Gaithersburg, MD: When Dr. David Graham testified at the federal drug panel July 30th, reviewing the fate of diabetes drug Avandia and its relationship to heart attack, stroke and kidney failure, he didn't mince words.
"It's well established that rosiglitazone increases congestive heart failure," he said. The drug safety reviewer with the U.S. Food and Drug Administration (FDA) appeared calm and relaxed, standing behind the lectern with a notebook computer staring up at him. As he looked out at a sea of faces, some fans of Avandia and others foes, he reiterated that the longer Avandia remained on the market, the more potential there was for harm, and in his view it should be recalled.
In spite of overwhelming data slamming Avandia for its risk to the heart and kidney, a majority of the panel voted in favor of keeping Avandia on the market, albeit with beefed-up warnings.
And in spite of manufacturer GlaxoSmithKline maintaining its position that Avandia is safe, there are new studies which seem to back up the findings of Cleveland-based cardiologist Steven Nissen, who authored a report published in the May edition of the New England Journal of Medicine that cast Avandia as a scourge to the heart and kidney and sent headlines around the world. Sales of the drug plummeted.
Just a few weeks before the much-heralded federal drug panel review, a new German study concluded that Avandia could worsen the complications of cardiovascular disease, and that Avandia use does little to improve quality of life, or length of life.
Dr. Bernd Richter of Duesseldorf's Heinrich-Heine University noted that his study found evidence that Avandia produced similar reductions in blood sugar levels as that of other oral anti-diabetes drugs. However, patients on an Avandia regimen gained up to 11 pounds on average and were twice as likely to suffer from edema, or swelling.
Together with the potential for heart failure, kidney failure and bone fractures, "I see a bundle of adverse effects, and I don't see really good positive effects," Dr. Richter said.
Another recent study, published in the August issue of Diabetes Care, found that patients taking Avandia – or its competitor, Actos – had twice the risk of developing heart failure.
Those findings are backed up by the FDA's own investigation, done prior to the federal drug review panel as a lead-up to the Avandia debate. Their findings reveal that Avandia carries a much higher risk of adverse affects than Actos, a competing diabetic drug manufactured by Takeda of Japan.
GlaxoSmithKline, the manufacturer of Avandia, has always maintained that their product is safe, and at worse – no worse than any other diabetic drug, and they maintained that position during the July 30th hearing.
However the FDA's own findings appear to dispute that claim. Additionally, Actos was found to be less of a risk for diabetics already on insulin therapy.
Dr. Sonal Singh, who headed the Diabetes Care study, says their researchers determined that risk factors for developing cardiovascular complication were present in both higher and the lower dosages more commonly prescribed. Heart failure onset was averaged at 24 weeks from the initiation of the drug, and risk factors were not confined to seniors. In Singh's study, 25 per cent of the participants who developed heart failure were under 60 years of age.
The Diabetes Care study group surmised that a factor in the onset of heart failure seen in patients taking Avandia as well as Actos was linked to fluid retention – a suspicion also identified in the German study.
GlaxoSmithKline, the second-largest drug maker in the global pharmaceutical marketplace, continues to defend Avandia as safe. While acknowledging it is in negotiations with the FDA on the prescribed wording for the black box warning on the product, Glaxo maintains that its science "…shows no increase in cardiovascular death, and does not support a difference in heart attack rates between Avandia and the other most commonly-prescribed oral anti-diabetics," Glaxo spokeswoman Mary Anne Ryhne told the New York Times in response to the release of the government report.
And there are other voices, beyond Glaxo, who support Avandia's continuance. Dr. Stephen Clement, with Georgetown University Hospital, told the Associated Press that in his view Avandia is "still a good drug for some patients. I would like to still have it available for use on patients who are already on it, that are doing well – and let the patients and physicians decide." And Dr. Larry Deeb, who serves as president for medicine and science at the American Diabetes Association, maintains that "the risk for heart failure with these drugs may be one in 50, but if you can correctly identify who that person [at risk] is, you can safely treat the other 49 and not hurt anybody."
Dr. Steven Nissen of Cleveland, who remains an outspoken critic of Avandia and other drugs in their class, disputes that position. He articulates his own view in the strongest terms. "The hazard for heart failure is pretty well known for these drugs," he says – adding that even more important than the actual hazard is the availability of complete and accurate information. Dr. Nissen believes that any patient having serious doubts about their medication should consult with their doctor, and avoid any urge to stop taking it of their own accord.
It is this degree of divergent, polarized viewpoint which ultimately led to the vote on July 30th to allow Avandia a continuance in the market, amidst a sea of conflicting data, opinion and spin.
However, the fact remains that in the U.S. diabetes is big business, with an estimated 18 million Americans suffering from some form of the disease, the majority afflicted by Type 2 diabetes, the most common. It should come as no surprise, therefore, that anyone with a vested interest in a drug aimed at such a large population base would fight tooth and nail to keep that product out there.