Rituximab and Desensitization for a Patient With Severe Factor IX Deficiency, Inhibitors, and History of Anaphylaxis

Abstract

We report the case of a 9-year-old boy with severe hemophilia B with an inhibitor and a history of anaphylaxis to factor IX (FIX), who was successfully treated with immune tolerance (IT) that included rituximab (Genentech, San Francisco, CA) and desensitization. The patient began the first course of IT at age of 7 years with daily recombinant FIX infusions that was aborted at day 32 because of a systemic allergic reaction. A second course of IT was attempted 11 months later, initiated with a desensitization protocol with escalating doses of plasma-derived FIX in addition to therapy with rituximab. This was well tolerated without allergic symptoms and with eradication of the inhibitor and improvement in factor kinetics. A second course of rituximab was given 13 months later for worsening FIX kinetics again with an excellent response and without evidence of adverse effects.

Successful treatment of immune tolerance induction with rituximab in a patient with severe hemophilia B and inhibitor

“…In the North American Immune Tolerance Registry, three of 10 patients with previous anaphylaxis developed nephrotic syndrome, and eight of 10 patients failed ITI [7]. Several reports have investigated ITI with rituximab and/ or the addition of other drugs, such as dexamethasone, mycophenolate mofetil and intravenous immunoglobulin [13][14][15][16]. There is no clear consensus as to the optimal method to manage hemophilia B patients who develop inhibitors, and recommendations for ITI in hemophilia B are substantially lacking.…”

Factor X Inhibitor: A Fulminant Presentation and Fatal Course of a Rare Syndrome in a 59-Year-Old Male

“…Similarly, rituximab cannot be advocated. There is some history of the use of rituximab in inhibitors to factor VIII and factor IX [28,29,30,31]. Rituximab has the ability to lower antibody levels to undetectable levels rapidly and needs to be studied further.…”

Diagnosis and treatment of factor VIII and IX inhibitors in congenital haemophilia: (4th edition)

“…This approach requires intensive inpatient monitoring and daily urinalysis. Others have reported successful desensitization to FIX, facilitating FIX infusions as part of ITI (Alexander et al , ; Chuansumrit et al , ). Mycophenolate mofetil combined with dexamethasone, intravenous immunoglobulin and high‐dose FIX has also been used in a few patients with success (Klarmann et al , ,b).…”