Plain Language Summaries in Clinical Trials: Regulatory Requirements and Best Practice

Plain language summaries (PLSs) play a vital role in making clinical trial results accessible to patients, caregivers and the wider public, while also meeting increasingly robust transparency requirements. In this blog, Laura Erwin explores why PLSs are now a regulatory and ethical priority for sponsors, and shares practical guidance on how to plan, write and quality-check summaries that are both compliant and genuinely meaningful for their intended audience.

Plain Language Summaries translate clinical trial results into clear, non‑technical language so patients, caregivers and the public can understand what was studied, why it mattered, and what the results mean for everyday life.

Regulatory mandates for plain language summaries

For sponsors, a PLS is now both an ethical responsibility and a regulatory deliverable: under EU Regulation 536/2014 sponsors must provide a PLS for all interventional clinical trials conducted in the EU/EEA, submit it to the Clinical Trials Information System (CTIS), and meet timing requirements (within 12 months of trial end; 6 months for paediatric trials). The revival of EMA transparency initiatives since 2022 has reinforced that PLSs are integral to publication plans and that sponsors must prepare clinical documents for public release while carefully managing redactions and confidentiality.

What sponsors should prioritise operationally

Operationally, sponsors should embed PLS planning into the study setup and master schedule, assigning clear roles for drafting, medical review, redaction/legal review, and final sign‑off. Starting a plain‑language outline early and updating it as data mature reduces the risk of last‑minute bottlenecks after database lock. It is essential to build a redaction workflow that aligns with publication timelines and privacy obligations, and to keep an audit trail documenting who prepared, reviewed and approved each PLS, for inspection readiness purposes. Sponsors should budget for and plan short patient or caregiver review cycles; even two to five targeted cognitive interviews will quickly reveal unclear phrasing and missing context and will strengthen the approval record.

Medical writing practices that deliver clarity and compliance

From a medical‑writing perspective there are several best practices to help ensure PLS meet regulatory expectations and minimize revisions throughout review cycles, define the target audience up front – trial participants, patients with the condition, caregivers or the general public – and tailor the tone, examples and level of detail accordingly. Structure the PLS around the simple questions readers instinctively ask: who participated, what was tested, when and where the study happened, why the trial was done, and what the results were. Lead with the most important takeaway, then provide brief context. Use everyday vocabulary, active voice, short sentences and concrete verbs; avoid jargon and, when a technical term is unavoidable, define it in one clear clause. Present only the numbers that help readers grasp magnitude and impact and frame them in relatable terms (for example, “about 1 in 5 people” rather than “20%”). When reporting results, state the outcome, the size of the effect and the practical implication for patients; include safety information and limitations in a concise, understandable way without reproducing full methodological nuance.

Quality control and testing

Quality control should combine automated readability checks with human review. Use readability tools as an early pass, then run short testing with representative readers and focused cross‑functional review rounds that separate clarity, accuracy and compliance checkpoints; keep review cycles limited and purposeful to avoid iterative delays. Actively involving people with lived experience during draft development and review brings practical insights that improve relevance and usability, these contributors help identify unclear concepts, preferred words and layout choices that resonate with the intended audience, and they can flag assumptions writers may take for granted. Rapid, small‑scale interviews or panels often reveal phrasing and informational gaps far faster than additional internal edits, and their feedback strengthens the summary’s usefulness for real readers. Maintain strict version control, capture review comments and approvals, and ensure the documentation needed for CTIS submission and inspection readiness is complete. In practice, sponsors should plan early, balance clarity with accuracy, test drafts with representative readers, and use regulatory‑aligned templates and checklists to reduce risk and maximise the PLS’s value for patients and caregivers.

Expert guidance

A well-crafted PLS does more than translate results – it connects research with the people it is meant to help, improving transparency, empowering participants and building public trust. If you need support producing clear, compliant PLSs that meet regulatory expectations and resonate with patients, our team can help. Boyds specialise in translating technical study results into accessible, patient-centred summaries while aligning with evolving transparency requirements across regions. Whether you need strategic guidance, regulatory-aligned templates or hands-on medical writing and patient testing, contact us to discuss how we can make your next PLS clear, compliant and publication-ready.