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Ezetimibe initiations declined, discontinuations increased after announcement of ENHANCE trial data
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After the announcement of the ENHANCE trial results in January 2008, in which ezetimibe failed to slow the progression of atherosclerosis, ezetimibe initiations declined and discontinuations increased. However, nearly 2% of all adults continuously enrolled in a large US pharmacy benefit manager continue to use the drug, according to a new report.
The retrospective study used anonymized data collected from the Express Scripts pharmacy manager from 2007 to 2010. In total, the researchers analyzed data on 597,296 continuously eligible adults aged 18 years and older.
After identifying all lipid-lowering therapy prescription claims for adult beneficiaries, the researchers classified prescriptions as those containing only ezetimibe (Zetia, Merck) or those containing ezetimibe plus simvastatin (Vytorin, Merck). New initiations and discontinuations of ezetimibe were recorded by month and year.
From 2007 to 2010, 29.1% of the continuously eligible adults received at least 1 prescription for lipid-lowering therapy. Of those, 17.8% obtained prescriptions for ezetimibe and 95.3% obtained prescriptions for another lipid-lowering medication, primarily a statin.
Peak ezetimibe use occurred in January 2008. At this time, 2.5% of all adults were using an ezetimibe regimen. By December 2010, the number of adults using an ezetimibe regimen decreased to 1.8%.
Announcement of the ENHANCE trial results was associated with a decline of 0.16% of monthly ezetimibe users (P=.11). The announcement was also linked to a 0.14% increase in users of monthly ezetimibe, and 0.3% fewer users of ezetimibe combined with other lipid-lowering medications (P=.01 for both). Release of the data was also associated with a 0.44% decrease in ezetimibe initiations (P=.002) and a 10.4% increase in monthly ezetimibe discontinuations (P<.001). The changes in initiations and discontinuations were pronounced with ezetimibe monotherapy.
More than half of adults who started ezetimibe therapy did so without a first prescription for another lipid-lowering medication. This trend was observed both before (50% to 60% of adults) and after (60% to 70%) announcement of the ENHANCE trial results.
Adults aged 50 to 64 years and those living in the East South Central US Census division were more likely to initiate ezetimibe and less likely to discontinue therapy after learning of the ENHANCE trial results.
According to the researchers, the continued use of ezetimibe after the ENHANCE trial results may be indicative of a lack of awareness regarding clinical trial failures.
“Whereas studies have demonstrated that robust positive trials, in which an intervention is found to be effective, have an impact on clinical practice, few studies have examined the impact of negative trials,” Joseph S. Ross, MD, MHS, from the Robert Wood Johnson Clinical Scholars Program, Section of General Internal Medicine, Yale University School of Medicine, and colleagues wrote.
Disclosure: See the full study for a list of the researchers’ relevant financial disclosures.
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