BRUSSELS—Researchers will have to disclose the results of clinical trials conducted in the European Union under a provisional agreement reached here today . Representatives of the European Union's 28 member states have approved a deal with the European Parliament—a decisive step forward as part of a wider reform to simplify and speed up authorization procedures for clinical trials across the bloc.

Advocates for easier public access to clinical trial results have praised the outcome of the negotiations, which they say sets a global example. Today's agreement is “a fantastic result at a very important stage of negotiation,” the AllTrials campaign in the United Kingdom said in a statement .

Between 2007 and 2011, the number of applications for clinical trials in the European Union dropped by 25%. In July last year, the European Commission tabled a proposal to overhaul the European Union's unpopular 2001 clinical trials directive to cut down on red tape, make Europe a more attractive location for clinical research, and improve the transparency of clinical trials information.

As the proposal moved forward through the E.U. system, activists succeeded in convincing E.U. policymakers to include further changes that help ensure that trial outcomes are made public whether the sponsor prefers to do so. One of the most notable novelties is a requirement to publish every trial's results in a database managed by the European Medicines Agency. “Irrespective of the outcome of the clinical trial, within one year from the end of a clinical trial in all member states concerned, the sponsor shall submit to the EU database a summary of the results of the clinical trial,” says the draft agreement, seen by ScienceInsider. This should also include a summary “written in a manner that is understandable to lay persons.”

In addition, if trials results are used as part of a marketing authorization application for a medicinal product, researchers must submit clinical study reports within 30 days after the end of the authorization process—whether the application is successful, rejected, or withdrawn.

Glenis Willmott, a center-left member of the European Parliament from the United Kingdom who led the negotiations on the Parliament's side, says the regulation would force the hand of drugmakers reluctant to disclose results . “For too long unflattering studies have gone undisclosed. Around half of all trials are never published, usually those with negative or disappointing results,” Willmott said in a statement issued before the vote .

The compromise maintains the main elements of the commission's initial plan for simplification. For example, one single application file will be enough to conduct clinical trials in several member states, instead of submitting an application in each country.

But the draft regulation softens some of the commission's bold proposals to expedite authorization decisions. The pharmaceutical industry prefers countries to make decisions about clinical trials fast, but member states are wary of excessive time pressure that might lead to botched assessments. Under the draft regulation, member states have to reach decisions on trial applications within 60 days—if not, the trials will be automatically approved.

The BioIndustry Association, a trade association in the United Kingdom, points out that this period can be extended to more than 100 days in the case of trials involving “advanced therapy medicinal products.” (This includes products using recombinant DNA technology and monoclonal antibody methods, among others.) That "is unlikely to boost clinical research in the EU,” said Steve Bates, the association's chief executive officer, in a statement released after the vote .

Before the regulation can be rolled out, today's agreement must be confirmed formally by the Council of Ministers and the European Parliament plenary. Willmott said this process could be finalized before the European elections in May.