FRENCH PREVIOUSLY UNTREATED PATIENTS WITH SEVERE HEMOPHILIA-A AFTER EXPOSURE TO RECOMBINANT FACTOR-VIII - INCIDENCE OF INHIBITOR AND EVALUATION OF IMMUNE TOLERANCE
C. Rothschild et al., FRENCH PREVIOUSLY UNTREATED PATIENTS WITH SEVERE HEMOPHILIA-A AFTER EXPOSURE TO RECOMBINANT FACTOR-VIII - INCIDENCE OF INHIBITOR AND EVALUATION OF IMMUNE TOLERANCE, Thrombosis and haemostasis, 80(5), 1998, pp. 779-783
Fifty French previously untreated patients with severe hemophilia A (f
actor Vm < 1%), treated with only one brand of recombinant factor vm (
rFVIII), were evaluated for inhibitor development, assessment of risk
factors and outcome of immune tolerance regimen. The median period on
study was 32 months (range 9-74) since the first injection of rFVIII.
Fourteen patients (28%) developed an inhibitor, four of whom (8%) with
a high titer (greater than or equal to 10 BU). All inhibitor patients
but one continued to receive rFVIII: either for on-demand treatment o
r for immune tolerance regimen (ITR). Among these patients, inhibitor
was transient in 2 (4%), became undetectable in 6 and was still presen
t in 6. The prevalence of inhibitor was 12%. Presence of intron 22 inv
ersion was found to be a risk factor for inhibitor development Immune
tolerance was difficult to achieve in our series despite a follow-up p
eriod of 16 to 30 months: immune tolerance was complete in only one ou
t of the 3 patients undergoing low dose ITR and in one out of the 5 pa
tients with high dose ITR.