Determinants of Prophylaxis Regimen Choice for Patients with Hemophilia Α Switching to Bay 81-8973: Real World Findings from the Taurus Non-Interventional Study

BACKGROUND: Prophylaxis dosing regimens with standard half-life FVIII products range from 2-3 times per week to every other day regimens, and are adjusted according to patient needs. BAY 81-8973 (Kovaltry®, Bayer) is an unmodified full-length recombinant FVIII indicated for prophylaxis and treatment of bleeds in patients with hemophilia A; BAY 81-8973 was launched in 2016 and has since accumulated 6765 patient-years of exposure. The TAURUS study (NCT02830477) was established to investigate BAY 81-8973 prophylaxis use in clinical practice.

OBJECTIVE: To report reasons for choosing dose regimens at the time of switching to BAY 81-8973 treatment, and patient and disease characteristics associated with choice of less frequent (≤ 2 times per week [≤ 2 xW]) versus more frequent (≥ 3xW) treatment.

METHODS: TAURUS is an international, open label, prospective, non-interventional, single arm study with a target recruitment of 350 previously treated patients with haemophilia A of all ages with moderate or severe hemophilia A (≤ 5% FVIII:C) with ≥ 50 exposure days to any FVIII who have been recently switched to prophylaxis with BAY 81-8973. At baseline, physicians document clinical information including their reason for choosing a specific prophylaxis regimen. The full study will run until 2020. A scheduled interim analysis (30% of patients recruited) was conducted using a cut-off date of 2 July 2018 to investigate the determinants of choosing a specific regimen when initiating BAY 81-8973.

RESULTS: At the cut-off date, 160 patients were enrolled: patient characteristics are shown in the table. For patients in the ≥ 3xW dosing category at baseline (n = 94, 59%), BAY 81-8973 regimens were: every day, n =2; 4xW, n= 2; every other day, n = 24; 3xW, n = 66. for patients dosed ≤ 2xW (n = 52, 33%) were: 2xW, n = 43; every 4th day, n = 1; 1.5xW, n = 1; 1xW, n = 7. Dosing regimen details were missing for 14 patients. Median patient age was 22 years. Pre-study, the majority of patients had been on prophylaxis (97%; 83% on rFVIII-FS). The most common reason for switching to BAY 81-8973 was 'physician decision' (in 79 patients, 49%). Most patients (79%) had been receiving BAY 81-8973 for less than 3 months prior to study entry. At baseline, ≥3xW patients were younger than ≤2xW patients (21.5 vs 27.0 years), had been on prophylaxis for a longer period pre-study (13 vs. 9 years), had severe haemophilia (88% vs. 79%), and more had a history of inhibitors (7% vs. 4%). The proportion of patients with ≥1 target joint and bleeding in the year prior to study was similar for both groups at baseline. The reasons for prescribing the specific dosing frequencies are shown in the table. 'Patient/caregiver preference' and 'bleeding history' were cited less frequently for ≤2xW patients, while 'current treatment regimen', 'adherence/compliance history', and 'activity level' were cited more frequently for ≤2xW patients vs ≥3xW patients. No recruited patients developed inhibitors with BAY 81-8973.

CONCLUSIONS: These real-world data from 160 patients show patients treated more frequently (≥3xW) with BAY 81-8973 were younger and had a longer prophylaxis treatment history than those treated less frequently ≤2xW. Patient preference, bleeding history, and current regimen, were the most frequently cited reasons for choosing a specific BAY 81-8973 regimen. Taken together, the data indicate that BAY 81-8973 treatment may be successfully individualized according to patient need and disease characteristics.

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