Preliminary results of the study are now available CAL-101 mw [48]. This retrospective

study involved PUPs with haemophilia A who were diagnosed between 2006 and 2011 in participating centres of the eastern German network for coagulation disorders (Kompetenznetzwerk hämorrhagische Diathese Ost; KHDO). By means of a detailed questionnaire developed specifically for study purposes, information collected from patients’ medical charts included: age at diagnosis and at start of prophylaxis; FVIII gene mutation; type of FVIII product; body weight relative to FVIII dose; number of exposure days to FVIII products until inhibitor formation; presence of danger signals; details of immune tolerance induction (ITI)

therapy. All 12 KHDO centres that treat children participated in the study and the number of patients treated per centre ranged from 1 to 24. During the study period 67 patients were newly diagnosed with haemophilia A, of whom 33 had severe, 4 moderate, 20 mild and 10 subclinical disease. The analysis centred around patients with severe haemophilia as this is the group at greatest risk of developing inhibitors. Among the 33 patients with severe haemophilia, eight had been treated with the historical FVIII prophylaxis regimen (30 U kg−1 2–3× per week) none of whom developed an inhibitor. Twenty-five patients had been treated with the low-dose 上海皓元医药股份有限公司 regimen (25 U kg−1 1× per week) of whom 9 (36%) developed an inhibitor (five high-responding, four Maraviroc manufacturer low-responding). At the time of investigation (July 2012), 27 of the 33 patients with severe haemophilia had had more than 100 exposure days to FVIII concentrates; three patients had <20 exposure days and the remaining three patients had between 20 and 100 exposure days. In order to identify possible strategies to avoid inhibitor development, the characteristics of patients with severe haemophilia A treated with prophylaxis (n = 33)

were examined based on the presence or absence of inhibitors (Table 5). In both groups, prophylaxis had been initiated at an early age – slightly earlier in patients with than without inhibitors (11.5 vs. 15 months) – although the range was broad in both groups. The FVIII dose at the start of once-weekly prophylaxis was the same in patients with or without inhibitors. In patients treated with the historical prophylaxis regimen, the FVIII dose was slightly lower in patients with than without inhibitors (22 vs 28 IU kg−1), but the clinical significance of this difference remains uncertain. Overall, 14 PUPs with severe haemophilia received plasma-derived products and 19 received recombinant products. All nine patients who developed inhibitors had been treated with recombinant FVIII (rFVIII) concentrates.