* Nikkei falls 0.9 pct, gains 4.3 pct on the week

* BOJ cuts benchmark rates to 0.10 pct from 0.30 pct

* Toyota slips after report to post operating loss

* Daiichi Sankyo jumps after Europe backs key product

By Rika Otsuka

TOKYO, Dec 19 (Reuters) - The Nikkei average slipped 0.9 percent on Friday as profit-taking before the weekend overshadowed a Bank of Japan rate cut, with Toyota Motor (7203.T: Quote, Profile, Research) retreating after a newspaper said it would post an annual operating loss.

Oil-related shares such as Inpex Corp (1605.T: Quote, Profile, Research) slid after U.S. crude prices dropped sharply, but drugmaker Daiichi Sankyo Co Ltd (4568.T: Quote, Profile, Research) jumped after European regulators backed a key drug candidate for approval.

The Nikkei briefly turned positive after the BOJ lowered its key policy rate to 0.10 percent from 0.30 percent and took other steps to ease corporate credit strains, as sharp yen rises and crumbling global demand hit an economy already in recession. [ID:nT108858]

But the market soon ran out of steam as investors booked profits on shares that had risen on expectations for a BOJ cut, ahead of the weekend and the winter holiday season.