A comparison of prophylaxis dosing frequency and associated clinical outcomes between rVIII-SingleChain and other rFVIII products commonly used in Italian patients with haemophilia A

Objective Several recombinant factor VIII (rFVIII) products are available in Italy to treat haemophilia A, including long-acting products with improved pharmacokinetic properties enabling extended dosing intervals. In the absence of head-to-head comparisons, an evaluation of their real-world utilisation may help to optimise treatment choice. The aim of this study was to determine factor consumption and annual bleed rates (ABR) following the prophylactic use of rVIII-SingleChain compared with other commonly used rFVIII products.

Material and Methods Haemophilia Treatment Centres provided de-identified chart information for 290 patients treated with one of the following four rFVIII products for a minimum of 8 weeks: rVIII-SingleChain (n=60), rFVIIIFc (n=73), BAY 81-8973 (n=74), and octocog alfa (n=83). Where possible, patients were matched by age and disease severity in order to ensure heterogeneity of the groups. To calculate mean ABR, the number of reported bleeds were annualised, and prophylactic factor consumption was calculated using the dose and infusion frequency on the patient’s latest prescription.

Results A data summary is shown in Table 1. Most patients treated with long-acting products were dosed ≤2 x weekly (rVIII-SingleChain, 56.7%/53%; rFVIIIFc, 76.7%/75.4% for all patients and those with severe disease, respectively). In contrast, most patients treated with standard acting products infused >2 x weekly (octocog alfa, 83.1%; BAY 81 8973, 63,5%). Mean ABR was 0.4 with rFVIIIFc, 0.7 with rVIII-SingleChain, 0.8 with BAY 81 8973 and 1.2 with octocog alfa. All products reported a median annual spontaneous bleed rate of 0.0; zero spontaneous bleeds were reported in 88.3%, 87.7%, 82.4%, and 71.1% of patients treated with rVIII-SingleChain, rFVIIIFc, BAY 81-8973 and octocog alfa, respectively. Overall, mean weekly consumption was lowest with rVIII-SingleChain (92.7 IU/kg), which was 10.7%, 17.7% and 24.3% less than rFVIIIFc, BAY 81-8973 and octocog alfa, respectively.

Conclusion Similar to other long-acting products, rVIII-SingleChain shows reduced dosing frequency and factor consumption whilst maintaining comparable efficacy to standard-acting rFVIII products. This retrospective patient chart review provides further evidence that the excellent outcomes observed during rVIII-SingleChain clinical trials can also be achieved in real-world practice.

Tab 1. Patient characteristics, bleeding rates, infusion frequency and factor consumption with selected long-acting and standard-acting rFVIII products.

Publication History

Article published online:
18 June 2021