NEW YORK (TheStreet) -- Stocks are up Wednesday, so why are shares of Regeneron Pharmaceuticals  (REGN) - Get Regeneron Pharmaceuticals, Inc. Report down nearly 4%? 

"You're going to see this stock down badly today," TheStreet's Jim Cramer, co-portfolio manager of the Action Alerts PLUS portfolio, said on CNBC's "Mad Dash" segment. A U.S. Food and Drug Administration panel recommended approval of Regeneron's cholesterol drug. 

Cramer noted there are concerns about whether the company's Praluent will gain the kind of massive success with prescription-writing doctors that investors desire when it will comes to market, likely later this year. 

Regeneron Pharmaceuticals REGN data by YCharts

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People are cautious, particularly the doctors, Cramer said. It's no surprise they want to see more data before feeling comfortable enough to wirte a prescription. For the time being, approval for smaller population targets may be the course of action, according to a Bloomberg report. 

"This is totally expected," he continued, adding that Esperion Therapeutics (ESPR) - Get Esperion Therapeutics, Inc. Report will also suffer as a result of these concerns, due to its higher dependency on its cholesterol treatment. Shares are down nearly 22% today.

While the news seems bad, Cramer insists "this is business as usual" for biotechs like Regeneron, and investors need to realize this treatment is a new major category in the health care world. 

(SNY) - Get Sanofi Sponsored ADR Report will benefit from full-scale production of Praluent, too, since it is partnered with Regeneron on the drug, Cramer pointed out.

At the time of publication, Cramer's Action Alerts PLUS had no position in companies mentioned.