Shares in Regeneron (NSDQ:REGN) rose today after the company beat revenue expectations on The Street with its 1st quarter financial results.

The company’s total sales rose to $1.32 billion, exceeding analysts’ estimate of $1.30 billion. Regeneron’s bottom line jumped 37% to $248.9 million.

Adjusted to exclude 1-time items, earnings per share were $2.92, which missed analysts’ estimate by 14¢. The company cited a larger-than-expected tax bill as the root cause of its missed earnings.

REGN shares jumped more than 6% to 434.12 apiece today in mid-afternoon activity.

In a post-earnings call, CEO Leonard Schliefer reportedly said that its eczema drug Dupixent was off to a strong start and that 3,500 prescriptions for it have been written since it was approved in late March.

Jefferies analyst Biren Amin lifted his estimate for Dupixent’s 2017 sales to $144 million after learning that the number of prescriptions was significantly higher than the 2,500 prescriptions partner Sanofi reported last week.

Regeneron added that 2 large U.S. pharmacy benefit managers have agreed to cover Dupixent. The drug costs $37,000 and is expected to bring in peak annual sales of more than $4 billion, according to Reuters. 

The company is hoping that 2 of its therapies, sarilumab and Dupixent, will reduce its reliance on Eylea, which has fueled much of the company’s growth since 2011. Eylea accounts for almost 70% of Regeneron’s total revenue.

The drug’s sales have slowed in recent years, thanks to competition from Roche’s Lucentis. Sales of Eylea in the U.S. climbed 9% to $854 million in the 1st quarter of this year, just missing analysts’ estimates.

Material from Reuters was used in this report.