Abstract Number: PB1001
Meeting: ISTH 2020 Congress
Background: Immune tolerance induction (ITI) with FVIII is the only proven strategy for eradication of FVIII inhibitors. The ongoing, international, open-label, observational ITI study (ObsITI; NCT02207894) is evaluating ITI with a range of FVIII products.
Aims: This analysis reports interim data for prospective patients treated for ITI exclusively with a single plasma-derived, von Willebrand factor-stabilised, FVIII concentrate (pdFVIII/VWF, octanate®) between December 2005 (study initiation) and January 2019.
Methods: Complete success of ITI was defined as achievement of the following 3 criteria: inhibitor titre < 0.6 Bethesda units [BU]/mL; FVIII recovery ≥ 66%; FVIII half-life ≥ 6 h. Partial success required achievement of two criteria and partial response required achievement of one criterion. ITI success in this analysis was defined as complete or partial success.
Results: 100 patients completed ITI. Most patients had poor prognosis factors (91.0%) or were high titre inhibitor patients (86.0%). A negative inhibitor titre was achieved in 71 (71.0%) patients in a median time of 4.01 months (interquartile range [IQR] 1.61-8.97). ITI success was achieved by 70 (70.0%) patients [60 (60.0%) complete success and 10 (10.0%) partial success], 5 (5.0%) achieved a partial response, and ITI failed in 25 (25.0%) patients. Partial and complete success were achieved in a median time of 5.55 (IQR 3.19-12.48) and 11.25 (IQR 6.52-18.56) months, respectively. ITI success was achieved in 56 of 72 (77.8%) primary ITI patients (49 [68.1%] complete success and 7 [9.7%] partial success), and 42 of 52 (80.8%) primary ITI patients ≤ 12 years (35 [67.3%] complete success and 7 [13.5%] partial success). Only two serious adverse drug reactions (catheter infections of moderate intensity in the same patient) were considered possibly related to treatment.
Conclusions: ITI with octanate® led to a rapid and safe eradication of FVIII inhibitors and normalisation of FVIII pharmacokinetics in largely poor prognosis patients.
To cite this abstract in AMA style:Escuriola-Ettingshausen C, ObsITI Study Group . Immune Tolerance Induction (ITI) with a Single Factor VIII/von Willebrand Factor Concentrate in Haemophilia A Patients with Inhibitors – Update from the ObsITI Study [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/immune-tolerance-induction-iti-with-a-single-factor-viii-von-willebrand-factor-concentrate-in-haemophilia-a-patients-with-inhibitors-update-from-the-obsiti-study/. Accessed September 29, 2023.
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