Japan's top drugmaker Takeda Pharmaceutical Co <4502.T> posted a 4.8 percent fall in first-half operating profit as currency losses and worries over a call for new warnings on its top-selling diabetes pill Actos offset higher revenue from treatments recently launched at home.

The company, which ranks ahead of Astellas Pharma <4503.T>, Otsuka Holdings Co <4578.T> and Daiichi Sankyo Co <4568.T> in terms of market value in Japan, booked an April-September operating profit of 211 billion yen ($2.7 billion).

Like many other Japanese companies, Takeda's profits are dented by a strong yen, while a request by European authorities to add warnings of possible link to bladder cancer to Actos pills weighed on the drug's sales.

Takeda, nearly 30 percent owned by foreign investors, cut its operating-profit forecast for the business year to end-March 2012 to 270 billion yen from its initial estimate of 390 billion yen.

That compares with the average estimate of 388.1 billion yen from 17 analysts polled by Thomson Reuters I/B/E/S.

The market is looking for details on Swiss drugmaker Nycomed's contribution to the company's forecasts. Takeda bought Nycomed for $13.7 billion earlier this year.

Shares of Takeda have fallen about 13 percent since the start of the calendar year, compared with a more 14 percent drop in the benchmark Nikkei average <.N225>.

($1 = 77.980 Japanese Yen)

(Reporting by James Topham; Editing by Vinu Pilakkott)