UPDATED: FDA OKs Amarin's blockbuster heart drug contender AMR101

Amarin has nailed down an FDA approval for its heart drug AMR101, which will now be called by its branded name Vascepa. But there's still no word on whether or not regulators will designate the triglyceride treatment as a new chemical entity, which will determine the length of market exclusivity--and market value--Amarin ($AMRN) can look forward to. That decision should arrive in a matter of days.

The uncertainty appears to be weighing on Amarin's shares, which were down 9.76% to $13.82 late this morning despite the approval late Thursday afternoon.

The approval marks the arrival of Amarin's first product. And possibly its last. You can expect the attention now will focus on whether the biotech can execute a major pact for the drug, or get a buyout offer it can't refuse. The right marketing partner/buyer could add more than a billion dollars in annual sales for the industrial strength fish oil treatment, according to analysts. And even if left to Amarin, most analysts still expect this blood fat cleanser to rank as a blockbuster.

"In Amarin's MARINE clinical trial, Vascepa demonstrated a statistically significant placebo-adjusted reduction in levels of triglycerides without elevation in levels of LDL-C, commonly referred to as 'bad cholesterol,'" said Amarin CEO Joseph Zakrzewski in a statement. "Amarin continues to anticipate commercial launch of Vascepa early in the first quarter of 2013, and we continue to consider three potential paths for the marketing and sale of the product: an acquisition of Amarin, a strategic collaboration, or self-commercialization, the latter of which could include third-party support. We are now focused on continued commercial preparations for Vascepa which includes, but is not limited to, finalizing the introduction of Vascepa to managed care plans to gain formulary access, building-up inventory levels and coordinating other pre-launch marketing activities."

There's no surprise here, but after years of work you can expect investors to breathe a big sigh of relief that the approval is now a done deal. Amarin was widely expected to win this approval on clean late-stage data. The focus now will be on the FDA's decision on whether Vascepa qualifies as an NCE, which could add two years of market exclusivity for whoever is marketing it.

"Typically, FDA's determination on the exclusivity of approved products is made public through the posting on FDA's website in the Orange Book," notes Amarin. "This typically occurs mid-month following the month of an NDA approval."

- here's the press release

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