In what could be a transformative moment for the pharmaceutical industry, tiny Amarin Corp., with research headquarters in Groton, has taken on the powerful U.S. Food and Drug Administration and won an initial ruling allowing it to promote off-label uses for its heart pill.

In a preliminary ruling, the U.S. District Court for the District of Columbia ruled Friday in a key free-speech case that Ireland-based Amarin can bypass FDA restrictions on marketing its fish-oil treatment Vascepa for indications not specifically spelled out on approved drug labels, so long as the information it provides is supported by scientific evidence and is not misleading in any way.

The 71-page decision was handed down by Judge Paul Engelmayer. But the Associated Press reported that legal experts said the decision applies only to Connecticut, New York and Vermont — the states covered by the 2nd U.S. Circuit Court of Appeals.

"The decision opens more direct and effective paths to communicate truthful and non-misleading information about Vascepa clinical trial results and the state of science relevant to the potential of Vascepa to reduce the risk of cardiovascular disease," the company said in a statement following the ruling.

Amarin's stock price immediately zoomed up on the Nasdaq exchange Friday, eventually settling at $2.33 a share, up more than 14 percent.

The pharmaceutical industry has been pressing the federal government to loosen restrictions on its right to promote drugs not specifically approved for certain health issues.

The move gained momentum in 2012 when a drug-company sales representative won a legal case in which he argued that he had the right to distribute true information about his firm's products based on First Amendment protections.

According to The New York Times, Amarin had been hoping to inform doctors about a clinical trial that showed Vascepa lowered fats in the bloodstream known as triglycerides for people with "persistently high" levels of these markers that some have equated with heart problems.

The company also has been pushing for the leeway given to makers of over-the-counter fish oil supplements that for years have been allowed to make claims that "supportive but not conclusive research" indicates the pills could reduce coronary risks related to heart disease.

"This lawsuit is based on the principle that better informed physicians will make better treatment decisions for their patients," John F. Thero, president and chief executive of Amarin, said in a statement.

The FDA approved Vascepa in 2012, but granted only a three-year patent. Amarin has sued the FDA over the patent term as well, saying the agency should have granted it five years of marketing exclusivity.

Vascepa is currently approved only for patients with unusually high triglyceride levels. Amarin is now in the midst of a long-term clinical trial that it hopes will show other patients with lower levels of triglycerides could benefit from the treatment.

An earlier study by Amarin that showed Vascepa lowering triglyceride levels in people with moderately elevated blood fat did not lead the FDA to approve the drug for that population. The FDA said the study did not prove that Vascepa actually reduced serious coronary incidents.

l.howard@theday.com

Twitter: @KingstonLeeHow