NEW ORLEANS – The success of icosapent ethyl in cutting triglyceride levels and reducing cardiovascular disease events in at-risk patients in the REDUCE-IT trial may make clinicians rethink the threshold for an unhealthy triglyceride level that merits intervention.
Study results are also showing that the patients enrolled in REDUCE-IT are common, with apparently millions of Americans who could potentially receive the icosapent ethyl–processed fish oil used in the study if the Food and Drug Administration were to approve new labeling for the drug that the manufacturer filed for in late March 2019. Icosapent ethyl (Vascepa) already has U.S. marketing approval for reducing triglyceride (TG) levels in patients with baseline values of 500 mg/dL or greater, while the REDUCE-IT trial enrolled patients with established cardiovascular disease or diabetes plus at least one more risk factor with a TG level of 150-499 mg/dL. REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl–Intervention Trial) enrolled only patients already on statin treatment and with a LDL cholesterol level of 41-100 mg/dL.
In reality, the clinicians who enrolled the 8,139 participants at 473 worldwide sites included patients with a TG level as low as 81 mg/dL, and 10% of entered patients had levels below the minimum threshold in the trial’s written design of at least 150 mg/dL. Initial results reported with the primary endpoint finding suggested that the icosapent ethyl treatment benefit extended to these patients who entered with what are currently considered normal TG values, and additional analyses reported by the study’s lead investigator, Deepak L. Bhatt, MD, which used a larger endpoint dataset that included total cardiovascular events rather than just first events, further confirmed that patients with lower baseline TG levels had reductions in their cardiovascular disease events that matched what was seen in patients who entered with substantially higher TG levels.
In the analysis that included total events, the tertile of patients with a baseline TG of 81-190 mg/dL had a statistically significant 26% relative reduction in events during an average 3.5-year follow-up, compared with the tertile of patients with a baseline level of 251 mg/dL or higher, who had a 40% reduction in their events during follow-up, reported Dr. Bhatt, professor of medicine at Harvard Medical School, Boston.
“We had patients [in REDUCE-IT] with lower triglycerides than the inclusion criteria. This shows that the study results apply to a broader range of patients,” he said in a talk at the annual meeting of the American College of Cardiology. “The total-event analysis gives us an appreciation of the large burden of ischemic events that statin-treated patients still have with baseline triglyceride levels of about 100 mg/dL.” Further analysis of the REDUCE-IT data, as well as future studies of TG-lowering drugs like icosapent ethyl, “may help redefine normal TG levels” in a manner similar to what happened over a 2-decade span as serial studies of statins and other drugs that reduced levels of LDL cholesterol led to incremental reductions in goal lipid levels.
In addition to providing greater precision in defining the impact of icosapent ethyl on events in patients with lower baseline TG levels, the total-event analysis “provided a better sense of what is actually going on” with patients clinically as they experience multiple cardiovascular events during follow-up, as well as the impact of treatment on reducing health-related costs. Concurrently with Dr. Bhatt’s report of the total-event analysis at the meeting, some of the new findings he presented also appeared online (J Am Coll Cardiol. 2019 March 18. doi: 10.1016/j.jacc.2019.02.032).
Recent analyses have also begun to assess the scope of patients who could potentially receive icosapent ethyl based on the enrollment criteria of REDUCE-IT. One analysis of more than 1 million people in the U.S. Veterans Affairs Health System during 2010 identified 439,019 people on statin treatment and with an LDL cholesterol of 41-100 mg/dL, the cardiovascular disease history or risk pattern that matched the trial, and not on treatment that could reduce TG levels such as fish oil. Among these people, 30% had a TG level at or above 150 mg/dL that would have qualified them to enter REDUCE-IT, said William E. Boden, MD, professor of medicine at Boston University. Among the 132,203 patients in this group who were on statin treatment and at their target LDL cholesterol level, the 5-year rate of cardiovascular disease events was 8.5% in those with higher TG levels and 6.3% in those with levels below 150 mg/dL, a statistically significant 19% increased risk after adjustment for some potential confounders, Dr. Boden reported in a poster he presented at the meeting. This analysis hinted at the magnitude of patients who are candidates for icosapent ethyl treatment based on REDUCE-IT, and the 19% residual increased risk they displayed showed what this treatment could address.
Analysis of another database identified 16% of more than 24,000 patients with stable coronary artery disease in the CLARIFY registry who would qualify for icosapent ethyl treatment by matching the REDUCE-IT enrollment criteria (J Am Coll Cardiol. 2019 March;73;doi: 10.1016/j.jacc.2019.01.016).
REDUCE-IT was sponsored by Amarin, the company that markets icosapent ethyl (Vascepa). Dr. Bhatt is an adviser to Cardax, PhaseBio, and Regado Biosciences, he is on the board of TobeSoft, and he has received research funding from several companies. Dr. Boden reported no disclosures.