[Clinical study on Rituximab in the treatment of idiopathic thrombotic thrombocytopenic purpura].

Objective: To study the efficacy and safety of rituximab (RTX) in the treatment of idiopathic thrombotic thrombocytopenic purpura (ITTP).

Methods: Among 17 ITTP patients, nine cases of the RTX group were administrated with RTX plus plasma exchange (PEX) and steroids. Eight cases of the control group received PEX plus steroids±other immune inhibitors. Patients received RTX 375 mg/m², 1 per week for 4 weeks. The laboratory parameters, including hemogram, LDH, ADAMTS13 activities and its inhibitors, and the ratio of B lymphocytes in peripheral blood were monitored. The number of PEX, total plasma volumes, remission time, relapse ratio and adverse effects in both groups were compared.

Results: The median number of PEX/median total plasma volumes in the RTX and control group were 5(2-8)/9.6(4.0-15.4) L and 6(4-9)/11.2(7.5-14.6) L, respectively. Patients in the RTX and control group achieved hematologic remission at the median time of 15(5-20) days and 22(7-36) days, respectively. And the median time of immunological remission in the two groups was 2(2-8) and 2(2-4) weeks, respectively. ADAMTS13 activities increased significantly after 2 weeks in both two groups. There was no relapse in the RTX group, while 4 patients relapsed in the control group. The percentage of B lymphocytes in peripheral blood obviously deduced one week after first dose of RTX infusion compared with the level before treatment [(2.19±5.11)% vs (18.39±7.15)%, P<0.001], and began to gradually increase 9 months later. Severe adverse events were not observed in RTX group during the therapeutic procedure and follow-up, but one patient, who had sustained immunologic remission, died of severe pneumonia 7 months later.

Conclusion: In the treatment of ITTP, RTX in conjunction with PEX and steroids appeared to be a safe and effective therapy, with fast and sustained remission in hematology and even in immunology, with lower relapse rate and less adverse effects. But patients needed to be paid attention to prevent and treat infectious events in time.