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 Amarin Corporation (NASDAQ:AMRN) are down over 20% today after the Office of New Drugs within the Food and Drug Administration denied Amarin's latest appeal to reinstate the Special Protocol Assessment, or SPA, agreement for the ANCHOR clinical trial, designed to expand the label of the company's prescription fish-oil pill called Vascepa.  As a refresher, the FDA repealed the ANCHOR SPA last October after questioning the clinical trial's design and ability of fish oil pills in general to improve cardiovascular outcomes. 

Vascepa is currently approved as a treatment for patients with severely high (≥ 500 mg/dL) triglyceride levels through the so-called MARINE indication. The ANCHOR trial data would expand the label to include adults with moderately high triglycerides (TG ≥200 mg/dL & < 500 mg/dL). But without the reinstatement of the SPA, it's highly unlikely that the FDA would approve this indication now. 

So What: Amarin is desperate to increase sales of its prescription fish oil pill and the coveted label expansion looked like the ticket to achieve this goal. Now that a near-term label expansion is potentially off the table, the company may have to seriously consider curtailing its other clinical activities as a cost-savings measure. 

Now What: This is Amarin's third, and potentially last available, attempt at getting the ANCHOR SPA reinstated. So at this point, the company could finally concede defeat and reassess its options moving forward. That said, Amarin did state in its press release that they are "evaluating potential next steps" in regards to fighting the FDA's decision on the matter. That could mean yet another appeal to an even higher official within the FDA. 

With generic versions of GlaxoSmithKline's (NYSE:GSK) competing fish oil pill, Lovaza, now on the market and a host of stellar cholesterol lowering drugs under regulatory review, Amarin looks like a company in deep trouble following its inability to get ANCHOR's SPA reinstated. Consequently, you may want to sit safely on the sidelines with this speculative biotech.   

  

George Budwell has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.