Occurrence of inhibitors in previously untreated or minimally treated patients with haemophilia A after exposure to a plasma-derived solvent-detergent factor VIII concentrate

A solvent-detergent virus-inactivated plasma-derived FVIII concentrate (SD-pdFVIII) has been employed for treatment of Italian patients with haemophilia A for 15 years. This product is a nonmonoclonally purified, high purity FVIII concentrate, containing large amounts of von Willebrand factor (VWF). A retrospective survey was carried out in Italy in order to evaluate the immunogenicity of SD-pdFVIII in previously untreated patients (PUPs) or in minimally treated patients (MTPs), i.e. previously exposed for up to 5 days only to other plasmaderived concentrates. The survey included 99 patients with ages ranging from 6 to 64 years (median = 21.3) of whom 31 PUPs and 68 MTPs, the latter with a median of four exposure days (EDs; range 1-5) to other plasma products. Surveyed patients had been exposed to SD-pdFVIII for a median of 83 EDs (range 21-1580). Seven patients (three PUPs and four MTPs), all with severe haemophilia, had developed inhibitors [7.1%, 95%; confidence interval: 3-14%] after a median of 11 EDs (range 4-22). Of them, two were low responders ( 645 BU mL-1) and five high responders. Two low responders and one high responder tolerated inhibitors spontaneously; one high responder underwent immunotolerance treatment with complete, long-standing response. These findings show that SD-pdFVIII is at low risk of inhibitor development in PUPs and MTPs with severe and moderate haemophilia, the risk of inhibitor development being similar to that previously reported for other plasma-derived VWF-containing FVIII products

Differences between patients', physicians' and pharmacists' preferences for treatment products in haemophilia : a discrete choice experiment

The provision of health care to patients with haemophilia through replacement of the deficient coagulation factor is the result of a complex interaction between patients, physicians and policy makers, each carrying their individual sets of preferences. Preferences of patients, physicians and pharmacists towards perceived viral safety, risk of inhibitor development, infusion frequency during prophylaxis, pharmaceutical dosage form, distribution modes and price were evaluated by conjoint analysis, using a discrete choice experiment. Overall 178 patients', 69 physicians and 58 pharmacists completed the study. Patients, physicians and pharmacists displayed preferences: (i) similar in direction and strength for risk of inhibitors and frequency of prophylaxis, (ii) similar in direction, but not in strength for perceived viral safety and price, with patients showing lower strength compared with physicians and pharmacists, and (iii) dissimilar in direction and/or strength for: (i) dosage form, which tested important only for pharmacists and (ii) distribution mode, which tested important for patients and physicians only. Our study provides evidence of the differences between different stakeholders in the preferences towards haemophilia replacement therapy, indicating that different opinions should be taken into account when planning optimal care