Adds details, background, comment

ZURICH, Jan 8 (Reuters) - Roche ROG.S on Wednesday said it planned to complete its purchase of U.S. biopharmaceutical company Poseida Therapeutics PSTX.O, a specialist in complex immune cell therapies to treat several types of blood cancer.

Roche said it has accepted for payment nearly 65 million shares in Poseida - equivalent to 66% of the California company's stock - which had been tendered by shareholders at a price of $9 per share, with an additional contingent payment of up to $4 per share.

The consideration takes the deal value up to around $1.5 billion.

The acquisition, announced in November , is the latest move by Roche to boost its development pipe-line to offset falling oncology sales.

"Later today, Roche intends to complete the acquisition of Poseida ...without a vote or meeting of Poseida's stockholders," Roche said on Wednesday.

In the takeover, all shares of Poseida not owned by Poseida, or Roche will be converted into the right to receive the same consideration per share, the Swiss company said.

Poseida, which will become a wholly owned subsidiary of Roche, will add so-called allogeneic CAR-T cell therapies, which use genetically modified immune cells to attack cancer cells or to treat auto immune diseases.

Poseida is also working on CAR-T programmes for solid tumours and autoimmune diseases.

(Reporting by John Revill, editing by Rachel More)

((John.Revill@thomsonreuters.com; +41 41 528 36 37; Reuters Messaging: john.revill.thomsonreuters.com@reuters.net))