ARBITER 6-HALTS trial comparing ezetimibe and niacin terminated early by steering committee


Click here to see all of CardioBrief‘s coverage of ARBITER-6


Updated with clarifications from Allen Taylor, Abbott, and Schering-Plough– ARBITER 6-HALTS, a trial comparing ezetimibe to extended-release niacin in 400 patients already taking statins, has been terminated early by an independent steering committee. According to a statement entered on June 16, 2009 on the trial’s page on the website, the early halt of the trial was “based on results of a prespecified, blinded interim analysis. It was not stopped due to safety concerns.”

News of the early termination was first reported today by Peter Loftus on DowJones Newswires. The trial was sponsored by Abbott and the Walter Reed Army Medical Center. Allen Taylor, who recently moved from Walter Reed to the Washington Hospital Center, is the principal investigator.

The primary endpoint of the study was the change in carotid intima-media thickness between groups after 14 months. Because  niaspan has been previously shown to regress CIMT while ezetimibe, famously, has not, some observers have speculated that niaspan may have outperformed ezetemibe. But no explanation has appeared from either the investigators or the sponsors.

Update (July 9, 2009):

Taylor provided some clarification to CardioBrief. Responding to the DowJones story which stated that Taylor “said more information might be provided at a later date,” Taylor told CardioBrief: “Data will be publicly disseminated in a scientific forum at the earliest possible time.”

Asked about Abbott’s role in the trial, Taylor wrote: “Abbott played/plays no role other than funding support through an independent third party foundation.”

Finally, Taylor emphasized that the steering committee is strongly in favor of limiting speculation about the trial: “We made a committee decision to solely utilize the NIH website for our public disclosure- the intent is to limit speculation/manage expectations in favor of future, more substantive communications.”

CardioBrief readers may recall that Taylor and Steve Nissen wrote a perspective for Circulation: Cardiovascular Quality and Outcomes on the media storm caused by the SEAS trial. After reading their conclusions the decision to not speak with the media or issue a press release should come as no surprise. Here is their conclusion:

“The manner of release of the SEAS trial and the unblinding of 2 other ongoing trials raises important questions about the scientific process in an era of mass media communications. Premature release of data via a highly orchestrated media event does not serve the scientific community well. Premature unblinding of ongoing trials for commercial purposes is highly undesirable and compromises the integrity of these studies. Finally, approval of a first-in-class drug on the basis of biochemical surrogates is fraught with hazard. The ultimate price may be widespread utilization of agents that lack a favorable balance between safety and efficacy.”

Abbott has confirmed with CardioBrief that ARBITER 6-HALTS is not an Abbott study and referred all questions about the study to Taylor. An Abbott spokesperson further clarified that “Abbott has not been informed of the results of the study — only that it was halted and that safety was not an issue.”

A representative from Schering-Plough, makers of ezetimibe, stated that Merck/Shering-Plough had no involvement in the study. “We do not know the results of ARBITER 6 nor the reason why the trial was stopped early — we know what others have seen, the statement on the website that said the trial ‘was not stopped due to safety concerns.'”

The spokesman further said that “speculation in the public domain ranges from the study may show no difference between the two arms to the study did show a difference, but at this point, the results are not available to us or to others, other than the investigators.”

The representative went on to point out that CIMT is, after all, a surrogate endpoint: “This IMT study compared niacin plus statin to ezetimibe plus statin for their effects on atherosclerosis, a surrogate endpoint. The study designed to assess the potential additional benefits of ezetimibe on reducing cardiovascular morbidity/mortality above and beyond those provided by simvastatin alone is IMPROVE-IT, and those results are expected in 2012.”

Click here to read the design and rationale of  the ARBITER 6 Trial (Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol)-6-HDL and LDL Treatment Strategies in Atherosclerosis (HALTS).


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