Interim analysis of AIM-HIGH study affirms positive impact of Niaspan on HDL and triglyceride lipid values

The National Heart, Lung and Blood Institute (NHLBI), a division of the National Institutes of Health (NIH), disclosed results from an interim analysis of the AIM-HIGH clinical trial.

AIM-HIGH was designed to test whether raising HDL and lowering triglycerides in a patient population with established cardiovascular disease and very well controlled LDL levels could produce an additional 25 percent benefit on cardiovascular outcomes.  The study compared extended release niacin (Niaspan®) added to simvastatin to simvastatin alone.  The interim study results concluded that this study objective could not be met.

The findings are important for the type of patients who were enrolled in the trial – those who had stable, non-acute, pre-existing cardiovascular disease and very well controlled LDL on simvastatin.  The relevance of these results to patients outside the study population is currently unknown and it would be premature to extrapolate these results to a broader patient population at this time.  The AIM-HIGH study population does not represent all patient populations in whom the importance of treating low HDL and lowering triglycerides with Niaspan may be significant.  Abbott will reflect the relevant study findings in the label after finalization of the AIM-HIGH study results and appropriate review.

The AIM-HIGH results affirmed the positive impact of Niaspan on HDL and triglyceride lipid values.  Previous studies support HDL as an independent risk factor for cardiovascular disease.

There are a number of unanswered questions that remain, based on these interim study results. Some of these issues may become clearer when the study database closes this Fall and a comprehensive analysis of the complete database can be conducted.

"Lipid disorders and cardiovascular disease are complex and varied.  Based on its long history of clinical evidence, Niaspan remains an important agent for patients with mixed dyslipidemia and primary hyperlipidemia," said Eugene Sun, M.D., vice president, Global Pharmaceutical Clinical Development, Abbott.

Based on an interim analysis of the data, there were a small number of ischemic strokes observed in the study, and more ischemic strokes were observed in the Niaspan plus simvastatin arm of the study.  This contributed to the NHLBI's decision to stop the trial before its planned conclusion.

Previous studies do not suggest that ischemic stroke is a potential complication of niacin or Niaspan.  It remains unclear whether this trend in AIM-HIGH arose by chance, or was related to niacin administration or other issues, including the fact that some of the ischemic stroke events reported in the Niaspan arm occurred after patients had stopped taking the medication and that other medications may have influenced the ischemic stroke risk.

The ischemic stroke data are also inconsistent with what is known about Niaspan's action as a vasodilator, its effect on platelet aggregation and the drug's anti-coagulative properties, all of which are inconsistent with stroke causation.  In addition, no stroke safety signals have been seen in post-marketing safety data over more than 6 million patient years of experience.  The event rates observed in AIM-HIGH are similar to what would be expected in the comparable background population observed in other trials.