06/01/2026  |  Gareth Macdonald  |  BioXconomy

https://www.bioxconomy.com/clinical-and-research/faster-approvals-only-half-the-battle-eu-trials-need-adaptive-protocols- 

Streamlined approvals alone won't fix Europe's clinical trial challenges, researchers say, pointing to enrollment problems and inflexible study designs.

Faster approvals only half the battle: Adaptive protocol would aid EU trials sector

Streamlined trial approvals would only solve one of the challenges firms face when testing drugs in Europe, say the authors of a study, who argue that operational issues like poor enrollment and rigid protocols are a bigger problem.

The study—published in Clinical Microbiology and Infection—shows that while initiatives like Accelerating Clinical Trials in the European Union (ACT-EU) are a positive move, there are other issues to be addressed.

“Even when hurdles in trial initiation are overcome, challenges remain: up to one-third of clinical trials are terminated prematurely, primarily due to operational issues such as poor enrolment. 

“It is a serious issue when valuable public resources are used for well-designed trials addressing important research questions, only for those to fail to deliver results,” they wrote.

Adaptive trials
Flexibility, or the lack thereof, is another challenge for Europe’s trials sector, according to the authors, who suggest greater regulatory support for adaptive protocols—that evolve while the study is ongoing—would be beneficial.

“As more trials adopt flexible structures to accommodate change, this represents a paradigm shift: rather than developing a new trial for each new research question, adaptive designs can in principle run perpetually and rely on frequent, structured adaptations. 

“Consequently, the regulatory focus shifts from the initial application to ongoing review of changes within an active trial,” they wrote.

Adaptive protocols can be particularly important in health emergencies, according to the authors, who cited CoVacc, a pediatric trial comparing different COVID-19 vaccine regimens conducted during the pandemic, as an example.

“The challenges faced by CoVacc … serve as an illustration of the tension between traditional trial processes and the rapidly evolving context of an emerging infectious disease. Multiple protocol updates were required in response to rapidly changing standards of care, vaccination policies, and epidemiological trends.

“Therefore,” they continued, “protocols for public health emergencies should be designed in a more agile way upfront.” 

Such agile designs would include “modular elements” that set out pathways for changes to, for example, eligibility criteria or sampling procedures in response to evolving epidemiology.