* 3.8 angina episodes per week with Ranexa vs 4.3 with placebo * Need for nitroglycerine less with Gilead drug * Ranexa being tested as diabetes treatment in other trials By Bill Berkrot SAN FRANCISCO, March 10 (Reuters) - Gilead Sciences Inc's angina drug Ranexa reduced incidents of chest pain in patients with diabetes, and the effect appeared to be more pronounced in those with poor blood sugar control, according to data from a clinical trial. Ranexa, known chemically as ranolazine, is already approved to treat angina - a type of chest pain associated with heart disease. This was the first trial to test it specifically in diabetics, who tend to have more complications and can be more difficult to treat that other heart patients. In the eight-week, 927-patient study, known as Terisa, those taking Ranexa reported an average of 3.8 weekly episodes of chest pain compared with 4.3 for the placebo group. The data was presented on Sunday at the American College of Cardiology (ACC) scientific meeting in San Francisco. "Ranolazine is an effective anti-anginal drug in patients with diabetes and may also have a glucose lowering effect," said Dr. Mikhail Kosiborod, the study's lead researcher. "If the glucose lowering action of ranolazine is confirmed in future studies, patients with diabetes and angina may derive dual benefit from this drug." After noting in earlier studies that Ranexa appeared to lower blood glucose levels, Gilead has begun a series of large, Phase III studies aimed at eventually seeking approval for the drug as a diabetes treatment. The primary result would have been more pronounced in the Gilead drug's favor were it not for an apparent geographic anomaly, researchers said. They found little difference in angina frequency between Ranexa and placebo in patients from Russia, Ukraine and Belarus. Excluding patients from those regions, Ranexa had a statistically significant reduction in angina episodes per week - 3.1 versus 4.1 for placebo. "The reasons for this geographic difference are not clear," Kosiborod said, adding that it appeared to be driven by several sites in Russia. Researchers also found that the Gilead drug was especially effective in patients with worse glucose control. American Diabetes Association guidelines call for A1c levels - a commonly used measure of blood sugar - of seven or less. "For patients with A1c of greater than seven, there was a strikingly better effect," said Dr. Miguel Quinones, chairman of the 2013 ACC meeting, who was not involved in the study. Subjects in the trial were already taking angina medicines such as beta blockers, and were given 1,000 milligrams of Ranexa twice a day or a placebo for eight weeks. Subjects in the study had type 2 diabetes, coronary artery disease and were experiencing at least one angina episode per week. Nearly all of them had high blood pressure and 74 percent had a history of heart attack. Angina episodes were reported in real time through an electronic device given study subjects. They also reported the need to take nitroglycerin for chest pain, which favored Ranexa - 1.7 versus 2.1 times per week. There were very few adverse side effects and they were about equal in both arms of the study, researchers said. There were nine patient discontinuations with Ranexa and 11 in the placebo group. Serious adverse events during the treatment were reported in 16 Ranexa patients and 20 in the placebo arm of the study. Gilead investors have been squarely focused on the company's experimental high profile hepatitis C drug, which is expected to eventually reap billions of dollars in sales. But Ranexa has quietly been a solid performer for the company with 2012 sales of $373 million, up 17 percent over 2011. A future approval for diabetes could substantially boost sales. "For patients who have angina and diabetes this would be a good option," said Ori Ben-Yehuda, Gilead's vice president of clinical research.