MarketWatch - Mar. 06, 2008 - Britain's top drug regulator on Thursday chided GlaxoSmithKline for not quickly releasing data on increased suicidal risk in patients under 18 who used its Seroxat antidepressant drug, but declined to press criminal charges.

The Medicines and Healthcare products Regulatory Agency, after four years of investigating and poring over one million pages of evidence, said there wasn't a "realistic" prospect that it could get a criminal conviction of GlaxoSmithKline GSKGSK.

The regulator said the law at the time -- 2003 -- wasn't clear enough. In particular, the MHRA said the rules for disclosing data on drug use outside of its license were too muddy to win a prosecution.

Drugmakers seek "indications" for particular use -- in Seroxat's instance, for treating depression in adults -- but often those drugs are prescribed, legally, for alternative uses, or so-called "off-label" use.

Up to 8,000 under-18s were taking Seroxat, called Paxil in the U.S., for depression, the regulator said.

Laws have subsequently been changed to require drugmakers to report adverse reactions in any clinical trial, though these rules don't apply outside of Europe -- and most of Glaxo's trials on Seroxat were conducted in the United States.

The MHRA said it will press for a law change in the U.K. and eventually Europe to force drugmakers to report adverse clinical data no matter where trials are conducted.

But the regulator did criticize GlaxoSmithKline in the report.

"I remain concerned that GSK could and should have reported this information earlier than they did," said Kent Woods, MHRA chief executive, in a statement.

A message left with GlaxoSmithKline wasn't immediately returned.

Shares in the drugmaker fell 1.8% in London. Seroxat and Paxil sales totaled 553 million pounds ($1.1 billion) last year, down 6% at constant currencies.