Photo courtesy of Baxalta
ORLANDO—Results of a phase 3 study suggest the full-length recombinant factor VIII therapy Adynovate (BAX 855) can be safe and effective as twice-weekly prophylaxis and to control bleeding in children with hemophilia A.
None of the patients in this study developed inhibitory antibodies, and there were no product-related adverse events.
The median annualized bleeding rate (ABR) was 2.0, and nearly 40% of patients did not have any bleeding episodes.
These results were presented at the World Federation of Hemophilia 2016 World Congress.* The study was funded by Baxalta, now part of Shire.
The study enrolled previously treated children younger than 12 years of age with no history of factor VIII inhibitors. The patients received twice-weekly prophylaxis with Adynovate (50 ± 10 IU/kg) for at least 6 months or 50 exposure days, whichever occurred last.
There were 66 evaluable patients with a median age of 6 (range, 1-11). Overall, 4,467,796 IU of Adynovate were infused. The mean number of exposure days was 53.98 per patient.
Safety
There was no indication of persistent binding antibodies against factor VIII, and none of the patients developed antibodies to host cell (Chinese hamster ovary) proteins.
There were 156 adverse events in 43 patients (65.2%), but none were considered related to Adynovate.
There were 4 unrelated serious adverse events in 3 patients—febrile neutropenia, pancytopenia, acute gastritis, and abdominal pain.
Efficacy
Patients received a median dose of 51.3 IU/kg per prophylactic infusion at a median frequency of 1.9 infusions per week.
Ninety-one percent of patients did not require dose adjustments. Reasons for dose adjustment included factor VIII trough levels less than 1%, increased risk of bleeding, and bleeding episodes.
Thirty-eight percent of patients did not experience bleeding events, 73% did not experience hemarthroses, and 67% did not experience spontaneous bleeding events.
The mean ABR was 3.0, and the median was 2.0. The mean joint ABR was 1.1, and the median was 0. The mean spontaneous ABR was 1.2, and the median was 0. The mean interval between bleeding episodes was 2.4 months.
There were a total of 70 bleeding episodes in 34 patients. All of these episodes were minor or moderate. Ninety-one percent of treated bleeding events were treated with 1 or 2 infusions. And 90% of bleeding events received treatment ratings of “excellent” or “good.”
