EU wants more transparency on AbbVie's Humira, world's top drug

London : Details of clinical trials involving AbbVie's rheumatoid arthritis drug Humira, the world's top-selling prescription medicine, are still being withheld without justification, according to the European Union's ombudsman.

Humira has been at the center of a protracted transparency row for several years, with AbbVie battling to keep some data secret in the face of plans by the European Medicines Agency (EMA) to make the information routinely available.

Many doctors and campaigners argue that free access to data is essential to inform medical decision-making and allow independent experts to test claims made about drugs.

Two years ago, AbbVie dropped a lawsuit against the EMA after the agency agreed to certain data redactions, resulting in the disclosure of some but not all of the information held by the EMA about Humira.

European Ombudsman Emily O'Reilly said on Friday that this was not good enough and the EMA was still withholding details from clinical trial reports on the grounds of commercial interest.

O'Reilly said public health was more important than commercial interest and she considered four specific redactions to be unjustified.

"I am asking EMA to reconsider the need for these redactions should it receive new requests for access to these reports," she said in a statement.

"Any clinical information of value to doctors, patients and researchers must be disclosed in the public interest."

The role of the ombudsman is to investigate complaints about maladministration in EU institutions.

The London-based EMA said it was pleased O'Reilly had found no maladministration in its handling of the matter, adding there was no agreed definition of commercially confidential data and that specific commercial interests would change over time.

An AbbVie spokeswoman said the U.S. drugmaker was committed to "responsible" transparency but there was a need to protect commercially confidential information.

Drug companies around the world have come under increasing pressure to provide full disclosure of clinical trial results in recent years, following complaints that they have tried in the past to bury bad news.

The EMA has taken a lead in pushing for transparency, since pledging in 2010 to lift the lid on previously secret trial data submitted by companies as part of the application process for new medicines.

That process was then stalled by the legal tussle with AbbVie and other U.S. company InterMune, which is now part of Roche.

(Reporting by Ben Hirschler; Editing by Susan Fenton)