Long-term follow-up of patients with congenital thrombotic thrombocytopenia purpura receiving a plasma-derived factor VIII (Koate) that contains ADAMTS13

Background :Hereditary thrombotic thrombocytopenia purpura (hTTP) is an ultra-rare disorder resulting from an inherited deficiency of ADAMTS13, a von Willebrand factor (VWF)-cleaving metalloprotease. The plasma-derived factor VIII/VWF Koate (FVIII/VWFKoate) has been shown to contain ADAMTS13, allowing for its use to treat hTTP at home by the patient/caregiver.Aim: Based on prior demonstration of safe and effective use of FVIII/VWFKoate in eight patients with hTTP, we conducted a retrospective study to gather additional data regarding the use of FVIII/VWF(Koate )for hTTP.Methods:This was a multicentre, retrospective, noninterventional chart review of patients who had received FVIII/VWFKoate for the management of hTTP. Data collected included demographics, medical history, relevant family history, past use and tolerability of fresh frozen plasma, and details regarding FVIII/VWFKoate therapy.Results:The cohort included 11 patients (seven males, four females) with hTTP, ranging in age at study entry from 2 to 28 years. The average duration of FVIII/VWFKoate therapy was 4.8 years (range, 0.5-6.5 years). Among nine patients using FVIII/VWF(Koat)e as prophylaxis, the normalized annual rate of breakthrough TTP episodes ranged from 0.2 to 1.1 episodes/year. All nine patients who received FVIII/VWFKoate prophylaxis had thrombocytopenia recorded at baseline, while eight (88.9%) did not have thrombocytopenia after using FVIII/VWFKoate. There was one AE (unspecified) attributed to FVIII/VWFKoate.Conclusion:These data suggest that FVIII/VWF(Koate )is a safe and well-tolerated source of the missing ADAMTS13 enzyme in patients with hTTP, producing a marked reduction in thrombocytopenia prevalence, low frequency of TTP episodes, and with the added benefit of self- or caregiver-administration.

Automated summary

This study retrospectively investigated the use of FVIII/VWF(Koate) for the management of hTTP. The results suggest that FVIII/VWF(Koate) is a safe and well-tolerated source of ADAMTS13 enzyme, leading to a significant reduction in thrombocytopenia prevalence and frequency of TTP episodes, with the added benefit of self- or caregiver-administration.