Using extended half-life products cuts bleeds in hemophilia B kids
Real-world data show need for fewer infusions, support switch to EHL-FIX
- Using longer-acting, or extended half-life (EHL), factor IX (FIX) products was shown to reduce bleeding episodes in children with hemophilia B in a new study.
- EHL-FIX therapy also required fewer infusions and less factor consumption, improving quality of life among patients.
- The researchers concluded that switching to EHL-FIX from standard therapy is safe, maintains joint health, and is cost-effective for pediatric patients.
Using longer-acting factor IX (FIX) products — known as extended half-life (EHL) products, or EHL-FIX — safely reduced factor use and helped children with hemophilia B experience fewer bleeding episodes and need less frequent infusions, according to real-world data from Germany.
These youngsters also maintained both joint health and quality of life, the researchers noted.
“This study shows a great benefit of the use of EHL-FIX products in patients with haemophilia B,” the team wrote, noting that the treatment outcomes seen could also help lower health care costs for children with the bleeding disorder.
The researchers noted that the data covered youngsters who switched from standard half-life (SHL) FIX products to EHL-FIX, as well as those who started preventive treatment directly on long-acting FIX replacement therapy.
As such, these findings support a move to EHL-FIX products for children on SHL therapy, according to the researchers.
The study, “HAEMFIX: Impact of Switching From SHL-FIX to EHL-FIX in Patients With Haemophilia B,” was published in the journal Haemophilia.
Hemophilia B is caused by a deficiency in factor IX, known as FIX, a protein the body needs for blood clotting. Without enough FIX, individuals can experience prolonged or spontaneous bleeding, often into the joints, which over time can lead to pain, stiffness, and lasting joint damage.
Comparing standard vs. extended half-life products in hemophilia B
To help prevent these bleeds, patients typically receive prophylactic FIX replacement therapy. With this preventive treatment, the missing clotting factor is infused into the bloodstream to temporarily restore blood clotting ability.
With older SHL products, which don’t last as long, this usually requires two or three intravenous, or into-the-vein, infusions each week. That’s because FIX is quickly cleared from the body.
Newer EHL-FIX products, including Idelvion (albutrepenonacog alfa), Alprolix (eftrenonacog alfa), and Rebinyn/Refixia (nonacog beta pegol), are designed to stay in the bloodstream longer. This allows patients to space out infusions to once weekly or even every other week while still maintaining protective levels of FIX.
“Since the approval of these products, patients have been switched to them consecutively,” the researchers wrote.
Now, the team set out to evaluate the real-world impact of switching from SHL-FIX to EHL-FIX products in pediatric patients.
To that end, the researchers launched a retrospective study, dubbed HEAMFIX, analyzing medical records from 37 boys with hemophilia B treated between 2010 and 2023 at two hemophilia care centers in Germany. The children ranged in age from 2 to 19 — with a median age of 12 — and most (70%) had severe disease.
A total of 38 boys (86%) were on preventive FIX replacement therapy, all using an EHL-FIX product at the time of the analysis. Among them, 19 children were taking Idelvion, 10 were on Alprolix, and three were taking Rebinyn/Refixia. The remaining five children (14%) received on-demand FIX treatment.
In the full group, 27 children had switched from a previous SHL-FIX to an EHL-FIX product.
Some children able to space out infusions to every 10 or 14 days
Children who received preventive treatment with EHL-FIX products were followed for a mean of four years. For 22 of these children, data were also available from their earlier SHL-FIX treatment, allowing the researchers to compare outcomes before and after the switch. The mean SHL-FIX follow-up in this group was 3.68 years.
While receiving SHL-FIX products, the boys had a mean annualized bleeding rate, or ABR — the average number of bleeding episodes a person experiences per year — of 6.01. During treatment with EHL-FIX products, the ABR fell to 2.85, indicating fewer bleeding episodes annually.
The proportion of children with no bleeds was similar between treatments (73.5% with SHL-FIX vs. 72.4% with EHL-FIX), but fewer children had higher bleed rates on EHL-FIX products, the researchers noted. With long-acting therapy, 14.2% had more than two bleeds per year, compared with 16.5% on SHL-FIX products.
Treatment burden was also lower with the new products. Children needed a mean of 145 infusions per year while on treatment with SHL-FIX products, versus 55.1 with EHL-FIX products. In this last group, most (88%) were able to reduce their infusion frequency to once a week, and 9% were able to space out their infusions even further, to every 10 or 14 days.
In addition to reducing infusion frequency, weekly dosing decreased by more than half, and total annual FIX consumption fell by about one-third. That indicated better bleed control with less factor, according to the researchers.
“These findings suggest that using FIX products with extended half-lives is cost-effective and provides economic benefits in addition to individual advantages for patients,” the researchers wrote.
Switching … to EHL-FIX [extended half-life factor IX products] in children with haemophilia B is safe and may improve outcomes by reducing bleeding rates, infusion frequency, and factor consumption while enhancing joint health and [health-related quality of life].
Despite reduced infusion frequency and lower dosing, joint health remained good, the team noted. Among the 33 children who were assessed, the mean Haemophilia Joint Health Score was 0.88, indicating little to no measurable joint damage in most patients. Two children showed signs of long-term joint damage from bleeding, and one had a joint prone to repeated bleeds.
Quality of life was assessed for 30 youngsters. Overall, children across all age groups reported good health-related quality of life while receiving EHL-FIX products. When families were asked to recall life on SHL-FIX products, scores were worse, particularly in children aged 4 to 7 and 8 to 16 years.
No serious safety concerns noted with switch to EHL-FIX
No serious safety concerns were identified, supporting a favorable safety profile for EHL-FIX concentrates in pediatric patients with hemophilia B, according to the researchers.
“Switching from SHL-FIX to EHL-FIX in children with haemophilia B is safe and may improve outcomes by reducing bleeding rates, infusion frequency, and factor consumption while enhancing joint health and [health-related quality of life],” the team concluded.
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