UPDATE 1-Organon to submit Remeron earlier in Japan

(Recasts, adds Organon comment, analyst, background)

AMSTERDAM, Jan 11 (Reuters) - Dutch chemicals group Akzo Nobel's (AKZO.AS) Organon pharma unit said it expected to submit its antidepressant mirtazapine, also known as Remeron, to Japanese health authorities three years earlier than expected.

Organon said on Thursday it expected to file a new drug application in Japan towards the middle of 2007.

The drug has been available in other countries since 1994, generating peak sales of around 700 million euros, Organon's most important drug ever.

Since it came off patent in the U.S. in 2001, annual sales of the drug fell to 283 million euros in 2005.

SNS analyst Danny van Doesburg said the statement was good news for Akzo Nobel AKZOY.O. "A rough calculation may indicate that this could bring about 25 million to 30 million euros additional EBIT per annum at the peak sales year and add some 0.20-0.30 euros per share to the company valuation," he said in a note to investors. "The Japanese market is an important market, and we are confident that mirtazapine's fast onset of action and tolerability will make it a first-line option for the treatment of depression in Japan," said Emile van Dongen, Organon's executive vice president of global sales.

The Japanese antidepressants market is estimated at 700 million euros in annual sales, an Organon spokeswoman said.

"We expect a response from the Japanese authorities by the first half of 2009," she said, declining to comment on the estimated introduction of the drug.

If accepted, the drug will receive six years' protection.

Akzo is in the process of splitting off its pharma unit, either via an initial public offering of part of its shares, or an outright sale, in which it could fetch around 10 billion euros, analyst estimated.