Immunotolerance induction effectivity in hemophilia A children and neutralizing alloantibodies

Abstract

The development of anti-factor VIII neutralizing antibodies in hemophilia A is the most severe complication related to treatment. Immune tolerance induction (ITI) is the only known treatment for eradicating inhibitors. A successful ITI allows using factor VIII (FVIII) again for the treatment or prophylaxis of hemorrhagic events.

Objective: To report the experience of pediatric patients who underwent ITI in the country’s public health care network.

Patients and Method: Retrospective and descriptive analysis of 13 pediatric patients with severe Hemophilia A and high-titer inhibitors persistence who underwent ITI and complete follow-up. Plasma-derived FVIII concentrate was used at 70- 180 IU/kg/day doses. The success of the treatment is defined by achieving a negative titer and a halflife recovery of the FVIII. The results were expressed in median (range).

Results: In 13 patients, the inhibitor was identified at an average age of 17.6 months, after 35.2 days of exposure to the FVIII. 11 patients (84.6%) recovered the half-life of FVIII after 49.6 months of treatment. In the patients who responded to treatment, the inhibitor titer was negative at 6 months on average.

Conclusions: ITI is the treatment of choice for patients with hemophilia A and inhibitors persistence. ITI must be personalized since the time response is variable in each patient.