Study Suggests Hypophosphatemia May Occur in Over 50% of Injectafer Patients

Published on April 8, 2019 by Sandy Liebhard

A recent study suggests that more than half of all patients who receive Injectafer for iron deficiency anemia may develop severe hypophosphatemia, a potentially life-threatening condition caused by low levels of phosphorus in the blood.

Injectafer and Iron Deficiency Anemia?

Injectafer (ferric carboxymaltose injection) is an intravenous medication for adults with iron deficiency anemia who can’t tolerate or otherwise use oral supplements.

Sufficient iron levels are required to make hemoglobin, the substance which enables red blood cells to carry oxygen throughout the body. People who suffer from iron deficiency anemia may experience severe fatigue and shortness of breath. Without treatment, they can eventually develop an enlarged heart, heart failure, and other life-threatening complications.

Patients with iron deficiency anemia generally take oral supplements.  Unfortunately, the side effects sometimes associated with iron tablets – constipation, upset stomach, and heartburn – cause many people to stop taking them. In other cases, medical conditions may prevent the digestive tract from absorbing oral iron.

Injectafer, Feraheme and similar intravenous iron supplements are reserved for these individuals. Because such drugs are administered directly into the bloodstream, malabsorption and gastrointestinal toxicity are not issues. Intravenous supplements also worker faster and longer, allowing patients to go months, even years, between treatments.

Injectafer and Hypophosphatemia

All intravenous iron treatments can cause hypophosphatemia. However, mounting evidence suggest Injectafer is more likely to cause severe, persistent low phosphorus levels.

The most recent study, published last December in the Journal of Clinical Investigation, involved nearly 2,000 adults treated for iron deficiency anemia from February 2016 to January 2017. Just over half received a single cycle of Injectafer infusions, while the remaining received Feraheme. The research team tested each patient for signs of hypophosphatemia at one, two, and five weeks post-treatment.

According to the study authors:

• 50.8% of the Injectafer patients had severe hypophosphatemia compared to just 0.9% of Feraheme patients.
• While 1 in 10 Injectafer patients developed extreme hypophosphatemia, none in the Feraheme group did.
• 29.1% of the Injectafer patients had persistent, severe hypophosphatemia by the end of study. However, none of the Feraheme patients did.

Injectafer Lawsuits Mounting in Pennsylvania Federal Court

The nation’s first Injectafer lawsuit involving hypophosphatemia was filed last January in the U.S. District Court, Eastern District of Pennsylvania. (Case No. 2:19-cv-00276).

According to the complaint, the drug’s label does not even mention severe hypophosphatemia as a possible side effect. Instead, the prescribing information merely notes that a transient or asymptomatic decrease in phosphorus levels is a possibility. The complaint seeks damages from the drug’s manufacturers for negligence in duty of care, failure to warn, design defect, misrepresentation, and fraudulent representation regarding Injectafer’s alleged risks.

Similar lawsuits have been filed since then, and many legal experts believe the Injectafer hypophosphatemia litigation will eventually include hundreds of additional claims.