Reuters is reporting that experts are clashing over the safety of the cholesterol drug Vytorin as full results from a controversial study were presented at Europe’s biggest medical congress. Researchers involved in the so-called SEAS study – highlights of which were first released in July – said there was no credible evidence linking Vytorin to cancer and that the higher number of cases seen in the trial was simply a fluke.
But an editorial in the influential New England Medical Journal, which published the full data from the Vytorin study online, said the safety of the drug was now in doubt, and several leading doctors also expressed concerns.
Although there may be concerns with some doctors, I don’t share them. Why is that?
The full report on the SEAS trial, involving 1,873 patients, showed a total of 105 cancer cases among Vytorin patients compared with 70 taking a placebo. That was an upward revision from the totals of 93 and 65 reported in July.
Nevertheless, the media is blowing this up by saying that if you take Vytorin, that you have a 40% increased risk of developing cancer.
And, although it’s true that that is the RELATIVE risk, what’s the absolute risk?
Well, 105 cases in 1,873 patients is an ABSOLUTE risk of 5.6%. But, could a study really show this much cancer risk in just three years? That seems unlikely, eh?
Furthermore, when researcher Terje Pedersen, of Ulleval University Hospital in Oslo, combined all three studies that have looked at patients taking Vytorin they found NO risk of cancer.
In other words, when they combined together into a large single study (meta-analysis), there was NO cancer risk found. When they cross-checked with cancer rates in the two much larger, ongoing trials, they found NO support for the idea that Vytorin was linked to cancer.
The meta-analysis (also published this week in the New England Journal of Medicine), showed that of the 11,263 patients who took Vytorin 414 developed cancer. However, in the 11,227 patients who took the placebo, 391 developed cancer.
So, statistically, there’s no cancer risk.
So, why do the editors of the New England now say, “Physicians and patients are unfortunately left for now with uncertainty about the efficacy and safety of the drug”?
Only because, as they note, Vytorin might interfere with gastrointestinal absorption not only of cholesterol but also other molecules that could conceivably affect the growth of cancer cells.
But experts I’ve talked to say there is absolutely no evidence for such a cancer-causing mechanism – echoing the conclusions of Richard Peto, a cancer epidemiologist at Oxford University.
Douglas Weaver, president of the American College of Cardiology (ACC), speaking of the small study showing a small risk of cancer, said he was more than 90 percent certain the association between Vytorin and cancer was chance.
But Timothy Gardner, president of the American Heart Association (AHA), was more cautious. “We need to be very careful and watch this. We are not able to definitively say that there is no risk here with this drug,” he told reporters.
But, Dr. Gardner, we have NO significant evidence upon which we can say that there is a risk.
The AHA issued a statement on Tuesday reiterating that Vytorin should not be used as a first-line treatment but only when patients failed to respond to top doses of statins.
I agree with that advice and with both the AHA and ACC which say patients should not stop taking any medications without first talking to their doctor.