The much-disputed European directive on clinical trials went into effect on 1 May (Nat. Med. 9, 1336; 2003), but some experts are warning against the restricted access provided to its new clinical trial database.

The database will include general information on a clinical trial, recommendations of the trial's ethics committee and any amendments to the protocol. At the end of the trial, researchers must also enter whether a trial ended early because of safety issues or lack of efficacy. To maintain confidentiality, the directive stipulates that the database will be accessible only to the relevant authorities of the states, the London-based European Agency for the Evaluation of Medicinal Products and the European Commission.

Because the database is not available to other researchers or to the public, however, experts warn that it will allow scientists to selectively publish favorable results.

“This is a missed chance to disclose the information which can prevent us from using biased information,” says Frank Buntinx, president of the Centre for Evidence-Based Medicine in Leuven, Belgium.

The directive has strong support from pharmaceutical companies. “Only authorities should have access to the database since the information could be of high economic value for other pharmaceutical companies,” says Uwe Dolderer, a spokesman for the German Pharmaceutical Industry Association.

Buntinx notes that similar information, from both publicly and privately funded trials, is freely available in the US as a result of increasing concerns over the nondisclosure of negative studies and early termination of trials.