Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of biopharmaceutical company Amarin (NASDAQ:AMRN) briefly screamed lower by as much as 10%, but now sits down less than 5% as of this writing, following the announcement of an additional supplier for its triglyceride-reducing drug, Vascepa.

So what: With Amarin shareholders still in limbo as they await word on a still-undecided new chemical entity status, or NCE, for Vascepa, it's easy to understand why any news not relating to that NCE is bound to irritate traders. Last week, the announcement that Amarin would take on $100 million in equity financing to hire a marketing staff for Vascepa crushed the share price. Today's announcement that it has added Slanmhor Pharmaceuticals to its active pharmaceutical ingredient supply chain for Vascepa simply wasn't enough to get investors' minds off that pesky NCE status.

Now what: Sales at VIVUS (NASDAQ:VVUS) and Dendreon (NASDAQ:DNDN) have limped out of the gate for VIVUS' Qsymia for chronic weight management and Dendreon's Provenge for advanced castration-resistant prostate cancer because they both lacked a marketing partner. Amarin shareholders have to be concerned that this could be their same fate given that Amarin is taking on debt to hire a marketing staff. In addition, with Vascepa's NCE status still up in the air, there's no guarantee that the drug will receive a five-year period of exclusivity which would be a major blow to the drugs' potential. While I agree that Vascepa has a lot of potential and that Amarin could be a buyout candidate, it's not a company I feel comfortable chasing at the moment.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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