Injectafer (ferric carboxymaltose) is an iron-replacement product that’s injected directly into the bloodstream, rather than taken in pill form. It is designed to help treat adults who have iron deficiency anemia (IDA) and who either can’t tolerate regular iron supplements or who did not experience good results with them.
Why Would People Need Injectafer?
Iron deficiency anemia is a condition in which the body, because it doesn’t have enough iron, can’t produce enough “hemoglobin.” Hemoglobin is a substance inside red blood cells that binds to oxygen and carries it around to the tissues and organs that require it.
Iron is required for hemoglobin production, so if a person is deficient, hemoglobin levels go down. With less hemoglobin inside the red blood cells, oxygen doesn’t get to where it needs to go, so the person experiences a form of oxygen deprivation. Symptoms may include fatigue, pale skin, cold hands and feet, shortness of breath, and others.
Iron deficiency anemia is usually treated with oral iron supplements. Iron pills have to go through the digestive system before the iron gets into the bloodstream, which means that only some of the iron makes it to the blood where it’s needed. Still, this treatment is effective most of the time, and helps replenish iron levels usually within a month or so. After that, the patient continues to take the supplements for a while to gradually restore iron levels to normal.
In some patients, however, iron pills don’t work very well. Digestive problems can affect how much iron is absorbed, for example. Those who have other medical conditions, like inflammatory bowel disease or chronic kidney disease, may also be unable to recover properly with oral iron supplements.
For these patients, injectable iron may work better. In a 2006 study, for example, researchers found that iron injections were significantly more effective at improving iron levels over 30 days than oral tablets. There are different types of injectable iron replacements available. Injectafer is one of them.
How Does Injectafer Work?
The FDA approved Injectafer in July 2013. They did restrict approval for the treatment of adult iron deficiency only in patients who:
- could not tolerate oral iron supplements
- had not had a good response to oral iron supplements
- or who had chronic kidney disease (CKD)
Injectafer is administered intravenously (IV), so it goes directly into the bloodstream. That means 100% of it is absorbed. The dosage is up to the doctor and depends on things like the severity of the anemia and the patient’s weight, but is not to exceed 1,500 mg given in two doses separated by at least seven days.
FDA Questions Safety of Injectafer Before Final Approval
It took many years and several tries before the FDA finally approved Injectafer as a treatment for iron deficiency anemia. The manufacturer—Luitpold Pharmaceuticals, a wholly owned subsidiary of Daiichi Sankyo—originally submitted the application for approval in 2007. Yet in 2008, the FDA denied approval for the product, noting that they were concerned about the possible side effects.
In the summary review, the FDA stated that studies on the product “showed an imbalance of deaths observed in controlled trials. More deaths occurred in ferrous carboxymaltose [Injectafer] treatment arms than in the control subjects.” In other words, there were more serious adverse events—including a condition called “hypophosphatemia”—among patients receiving Injectafer compared to those receiving oral iron supplements.
Hypophosphatemia is a condition in which the body becomes deficient in phosphate. It causes symptoms like muscle weakness, fatigue, bone pain, and tingling, and at its most severe, can cause respiratory failure, coma, and fatal heart rhythm abnormalities.
Because of these dangerous side effects, the product was not approved, and the manufacturer had to go back and start over.
FDA Withholds Injectafer Approval Because of Issues at Manufacturing Site
After a few years passed, Luitpold Pharmaceuticals submitted another new drug application in October 2011. They had new data from two new clinical trials, but again in 2012, the FDA decided to withhold approval. This time, the administration hesitated because they found issues during an inspection of one of the company’s manufacturing facilities—the very one that would be used to produce Injectafer.
It wasn’t until July 2013 that the FDA finally approved Injectafer for the treatment of iron deficiency anemia, as noted above.
But after the product had been on the market for a few years, studies began to show that Injectafer—more than other injectable iron supplements—increased risk of not only hypophosphatemia, but life-threatening “severe hypophosphatemia.”