By Ransdell Pierson

NEW YORK (Reuters) - Genentech Inc notified doctors of 36 cases of eye inflammation among patients who received injections with the company's cancer drug Avastin (bevacizumab) to treat wet macular degeneration. The "off-label" use of Avastin for this eye condition is not approved by the U.S. Food and Drug Administration.

Wet macular degeneration, which is often age-related, is caused by an abnormal increased leakage from blood vessels under the retina, leading to loss of central vision.

Genentech, in a letter to healthcare providers, said its partner Roche Holding AG had informed it of the cases, which included 32 serious inflammatory reactions.

"These events were reported to Roche between November 4 and 20, 2008, from four different reporting sites," Genentech said.

Roche, which holds a majority stake in Genentech, markets Avastin to treat cancer in many markets outside the United States, including Canada.

Genentech sells Avastin in the United States for the treatment of lung and colon cancer. It also sells a similar drug called Lucentis (ranibizumab injection), a fragment of the Avastin antibody, which is approved to treat wet macular degeneration.

Although Avastin is not approved to treat this eye condition, many doctors have divided it into multiple doses and used it instead of the more costly Lucentis.

Genentech spokeswoman Krysta Pellegrino said 25 of the cases were from one lot of Avastin. A lot consists of 66,000 single-use vials. She said all quality specifications established for approved uses of Avastin were met.

About 2 percent of patients who receive Lucentis develop eye inflammation, Pellegrino said, but Genentech does not know what percentage of patients who receive off-label Avastin develop such inflammation.

The U.S. National Institutes of Health is sponsoring a head-to-head trial comparing Avastin and Lucentis for macular degeneration.

Should the drugs show comparable safety and effectiveness, the U.S. government could shift patients in the Medicare insurance program to less costly small doses of Avastin.

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