FDA Updates ALTUVIIIO Label with Full Pediatric Data in Hemophilia A


Announced by Sanofi on May 10, 2024, the updated FDA label is based on full results from the pivotal phase 3 XTEND-Kids study.

FDA Updates ALTUVIIIO Label with Full Pediatric Data in Hemophilia A | Image Credit: US Food and Drug Administration

Credit: US Food and Drug Administration

The US Food and Drug Administration (FDA) has approved an update to the label for Antihemophilic Factor (Recombinant), Fc-VWF-XTEN Fusion Protein-ehtl (ALTUVIIIO®) for pediatric hemophilia A based on data from the phase 3 XTEND-Kids study.1

Announced by Sanofi on May 10, 2024, the label update included the full XTEND-Kids results, showing that once-weekly dosing with ALTUVIIIO delivered highly effective bleed protection for children with hemophilia A. Granted FDA approval in February 2023, this label update builds on interim trial data included in the initial label.2

“Hemophilia is a lifelong condition, so starting children on an early prophylactic regimen can help them stay ahead of bleeds and reduce other potential complications, such as joint damage and pain,” Mindy Simpson, MD, a pediatric hematology/oncologist and assistant professor of pediatrics at Rush University Medical Center, said in a statement.1

A rare condition that impacts the ability of blood to clot properly, hemophilia A can lead to excessive and spontaneous bleeds into joints leading to chronic pain and impaired quality of life.3 The severity of hemophilia A is designated by the level of clotting factor activity in blood, suggesting a negative association between bleeding risk and factor activity levels.

ALTUVIIIO is a first-in-class, high-sustained factor VIII therapy designed to extend protection from bleeds with once-weekly prophylactic dosing in adults and children with hemophilia A.1 For adults and adolescents, ALTUVIIIO has shown a 3- to 4-fold longer half-life, compared with standard and extended half-life treatments.

XTEND-Kids was a phase 3 open-label, nonrandomized interventional study of the safety, efficacy, and pharmacokinetics of once-weekly ALTUVIIIO in patients ≤12 years previously treated for severe hemophilia A. A total of 74 patients received once-weekly ALTUVIIIO prophylaxis (50 IU/kg) for 52 weeks—the primary endpoint was designated as the occurrence of inhibitor development.

Evidence from XTEND-Kids suggested ALTUVIIIO’s benefit as a treatment option for hemophilia A, particularly in bleed protection for children. Children typically clear administered factor concentrates in blood faster than adults, requiring multiple weekly injections of factor products.

Full data from XTEND-Kids show that a once-weekly 50 IU/kg dose of ALTUVIIIO provided highly effective bleed protection in children with hemophilia A. The therapy met the primary endpoint of safety with no detection of factor VIII inhibitor development (0% [95% CI, 0–4.9]).

Key secondary endpoints in XTEND-Kids were also met, with a mean annualized bleeding rate (ABR) of 0.6 (95% CI, 0.4 - 0.9) and a median ABR of 0.0 (interquartile range [IQR], 0.0 - 1.0) in the analysis of 72 patients evaluable for efficacy.

The safety profile of ALTUVIIIO remained consistent with that of the XTEND-1 trial, with no serious allergic reactions, anaphylaxis, or embolic or thrombotic events reported in the data. Sanofi indicated the formation of inhibitors and allergic reactions remains possible when receiving ALTUVIIIO. The most common adverse drug reactions (>10%) were fever and no adverse events led to treatment discontinuation.

“Delivering significant bleed protection with a reduced treatment burden can allow families to spend more time on activities and less time focused on infusion schedules,” Simpson added.1

Previously, ALTUVIIIO was granted Breakthrough Therapy designation by the FDA in May 2022 and received Fast Track Designation in February 2021 and Orphan Drug designation in August 2017.1


  1. Press releases. Press Room - Press Releases. May 13, 2024. Accessed May 13, 2024. https://www.news.sanofi.us/2024-05-10-FDA-approves-updated-ALTUVIIIO-R-label-with-expanded-pediatric-data-confirming-highly-effective-bleed-protection-in-children-with-hemophilia-A.
  2. Iapoce C. FDA approves first-in-class factor VIII therapy for hemophilia A. HCP Live. February 23, 2023. Accessed May 13, 2024. https://www.hcplive.com/view/fda-approves-first-in-class-factor-viii-therapy-hemophilia-a.
  3. Mehta P, Reddivari AKR. Hemophilia. [Updated 2023 Jun 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551607/
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