Fewer Bleeds Follow Move to Extended Half-life Therapy, Study Finds

People with severe hemophilia A who switch from standard to extended half-life replacement therapies experience fewer bleeds and require less frequent infusions, an analysis of patients in Austria indicates.

Whether these gains are reflected in lower overall treatment costs, however, is less clear, its researchers added.

Data from this analysis were described in the study, “Bleeding outcomes and factor utilization after switching to an extended half-life product for prophylaxis in haemophilia A in Austria,” published in the journal Scientific Reports.

Hemophilia A is caused by mutations that make the body unable to produce sufficient amounts of the clotting protein factor VIII (FVIII). Replacement therapy, which, as its name implies, involves administering a form of FVIII to “replace” the missing protein, and is a standard treatment for hemophilia A.

In recent years, extended half-life (EHL) replacement therapies have been approved for use. These therapies are chemically modified to make them last longer in the body, with the aim of achieving higher therapeutic potency and requiring less frequent infusions.

A team of researchers in Austria reported on the real-life, clinical outcomes of 20 people with severe hemophilia A (FVIII activity less than 1% of normal) who switched from standard replacement therapies to EHL products.

“While real-world data regarding EHL is becoming increasingly available for other countries, this is the first analysis of its kind in Austria,” the researchers wrote.

Prior to switching, the most commonly used prophylactic (preventive) replacement therapies were Advate (rurioctocog alfa; 40% of patients) and Helixate (octocog alfa; 25% of patients).

Over a third of these patients were given infusions every other day, while 25% had infusions three times weekly, and another 25% had infusions twice a week. In the six months prior to switching to EHL products, patients’ median annualized bleeding rate (ABR) was one bleed per year.

All 20 patients switched to an EHL called Elocta (efmoroctocog alfa), which is marketed as Eloctate in the U.S. and other countries. The most common reason for switching, given by five patients (25%), was a high number of bleeds. In the three months after switching, patients’ median ABR was zero, and their median number of weekly infusions was two.

Statistical analyses demonstrated that, for 10 patients, bleed rates decreased following the switch to EHL. Bleeding rates post-switch did not notably change for eight others, and increased in one patient. A last patient had missing data and could not be analyzed.

Other analyses indicated that 12 of the patients experienced less frequent infusions after the switch. Two others had more frequent infusions, four had no change, and two had incomplete data.

Overall, researchers concluded that the switch to EHL was broadly in line with what would be expected given prior data, “as we observed a statistically significant reduction in ABR and prophylactic infusion frequency per week after switching from [standard therapies] to EHL.”

As such, patients with severe hemophilia “may benefit from prophylaxis with EHL,” the researchers wrote.

Seven patients found their monthly cost of treatment lower after moving to EHL, while 11 others found those monthly costs rose.

Researchers noted that studies are conflicting on the financial costs and benefits of EHLs. Some studies suggest that less frequent infusions and fewer bleeds end up saving more money than these expensive therapies cost. Others, including the present analysis, argue against a powerful cost-saving effect.

“This issue is still being debated as the benefits in ABR reduction, and thus improved joint health may positively impact factor usage and cost-effectiveness in the long term,” the researchers wrote. “However, it can be challenging to compare changes in costs across studies conducted in different countries as factor product pricing may vary.”

Researchers emphasized the need for more research in this area.