Introduction
Plain Language Summaries (PLS) have become a defining feature of modern clinical trial transparency. Under the EU Clinical Trials Regulation (EU CTR), they are mandatory and publicly visible through the Clinical Trials Information System (CTIS).
For pharma and biopharma organisations, this shift creates both pressure and opportunity. The opportunity lies in using PLS to demonstrate maturity in transparency, respect for trial participants, and commitment to responsible scientific communication.
This article examines Plain Language (lay) Summaries through that broader lens. It explores what they are, why they matter strategically, and how sponsors can embed them into sustainable medical writing and disclosure models. It also considers the growing role of Plain Language Summaries for publications (PLS(P)), which extend transparency beyond regulatory systems into the public scientific record.
What Are Plain Language (Lay) Summaries in Clinical Trials?
Plain Language Summaries explain the results of a clinical trial in language that can be understood by people without specialist scientific or medical training. Their intended audiences include trial participants, patients, carers, and members of the public with an interest in the research.
A PLS is not a simplified version of a scientific abstract. Technical abstracts are written for expert readers and rely on shared terminology, abbreviations, and prior knowledge. A Plain Language Summary removes those assumptions. It prioritises clarity, context, and meaning, focusing on what was studied, why it mattered, what happened, and what the results mean in real terms.
This distinction is fundamental. Abstracts are designed for efficiency and precision among experts. Plain Language Summaries are designed for understanding, inclusion, and trust.
Terminology Note: Plain Language vs Lay Summaries
Across regulatory guidance, journals, and industry communications, multiple terms are used to describe Plain Language Summaries. These include lay summaries, layperson summaries, and plain English summaries.
In practice, these terms are interchangeable and refer to the same core concept: explaining clinical research in accessible language. In this article, “Plain Language Summary (PLS)” is used as the primary term, with “lay summary” used where it aids readability or reflects common usage. This mirrors how stakeholders discuss the topic and supports discoverability without introducing unnecessary distinctions.
EU CTR Requirements and Timelines: The Regulatory Baseline
The EU Clinical Trials Regulation requires sponsors to submit a Plain Language Summary of trial results for publication in CTIS. This requirement applies across interventional clinical trials conducted in the EU.
Annex V of the regulation defines the essential elements that must be included. While sponsors should always consult the regulation directly, the intent is clear: results must be communicated in a way that non-specialist readers can understand, without distortion or promotional tone.
Timelines are fixed. For most trials, results and the associated PLS must be submitted within 12 months of trial completion, with a six-month deadline for paediatric studies. These requirements leave no room for reactive or last-minute work. Plain Language Summaries therefore need to be planned and authored in parallel with clinical study reports (CSRs), not added at the end of the reporting process.
In practice, EU CTR has reframed Plain Language Summaries as regulated deliverables with defined scope, content, and deadlines.
CTIS Submission and Operational Reality
In the Clinical Trials Information System, or the CTIS, Plain Language Summaries are submitted alongside technical trial results. This operational coupling often exposes gaps in internal processes.
CTIS is the EU’s central portal and public database for clinical trials under the EU Clinical Trials Regulation. Sponsors use CTIS to manage regulatory submissions and to publish trial information and results, including Plain Language Summaries, for public access.
Practical CTIS submission tips include the following:
- Upload the PLS in the trial CTIS record under the ‘trial results’ area, using the layperson summary placeholder (alongside the technical summary of results).
- Use the EU CT number to locate the correct trial record, then add the document to the layperson summary of results placeholder and complete the save/submit steps required in CTIS.
- Treat ‘trial completion’ as a controlled milestone in your disclosure plan, because the results package and layperson summary are expected within the EU CTR timelines once the trial ends.
Subsequently, some common pitfalls to keep in mind include:
- Avoid uploading to the wrong trial record (mis-keyed or out-of-date identifiers).
- Avoid late authoring and weak version control, which can delay submission and drive rework.
- Avoid readability issues and unexplained terminology by writing for non-specialist readers, not CSR-style audiences.
- Avoid inconsistent terminology between technical results and the plain language summary, which can create misalignment.
- Avoid leaving submission until the end, creating avoidable rework against fixed timelines.
In practice, organisations that manage CTIS submissions effectively treat PLS as part of an integrated disclosure workflow. Responsibilities are clearly defined, timelines are aligned across teams, and CTIS requirements are understood early. This reduces rework, avoids missed deadlines, and supports consistent quality.
Why Plain Language Summaries Matter Beyond Compliance
Regulatory compliance is the baseline requirement. The broader value of Plain Language Summaries lies in what they reveal about an organisation’s approach to research, communication, and accountability.
PLS support transparency by making trial outcomes accessible to participants and the public. They contribute to patient empowerment by explaining not only what happened, but why the research was undertaken and what the results may mean. They also support public trust by demonstrating openness about both benefits and risks.
Poorly written Plain Language Summaries carry risk. They can confuse readers, invite misinterpretation, and undermine confidence in the research itself. For sponsors, this may translate into reputational impact, regulatory questions, or avoidable rework.
Viewed strategically, PLS form part of a sponsor’s scientific and ethical identity, not merely an administrative obligation.
How to Write a Plain Language Summary: A Strategic Checklist
Effective Plain Language Summaries are driven by reader needs rather than internal document structures. While wording and emphasis will vary, most strong PLS address the same core elements:
- Purpose: Why was the study done?
- Who, where, and why: Who took part, where the study took place, and why the question mattered.
- What happened: What treatments or interventions were studied, described simply.
- Results: The main findings, explained clearly and without unnecessary statistical detail.
- Harms and side effects: What safety issues were seen, presented honestly and neutrally.
- Next steps: What the results mean for future research or patient care.
This approach shifts the emphasis from reporting to communication.
Readability, Lay Testing, and Evidence of Understanding
Plain language can be assessed and improved systematically. Readability tools, such as the Flesch Reading Ease score, provide an objective check on sentence length and word complexity.
However, numerical scores alone do not guarantee understanding. Lay-reader testing focuses on whether non-specialist readers can accurately explain the content in their own words. This type of testing highlights ambiguity, unexplained concepts, and assumptions that automated tools cannot detect.
Governance for PLS: From Ad Hoc Activity to Embedded Practice
Treating Plain Language Summaries as an afterthought increases operational and compliance risk. Treating them as a standard medical writing deliverable improves control and consistency.
Effective governance typically includes defined author and reviewer roles, structured version management, and focused quality checks for neutrality, balance, and readability.
In practice, this approach signals organisational maturity. It reflects an understanding that transparency is a continuous consideration across the study lifecycle, not a final administrative step.
Patient and public involvement (PPI) is increasingly recognised as good practice in the development and review of Plain Language Summaries.
Robust governance includes documenting PPI feedback and recording how decisions were made. This supports transparency, audit readiness, and alignment with wider expectations for patient involvement in research.
Plain Language Summaries for Publications (PLS(P))
Text-based Plain Language Summaries remain the standard format for CTIS submission. Other formats can add value when used with clear intent and appropriate governance.
- Text PLS: The foundation for regulatory compliance and suitable for most trials.
- Graphical summaries: Visual elements can support understanding of complex designs or outcomes, but should complement, not replace, clear text.
- Standalone Plain Language Summary Publications (PLS(P)): Designed for wider dissemination beyond regulatory systems.
Format choice should be guided by audience needs, regulatory context, and internal capability, rather than design preference alone.
Plain Language Summaries for publications, often referred to as PLS(P), extend the principles of accessibility into the scientific publishing landscape. They are typically published alongside journal articles or as linked, standalone outputs.
PLS(P) are intended for readers who encounter trial results through journals, repositories, or advocacy platforms rather than regulatory databases.
When developed thoughtfully, PLS(P) can increase the reach and understanding of published research and help bridge the gap between peer-reviewed literature and patient-facing communication. Depending on journal practice, they may be published as standalone outputs, linked to the primary article, and in some cases indexed or associated with a digital object identifier (DOI).
PLS(P) governance remains critical. They must remain neutral, balanced, and aligned with the underlying publication, with clear linkage between technical and plain language outputs to avoid misinterpretation or selective emphasis.
Example Plain Language Summary Outline
If you need an outline that more explicitly mirrors Annex V, a short template might include the following:
1. Trial identification (trial title, protocol number, EU CT number, other identifiers)
2. Sponsor details (name and contact information)
3. General information about the trial (what the trial studied, where/when it ran, and its main aim)
4. Who took part (who was eligible, how many people took part, and basic participant characteristics)
5. What treatments were studied (study treatments and comparators, described simply)
6. Side effects and adverse reactions (what happened and how often, in neutral language)
7. Overall results (main findings, explained clearly)
8. Comments on the outcome (what the results mean and key limitations, without promotion)
9. Follow-up research (whether further studies are planned)
10. Where to find more information (registry identifiers and/or sponsor information sources)
This structure keeps attention on reader questions rather than internal reporting conventions.
Conclusion
Plain Language Summaries now sit at the intersection of regulation, ethics, and public expectation. They are no longer isolated disclosure tasks, but indicators of how thoughtfully a sponsor approaches transparency and communication.
Organisations that plan PLS early, govern them clearly, and involve patients meaningfully are better positioned to meet EU CTR requirements with confidence. More importantly, they help create a research environment where results are shared responsibly and understood beyond specialist audiences.
At QInscribe, we help sponsors plan, write, and govern Plain Language Summaries that meet EU CTR expectations and work in practice within CTIS timelines. If you need support building a scalable PLS workflow, request a consultation and a member of our team will be in touch.