Vytorin is being investigated by federal regulators for a possible link to cancer. The investigation stems from the publication last month of the SEAS study, which found that patients taking Vytorin had a higher rate of cancer than those taking a placebo.
The SEAS study investigated the effects of Vytorin in patients with partial blockages of the aortic valve of the heart, known as aortic stenosis. Left untreated, it can progress to death from heart failure or cardiac arrest. According to the SEAS findings, Vytorin did little to help patients with aortic stenosis avoid other heart problems.
But even more disturbing, a subsequent safety analysis of SEAS found that Vytorin patients in the study had higher rates of cancer and cancer deaths. In the trial 102 patients taking Vytorin developed cancer, compared with 67 taking the placebo. Of those, 39 people taking Vytorin died from their cancer, compared with 23 taking placebo.
Researchers conducting the study said that while those numbers don’t prove a definitive cancer link, they were “statistically significant”, meaning the odds were less than 5 percent that they were the result of chance.
In a notice on its website, the Food & Drug Administration (FDA) announced that it was going to investigate the possible association between the use of Vytorin and cancer reported in the SEAS trial.
Despite the safety review, the agency is not telling anyone to stop taking Vytorin. That’s because, according to the FDA, interim data from two large ongoing cardiovascular trials of Vytorin – the Study of Heart and Renal Protection (SHARP) and the Improved Reduction in High-Risk Subjects Presenting with Acute Coronary Syndrome (IMPROVE-IT) – so far have not shown an increased risk of cancer with Vytorin. The SHARP trial is expected to be completed in 2010. The IMPROVE-IT trial is scheduled for completion around 2012.
The FDA said safety data from both SHARP and IMPROVE-IT are being evaluated on a regular basis by independent data safety monitoring boards. For now, the FDA says the cancer findings in the SEAS trial plus the interim data from SHARP and IMPROVE-IT should not prompt patients to stop taking Vytorin or any other cholesterol lowering drug.
The FDA will be receiving a final SEAS study report in about 3 months. Once FDA receives the final study report, it will likely take 6 months to fully evaluate the clinical trial data and other relevant information. As soon as this review is complete, the FDA says it will communicate its conclusions and recommendations to the public.
The FDA is already reviewing another Vytorin study, ENHANCE, that was released earlier this year. EHANCE showed Vytorin was ineffective in preventing clogged arteries, and might actually increase plaque in some users.
The ENHANCE study was supposed to have been released by Merck and Schering-Plough in November 2006. However, the release of ENHANCE was delayed twice by the companies. The drug makers also tried changing the ENHANCE study’s endpoint – the main medical result the study was meant to measure. It is generally accepted that for a clinical trial to be effective, a study’s endpoint must be set at its beginning and remain unchanged.
Merck and Schering-Plough backed off changing the ENHANCE endpoint and finally released the preliminary results of the study on January 14 in the form of a press release. But some have likened the companies’ delays and their attempt to change the endpoint of ENHANCE to fraud. As a result, Vytorin faces a Congressional investigation, as well as probes by the Department of Justice and several state Attorneys General.