LONDON U.S. regulators have rejected GlaxoSmithKline (GSK.L) experimental drug gepirone ER for adults with major depression.
The U.S. Food and Drug Administration (FDA) issued a not approvable letter for the extended-release tablets, which Glaxo had licensed from privately owned Fabre-Kramer Pharmaceuticals Inc in February, Europe's biggest drugmaker said on Saturday.
The news is a blow to Glaxo, which needs new drugs to make up for pending patent expiries on key blockbusters and a recent slump in sales of its second-biggest seller, the diabetes pill Avandia, which has been hit by fears over a possible link to heart attacks.
Industry analysts had forecast that gepirone ER, if successful, could eventually have sold between $800 million (383 million pound) and $1.6 billion a year. But the product was always viewed as high risk, following a chequered history in development.
Akzo Nobel NV (AKZO.AS) of the Netherlands had originally been developing gepirone ER with Fabre-Kramer but the Houston-based drug company bought back rights to the drug in June 2005 after Akzo abandoned development in the wake of two earlier rebuffs from the FDA.
Despite these setbacks, Glaxo had hoped that gepirone ER might still be approved if it provided data from an additional positive clinical trial. Those extra results were submitted to in May 2007 but, in event, proved insufficient to sway the U.S. regulator.
Glaxo and Fabre-Kramer said they were now evaluating the response from the FDA to determine appropriate next steps.
The financial terms of February's deal between Glaxo and Fabre-Kramer were never disclosed but Moncef Slaoui, Glaxo's head of research and development, said at the time that gepirone ER was an important addition to the company's late-stage pipeline.
It was one of a number of product acquisitions made by Glaxo in the past year that reflect a new drive by the group to tap into external sources of drug discovery.
In December, Glaxo struck a record-breaking licensing deal valued at up to $2.1 billion with Danish firm Genmab (GEN.CO) for a new blood cancer and arthritis drug.
Other big-ticket deals include a alliance worth up to $1.5 billion for Targacept Inc's TRGT.O nicotine-based brain drugs in July and a $1 billion collaboration last month with Synta Pharmaceuticals Corp (SNTA.O) for an experimental melanoma drug.
Glaxo has a large new product pipeline by comparison with many pharmaceuticals companies but confidence in the portfolio has been dented by some recent delays and setbacks.
In its most recent pipeline update, given three weeks ago, Glaxo said it had dropped a number of experimental medicines but still had 30 assets in late-stage development.
This total covers 25 products in final Phase III trials, some of which have more than one use.