(Corrects headline, bullet and paragraph one to say Dupixent is an "eczema", not "allergy" drug)
* Co backs Eylea full-year sales growth forecast
* Eylea Q1 sales miss estimates by less than feared
* Launch of eczema drug Dupixent going well - CEO
* Shares rise nearly 6 pct, up for 5th day in a row
By Natalie Grover and Divya Grover
May 4 (Reuters) - Regeneron Pharmaceuticals Inc stood by its full-year sales forecast for its flagship drug Eylea and said the early adoption of its eczema drug Dupixent was encouraging, easing concerns about the company's reliance on Eylea as competition heats up.
Regeneron's shares jumped nearly 6 percent to $430.93 on Thursday, rising for the fifth day in a row to touch levels last seen in November.
Eylea, used to treat macular degeneration and other eye disorders, has powered much of the company's growth since late 2011 and accounts for nearly 70 percent of total revenue.
However, the drug's sales growth has slowed in recent quarters, mainly due to competition from Roche' Lucentis.
U.S. sales of Eylea rose 9 percent to $854 million in the first quarter – in line with Regeneron's expectations of single-digit growth this year and about $4 million shy of analysts estimates.
However, after Roche reported strong Lucentis sales, investors were expecting Eylea to fare much worse, with some expecting sales as low as $800 million, Cowen and Company analysts said.
The company backed its expectations that Eylea sales would increase in the single-digit percent range this year from $3.32 billion last year.
Regeneron is betting on two key treatments – Dupixent to treat eczema and sarilumab to treat rheumatoid arthritis – to diversify its revenue stream.
Dupixent was approved in late March and about 3,500 prescriptions have been written so far, Chief Executive Leonard Schleifer said on a post-earnings call.
Two of the largest U.S. pharmacy benefits managers have agreed to cover Dupixent and the drug is well positioned to secure broad coverage by the end of the year, executives said.
Dupixent costs about $37,000 and is expected to generate peak annual sales of more than $4 billion.
Regeneron also said it expects the FDA to approve the arthritis drug, sarilumab, by May 22, and is gearing up for a launch.
Sales of Regeneron's cholesterol fighter Praluent were $36 million in the first quarter, well short of estimates of $62 million, which the company blamed on an ongoing lawsuit.
However, total revenue rose nearly 10 percent to $1.32 billion, edging analysts' estimate of $1.30 billion, due to strong collaboration revenue from partners Sanofi and Bayer.
Net income jumped 37.2 percent to $248.9 million. But, its adjusted profit of $2.92 per share missed analysts' estimate of $3.06, according to Thomson Reuters I/B/E/S, due to a bigger-than-expected tax bill. (Reporting by Natalie Grover and Divya Grover in Bengaluru; Editing by Savio D'Souza)