UPDATE 3-Roche's Tarceva extends lung cancer survival

* Study shows patients treated with Tarceva live longer

* Lung cancer most common cancer worldwide

* Positions drug well versus competitor

* Shares in U.S. partner OSI gain 6 pct, Roche down 0.2 pct

(Adds more comment, US share reaction)

By Sam Cage

ZURICH, July 13 (Reuters) - Roche Holding AG's (ROG.VX) Tarceva cancer drug improved the survival of patients with advanced lung cancer when used immediately after initial chemotherapy, the Swiss group said on Monday.

The news helps the position of Tarceva, which is co-marketed by U.S. biotech company OSI Pharmaceuticals (OSIP.O) against Eli Lilly's (LLY.N) Alimta and supports filing for approval in the United States and European Union, analysts said.

"Detailed data are not yet available, but delivering an overall survivial benefit is well ahead of expectations, and in our view negates a significant competitive disadvantage to Alimta," said JP Morgan analyst Geoff Meacham.

Roche stock fell 0.2 percent to 145.10 Swiss francs by 1340 GMT, versus a 0.4 percent rise in the DJ Stoxx European health care index.SXDP, and OSI shares rose 6.3 percent. Eli Lilly fell 1.4 percent.

Treating patients immediately following first-line chemotherapy versus waiting for the cancer to grow or spread before giving additional treatment represents a new approach in advanced non-small cell lung cancer (NSCLC), Roche said.

Data from a late stage study called SATURN showed Tarceva met a key secondary target, showing a statistically significant improvement in overall survival. Full data will be presented at a lung cancer conference in San Francisco, which starts July 31.

"We have made no changes to our estimates, but this new data reinforces our view of Tarceva's approval and commercial potential," Sal Oppenheim analysts said.

Tarceva is already approved to treat pancreatic cancer in the United States and EU.

Lung cancer is the most common cancer worldwide with 1.5 million new cases annually and NSCLC accounts for almost 85 percent of all lung cancers, it said. (Additional reporting by Sven Egenter; Editing by Mike Nesbit/Will Waterman)