CORRECTED - UPDATE 1-Novartis says to buy Speedel for $880 mln

(Corrects Novartis' stake in Speedel in second paragraph)

ZURICH, July 10 (Reuters) - Novartis (NOVN.VX) plans to fully acquire its research partner, Swiss biotech company Speedel SPPN.S, for about $880 million to speed up development of blood pressure drug Rasilez, it said on Thursday.

In a first step, Novartis raised its stake in Speedel by 51.7 percent to 61.4 percent by buying shares from major Speedel shareholders -- including 21.5 percent from Speedel Chief Executive Alice Huxley -- for 130 Swiss francs per share in cash.

Novartis said it would offer the same price in cash to shareholders for the remaining stake and said it expected the full acquisition to cost about 907 million Swiss francs ($882.3 million).

This excludes the 9.7 percent stake Novartis already owned.

The offer represents an 80 percent premium to the volume-weighted average price of Speedel's shares for the 60 trading days prior to the announcement, Novartis said.

"With the integration of Speedel into Novartis, we can accelerate development of Tekturna/Rasilez, particularly in combination with other medicines, and further advance Speedel's pipeline of novel compounds," said Joseph Jimenez, chief executive of Novartis Pharma in a statement.

Novartis develops Rasilez, which is known as Tekturna in the United States, together with Speedel.

Novartis expects annual cost synergies of about $30 million within two years after the closing of the deal, it said. (Reporting by Eva Kuehnen, editing by Will Waterman)