UPDATE 2-Takeda sees difficult year ahead

* Outlook for 2009/10 below analyst estimates

* Blames stronger yen, patent loss on key ulcer drug

* Shares up 3.0 percent vs 0.2 percent gain in Nikkei

* Forecasts pretax profit falls in real terms

* Annual recurring profit at eight-year low in 2008/09

TOKYO, May 11 (Reuters) - Takeda Pharmaceutical Co (4502.T), Japan's biggest drugmaker, forecast weaker-than-expected growth in recurring profit on Monday for the current business year, blaming a stronger yen and the expiry of a U.S. patent on its mainstay ulcer drug.

The drugmaker forecast a recurring profit of 400 billion yen ($4.07 billion) for the year to March 2010, short of a consensus forecast of 448.4 billion yen in a poll of 20 analysts by Thomson Reuters.

The forecast means recurring profit would still be close to the eight-year low marked in the business year ended March 31 on hefty acquisition costs.

"Takeda's forecasts are weak on a pretax level compared with both my projection and the market consensus, although the stock market may welcome the better-than-expected net profit forecast, which appears to be due to one-time tax effects," said Kenji Masuzoe, an analyst at Deutsche Securities.

Takeda shares closed up 3 percent at 3,800 yen, extending gains after the company's announcement. By comparison, the benchmark Nikkei average .N225 finished up 0.2 percent.

"We expect profit declines this financial year in real terms, excluding the impact of acquisitions and other one-time costs, due to a fall in revenue and increased R&D spending," Takeda president Yasuchika Hasegawa told a news conference.

Takeda, half of whose revenues come from overseas, sees its revenues falling for the first time in 19 years on the stronger yen, while it expects a plunge in sales of its Prevacid ulcer drug, for which a U.S. patent expires in November, to offset most of the contribution from sales growth in other products such as Actos, its blockbuster diabetes drug.

It expects combined sales of Prevacid and its successor drug Kapidex this business year to reach only about 80 percent of the sales Prevacid racked up last year, Hasegawa said.

The company did not elaborate on details of an expected 5.8 percent rise in real terms in research and development spending this year, but analysts suspect one reason to be additional studies on a successor to Actos, which will lose U.S. exclusivity in 2011.

Takeda had a major setback in the development of a successor to Actos in March, raising concerns it may have to spend more in the coming year to develop a candidate to replace the key drug, and may not have a timely successor to it. [ID:nT239013]

In the final quarter of the business year ended March 31, Takeda's recurring profit more than doubled to 72.6 billion yen, but for the full year it slumped 39 percent to 327.2 billion yen due to hefty one-time costs related to acquisitions in the first quarter.

Joining other drugmakers using acquisitions to stave off earnings declines stemming from patent expirations, Takeda bought U.S. biotech firm Millennium Pharmaceuticals and absorbed its share of U.S. firm TAP Pharmaceuticals, formerly a joint venture with a U.S. firm.

Takeda is seeking to capitalise on Millennium's cancer drug pipeline and TAP's marketing network to counter U.S. patent expirations on its mainstay Prevacid in November and Actos 2011. ($1=98.30 Yen) (Reporting by Yumiko Nishitani; Editing by Michael Watson)