The FDA has approved a new fibrinogen concentrate — fibrinogen, human-chmt (Fesilty, Grifols Therapeutics, LLC) — for the treatment of acute bleeding episodes in pediatric and adult patients with congenital fibrinogen deficiency (CFD).

While Fesilty is indicated for acute bleeding associated with hypo- or afibrinogenemia, it is not indicated for dysfibrinogenemia.

The approval of the human blood coagulation factor was based on findings from a prospective, open-label, phase 1/3 study that evaluated the pharmacokinetic properties, efficacy, and safety of the product for the treatment and prevention of bleeding in patients with CFD, according to a press release announcing the approval.

CFD is a rare inherited bleeding disorder caused by genetic mutations that affect the production or function of fibrinogen, which is essential for blood clotting and wound healing. The novel fibrinogen concentrate, which is a “highly purified product with a precisely defined amount of fibrinogen,” was shown to “enable rapid and predictable restoration of fibrinogen levels” in patients with CFD, according to the press release.

Conversely, other treatment options for CFD, such as fresh frozen plasma or cryoprecipitate, include proteins and components that are unnecessary for fibrinogen replacement and often require large-volume infusions to achieve adequate fibrinogen levels to treat acute bleeding, the company explained.

In a prior phase 3 study evaluating the product in patients with major hemorrhage while undergoing orthopedic or abdominal surgery, fibrinogen, human-chmt (also known as BT524) was found to be noninferior to existing treatments. The least squares mean intraoperative blood loss was 1381 mL for patients treated with fibrinogen, human-chmt, vs 1660 mL for those treated with fresh frozen plasma or cryoprecipitate. The difference indicated “a notable treatment difference beyond non-inferiority,” the investigators wrote in their paper published in eClinical Medicine in July 2025.

Serious adverse reactions observed in patients with CFD treated with fibrinogen, human-chmt were t hrombotic events, including portal vein thrombosis, deep vein thrombosis, and pain in extremities with clinically suspected thrombosis. One patient experienced an episode of epilepsy and died due to an extradural hematoma 4 weeks after treatment.

The most common adverse reactions occurring in over 2% of patients were extremity pain, back pain, hypersensitivity reactions, pyrexia, thrombosis, increased fibrin D dimer, headache, and vomiting.

Grifols stressed that fibrinogen, human-chmt is “made from pooled human plasma and may carry the risk of transmitting infectious agents.”

The product is contraindicated in patients who have severe hypersensitivity reactions, including anaphylaxis to the product or its components, which include arginine hydrochloride, polysorbate 80, sodium citrate dihydrate, and trehalose dihydrate.

Grifols expects the product to be available in the United States in the first half of 2026.

Sharon Worcester, MA, is an award-winning medical journalist based in Birmingham, Alabama, writing for Medscape, MDedge, and other affiliate sites. She currently covers oncology, but she has also written on a variety of other medical specialties and healthcare topics. She can be reached at sworcester@mdedge.com or on X: @SW_MedReporter.