FDA Approves First Anticoagulant for Children with Potentially Life-Threatening Blood Clots

Officials with the FDA today approved dalteparin sodium (Fragmin, Pfizer) injection, for subcutaneous use, to reduce the recurrence of symptomatic venous thromboembolism (VTE) in pediatric patients age 1 month and older. It is the first anticoagulant indicated for pediatric patients approved by the agency.

VTE can include deep vein thrombosis and pulmonary embolism, which can lead to death.

“Most children who have VTE are fighting a serious underlying primary illness such as cancer or congenital heart disease. Not only are they fighting a serious illness, having a condition like VTE can then lead to significant complications and even death,” said Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, in a prepared statement.

Pfizer’s application for dalteparin sodium was given Priority Review status, according to the FDA, due to a need that was unmet, according to the agency.

“Prior to this approval, there had been no FDA-approved therapies to treat VTE in pediatric patients,” said Pazdur. “We remain committed to advancing treatments for children with unmet medical needs.”

VTE usually develops as a secondary complication of underlying clinical conditions such as a venous catheter, cancer, infection, congenital heart disease, and trauma or surgery. Pediatric VTE is associated with an increased risk of in-hospital mortality, recurrent VTE and post-thrombotic syndrome.

Dalteparin sodium was first approved by the FDA in 1994. The efficacy of dalteparin sodium in children was based on a single trial with 38 pediatric patients with symptomatic deep vein thrombosis and/or pulmonary embolism. Patients were treated with dalteparin sodium for up to 3 months, with starting doses by age and weight.

At study completion, 21 patients achieved resolution of the qualifying VTE, 7 patients showed regression, 2 patients showed no change, no patients experienced progression of the VTE and 1 patient experienced recurrence of VTE.

Common adverse effects of patients taking dalteparin sodium are bleeding, including hemorrhage, thrombocytopenia, hematoma, or pain at the injection site and transient elevation of transaminases.

Health care professionals are advised to use caution in conditions with increased risk of hemorrhage and monitor thrombocytopenia of any degree closely. Health care professionals also are warned not to use benzyl alcohol preservative multiple-dose formulations in infants as they contain benzyl alcohol and should not be used.

Patients are advised to have blood count laboratory tests periodically. Health care professionals are advised to monitor patients closely for bleeding when administering dalteparin sodium to patients who currently take anticoagulants. Patients at risk for VTE may receive certain treatments or interventions to help reduce the likelihood of the formation of blood clots, including taking anticoagulants.

The label for Pfizer’s dalteparin sodium contains a boxed warning to alert health care professionals and patients that epidural or spinal hematomas may occur in patients who are anticoagulated due to taking certain medications called low molecular weight heparins (LMWH) or heparinoids and are receiving neuraxial anesthesia or undergoing spinal puncture. These hematomas may result in long-term or permanent paralysis. Health care professionals are advised to consider these risks when scheduling patients for spinal procedures as patients may be at a higher risk of developing VTE.

Reference

FDA approves first anticoagulant (blood thinner) for pediatric patients to treat potentially life-threatening blood clots [news release]. Silver Spring, MD; May 16, 2019: FDA website. https://www.fda.gov/news-events/press-announcements/fda-approves-first-anticoagulant-blood-thinner-pediatric-patients-treat-potentially-life-threatening. Accessed May 16, 2019.