A prominent statistician is continuing to insist that there is no link between Vytorin and cancer. In a blunt letter to a Congressional Committee investigating Vytorin, Sir Richard Peto, of Oxford University, said that “any competent trial statistician would endorse” his conclusion that there’s “no credible evidence” that the cholesterol drug is tied to increased cancer risk. While Peto’s letter is rather scathing in its dismissal of the Committee’s concerns, it does not answer other criticism of his conclusions recently raised by a prominent medical journal.
Peto conducted an analysis of cancer data in three Vytorin trials that was released at the same time as the now notorious SEAS trial. SEAS was designed to see if the drug helped people with aortic stenosis avoid heart attacks. Not only did SEAS show that Vytorin offered no additional heart attack prevention, but Vytorin patients enrolled in the study had higher rates of cancer than those taking a placebo. 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. But based on his analysis, Peto called the idea that Vytorin was linked to cancer or cancer deaths bizarre.
The House Energy and Commerce Committee, which had already been probing the controversial Vytorin study known as ENHANCE, expanded its investigation to the SEAS controversy. The Committee has since written two letters to Merck and Schering-Plough, asking for more information on SEAS and Peto’s analysis.
In his letter to the Committee, Peto writes that he can best answer many of its questions. The letter states that “the main conclusion (of the SEAS trial) was that the trial results provide ‘no credible evidence’ that (Vytorin) affects cancer rates. He goes on to say that the “key scientific points that our reports make would be selfevidently true to any competent statistician.”
Peto also denies assertions that he may have a conflict of interest. He and his colleagues, he writes, take no honoraria, consultancy fees or other payments, although companies occasionally pay for their travel accommodations. Peto also states that salaries of researchers are “not directly or indirectly paid for by industry or industry-sponsored projects.”
Finally, Peto calls the Committees request for all correspondence with Merck & Schering-Plough “inappropriate harassment”. Peto says that complying with the request required an “unreasonably vast amount of effort,” as his unit at Oxford has worked with the companies on trials involving about 60,000 patients.
What Peto does not address in his letter, however, is the New England Journal of Medicine’s recent criticism of his Vytorin analysis. When the journal published the SEAS study and Peto’s analysis, it also issued an editorial saying that the Vytorin cancer link shouldn’t be attributed to chance “until further data are in.”