Akorn Inc.  (AKRX - Get Report) shares plunged Tuesday after Germany's Fresenius SE (FSNUY) said a probe into possible data breaches at the generic drugmaker could force it to drop a planned $5 billion takeover.

Fresenius said it's conducting an "independent investigation, using external experts" into alleged data breaches at Lake Forest, Ill.-based Akorn linked to data integrity regulations governed by the U.S. Food and Drug Administration relating to product development at Akorn. The probe follows concerns raised earlier this month by the Federal Trade Commission regarding greater scrutiny of complex inhalant and injectable products involved in big pharmaceutical takeovers.

"The Management and Supervisory Boards of Fresenius will assess the findings of that investigation," the company said in a statement. "The consummation of the transaction may be affected if the closing conditions under the merger agreement are not met. Fresenius does not intend to provide further updates as the investigation proceeds (and) continues to seek FTC clearance."

Akorn shares were marked 31.6% lower in the opening hour of trading Tuesday and changing hands at $20.70 each, the lowest in more than a year.

Fresenius offered $34 per share for Akorn last April in a deal that valued the group at 4.3 billion plus approximately $450 million of net debt. 

Akorn shareholders overwhelmingly voted to approve the merger a few months later and the company said Tuesday that the proposed deal is still on.

"To date, the company's investigation has not found any facts that would result in a material impact on Akorn's operations and the company does not believe this investigation should affect the closing of the transaction with Fresenius," the company said in a statement.