'Femi Fajimi

The Investigational Medicinal Product Dossier (IMPD): An Overview from a Developing Medical Writer 

By Femi Fajimi | 23 June 2025 

Regulatory medical writing requires a blend of scientific insight, structured communication, and regulatory awareness. 

As a developing writer, I’ve come to realise that the work extends beyond writing well; it’s about presenting data, safety, and strategy in ways that support informed regulatory decisions. One of the documents that reflects this blend is the Investigational Medicinal Product Dossier (IMPD). 

In the EU, no clinical trial involving an investigational medicinal product (IMP) can proceed without this document. The IMPD helps bring investigational therapies to trial safely and how medical writers contribute meaningfully to that process. 

What Is the IMPD? 

The Investigational Medicinal Product Dossier (IMPD) is a key regulatory document required as part of the Clinical Trial Application (CTA) submitted to European Union (EU) authorities and ethics committees. It provides a comprehensive overview of the IMP, detailing its quality, safety, and clinical use to justify its inclusion in a proposed trial. 

It is required under: 

• EU Clinical Trials Regulation (EU CTR 536/2014) 

• Directive 2001/20/EC (for ongoing trials prior to CTR implementation) 

What I’m Learning as a Developing Writer 

Writing or reviewing parts of an IMPD has shown me: 

• The importance of cross-functional collaboration: engaging with clinical, regulatory, and manufacturing teams 

• How clarity and consistency across documents like protocols, IBs, and SmPCs is vital 

• Why understanding the scientific rationale behind a drug’s development journey helps shape accurate and compliant documentation 

• That every section, even the annexes, must be aligned and justifiable to regulators and ethics reviewers 

What Does the IMPD Contain? 

Here’s a simplified breakdown: 

Section	Content
1. Quality (CMC)	Composition, manufacturing process, batch control, stability, GMP compliance
2. Non-Clinical Data	Pharmacology, toxicology, pharmacokinetics (ADME), safety studies
3. Clinical Data	Prior human exposure, clinical pharmacology, efficacy/safety summaries
4. Summary of Product Characteristics (SmPC)	Draft version (if available)
5. Investigator’s Brochure (IB)	Referenced or included
6. Annexes	Supporting documents, certificates, references, mock labels

What Medical Writers May Contribute 

• Draft or review non-clinical and clinical sections 

• Edit for clarity, accuracy, and GCP compliance 

• Ensure consistency with the Investigator’s Brochure and Protocol 

• Format the document in line with EMA or sponsor submission standards 

• Track version control and ensure updates are integrated smoothly 

IMPD vs Investigator’s Brochure (IB): What’s the Difference? 

Aspect	IMPD (Investigational Medicinal Product Dossier)	IB (Investigator’s Brochure)
Purpose	Regulatory document supporting CTA (Clinical Trial Application)	Scientific document informing investigators about the IMP
Audience	Regulatory authorities (e.g. EMA, MHRA)	Investigators and trial site personnel
Focus	Quality, safety, and manufacturing data (CMC) + supporting nonclinical/clinical data	Clinical and non-clinical data in a format useful for trial conduct
Format	Follows structured regulatory format (e.g. as outlined in EMA guidance)	Flexible format per ICH E6(R2); narrative-driven
Update Frequency	Updated when significant changes occur (e.g. manufacturing, formulation)	Reviewed and updated annually (or as needed)

Why it matters for writers: 

Writers working on both documents must ensure consistency in data across sources while adapting the content for the intended audience, specifically between regulators (IMPD) and investigators (IB). Each requires precision but serves different parts of the trial ecosystem. 

Helpful Writing Considerations 

• Use precise, scientific language, and avoid vague claims or promotional tone. 

• Maintain internal consistency with supporting documents. 

• Collaborate early with CMC, clinical teams, and regulatory affairs. 

• Review relevant ICH guidelines, such as: 

• ICH M4 (CTD organisation) 

• ICH E6(R2) (Good Clinical Practice) 

Final Thoughts 

Working with the Investigational Medicinal Product Dossier (IMPD) has helped me better understand how regulatory writing contributes to the authorisation of clinical trials. As a developing writer, I’ve come to realise that writing or reviewing an IMPD is not just about assembling technical content; it’s about clarifying complex decisions made across pharmaceutical development. 

Here’s what stood out to me: 

• The IMPD draws heavily on cross-functional input from non-clinical pharmacology to clinical rationale and CMC data. Understanding how these connect strengthens the writer’s role in aligning messages across teams. 

• It demands clarity and structure. Even if writers aren’t responsible for drafting every section, they often play a vital role in ensuring consistency across referenced documents such as the Investigator’s Brochure (IB) or Clinical Protocol. 

• The IMPD reinforces the importance of regulatory awareness. Referencing EMA and ICH guidelines helps ensure that the document meets submission requirements and reviewer expectations. 

If I were to share one message with other developing or early-career regulatory writers, it would be this: 

Don’t be afraid of complex documents — take them as learning opportunities. Understand the “why” behind each section. Ask questions. Over time, it becomes easier to see the logic behind regulatory documents like the IMPD, and that clarity helps you write with more confidence and purpose. 

References 

• EMA: Investigational Medicinal Product Dossier 

• European Commission. Clinical Trials Regulation (EU CTR 536/2014) 

• ICH M4: Organisation of the Common Technical Document 

• EudraLex Volume 10: Clinical Trial Guidelines