Omthera on Monday filed a Form S-1 with the Securities and Exchange Commission, outlining plans to raise $75 million through an initial public offering. Princeton, N.J.-based Omthera has yet to price the IPO, but it will trade on Nasdaq under the symbol OMTH once it goes public.

Omthera is developing Epanova, an omega-3 fatty acid designed to lower triglyceride levels, a risk factor for heart attacks, strokes and other cardiovascular events. The company unveiled data from Epanova's Phase 3 trials in November and plans to submit a new drug application with the Food and Drug Administration in mid-2013.

Epanova would directly compete with Amarin's Vascepa, which was approved by the FDA in July, and GSK and Pronova BioPharma ASA's Lovaza, the current market leader. Vascepa is approved to treat patients with very high triglyceride levels, or more than 500 milligrams per deciliter of blood, the same indication Omthera is chasing. And just like Amarin, Omthera hopes to win approval for a much larger patient population, namely those with triglyceride levels between 200 and 500 mg/dl of blood.

Lovaza brings in about $1 billion annually. But certain analysts have expressed lofty hopes for Vascepa, which may be superior to Lovaza. In fact, Vascepa's approval by the FDA sparked buyout speculation regarding Amarin, which was very public about setting itself up for an acquisition by keeping Vascepa partnership-free during development.

No deal has materialized since, however, and the company has been waiting for the FDA to grant it new chemical entity, or NCE, status for the drug, which would give it two additional years of market exclusivity before someone can file a legal challenge to it.

The FDA has delayed making a decision on the designation several times. Amarin also delayed its decision on launching Vascepa by itself before announcing a $100 million nonequity financing in December to give it the financial wherewithal to market the drug on its own.

Amarin shares promptly tumbled as investors awaiting a buyout fled the stock. Shares now trade for $8.64 per share, down substantially from the $15.31 they traded for when the FDA approved Vascepa. Amarin launched Vascepa in late January.

Amid the uncertainty surrounding Amarin, Omthera is preparing to enter the market and grab share. Omthera believes Epanova is differentiated by being a "free fatty acid" form of omega-3, as opposed to ethyl-ester forms such as Lovaza and Vascepa. The advantage Omthera believes this gives Epanova is that patients taking it can get the same results from a smaller dose of the drug than the amount of Lovaza they would otherwise ingest.

Omthera also said in its S-1 that it believes it may be eligible for NCE status.

Omthera estimates that the omega-3 market was worth $2 billion in 2012 and will grow as awareness of new prescription products increases. Once it launches Epanova, it plans to develop and commercialize the drug in combination with statins as a therapy for cholesterol and triglyceride reduction. Cholesterol-lowering statins include Lipitor, Zocor and Crestor.

Omthera's largest stockholders are Paris-based Sofinnova Partners (38.8%) and New Enterprise Associates Inc. (29.9%). The two have helped Omthera raise about $40.4 million in venture capital since it began operating in 2009, according to the company's website.

Bank of America Merrill Lynch, Barclays plc, Leerink Swann LLC, Stifel, Nicolaus & Co. and Piper Jaffray & Co. will underwrite Omthera's IPO.