Dr. Anker said the fast action may relate to his hypothesis to explain how iron supplementation exerts a benefit that is apparently independent of a hemoglobin effect. “Iron is needed for the proper function of mitochondria to generate energy in both the heart and in peripheral muscles,” Dr. Anker said. “I think intravenous iron is a powerful intervention; it's a legal way to do doping.”
During the study, mortality rates were 3% in the iron group and 6% in the control patients, a nonsignificant difference. Hospitalization for any cardiovascular reason occurred in 10% of the iron patients and 20% of the controls, a difference that came close to, but did not reach, statistical significance. Cardiac disorders of any type were significantly more common in the control patients, 50%, than in those on iron, 28%. The most notable adverse event more common in the iron patients was gastrointestinal disorder, in 17% of the iron patients and 7% of the controls, a difference that just missed statistical significance.
Dr. Anker noted that his findings show no suggestion of a safety concern, but he conceded that the current experience is limited and the drug needs testing in more patients. Vifor Pharma is currently discussing what further steps it will take in studying its ferric carboxymaltose formulation in patients with heart failure, said Dr. David R. Ebsworth, Vifor's chief executive officer.
My Take
'The Effect Occurs So Quickly'
This is a remarkable result. I am especially impressed that the separation in the primary end points between the patients receiving iron and those on placebo began to be statistically significant after the first 4 weeks on treatment and then continued to separate further.
The effect occurs so quickly. This is probably the fastest separation we've seen in a clinical trial in heart failure.