EU Clinical Trials Regulation Has Governed All EU Trials Since 31 January 2025

The Clinical Trials Regulation, Regulation (EU) No 536/2014, replaced the earlier Clinical Trials Directive with a single set of rules for authorising and supervising clinical trials of medicinal products across the EU. Its application was followed by a three-year transition period, during which trials authorised under the Directive could continue under the old rules. That period ended in January 2025.

In its announcement dated 31 January 2025, the European Medicines Agency stated that from that date all clinical trials in the EU, including ongoing trials authorised under the previous framework, are subject to the Clinical Trials Regulation. The Clinical Trials Information System (CTIS) now supports the submission, assessment and oversight of all trials in the EU, and it includes a public searchable database intended for healthcare professionals, patients and the general public. A published copy of the EMA release reports that more than 5,000 trials were transitioned to the Regulation through CTIS during the transition period.

Transition was required only for Directive trials that had an expected completion date after 30 January 2025 and at least one active site in the EU or EEA after that date. EMA had advised sponsors to allow for Member State authorisation of a transition, which could take up to three months.

According to EMA, trials that remained ongoing after 30 January 2025 without having been moved to the new system may be subject to corrective measures applied by EU Member States. The simplified transition procedure is no longer available. Sponsors of ongoing Directive trials must instead submit a new application through CTIS, which is assessed under the full procedures of the Regulation.

For sponsors, this means that every new trial, every substantial modification and all required safety and results reporting for EU trials now run through CTIS under a single legal framework. Because CTIS includes a public searchable database, sponsors should expect information submitted for their trials to be visible to healthcare professionals, patients and the public.

Sponsors that still hold legacy Directive authorisations in their portfolio, for example for long-term follow-up studies, should confirm whether those trials met the transition criteria and, if they did and were not transitioned, take advice from the relevant national competent authorities on the steps required.

In December 2025 the European Commission proposed the European Biotech Act, which includes targeted amendments to Regulation (EU) No 536/2014. A Council working document published in 2026 shows the Regulation as it would be amended. Law firm and industry summaries report that the proposal would apply to all clinical trials of medicinal products, whether biological or chemical, and would shorten the approval timeline for multinational trials from about 106 days to about 75 days. They also report a reduction in the assessment timeline for substantial modifications from 96 days to 47 days, removal of the additional 50-day assessment step for advanced therapy trials, a minimal-intervention trial category requiring only ethics approval, and a harmonised legal basis under the GDPR for processing trial data.

These changes are not yet law. The file is being handled under the ordinary legislative procedure (2025/0406(COD)). Secondary sources checked for this brief gave differing timetables: one reported that lead committees in the European Parliament were expected to vote in December 2026, with a plenary vote around the end of 2026 or in early 2027, and another reported an EMA expectation that the first changes to the Clinical Trials Regulation could apply no earlier than early 2028. The current stage should be confirmed in the Legislative Observatory and Council records before planning around any proposed timeline.

Sponsors should treat CTIS as the sole route for EU trial applications and maintain internal processes for the Regulation’s timelines, Protocol and lay summary authors should prepare documents with publication in mind, because CTIS makes much trial information public.

Teams planning trials for 2027 and beyond should monitor the Biotech Act negotiations, since shorter assessment timelines and a new minimal-intervention category could affect submission planning and site activation estimates once adopted and applicable. Until then, the Regulation as it currently stands, together with the guidance and question-and-answer documents published for CTIS users, remains the basis for planning EU trial submissions.