REQUIREMENT

Plain language summaries, at portfolio scale.

Every EU trial owes a plain language summary clinical trial participants can actually read — in their languages, on a deadline. TrialAssure® runs a proven workflow for delivering them.

Last verified October 2026 against primary sources.

At a glance

Authority
European Medicines Agency (runs the CTIS database) and EU/EEA Member States; the European Commission publishes the GLSP guidance in EudraLex Volume 10
Legal basis
Regulation (EU) No 536/2014 (EU CTR), Article 37(4) and Annex V; Good Lay Summary Practice guidance (EudraLex Vol. 10, 4 October 2021)
Applies to
Every interventional clinical trial of a medicinal product conducted in the EU/EEA under the EU CTR — irrespective of outcome, including trials terminated early
Trigger
End of trial in all Member States concerned — last visit of the last subject or a later protocol-defined time point (Article 2(2)), or the early-termination date under Article 37(7)
Deadline(s)
12 months from trial end; 6 months where the trial includes pediatric participants; 1 year from any protocol-defined intermediate data analysis date (Article 37(8))
Language & readability
EU guidance recommends the local official language(s) of every trial country, matching PIS/ICF languages; text readable from age 12 per GLSP
Enforcement
Member State penalties under Article 94 — ‘effective, proportionate and dissuasive’; non-submission of information intended for the public EU database is explicitly named as an infringement
Status & key dates
Fully in force: CTR applied 31 Jan 2022; CTIS mandatory for new applications 31 Jan 2023; all ongoing EU trials in CTIS since 31 Jan 2025; revised transparency rules (deferrals removed) since 18 June 2024

Who reads these

A participant, not a regulator.

Plain language summaries are the one document written for the people who joined the trial. Drafting for readability from the start is what makes them readable.

Deadlines that matter

Event Deadline Notes
Trial ends in all Member States concerned (adult trial) 12 months Article 37(4): lay summary (Annex V content) plus scientific summary of results (Annex IV content), both submitted to the EU database (CTIS)
Trial includes pediatric participants 6 months from trial end Per EMA CTIS guidance (EMA/441151/2024, 10 Dec 2024) — half the adult clock, same content requirements
Protocol defines an intermediate data analysis date 1 year from that analysis date Article 37(8): a plain language summary of those results is due in addition to — not instead of — the end-of-trial submission
Early termination of the trial 12/6-month clock starts at the termination date Article 37(7): the early-termination date is deemed the end-of-trial date; stopped trials still owe a lay summary
Results not possible within 12 months for scientific reasons As soon as results are available Article 37(4): only if the protocol already specifies when results will be submitted, with justification — not a discretionary after-the-fact extension
Marketing authorisation granted, procedure completed, or application withdrawn Clinical study report to CTIS within 30 days Article 37(4); obligation sits with the marketing authorisation applicant
Publication on the CTIS public portal Upon submission (Category 1 adult-only trials: 30 months after EU/EEA trial end) Under revised transparency rules applicable since 18 June 2024; the deferral mechanism is gone and redaction is the only protection for personal data and CCI

Regulatory guidance changes. Deadlines and requirements shown here are a summary, not legal advice — confirm them against the current text published by the relevant authority before you rely on them for a submission.

When is your lay summary due?

  • Lay summary due in CTIS In local languages of participating countries +12 months
  • Pediatric trials Shortened clock for trials in minors +6 months
  • Scientifically justified exception Later submission may apply when specified and justified in the protocol —

Informational only — confirm against the regulation and your regulatory counsel.

Regulatory guidance changes. Deadlines and requirements shown here are a summary, not legal advice — confirm them against the current text published by the relevant authority before you rely on them for a submission.

The compliance workflow

  1. Plan the lay summary at protocol stage.

    GLSP’s first step: scope languages, budget, template, and patient involvement while the protocol is being written. If scientific reasons will push results past 12 months, the protocol itself must say when results will come and why — you cannot add that justification later.

  2. Draft to Annex V and health-literacy standards.

    Cover all 10 of the Annex V lay summary requirements — order can change, content cannot. Write for readers aged 12 and up, in neutral non-promotional language, applying numeracy principles: use clear, understandable numbers and present them consistently for the intended audience.

  3. Review and user-test with laypeople.

    Pair medical-writer accuracy review with user testing by people unfamiliar with clinical research, as GLSP recommends. Readability formulas such as Flesch–Kincaid are a supplement to gauge reading level, not a substitute for testing with real readers.

  4. Translate into each trial country’s language.

    EU Expert Group recommendations call for, at minimum, the local official language(s) of every country where the trial ran, matching the PIS/ICF languages. GLSP recommends qualified medical translators, optional back-translation as QC, and user testing of translated versions.

  5. Submit to CTIS and run the clock portfolio-wide.

    Upload the lay summary EU CTR Article 37(4) requires, plus its translations, to CTIS within 12 months of trial end (6 for pediatric trials) unless the scientifically justified exception applies, and disseminate per your plan. Every completing trial adds to the queue, so track end-of-trial dates and due dates across the whole portfolio, not per study.

Lay summary: what the EU requires and the US does not

A narrower question than the full EU/US comparison — whether the lay summary EU CTR sponsors owe has any US counterpart at all. For the two disclosure regimes side by side, see the EU CTR page.

Dimension EU CTR lay summary (Annex V) ClinicalTrials.gov results (FDAAA 801)
Is a lay summary required? Yes — mandatory, covering the ten elements set out in Annex V. No. ClinicalTrials.gov requires structured tabular results; no plain-language summary is required at all.
Who it is written for Laypersons. Readability is the standard the summary is judged against, and translation into the languages of the trial countries is recommended. No lay audience is specified — the required output is the registry record itself (42 CFR 11.48).
Deadline 12 months from end of trial in all Member States concerned; 6 months where pediatric participants are included. 12 months after the primary completion date; a delay certification for an unapproved product can push it to 2 years.
What it sits alongside The Annex IV summary of results written for a scientific audience — both are published, so the same trial is described twice for two audiences. Nothing — participant flow, demographics, outcome measures and adverse-event tables, plus the protocol and statistical analysis plan, are the whole deliverable.
Enforcement Set by each Member State under Article 94, which requires penalties that are “effective, proportionate and dissuasive” — there is no EU-wide fixed fine. FDA pre-notices, notices of noncompliance and civil money penalties of up to $10,000, plus up to $10,000 for every day a violation stays uncorrected after FDA’s notice: $15,107 a day with the 2025 inflation adjustment (21 U.S.C. 333(f)(3)).

Where they agree Both clocks run from the trial’s own end rather than from the publication of a paper, and in both regimes the obligation sits with the sponsor.

Daiichi Sankyo · flagship

Daiichi Sankyo pairs LINK AI drafting with TrialAssure’s medical writers

Up to 80%
faster delivery
~50%
lower cost/document
Read the case study →
LINK AI editor for a plain language summary of protocol PRM001: beside the template, the Rationale section’s prompt asks for lay language without technical terms, and LINK AI answers why the study was done in plain words.

Last reviewed: October 1, 2026

What is a Plain Language Summary under EU CTR Annex V?

A plain language summary — the EU CTR’s ‘summary for laypersons’ — is a results summary every interventional clinical trial of a medicine in the EU/EEA must submit to CTIS under Article 37(4) of Regulation (EU) No 536/2014. It must cover the 10 content elements of Annex V, be understandable to laypersons, and be submitted within 12 months of trial end unless a scientifically justified later submission is specified in the protocol.

What the PLS obligation actually is

The EU CTR requires a summary of results written for laypersons within 12 months of trial end (6 months for pediatric trials), unless the scientifically justified exception in Article 37(4) applies. EU guidance then expects it in the local official language(s) of each participating country. Beyond the EU, PLS is becoming the industry’s default expression of respect for participants: people who joined your trial deserve to learn what it found, in words they can use.

What that means operationally

The workflow that’s already public

LINK AI drafts the PLS from your results data; medical writers — yours or ours — review for accuracy and readability; translations follow; REGISTRY handles posting and the clock. This is a named, published workflow that Sponsor clients run: up to 80% faster delivery, around 50% lower cost per document, partnership renewed.

Plain Language Summaries — frequently asked questions

Who writes plain language summaries for clinical trials?

The obligation to deliver a plain language summary clinical trial participants can trust sits with the sponsor, but the drafting can be shared. TrialAssure LINK® AI produces the first draft from your results data, then professional medical writers — ours or your own — review every statement for scientific accuracy and readability before sign-off; translation and delivery follow in the same pipeline. This is the named, published workflow Daiichi Sankyo runs, reporting PLS delivery up to 80% faster at around 50% lower cost per document. AI removes the blank page. It does not remove the writer, or the accountability that comes with the byline.

What are the Annex V lay summary requirements under the EU CTR?

A layperson summary of the results, submitted to CTIS within 12 months of trial end — 6 months where the trial includes pediatric participants. Content follows the 10 elements of Annex V to Regulation (EU) No 536/2014 — among them what the trial looked at, who took part, what was found, what side effects occurred, and where to read more. The order can change; the coverage cannot. It is submitted alongside the Annex IV scientific summary, in the local official language(s) of each participating country as EU guidance recommends, and Good Lay Summary Practice sets the readability bar.

Can our writers stay in control?

That’s the design: AI produces the draft, and your writers (or ours) make every decision and sign off. Cancer Research UK’s Centre for Drug Development runs it exactly that way, with its own medical writers central to every review. LINK AI drafts inside Microsoft Word on your own templates, and each generated statement carries a reference back to the source it came from — so a reviewer verifies a claim instead of trusting it. Every transformation is logged and attributable. That is what AI Enabled. Human Driven.™ means in practice.

Do you handle translations?

Yes. Drafting, medical-writer review, translation into the local official language(s) of your trial countries, and delivery run as one pipeline — so a lay summary doesn’t stall waiting on a separate translation vendor. Good Lay Summary Practice treats translation into every trial-country language as good practice and expects translated versions to be readable, not merely accurate, which is why they warrant user testing rather than a back-translation check alone. Scope the language list at protocol stage: languages discovered late are what turn a comfortable 12-month clock into a missed one.

A layperson summary of what, exactly?

Results summaries first — that is the EU CTR deliverable — but also plain language versions of publications, protocols, and informed consent forms. LINK AI covers the whole family because the underlying job is the same: restate a technical source document at a lay reading level without changing what it says or adding anything it does not support. Only the results summary is a legal obligation under Article 37(4); the others are usually driven by journal policy, patient-group commitments, or ethics committee expectations.

Which clinical trials must submit a lay summary under the EU CTR?

Every interventional clinical trial of a medicinal product conducted in the EU/EEA under Regulation (EU) No 536/2014 owes a lay summary — irrespective of the trial’s outcome. That includes low-intervention trials and trials that stop early: under Article 37(7), the early-termination date becomes the end-of-trial date and starts the same 12-month clock (6 months where pediatric participants are involved). Non-interventional studies and trials run entirely outside the EU/EEA fall outside Article 37(4).

What happens if a sponsor misses the lay summary deadline?

Missing the deadline is an infringement each Member State can penalize under Article 94 of the EU CTR, which requires penalties that are ‘effective, proportionate and dissuasive’ and explicitly names failure to submit information intended for the public EU database. There is no EU-level fine schedule — exposure varies by country. The gap is also visible: CTIS publicly shows each trial’s end date, so an overdue summary is plain to regulators and patients. TrialAssure REGISTRY exists to keep that queue visible before it becomes a finding.

When is the lay summary published on the CTIS public portal?

Immediately on submission, in most cases. Since the revised CTIS transparency rules took effect on 18 June 2024, results documents are published as soon as the sponsor uploads them — the old deferral mechanism is gone, and redaction is the only remaining protection for personal data and commercially confidential information. The one exception: results of ‘Category 1’ trials conducted solely in adults are published 30 months after the EU/EEA end-of-trial date.

Can the 12-month lay summary deadline be extended?

Only if the protocol already provides for it. Article 37(4) permits later submission solely for scientific reasons detailed in the protocol — the protocol must specify when results will be submitted and justify why, and the summary is then due as soon as it is available. There is no discretionary extension request after the fact. Separately, Article 37(8) adds a clock: if the protocol sets an intermediate data analysis date, a summary of those results is due within one year of that date.

What reading level should a plain language summary target?

Understandable to readers aged 12 and up, per the EU Expert Group recommendations adopted in Good Lay Summary Practice (GLSP, EudraLex Volume 10, October 2021). GLSP calls for conversational language, health-numeracy principles — whole numbers, consistent denominators, no calculations left to the reader — user testing with laypeople, and readability formulas like Flesch–Kincaid only as a supplement. TrialAssure LINK AI drafts to these health-literacy standards, with medical writers reviewing every summary before it ships.

Does the EU CTR require the lay summary in every EU language?

No. Regulation 536/2014 does not itself mandate translations. The EU Expert Group on Clinical Trials recommends, at minimum, the local official language(s) of each country where the trial took place, matching the languages of the Patient Information Sheet and Informed Consent Form — and GLSP treats translation into all trial-country languages as good practice, with user testing of translated versions. An English version is suggested where resources allow, for accessibility across the EU.

Have our medical writers run your lay summaries

Tell us the shape of the work in the scope box: how many trials are completing, which countries they ran in, and when each 12-month clock runs out (6 months where pediatric participants are involved). We come back with who would draft, review, translate, and get each Annex V lay summary into CTIS, what the work takes, and how soon we can start. A medical writer replies within one business day.

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