UPDATE 1-Boehringer's HIV drug has edge over BMS's Reyataz

* Boehringer's Viramune as effective as BMS' Reyataz-study

* Cardiovascular risks lower under Viramune-study

(Adds details, background)

FRANKFURT, July 20 (Reuters) - Patients on Boehringer Ingelheim's HIV drug Viramune run a lower risk of cardiovascular disease than a rival drug sold by Bristol Myers Squibb (BMY.N), a study released on Monday showed.

The drug trial, involving 569 participants, yielded that Viramune, while being as effective at suppressing HIV as Bristol Myers' blockbuster Reyataz, had a more favourable effect on patients' cardiovascular risks, as measured by certain blood lipids.

Bristol Myers last year made $1.3 billion in sales from Reyataz, a once-daily pill based on the active ingredient atazanavir.

Standard anti-HIV treatment Viramune was brought to U.S. and European markets in 1996 and 1998, respectively, but was challenged in 2003 by the launch of rival drug Reyataz.

As part of the study, both drugs were taken with Gilead Sciences' (GILD.O) anti-viral drug combination Truvada to amplify their effects. Reyataz was also combined with Abbott Laboratories' (ABT.N) Norvir.

Advances in so-called antiretroviral drugs have helped suppress the outbreak of AIDS, making the HIV infection a treatable chronic condition where the drugs are available and affordable.

As a result, patients are growing older, bringing other symptoms of an HIV infection, such as cardiovascular diseases, to the fore.

Viramune-treated patients in the study had more than twice the level of HDL cholesterol, known as "good cholesterol" for its benefitial effect on blood vessels, than those on Reyataz, Boehringer said in a statement on Monday.

The ratio of total cholesterol over HDL cholesterol, a measure that points to higher cardiovascular risks, was more favourable in the Viramune-treated patient group compared to the Reyataz group, Boehringer added.

The privately-held German company earlier this month said that the European Commission approved an update of Viramune's product description to account for its effects on blood lipids.

Boehringer does not publish sales figures for Viramune. Generic versions of the drug are marketed by India's Cipla Ltd (CIPL.BO) and Daiichi Sankyo's (4568.T) Ranbaxy (RANB.BO).

Results from the trial were presented at the 5th International AIDS Society conference in Cape Town, South Africa, over the weekend.

(Reporting by Ludwig Burger)