XVIII Congress of the Italian Society for Hemostasis and Thrombosis Research, Rome, Sept. 30-Oct. 3, <strong>2004</strong>29During 1997-2000, subcutaneous ports were used atour Center by 23 children without feasible peripheralaccess. Ports removal was required, after a median of5 years, in 17 patients (74%) for infections and onedislocation. In 1999, we started to create AVF in 5 childrenwho had their ports removed. Since 2000, wehave introduced the use of AVF in patients needing avascular access either as first option or after portremoval. Prospective data have been collected to evaluatethe safety and feasibility of AVF as alternativevascular access. To date, 32 hemophiliacs (median age:3 years), 18 with inhibitors (56%), underwent the creatio<strong>no</strong>f 36 proximal AVF in the forearm. Mild forearmhaematomas were observed after 7 procedures (19%)in patients with inhibitors. Inadequate AVF maturationwas observed after 5/35 procedures (14%) in 4children. AVF were first accessed after a median of 45days (21-120) and regularly used at home by 30/31patients (97%) for a median of 39 months (2-56).Thrombosis of a ve<strong>no</strong>us branch occurred in one AVF(3%) after 9 months of uncomplicated use in a childwith inhibitor who spontaneously recovered fromsymptoms and still used AVF for 21 additional months.Mild symptoms of distal ischemia were transientlyreported by 3 children (9%) who needed <strong>no</strong> remedialintervention. Our data referred to a median follow-upperiod of 40 months (3-57) demonstrates that the useof AVF allowed long-term treatment at home in 97%of hemophiliacs.CO-021INHIBITOR DEVELOPMENT IN PREVIOUSLY TREATED PATIENTSWITH HEMOPHILIA A SWITCHED TO A B DOMAIN-DELETEDRECOMBINANT FACTOR VIIIGringeri A,* Tagliaferri A,° Tagariello G,^ Morfini M, §Santagosti<strong>no</strong> E,* Mannucci PM* and theREFACTO-A.I.C.E. Study Group*Angelo Bianchi Bo<strong>no</strong>mi Haemophilia andThrombosis Centre and Department of InternalMedicine and Dermatology, IRCCS MaggioreHospital and University of Milan, Milan, Italy;°Hemophilia and Thrombosis Centre, Ospedale diParma, Italy; ^Haemophilia Centre, Ospedale Civile,Castelfranco Veneto (TV), Italy; § HaematologyDepartment and Haemophilia Centre, UniversityHospital of Florence, ItalyBackground. There are recent reports of the unexpecteddevelopment of inhibitors in previously treatedpatients (PTPs) switched to a B-domain-deletedrecombinant factor VIII (BDD-rFVIII). Aim and methods.To evaluate inhibitor development we report theresults of a 6-month prospective study of 25 severePTPs and of a retrospective survey of 94 PTPs (53severe, 33 moderate and 8 mild hemophiliacs), allswitched from other products to BDD-rFVIII. Results.In the prospective study one patient, previously treatedwith plasma-derived concentrates only, developeda high titer inhibitor (30 BU) after 5 exposure days.Discontinuation of BDD-rFVIII led to inhibitor loss andallowed effective treatment with a plasma-derivedconcentrate, without reappearance of inhibitors. Theretrospective survey, carried out in the whole ItalianPTP population who had switched to BDD-rFVIII inthe recent past, involved high risk 19 PTPs becausethey were previously exposed to other FVIII concentratesfor up to 50 days and low risk 75 PTPs becausepreviously exposed for more than 50 days. One of 53severe haemophiliacs developed an inhibitor: he wasa high-risk PTP previously exposed to a<strong>no</strong>ther recombinantFVIII for 3 days only. Among the entire low-riskpopulation of Italian PTPs with severe haemophiliaswitched to BDD-rFVIII (25 in the prospective study,49 in the retrospective cohort) only one patient developedan inhibitor (1.3%), an incidence similar to thatfound for other recombinant products. Conclusions.Overall these data indirectly support the views thatBD-rFVIII is equivalent to other recombinant productsin term of inhibitor development.CO-022IMMUNE TOLERANCE INDUCTION WITH RECOMBINANTFACTOR VIII IN HEMOPHILIA A PATIENTS WITH INHIBITORSRoci<strong>no</strong> A,* Santagosti<strong>no</strong> E,^ Mancuso ME^*Hemophilia and Thrombosis Center San GiovanniBosco Hospital, Napoli, Italy; ^Angelo BianchiBo<strong>no</strong>mi Hemophilia & Thrombosis Center, IRCCSMaggiore Hospital, Milan, ItalyIntroduction: Inhibitors develop in up to 25-30% ofpatients with severe haemophilia A. Treatment optionsare effective in bleeding management but are <strong>no</strong>t optimalin providing good long-term outcome. Inhibitoreradication by immune tolerance induction (ITI) representsthe best current treatment option. Few data existon ITI using recombinant FVIII (rFVIII). Objectives: toevaluate the success rate of ITI using rFVIII and theimpact of FVIII gene mutations on ITI response. Studydesign and patients: a retrospective/prospective studywas carried out in 2 Centers including 27 patients withsevere haemophilia A (age: 1-25 years, 19 with intron22 inversion), 25 high-responders and 2 low-responders,given rFVIII for ITI. Successful ITI was defined asthe achievement of an inhibitor titer
30Oral Communicationsmonths (2-39) and <strong>no</strong> relapse was observed. Amongpatients who achieved success, 13 (76%) had intron 22inversion. Conclusions: the observed rate of successfulITI using rFVIII was similar to the rates reported usingplasma-derived FVIII concentrates. Intron 22 inversiondid <strong>no</strong>t reduce the chance of successful response to ITIin this cohort.CO-023IMPACT OF EARLY FVIII EXPOSURE, PROPHYLAXIS ANDPRENATAL/PERINATAL EVENTS ON INHIBITOR RISK INCHILDREN WITH HEMOPHILIA A: A CASE-CONTROL STUDYSantagosti<strong>no</strong> E,* Roci<strong>no</strong> A,^ Mancuso ME,*Mazzucconi MG,° Mancuso G, # Messina M, §Tagliaferri A,°° Luciani M,^^ Boeri E,** Mannucci PM**Angelo Bianchi Bo<strong>no</strong>mi Hemophilia & ThrombosisCenter, IRCCS Maggiore Hospital, Milan, Italy;^Hemophilia & Thrombosis Center, San GiovanniBosco Hospital, Naples, Italy; °Hemophilia Center,Policlinico Umberto I Hospital and La SapienzaUniversity, Rome, Italy; # Hemostasis & ThrombosisCenter, "G. Di Cristina" Hospital, Palermo, Italy;§Hemophilia Center, "Regina Margherita" Hospital,Turin, Italy; °°Hemophilia Center, Parma Hospital,Parma, Italy; ^^Hemostasis & Thrombosis Center,"Bambi<strong>no</strong> Gesù" Hospital, Rome, Italy;**Hemophilia Center, "G. Gaslini" Hospital, Ge<strong>no</strong>aIn a multicenter case-control study we investigatedthe impact of prenatal/perinatal events and earlyFVIII exposure on the inhibitor risk in hemophiliacs.Patients: 102 children (age:13-196 months) withhemophilia A (FVIII
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