The recombinant factor VIII (FVIII) therapy BAY 94-9027 demonstrated long-term safety and efficacy at reducing bleeds in pediatric patients with severe hemophilia A, according to results of a long-term analysis published in the journal Haemophilia.

The analysis was the extension study of the phase 3 PROTECT VIII Kids trial (ClinicalTrials.gov Identifier: NCT01775618), which evaluated BAY 94-9027 in male patients younger than 12 years of age who had severe hemophilia A that had been previously treated. Patients were divided by age, with 1 group of patients below 6 years of age (32 patients), and the other group with patients of age 6 or above (27 patients). The extension phase of the PROTECT VIII Kids study was optional and involved possible dosing regimens of BAY 94-9027 that were in accordance with earlier stages of the study. Long-term safety was the primary goal of the extension analysis, based on inhibitor development. The main efficacy outcome involved annualized bleeding rate (ABR) and other efficacy and safety outcomes were examined.

A total of 59 patients enrolled in the extension phase. The median time spent in the study, including main and extension phases, was 5.8 years, with a median time in the extension phase of 5.0 years. Patients had a median total number of infusions per year of 77.5.


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A total of 3 patients had suspected FVIII inhibitor development, but this was not confirmed in these patients upon further examination. Development of antibodies against BAY 94 9027 or a component of the therapy, polyethylene glycol, was not seen in any patient during the extension study. Discontinuations were reported in 2 patients in the younger group, 1 of whom discontinued because of a severe adverse event of cardiomyopathy that was considered related to a congenital condition.

For total bleeds, the median ABR was 1.6 across the entire population. In patients younger than 6 years, this rate was 1.5, and it was 1.9 in the older group. The study investigators reported that the ABR for total bleeds during the extension phase was an improvement compared with the main study. In both age groups, the median spontaneous ABR during the final 12 months of therapy was 0.0.

“These findings showed that most children who started BAY 94-9027 prophylaxis when aged <12 years continued treatment into adolescence with sustained safety and efficacy,” the study investigators wrote in their report.

Disclosures: Some authors have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.

Reference

Mancuso ME, Biss T, Fischer K, et al. PROTECT VIII Kids extension study: long-term safety and efficacy of BAY 94-9027 (damoctocog alfa pegol) in children with severe haemophilia A. Haemophilia. Published online March 16, 2021. doi:10.1111/hae.14294