Early Trial Offers New Hope for People With Hemophilia

To Mannucci, who wrote an editorial published with the study, the findings represent “more amazing progress” in treating hemophilia.

He pointed to key developments in recent years — including promising findings on gene therapy, which might provide a cure to at least some people with hemophilia.

And already, patients have options other than factor VIII replacement. In 2017, the U.S. Food and Drug Administration approved a drug called emicizumab — a lab-engineered antibody that mimics the activity of factor VIII.

Emicizumab has the advantage of being taken weekly, or even less often, and it’s injected under the skin rather than into a vein, Mannucci pointed out.

But, he said, the drug lacks some benefits of an “authentic” factor VIII — including the ability to treat sudden bleeding. So a longer-acting factor VIII could be an alternative to emicizumab, Mannucci said.

An ongoing “phase 3” trial is testing the new factor VIII product over the longer term, with patients receiving weekly doses.

Konkle said no safety issues emerged in this early study, published in the Sept. 10 New England Journal of Medicine. But the longer-term trial is needed to see whether any adverse effects, like allergic reactions, turn up.

Drugmakers Sanofi and Sobi, which are funding the research, developed BIVV001 together.

“It’s really an incredible feat of bioengineering,” Konkle said.

Historically, she explained, it’s been difficult to create a longer-acting factor VIII. That’s because the replacement protein interacts with a natural blood protein — called von Willebrand factor — which limits its half-life.

BIVV001, Konkle said, essentially “uncouples” the factor VIII replacement from von Willebrand factor circulating in patients’ blood.

She believes the new therapy, if approved, “will be a really important addition to our treatment options.”

But, Konkle added, “different approaches will be right for different patients.”

No one knows what the new factor VIII therapy could cost. But on the whole, hemophilia treatments are highly expensive, according to the American Society of Hematology — in the range of $300,000 to $500,000 a year.