Avastin, a cancer drug made by Roche Holding, was about as effective as the company's far more expensive eye drug, Lucentis, at preventing vision loss in people with age-related macular degeneration, the New York Times reported.

The two drugs were compared in a federally funded US study due to be released on Sunday at a medical meeting and in the New England Journal of Medicine. The results are now expected some time on Thursday.

The Times report cited two anonymous sources who said the study found injections of Lucentis and Avastin given every four weeks had similar results after one year. Release of trial results ahead of their publication is considered a scientific and ethical breach.

At stake are billions of dollars in Lucentis sales for both Roche, which sells the medicine in the US, and Novartis, which sells the medicine outside the US.

Avastin could cannibalize Lucentis sales because it costs about $50 per shot, compared with about $2,000 for a dose of Lucentis and would be a more attractive treatment if its efficacy and safety profiles are similar.

Age related macular degeneration, or AMD, is the leading cause of blindness in people over 60. Some 13 million Americans have signs of AMD and more than 1 million Americans have the wet form, the most severe type.

Avastin is not licensed for use in the eye but it works in a similar way to Lucentis, and doctors often use Avastin off label in these patients.

Most analysts expected Avastin to prove as effective as Lucentis in the 1,200-patient test.

Last year, Roche and Novartis each generated around $1.5 billion in Lucentis sales and some analysts suggest it could go on to become a $10 billion-plus drug.

The New York Times said researchers taking part in the study met on Tuesday in Chicago to hear the results, but were sworn to secrecy. The study was conducted by the National Eye Institute, part of the National Institutes of Health.

NEI spokeswoman Jean Horrigan confirmed that the meeting took place but could not comment on whether the institute will investigate who leaked the results, or when they would become available.

What the study may not settle is a growing debate over whether using a cancer drug to treat an eye disease exposes patients to additional safety risks.

Yaron Werber of Citigroup said in a note to clients on Wednesday the study is too small to detect any safety differences between the two drugs, echoing claims by Roche's Genentech unit.

Anthony Adamis, global head of ophthalmology at Genentech, said in an interview this week there is an emerging body of data suggesting there may be safety differences between the two molecules. Genentech has not seen the results of the full study.

Adamis said Lucentis is a much smaller molecule than Avastin and is cleared out of the blood stream within two hours, as opposed to Avastin, which takes 20 days to be cleared.

'The thinking is that would be a good thing because the more it is exposed to the body the greater the risk for side effects,' Adamis said. – Reuters