How to Write a Clinical Study Report

Morula Health’s guide to writing a clear and compliant CSR

Clinical Study Reports (CSR) are regulatory documents which provide a comprehensive account of the design, conduct, analysis, methods, and outcomes of a clinical trial. Well-written CSRs help regulators evaluate the safety and efficacy of a drug. Depending on the type of trial, amount/quality of data, and the purpose of the report, different types of CSRs can be written (Abbreviated, Synoptic, Supplemental, etc.). This article focuses on Full CSRs and provides instructions on how to develop high-quality CSRs.

What is a Clinical Study Report?

Typically, a CSR is submitted after the completion of a Phase I, II, or III trial. Its main purpose is to provide regulators with a detailed report of the purpose, methods, and results of a study so they can make informed decisions on the development or approval of drugs. CSRs play a vital role in ensuring transparency and accountability in clinical research, as they serve as a formal record of what occurred during a study. The International Council for Harmonisation (ICH) guidelines set out clear requirements for what must be included in a CSR. Complying with ICH guidelines is essential for regulatory approval and ensures trials are reported in a consistent and clear format. (1)

Key components of a CSR:

Introduction: provides an overview of the trial, including its objectives and background.
Study Methods: details the study design, patient population, interventions, randomization procedures, and statistical methods.
Results: summarizes trial outcomes, including data on the safety and efficacy of the drug or treatment being tested.
Discussion and Conclusions: evaluates the significance of the findings and their implications for further research or clinical use.
Supporting Information: contains the appendices, such as case report forms, investigator information, and raw data tables.

Writing a Clinical Study Report

Start with source documents

Before beginning to write a CSR, ensure final versions of all the key source documents are available and that the data readout timelines are known. Key source documents are outlined below.

Statistical Analysis Plan (SAP): outlines the statistical methods and procedures used to analyze the data from the clinical trial. Includes details on how specific outcomes will be evaluated, ensuring consistency and transparency in the statistical approach.
Protocol: the blueprint of the clinical trial, detailing the study objectives, design, methodology, patient selection criteria, and procedures. Provides the framework for how the trial was conducted.
Investigator's Brochure (IB): a compilation of clinical and non-clinical data about the investigational drug or treatment being studied. Helps investigators understand the background, risks, and potential benefits of the treatment.
Tables, Listings, and Figures (TLFs): visual and tabular representations of the clinical trial data. TLFs are key for summarizing statistical findings, safety profiles, and efficacy results, making complex data more accessible and interpretable.
CSR Template: a pre-defined structure or format used for writing the CSR. Ensures that all necessary sections and information are included and presented consistently, often following regulatory guidelines like those of ICH E3.
Style Guide: ensures consistency, clarity, and professionalism throughout the document. Helps standardize the structure, language, formatting, and data presentation, making the CSR easier to read and review by sponsors and regulatory authorities.

Writing a CSR involves several distinct stages, from data collection to final submission. Below is a structured approach to developing a high-quality CSR:

Step 1: Prepare timelines

Like with any regulatory document, preparation and planning are key. To plan CSR timelines, you must first identify key dates such as when the TLFs will be available, regulatory deadlines, and any periods where key team members will be unavailable.

The timeline graphic below outlines the typical structure of a CSR project, allowing sufficient time for drafting, reviews, and finalization.

Step 2: Schedule Key Meetings

Once the project timeline is established, the Project Manager should schedule the following strategic meetings.

Kick-Off Meeting (KOM): defines objectives, timelines, and roles for CSR development
Key Messages Meeting (KMM): aligns team members on the key findings to focus on in the report, based on the available data
Comment Resolution Meeting (CRM): an opportunity to provide feedback and resolve comments to be addressed in the next draft

These meetings facilitate effective communication and help to ensure organization, consistency, and adherence to timelines.

Step 3: Develop the CSR Shell

To optimize timelines, medical writers should draft a CSR shell prior to data readout/TLFs availability (usually starting ~2 weeks before). Drafting a shell allows the medical writer to include information that is not dependent on the data and expedites post-data readout timelines. This gives the Sponsor time to review and provide feedback on sections such as introductory/background material, ethical considerations, objectives and endpoints, investigational plans, and statistical methodology - all before the TLFs are available!

Once the data is available, allow a few days for the Sponsor to review it and decide on key messages for the CSR. Following this, a KMM should be held to ensure all parties are aligned on objectives and direction for CSR development.

Step 4: Develop Draft 1 of the CSR

Once the data is available and key messages have been confirmed, the main CSR drafting can begin. The first draft will be the most comprehensive writing task and will involve the incorporation of all the relevant data, supported by source documents. Any questions/comments/suggestions that the writer has should be included as comments in the document ahead of the CRM.

Once the first draft is ready, the Sponsor completes their round of review. It is good practice to keep the first review team as streamlined as possible and to make sure all comments are relevant, actionable, and not repeated.

Step 5: Comment Resolution Meeting

Holding a CRM after the first round of review provides an opportunity for all questions and comments to be discussed. Both the writer and Sponsor team can provide feedback and agree on the best way to proceed. CRMs provide critical guidance to the writer for the next stage of CSR development. Once all the comments have been discussed and all team members are aligned, the writer can begin work on draft 2.

Step 6: Draft 2 of the CSR

Repeat Steps 4-5 for the second draft, focusing exclusively on content changes and points discussed at the CRM. As standard, two main drafts and rounds of review should be sufficient for the development of a CSR (followed by a final draft/finalization to implement minor edits following the second CRM). Additional drafts and rounds of review result in elongated timelines, inflated budgets, and general inefficiency.

Step 7: Quality Control

To produce an accurate, consistent CSR, ready for publishing and submission, independent Quality Control should be performed on the document. This should be done by a different, equally experienced writer. To increase efficiency, use a standardized, CSR-specific QC checklist. The lead medical writer then reviews and implements QC comments in the final draft.

Step 8: Finalization and Submission

Once the content is finalized, the CSR appendices (including case report forms and safety narratives) must be compiled as part of eCTD Publishing. At this point, the CSR is ready for submission.

Summary

CSRs are some of the most important documents in a drug’s development journey. A well-written, compliant CSR can be the difference between regulatory approval and costly delays or rejections. From preparation to final submission, medical writers and project teams must ensure consistency with source documents, effective communication of key messages, and regulatory compliance throughout.

How Morula Health can help

Standardized CSR SOPs, style guides, templates, and QC checklists maximize quality, efficiency, and consistency in CSR writing. A combination of refined, effective medical writing processes and highly experienced medical writers is essential for biotechs advancing to the next stage of clinical drug development. Morula Health helps global biotech companies write compliant CSRs in a timely and cost-effective manner.

Planning for a clinical data readout later this year? Unsure of how best to manage CSR writing? Looking to work with a team of medical writing experts?

Our team will be happy to help you consider your options and make an informed decision on your CSR medical writing strategy.

Speak with our team: https://www.morulahealth.com/contact

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References

1 ICH CSR Guidelines: https://database.ich.org/sites/default/files/E3_Guideline.pdf