(CNN) Irish pharmaceutical company Amarin sent a glowing announcement to investors Monday that its drug Vascepa, a purified fish oil derivative, was linked to a 25% reduced risk of major cardiovascular events such as heart attack and stroke.
While some doctors saw this announcement as a stunning and unexpected result that could change medical practice, others are reserving their judgment until the company shares its data, which have not been published in a peer-reviewed journal.
"This trial certainly strengthens the idea that treating people with cardiovascular disease [and] with elevated triglycerides resulted in a reduction in cardiovascular events," said Dr. Howard Weintraub, a preventive cardiologist and clinical director of the Center for the Prevention of Cardiovascular Disease at NYU Langone Health. Weintraub was a co-investigator of the trial.
But experts say these findings were not widely expected. The science behind fish oil and cardiovascular health has been inconclusive, and many studies have not shown a benefit. Vascepa is derived from a single omega-3 fatty acid isolated from fish.
"I want to see the numbers," said cardiologist Dr. Russell Luepker, a Mayo professor of public health at the University of Minnesota who was not involved in the trial. "This is just a tiny fraction of the data that they undoubtedly have. And undoubtedly what they've given us is the best data they have.
"This is almost like a press release to generate buzz."
Amarin shares closed on Friday at $2.99, opened Monday above $10 and rose throughout the day.
Cardiologist Dr. Rita Redberg described the announcement as "remarkably free of data" and said that initial buzz surrounding drug-related announcements hasn't always panned out.
"This is potentially very interesting. I just don't think there's enough here to know," said Redberg, also a professor of medicine at the University of California, San Francisco.
In its statement, the drug maker also cautioned, "Existing and prospective investors are cautioned not to place undue reliance on topline results."
More results from the trial will be presented on November 10 at a meeting of the American Heart Association in Chicago. Investigators say they also plan to publish the results in a peer-reviewed journal, according to the company statement.
Weintraub said that the trial could have succeeded where others failed for three reasons: the specific fish oil component they used, the higher dose of four grams per day and the type of patient it was given to.
The 8,179 patients in the double-blinded study had LDL levels in the normal range, controlled by statins, as well as "persistent elevated triglycerides," another kind of lipid, ranging from 150 to 499 mg/dL. In addition, they either had "established cardiovascular disease," or they had Type 2 diabetes and at least one other cardiovascular risk factor. Patients were followed for a median 4.9 years.
Weintraub said that while there have been plenty of studies on statins and cholesterol, triglycerides haven't gotten the same attention on their own -- part of what makes this trial unique.
"I've always viewed triglycerides as the Rodney Dangerfield of lipids -- they didn't get enough respect," he said.
Still, he said it's unclear whether the drug prevents cardiovascular events by acting directly on triglycerides, or whether they are a marker for some other process going on in our bodies -- "secret sauce," as he says. Or perhaps some combination of the two, he added.
The company described the drug as "well tolerated," with "similar" rates of adverse events between those who got the drug and those who received a placebo.
The drug was approved by the US Food and Drug Administration in 2012 to lower triglycerides in excess of 500 mg/dL.
Roughly a quarter of Amercans age 20 and older have elevated triglycerides, according to data from the National Health and Nutrition Examination Survey. High triglycerides are associated with an increased risk of cardiovascular disease in combination with low HDL and high LDL, according to the US Centers for Disease Control and Prevention. The agency says lifestyle choices can help lower triglycerides, including exercise, weight loss, diet and quitting smoking.
Heart disease is the top cause of death in the US, leading to the deaths of more than 600,000 per year.
"There's still some debate on how important [triglycerides are], but I've gradually come to the opinion that it is important. But whether treating it is important -- there are a bunch of trials that have been, at best, ambiguous about that," Luepker said.
A bottle of 120 1-gram capsules of Vascepa has an average cash price of nearly $350, though many consumers will likely pay less, according to GoodRx, whose numbers are based on sources including published price lists, purchases, claims records and pharmacy data.
Weintraub said that the topline results may have granted a sneak peek, but that's hardly the end of the story. A deeper dive into the data could help illuminate whose risk was slashed the most, to what degree, and what other differences were seen between subgroups in the trial. For example, do the people with the highest triglycerides derive the greatest benefit? Is the effect the same in men and women, in people with or without diabetes?
"It may turn out to be worthwhile," said Luepker, but the announcement "does not give me enough information to make a reasoned judgment of whether this is good, bad or indifferent."
Weintraub, however, said that he wouldn't hesitate to prescribe the drug to patients like those in the trial, given what he described as a very favorable side effect profile and strong topline results.
"I would do it in a heartbeat," he said.