No bleeds seen over 1 year on Altuviiio for many Hem A children

New XTEND-Kids trial data confirm efficacy, safety of therapy

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

Share this article:

Share article via email
A half-filled bottle is labelled

Nearly two-thirds of children with severe hemophilia A given once-weekly Altuviiio (efanesoctocog alfa) in a Phase 3 clinical trial were completely free of bleeds over about one year of treatment.

That’s according to new findings from the recently-completed XTEND-Kids study (NCT04759131), which were presented as late-breaking data at the Annual Meeting of the International Society on Thrombosis and Haemostasis (ISTH), held in Montreal, Canada, June 24-28. The presentation was titled, “Efanesoctocog Alfa Prophylaxis for Previously Treated Patients <12 Years of Age With Severe Hemophilia A.” The work was funded by Altuviiio’s co-developers, Sobi and Sanofi.

“Today’s XTEND-Kids results reinforce the ability of Altuviiio to provide effective bleed protection with once weekly dosing and reinforce our commitment to developing new treatment options designed to redefine the standard of care for people living with rare blood disorders,” Karin Knobe, MD, PhD, therapeutic area head of rare diseases and rare blood disorders at Sanofi, said in a company press release.

Lynn Malec, MD, professor at The Medical College of Wisconsin and presenting author of the talk, added that these results “mark an important breakthrough as we strive for optimized bleed protection as the standard of care.”

“Achieving high-sustained factor activity with once weekly dosing means a freedom from the tradeoffs between treatment burden and efficacy we often see in treating severe hemophilia A,” Malec said, adding, “The reliable and consistent bleed protection Altuviiio provides offers confidence for children living with hemophilia and their families to manage hemophilia with less worry.”

Recommended Reading
A row of hands giving the thumbs up sign is shown in this approval illustration.

Efanesoctocog alfa, now Altuviiio, approved in US for hemophilia A

No bleeding episodes for 64% of hemophilia A children in study

Altuviiio is a long-lasting replacement therapy designed to provide patients with a working version of factor VIII (FVIII), the clotting protein that is missing in hemophilia A. The therapy was approved in the U.S. earlier this year to treat adults and children with hemophilia A, and an application seeking its approval in Europe is now under review.

The Phase 3 XTEND-Kids study enrolled 74 children with hemophilia A younger than age 12. All of them were male, and slightly more than half were younger than 6. All had severe hemophilia A, defined as FVIII activity levels below 1 international unit per deciliter (IU/dL).

Participants were treated with Altuviiio, given intravenously once weekly via an injection into the bloodstream, for about 50 weeks, or nearly one year. Top-line results from the study, announced in March, showed that the mean annual bleeding rate was less than one bleed per year.

The newly-announced data now showed that 64% of the children had no bleeding episodes over the course of treatment. Nearly 9 in 10 (88%) had no spontaneous bleeds, and fewer than 1 in 5 (18%) experienced any bleeding in their joints.

Among bleeds that did occur, most were resolved with a single 50 IU/kg dose of Altuviiio. The response to on-demand treatment was rated as excellent or good for 98% of evaluated injections.

Pharmacological data showed that, in the first days following the administration of Altuviiio, mean FVIII activity in the patients’ blood was higher than 40 IU/dL, which is near the normal range. By one week after the injection, mean FVIII activity had dropped to about 10 IU/dL — lower than what’s seen in people without hemophilia, but still more than 10 times higher than the levels seen without treatment.

Altuviiio’s expanding evidence of a first and best-in-class profile supports Sanofi’s commitment to delivering paradigm shifting therapies for rare diseases.

None of the patients developed neutralizing antibodies against the therapy (known as inhibitors), and the safety profile of Altuviiio in these young children was broadly consistent with earlier clinical findings from older patients. No side effects led to patients stopping treatment.

“Once-weekly efanesoctocog alfa was well tolerated and provided highly effective bleed protection and treatment in children with severe hemophilia A,” the researchers wrote.

According to its developers, “Altuviiio’s expanding evidence of a first and best-in-class profile supports Sanofi’s commitment to delivering paradigm shifting therapies for rare diseases.”