Clinical effect of rituximab as early administration for refractory thrombotic thrombocytopenic purpura associated with connective tissue diseases

As previous reports regarding rituximab usage for refractory thrombotic thrombocytopenic purpura (TTP) patients with connective tissue diseases (CTD) are limited, it is essential to clarify the clinical effect of early rituximab administration for refractory TTP with CTD in clinical practice. We retrospectively analysed three refractory TTP patients with CTD (plasma exchange [PE]-refractory case (case 2) or cases (case 1 and case 3) with high titers of von Willebrand factor-cleaving protease [ADAMTS13] inhibitor) in a single institution during 2012–2015. The patients were treated with PE/plasma infusion, steroids, and off-label use of rituximab treatment as early administration, at a dosage of 375 mg/m2 weekly with four or eight repeats. Owing to the early diagnosis of refractory TTP with ADAMTS13 activity-deficiency and presence of ADAMTS13 inhibitors (case 1: 2.5, case 2: 1.0, case 3: 6.6), and the subsequent early rituximab treatment combined with PE (case 1: day 1, case 2: day 12, case 3: day 1), all three patients achieved early complete remission and survived without relapse to 779, 498 and 388 days, respectively. In all three cases, the recovery of platelet counts (>50 × 109/L) was achieved within three weeks of rituximab administration. The adverse effect (only an infusion reaction) was safe and tolerable. In contrast to previous reports regarding rituximab treatment for TTP in CTD patients, in our case series study, it’s to the credit that we described the detailed clinical course and short- and long-term effect of early rituximab administration at refractory TTP patients with CTD in clinical practice.