UPDATE 1-Takeda Q3 profit up 9.9 pct, outlook steady

* Q3 operating profit rises 9.9 percent

* Additional revenue from Millennium, TAP boosts profit

* Keeps full-year forecast (Recasts with quarterly operating figures)

TOKYO, Feb 3 (Reuters) - Takeda Pharmaceutical (4502.T), Japan's largest drugmaker, said third-quarter operating profit rose 9.9 percent, helped by the acquisition of U.S. biotech firm Millennium and the absorption of part of a former U.S. joint venture.

Japanese drugmakers, racing with bigger global rivals to fill revenue gaps caused by patent expirations, are looking to expand drug pipelines through acquisitions, buying rights to new drugs and increasing in-house research spending.

Takeda booked goodwill amortisation and other relatively minor costs related to Millennium and the venture TAP Pharmaceuticals, but this was offset by the additional revenue and a reduction in overseas costs due to a firmer yen.

Takeda posted an operating profit of 154.9 billion yen ($1.7 billion) in October-December, as revenues rose 7.6 percent to 395.6 billion yen, led by its acid-reflux drug Prevacid.

Prevacid will lose U.S. patent protection in November although Takeda won approval for Prevacid's successor drug this week.

It maintained its annual operating forecast of 270 billion yen, in line with a consensus estimate of 279.8 billion yen from 19 analysts polled by Reuters Estimates.

Takeda shares finished down 1.4 percent at 4,150 yen after the earnings announcement. (Reporting by Yumiko Nishitani; Editing by Edwina Gibbs)