Wowzers. 

"Holy cow." That's what Jim Cramer said on CNBC's "Mad Dash" segment Thursday when he pulled up a chart of Celgene (CELG) . Shares are being hammered in the session, down about 20% after the company reported earnings.

"I am in shock," Cramer said, as Celgene is now down more than 33.5% since October 1. Celgene is considered "consistent of consistence" in biotech, he added, "and people have turned." Investors are ignoring the company's other positives, like its assets and investments. They're not giving management any credit.

Admittedly, Celgene's 2015 purchase of Receptos for $7.2 billion has paid little dividends thus far, he reasoned. Still, Cramer said he would not be a seller down at these levels. "No one ever made a dime by panicking" and that's exactly what a number of investors are doing, explained Cramer, who also manages the Action Alerts PLUS charitable trust portfolio.

This quarter has been all about the cyclicals and industrials, while biotech has been under pressure. Biogen (BIIB) , Amgen (AMGN) , Bristol-Myers Squibb (BMY) and now Celgene have all felt pricing pressures, Cramer said.

Revlimid growth was "OK" during the quarter, coming in at 10%, Cramer noted. But Otzela was disappointing. Even though sales clocked in at $308 million, up 12% year-over-over, it was vastly below expectations.elgene beat on earnings per share estimates and while it grew year-over-year revenue by 10.4%, it missed analysts' expectations.

Worse, Celgene cut its full-year outlook on total revenue to roughly $13 billion, from between $13 billion and $13.4 billion. It now expects Otzela sales to come in at $1.25 billion for the year, down from its prior guide of $1.5 to $1.75 billion.

It also trimmed its 2020 total net product sales estimate to between $19 billion and $20 billion, from above $21 billion.

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

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