Deena Beasley

LOS ANGELES, Nov 19 (Reuters) Swiss drug maker Roche Holding AG has said a clinical trial had shown its experimental anemia drug Cera worked as well as Amgen Inc.'s drug Aranesp in patients with chronic kidney disease.

A Phase III study involving 324 patients not on dialysis found both drugs were effective in about 97 percent of patients, Roche said.

Cera was given once every two weeks, while Aranesp was given once a week.

The safety level of both drugs was identical, said trial investigator Dr. Bob Provenzano, head of nephrology and transplantation at St. John Hospital in Detroit.

Amgen, the world's largest biotechnology company, questioned the results presented at a meeting of the American Society of Nephrology in San Diego.

''It appears that Roche incorporated an exclusion criteria that selected a relatively healthy population,'' said Dr Robert Brenner, Amgen's senior director of medical affairs.

The Roche trial excluded patients with high levels of C-reactive protein -- a marker of inflammation that is associated with heart risk.

Provenzano said such patients were excluded because they were known not to respond to that class of drugs, adding that because they were excluded from the group treated with Cera as well as the one treated with Aranesp, ''there is no bias.'' Roche has filed for US Food and Drug Administration approval of Cera and a decision is expected in February.

Amgen, based in Thousand Oaks, California, has sued Roche for infringing six patents related to Epogen, a bioengineered protein that boosts production of red blood cells, and the case is set to go to trial in September 2007.

Aranesp, a longer-lasting version of Epogen, was approved by the FDA in 2001 for treating anemia in patients with kidney failure. The label was expanded in 2002 to include treatment of cancer patients undergoing chemotherapy.

Amgen posted combined sales of Epogen and Aranesp of billion last year.

Wall Street analysts have expressed differing opinions on the rivalry between Roche and Amgen.

''In our opinion, these studies show evidence of further differentiation versus Aranesp,'' which should support regulatory approval of the drug early next year in the United States and Europe, said Bear Stearns analyst Alexandra Hauber.

Christopher Raymond, an analyst at Robert W Baird&Co, said he believed Amgen could weather the commercial threat posed by Roche, as nephrologists see little need for new anemia agents, tend to administer the drugs according to dialysis center contracts and already dose Aranesp at monthly intervals.

REUTERS DKS PM0435