Amarin Corporation (NASDAQ: AMRN) presented a new post hoc analysis from the REDUCE-IT cardiovascular outcomes trial at the European Society of Cardiology Congress 2026 in Munich, Germany, on Aug. 28, 2026.

The analysis examined the relationship between treatment adherence and cardiovascular outcomes among patients treated with icosapent ethyl (IPE), as well as whether cardiovascular benefits persisted after treatment discontinuation.

Among the 8,179 participants enrolled in REDUCE-IT, the intention-to-treat analysis showed a 25% relative risk reduction in the primary composite endpoint with IPE versus placebo. Among participants who remained on the study drug for at least 1.5 years, defined as high adherers and numbering 6,921, IPE was associated with an approximately 29–30% relative risk reduction in the primary endpoint.

In a separate finding, 1,318 secondary prevention participants who discontinued treatment after a mean of 2.3 years on therapy maintained separation of Kaplan-Meier event curves throughout their entire study follow-up, with a hazard ratio of 0.73. A similar hazard ratio of 0.73 was observed for cardiovascular events occurring after study drug discontinuation, with participants off the study drug for a mean of 2.1 years and no apparent diminution in benefit over one to four subsequent years of follow-up.

"The observed pattern is consistent with a potential legacy effect and reinforces the importance of long-term adherence to treatment in high-risk CV patients," said Chris Packard, Ph.D., D.Sc., Professor of Vascular Biochemistry at the University of Glasgow.

Steven Ketchum, Ph.D., EVP and Chief Scientific Officer at Amarin, noted that the findings are "exploratory in nature" and said they "provide important insights into the durability of the treatment effect."

The analysis was described as a post hoc, exploratory study based on data from the REDUCE-IT trial, which was completed in 2018. The primary results of the trial were published in The New England Journal of Medicine in November 2018.