* U.S. firms seeking to block release of drug data by EMA
* EU's top court refers case back to lower court
By Ben Hirschler
LONDON, Dec 5 (Reuters) - A legal case over access to details of clinical trials held by Europe's drugs regulator - sparked by two U.S. firms wanting to keep their data secret - has been hit by delay after the EU's top court sent it back to be re-examined by a lower body.
The decision leaves in limbo a high-profile fight that has pitched the European Medicines Agency (EMA), Europe's equivalent of the U.S. Food and Drug Administration, against AbbVie (Frankfurt: A1J84E - news) and InterMune.
Officials said on Thursday that the vice president of the European Court of Justice had annulled earlier interim orders preventing the release of data and had referred the matter back to the European Union's General Court for further consideration.
With the legal situation still uncertain, sensitive data from trials involving AbbVie's rheumatoid arthritis treatment Humira - the world's top-selling prescription medicine - and another drug from InterMune will remain under wraps for now.
Still, the London-based watchdog does not intend to let uncertainty in this case prevent it from continuing its policy of responding to outside requests for documents about clinical trials on other medicines.
The EMA has already released millions of pages of detailed clinical trial information about different drugs - an approach it says reflects growing public demands for more openness to ensure that drugmakers cannot conceal adverse side effects.
The vast majority of all documents released by the EMA - some 76 percent in the past 12 months, according to Harvey - have been handed over to academic groups and researchers.
AbbVie and InterMune argue in a case brought earlier this year that they have a right to the protection of their business secrets, since this information could be used by competitors.
Spokeswoman Fiona Olivier said AbbVie remained confident the General Court would rule in favour of upholding the provisional injunction, since the clinical study reports held by the EMA contained commercially confidential information.
AbbVie backed sharing of data with qualified researchers when this did not undermine its ability to innovate, she added.
Europe's medicines body has been on a collision course with parts of the pharmaceuticals industry since deciding to lift the lid on previously secret clinical trial data.
This data is routinely submitted by manufacturers as part of the application process for new medicines and, until recently, it had been view as confidential.
But in 2010 the European Ombudsman, which investigates complaints about EU institutions, ruled that the EMA should provide access to it - and the EMA plans to proactively release detailed data, rather than just waiting for requests, from 2014.
A number of drug companies have recently shifted their position towards more transparency in the face of this pressure from the agency and some stern critics in academia.
Pfizer (NYSE: PFE - news) , the largest U.S. pharmaceutical company, became the latest to take a step down this path on Wednesday by broadening access to information from its clinical trials to independent researchers and to patients.