Then and Now: Quality Differences in ENHANCE Data

Did Schering-Plough use data-quality problems as an excuse to forestall publication of ENHANCE's negative outcome, or did the company do a yeoman's job of cleaning up suboptimal data from John Kastelein's imaging lab? That's the latest question raised by the protracted coverage of the study.

According to statements made by John Stein, University of Wisconsin imaging expert, to Forbes, there are substantial differences in the quality of the carotid-imaging data presented by SP at the independent review of the ENHANCE study data in November 2007 and those revealed publicly last month, which looked "quite good" according to the doctor. Forbes reports today that the independent-review panelists saw only 75 of the approximately 40,000 images taken during the study. On the basis of these selected images, Stein had concluded that the ENHANCE data were "not acceptable."

However, Stein's view of the data quality changed considerably when he (and everyone else) viewed the ENHANCE results at the recent ACC meeting and in the NEJM. Stein is now quoted by Forbes: "For anyone to say the data in the study are bad, they either need to say that John Kastelein [ENHANCE primary investigator] is a liar, which I'm certain he is not, or they need to talk to the [SP] statisticians for the study and ask them if there are any problems with the data." SP's ENHANCE study director, Enrico Veltri, MD, argued to Forbes that the reason the public data look so good is because SP put so much effort into their cleanup.

Regardless of what you believe about the data quality in ENHANCE, it's important to remember that image cleanup would not remedy the very sizeable problem of missing data, which affected approximately 75% of the subjects in the trial.