different types of CSRs:

Type 1: Full CSRs

Their purpose is to support approval by the regulatory agency and/or product label information. Full CSRs contain comprehensive clinical and statistical descriptions of the study conduct, and full output sections (efficacy, safety and, if applicable, PK/PD).

FDA, EMA, and PMDA all provided clear ICH E3 guidance on the structure and content of full CSRs.

Type 2: Abbreviated CSRs

These are condensed versions of full CSRs, evaluating whether the findings cast doubt on the safety claims and used for studies not intended to support the efficacy claim for the dose/regimen/population/indication. The structure and content of both abbreviated and synoptic CSRs (see below) are addressed in a specific FDA guidance, with abbreviated CSRs containing condensed study design/conduct, subjects, efficacy, and appendices sections, but including comprehensive safety.

An abbreviated CSR can be used for:

• Controlled studies examining conditions unrelated to the main claim (e.g., failed indication).
• Uncontrolled/other studies not designed to establish efficacy (e.g., studies with different indication/dosage forms not being registered).
• Flawed/aborted studies, including unsuccessful pivotal studies, the FDA agreed to be abbreviated.
• Open-label extensions, including total exposure.

Type 3: Synoptic CSRs

Synoptic CSRs only contain an expanded synopsis with full safety data (or referenced publications), no in-text tables (unless the serious adverse events [SAEs] need one) and summarised disposition/clinical pharmacology/efficacy data.

Synoptic CSRs are acceptable for:

• Different indications/dosage forms/administration routes not being registered
• Studies with defective design/conduct/data analysis, or uncontrolled/incomplete/discontinued studies.
• Early general Phase I safety-tolerance (but not required toxicity) studies.

Type 4: Supplemental CSRs

Supplemental CSRs provide relevant safety and/or efficacy results from cross-study analyses or (un)planned analyses not completed in time to be included in the full CSR, which is generally referenced. While there are no dedicated guidelines, supplemental CSRs can follow the ICH E3 guideline, with its structure typically including an introduction, objectives, methods, results, and discussion sections.

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Building on decades of experience in the EU and US regulatory requirements, ProductLife Group provides practical support, resources, and expertise for effective CSR writing.

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* FDAAA 801, final rule of 2017 [42 CFR Part 11], Commission Guideline 2012/C 302/03)

** International Council on Harmonization E6 guideline