Regeneron CEO Leonard Schleifer said on Tuesday Eylea has pronounced advantages over Lucentis - Roche's older treatment for the leading cause of blindness among the elderly - including a 45 percent lower annual cost and the need for roughly only half as many injections into the eye.

Regeneron shares have more than doubled since Eylea was approved by U.S. regulators on November 18 for the dangerous "wet" form of macular degeneration. More than 200,000 cases of the sight-robbing condition are diagnosed in the United States each year.

The Regeneron drug only needs to be administered every other month, after being injected monthly for the first three months. Lucentis - which, like Eylea, works by blocking a protein called VEGF - was approved in 2006 for injections once a month.

Lucentis costs about $2,000 per dose, slightly more than a dose of Eylea. But many macular degeneration patients instead take specially formulated injections of a Roche cancer drug called Avastin that costs only about $50 and is not approved to treat macular degeneration.

A study last year showed Avastin, which is chemically similar to Lucentis, was as effective as the more costly Roche drug for the eye condition. But Schleifer, speaking at the Barclays Capital Global Healthcare Conference, said surveys suggest a large group of patients have switched from Lucentis and Avastin to Eylea.

"Initial uptake continues to exceed expectations," he said, referring to overall U.S. sales of Eylea, with surveys suggesting 60 percent coming from former Lucentis and Avastin users and the remaining 40 percent from patients taking anti-VEGF drugs for the first time.

Last month, Regeneron significantly boosted its 2012 U.S. sales forecast for Eylea to between $250 million and $300 million. The news sent its stock to nearly a lifetime high of $115.

Some industry analysts expect Regeneron shares to reach $135 or $140 within a year, as sales of Eylea continue to outpace industry expectations.

(Editing by Andre Grenon)

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