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The development of antibodies against infused factor VIII (FVIII) in patients with haemophilia A is a serious complication leading to poorly controlled bleeding and increased morbidity. No treatment has been proven to reduce high titre antibodies in patients who fail immune tolerance induction or are not candidates for it. The Rituximab for the Treatment of Inhibitors in Congenital Hemophilia A (RICH) study was a phase II trial to assess whether rituximab can reduce anamnestic FVIII antibody (inhibitor) titres. Male subjects with severe congenital haemophilia A and an inhibitor titre ≥5 Bethesda Units/ml (BU) following a FVIII challenge infusion received rituximab 375 mg/m² weekly for weeks 1 through 4. Post-rituximab inhibitor titres were measured monthly from week 6 through week 22 to assess treatment response. Of 16 subjects who received at least one dose of rituximab, three (18.8%) met the criteria for a major response, defined as a fall in inhibitor titre to <5 BU, persisting after FVIII re-challenge. One subject had a minor response, defined as a fall in inhibitor titre to <5 BU, increasing to 5-10 BU after FVIII re-challenge, but <50% of the original peak inhibitor titre. Rituximab is useful in lowering inhibitor levels in patients, but its effect as a solo treatment strategy is modest. Future studies are indicated to determine the role of rituximab as an adjunctive therapy in immune tolerisation strategies.

Chronic idiopathic thrombocytopenic purpura (ITP) can be categorized as mild, moderately severe, or severe. Severe chronic ITP during childhood is a rare disorder characterized by clinically significant mucocutaneous hemorrhage, usually in the setting of marked thrombocytopenia. It can cause substantial morbidity and rarely mortality. Many patients improve with time or even fully recover, but for those whose quality of life is negatively influenced by hemorrhage or side effects of conventional therapy (corticosteroids, intravenous immunoglobulin G, or anti-D), splenectomy is recommended. If splenectomy is unsuccessful or not feasible, other drug treatments are available, but few efficacy data exist, and the toxicity and cost of these treatments can be appreciable. Their use is best avoided outside of clinical trials conducted in specialty centers or in multi-institutional networks.