Rituximab in Three Cases of Refractory Thrombotic Thrombocytopenic Purpura.

Thrombotic Thrombocytopenic Purpura (TTP) etiology remains elusive, recently has been associated with von-Willebrand Factor-cleavage protein inhibitory antibodies. Plasma exchange (PE) remains the gold standard therapy, however there are some cases resistant to it. Rituximab has been proved useful in antibody mediated immune disorders. We report our experience in 3 consecutive TTP patients, refractory to PE and successfully treated with Rituximab 375 mg/m2 weekly x 6.

Case 1. A 41 years old female diagnosed with Hasimoto thyroiditis 4 years before. In January 2003 she was admitted to hospital with headache, abnormal behaviour, 16x10⁹/L platelets and 4–5% schistocytes. 47 PE sessions with a total of 235 fresh frozen plasma units (FFP) for replacement were made. Corticosteroids, IVIG and vincristine were added, but no improvement was achieved. Then, Rituximab was administered, after the second dose a complete clinical response was attained, and she remains well by now.

Case 2. A 21 years old female was into hospital in October 2003 with bruises, paraesthesia, skin pallor and jaundice. Hb 6.5 g/dL, platelets 4.6x10⁹/L, LDH 1223 U/L and 13% schistocytes. She received 24 PE with 96 FFP units, plus corticosteroids and vincristine, with no response. Rituximab was administered, after the third dose she experienced a complete response, and remains stable since then.

Case 3. female, 35, she was into hospital in January 2005 with diarrhoea, vomiting, jaundice, seizures and bruises, Hb 4.5 g/dL, platelets 10x10⁹/L, LDH 2486 U/L and 20% schistocytes. She received 43 PE with 129 FFP units and corticosteroids, but her neurological situation worsened. Rituximab was administered, after the first dose she experienced a complete response which maintains nowadays

Conclusions: intense PE remains the gold standard therapy, it is expensive, scarce, and not free of secondary effects. In a group of patients refractory to PE Rituximab is emerging as useful safe option, it was very well tolerated in ours cases. Unfortunately, we were not able to test the vWF-CP activity and its inhibitor. Our results encourage us to use Rituximab earlier than the first case, in order to avoid too much PE, and now we are considering Rituximab as a second option in patients refractory to PE, but much more cases must be considered.