Shares of biotech firm Amarin (AMRN, quote) were crushed in after hours trading on Thursday after the company announced plans to raise $100 million in debt financing and to hire 250-300 sales reps to market its fish-oil drug Vascepa. The stock finished the after hours session down more than 18 percent at $9.75. Shares traded as low as $8.76 in the immediate aftermath of the announcement.

Vascepa is a prescription medication which is to be used along with a low-fat and low-cholesterol diet to help lower high levels of triglycerides in adults. The product is an ultra-pure omega-3 fatty acid derived from fish oil.

The launch of Vascepa has been delayed since it gained approval on July 26, 2012 as Amarin searched for a Big Pharma marketing partner. The company has also been the subject of takeover rumors and speculation in the wake of the drug's approval.

The announcement of financing and plans to hire a sales force would seem to indicate that Amarin's efforts to find a marketing partner or reach a buyout deal have failed. This is the reason for the heavy selling in Amarin shares in Thursday's after hours trading session.

Although Amarin CEO Joe Zakrzewski said on a conference call that "all options are still on the table" and "partner discussions were still active," it is now very likely that the company will be forced to handle the drug launch on its own. A decision on Vascepa's New Chemical Entity (NCE) status is still up in the air and Zakrzewski said that he does not know when the FDA may make a ruling.

If the drug were granted NCE status, it would give it a 5-year window of market exclusivity, which in turn would make Amarin more attractive to a Big Pharma partner.

For now, however, investors are forced to confront the fact that help may not be on the way and Amarin will have to finance the Vascepa launch on its own. On Friday, Amarin's stock price will also reflect the unlikelihood of any kind of buyout from a large pharmaceutical company -- at least in the near-term.

Content courtesy of Benzinga written by Scott Rubin, Benzinga Staff Writer