Drug Safety Studies Failing to Publish Findings, BMJ Research Reveals

A new study published in the British Medical Journal has raised concerns about significant gaps in the transparency of post-authorisation safety studies (PASS) registered with the European Medicines Agency, with researchers finding that many approved medicines studies are failing to comply with legal requirements to make their findings publicly available.

Post-authorisation studies are an important part of medicines regulation, conducted after a drug has been approved for use to monitor its safety and effectiveness in real-world conditions. These studies can identify serious side effects that were not detected during initial clinical trials, or reveal how medicines perform in patient populations not included in original testing.

The research reveals a troubling pattern: only around six out of every ten finalised and ongoing post-authorisation studies had uploaded their protocols to publicly accessible registers, and fewer than seven out of ten had made their findings available as required. This lack of transparency means that healthcare professionals, patients, and regulators may not have access to crucial information about how medicines perform after they have entered widespread use.

The European Medicines Agency operates the EU Post-Authorisation Study Register (EU PAS Register) specifically to promote transparency in medicines monitoring. Under current European regulations, pharmaceutical companies are legally required to register these studies and, in many cases, to publish their results. The regulatory guidance emphasises that results should be made available to support transparency in decision-making and to help regulators evaluate whether medicines continue to meet safety and efficacy standards.

However, research examining regulatory outcomes for completed post-authorisation studies between 2012 and 2020 found significant inconsistencies. Whilst information availability has improved over time—increasing from 25 per cent for studies completed between 2012 and 2014 to 56 per cent for those completed between 2018 and 2020—substantial gaps remain. When information was available, it was often vague and lacking in detail, making it difficult for independent researchers or regulators to understand the actual findings or regulatory impact of these studies.

Across 84 post-authorisation studies examined in detail, fewer than half had identifiable regulatory outcomes documented anywhere on the EMA website or related regulatory documents. The lack of standardisation across different EMA sources—including meeting minutes, public assessment reports, and webpages—created additional barriers to accessing this information. Researchers noted that many studies were difficult to identify and track, hampered by the absence of unique identifiers and inconsistent record-keeping across regulatory platforms.

Interestingly, studies that were formally imposed by regulators as conditions of approval were more likely to have documented outcomes (78 per cent) compared to voluntary studies (34 per cent), suggesting that mandatory studies receive greater regulatory scrutiny and documentation.

The findings underscore a critical principle in medicines regulation: serious adverse drug reactions are sometimes only discovered after approval, when medicines are used across much larger and more diverse populations than those included in initial clinical trials. Post-authorisation studies serve as an early warning system, potentially identifying safety issues that could affect thousands of patients.

Without timely publication of study findings, healthcare professionals cannot make fully informed prescribing decisions, patients cannot make informed choices about their treatments, and regulators cannot take swift action if safety concerns emerge. The delay or failure to publish results also creates the potential for duplication of research effort, wasting resources and unnecessarily exposing additional research participants to studied interventions.

Researchers are calling for better adherence to transparency requirements, recommending several improvements: the introduction of unique identifiers for each post-authorisation study to facilitate tracking; complete and timely publication of regulatory outcomes; greater standardisation across EMA information platforms; and clearer communication about how individual studies influenced regulatory decisions.

The British Medical Journal research emphasises that improving transparency is not merely an administrative matter—it is fundamental to public trust in medicines regulation and to the safety monitoring systems designed to protect patients. Enhanced transparency would also support healthcare research more broadly, allowing independent researchers to access data needed for analysis and evidence synthesis.

Key Takeaways

• Many post-authorisation studies registered with the European Medicines Agency do not publish their findings as legally required
• Only around 60 per cent of finalised studies had uploaded protocols, and fewer than 70 per cent published their results
• Lack of transparency stems partly from inconsistent record-keeping and absence of unique study identifiers across regulatory platforms
• Better compliance is essential for patient safety, as post-authorisation studies identify side effects that emerge after medicines are widely used

What This Means for Kent Residents

For patients in Kent and across the UK, these findings highlight the importance of robust medicines monitoring systems. Whilst the EMA oversees licensing at the European level, the UK Health Security Agency and NHS England work with the Medicines and Healthcare products Regulatory Agency to monitor medicines safety within the UK health service. Any delays or gaps in transparency around post-authorisation study findings can indirectly affect how medicines are prescribed and monitored in NHS settings across Kent and Medway. Kent residents who have concerns about a medicine they are taking can report adverse effects through their GP or directly via the Yellow Card scheme run by the UK medicines regulator. Improved transparency at the European level will ultimately strengthen the evidence base available to NHS clinicians when making treatment decisions.