FDA Approves Updated Label for Altuviiio for Effective Bleed Protection in Children Younger than 12 Years

The FDA has approved an updated label for antihemophilic factor (recombinant), Fc-VWF-XTEN Fusion Protein-ehtl (Altuviiio), now including the full results of the phase 3 XTEND-Kids (NCT04759131) clinical trial which demonstrated the effectiveness of once-weekly Altuviiio in providing bleed protection in pediatric patients aged younger than 12 years with hemophilia A.¹

Initial approval for Altuviiio was granted in February 2023.² The drug, previously known as efanesoctocog alfa, is a first-in-class, high-sustained factor VIII replacement therapy indicated for both routine prophylaxis, on-demand treatment to control bleeding episodes, and perioperative management for both adults and children with hemophilia A.² Approval was granted after FDA evaluation under the agency’s Priority Review program. Altuviiio also received a Breakthrough Therapy Designation in May 2022, a Fast Track Designation in February 2021, and an Orphan Drug Designation in August 2017.

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Because children with hemophilia “typically clear administered factor concentrates in the blood at a higher rate than adults,” multiple injections of factor replacement products per week are often necessary. However, the full results from the XTEND-Kids study show that a once-weekly dose of 50 IU/kg Altuviiio “provides highly effective bleed protection” in this patient population.

XTEND-Kids is an open-label, nonrandomized interventional study of the safety, efficacy, and pharmacokinetics of once-weekly Altuviiio in previously treated patients, aged younger than 12 years, with severe hemophilia A. The study population included 74 patients who received once-weekly Altuviiio prophylaxis for a 52-week period.

The drug met the primary study endpoint of safety with no factor VIII inhibitor development detected (0%; 95% CI, 0-4.9). Key secondary study endpoints were also met, including mean annualized bleeding rate of 0.6 (95% CI, 0.4-0.9) and median annualized bleeding rate of 0.0 (interquartile range, 0.0-1.0).

The safety profile of Altuviiio in XTEND-Kids was similar to the safety profile demonstrated in the XTEND-1 clinical trial (NCT04161495). There were no serious allergic reactions, anaphylaxis, or embolic or thromboembolic events reported. The most common adverse drug reaction, present in less than 10% of participants, was fever. There were no adverse events leading to treatment discontinuation.

“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,” said Mindy Simpson, MD, a pediatric hematologist/oncologist and an assistant professor of pediatrics at Rush University Medical Center, in a press release.¹ “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.”

Hemophilia A is the most common type of hemophilia, also known as classic hemophilia. The disease is characterized by a deficiency in clotting factor VIII (FVIII). Hemophilia A is heridetary, and is more common in males. According to the CDC, the exact number of individuals in the US with hemophilia is not known, but it is estimated that there are as many as 33,000 males living with the disorder.³

In addition to XTEND-1 and XTEND-Kids, an ongoing extension study, XTEND-ed (NCT04644575), is also underway.

READ MORE: Pediatric Resource Center

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References

1. FDA approves updated Altuviiio label with expanded pediatric data confirming highly effective bleed protection in children with hemophilia A. News release. Sanofi. May 10, 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. FDA approves once-weekly Altuviiio, a new class of factor VIII therapy for hemophilia A that offers significant bleed protection. News release. Sanofi. February 23, 2023. Accessed May 13, 2024. https://www.news.sanofi.us/2023-02-23-FDA-approves-once-weekly-ALTUVIIIO-TM-,-a-new-class-of-factor-VIII-therapy-for-hemophilia-A-that-offers-significant-bleed-protection

3. Data and statistics. CDC. Reviewed July 12, 2023. Accessed May 13, 2024. https://www.cdc.gov/ncbddd/hemophilia/data.html