Rituximab prevents recurrence of thrombotic thrombocytopenic purpura: a case report

Management of acquired, immune thrombocytopenic purpura (iTTP): beyond the acute phase

Modern therapy for acute TTP has resulted in a dramatic improvement in outcomes, with the combination of plasma exchange, immunosuppression, and caplacizumab being associated with >90% survival rates following an acute episode. TTP is no longer associated with just the acute episode, but requires long-term follow-up. There remains significant morbidity associated with acute TTP, and many patients suffer marked neuropsychological sequelae, including impairment in cognitive functioning, affective disorders, and reduction in health-related quality of life measures. The focus of management beyond the acute phase centres on relapse prevention, via careful monitoring of patients and the use of either ad hoc or regular immunosuppressive therapies. The main therapy used is rituximab, but despite more limited evidence, other immunosuppressive therapies may be required to aim for normalisation of ADAMTS 13 activity. Follow-up with a reduction in ADAMTS 13 activity levels (ADAMTS 13 relapse), rituximab is central to normalisation of activity levels and prevention of a clinical relapse. Fundamental to elective therapy is the role of ADAMTS 13 activity monitoring, and impact of reduced ADAMTS13 activity on end organ damage. This review discusses monitoring and treatment strategy for long-term management of TTP, including the variety of therapies available to maintain remission, prevent relapse and a summary of a long-term treatment pathway.

Rituximab in autoimmune thrombotic thrombocytopenic purpura: A success story

Despite a significant improvement of thrombotic thrombocytopenic purpura (TTP) prognosis since the use of plasma exchange, morbidity and mortality remained significant because of poor response to standard treatment or exacerbations and relapses. Rituximab, a chimeric monoclonal antibody directed against the B-lymphocyte CD20 antigen, has shown a particular interest in this indication. Recent studies also reported strong evidence for its efficiency in the prevention of relapses. This review addresses these recent progresses and still opened questions in this topic: should rituximab be proposed in all patients at the acute phase? Should all patients benefit from a preemptive treatment? Is the infectious risk acceptable in this context?

Idiopathic Relapsing Thrombotic Thrombocytopenic Purpura with Persistent ADAMTS13 Inhibitor Activity Treated Sequentially with Plasmapheresis, Rituximab, Cyclophosphamide and Splenectomy

We here describe a patient with an idiopathic thrombotic thrombocytopenic purpura (TTP) secondary to an ADAMTS13 inhibitor that continued to be dependent on plasmapheresis until the patient was treated with rituximab. TTP manifestations subsided with rituximab treatment in spite of a persistently low ADAMTS13 activity and continued a detectable inhibitor activity until the patient developed an intolerance to rituximab due to an allergic reaction when cyclophosphamide was added; this resulted in a normalization of ADAMTS13 activity and the disappearance of the inhibitor. Later, the patient developed an intolerance to rituximab due to a severe allergic reaction. Soon after stopping rituximab, the ADAMTS13 activity level dipped below 5% in addition to the appearance of the ADAMTS13 inhibitor. The patient had a splenectomy after rituximab and cyclophosphamide treatment; the medication was stopped based on several case reports of a complete remission of TTP after splenectomy. We believe that the reason TTP went into remission in our patient was because of rituximab treatment, in spite of both persistently low ADAMTS13 activity and a detectable inhibitor activity due to reducing the release of von Willebrand factor large multimers from the endothelial cells. We found that ADAMTS13 activity normalized and the inhibitor activity became undetectable when cyclophosphamide was added to rituximab. We suggest adding cyclophosphamide to rituximab for the treatment of patients with persistent ADAMTS13 inhibitors in order to prolong the remission period and lower the rate of relapse.

Efficacy and Safety of Rituximab for Refractory and Relapsing Thrombotic Thrombocytopenic Purpura: A Cohort of 10 Cases

OBJECTIVE

Idiopathic thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder mediated by autoantibodies directed against ADAMTS13. This provides a rationale for the use of rituximab in this disorder. We report our experience and the outcome of 10 cases of TTP (9 refractory and 1 relapsing) successfully treated with rituximab in combination with plasma exchange (PE) and other immunosuppressive treatments.

METHODS

The diagnosis of TTP was based on clinical criteria and supported by severe deficiency of ADAMTS13 activity and presence of inhibitors in seven cases. Rituximab was started after a median of 18.6 sessions of PE (range: 5–35) at the dose of 375 mg/m²/week for 4–8 weeks.

RESULTS

Complete remission was achieved in all patients after a median time of 14.4 days of the first dose (range: 6–30). After a median follow-up of 30 months (range: 8–78), eight patients were still in remission and two developed multiple relapses, treated again with the same therapy, and achieved complete responses; they are alive, and in complete remission after a follow-up of 12 and 16 months.

CONCLUSION

Rituximab appears to be a safe and effective therapy for refractory and relapsing TTP. However, longer follow-up is recommended to assess relapse and detect possible long-term side effects of this therapy.

Thrombotic microangiopathy, cancer, and cancer drugs

Thrombotic microangiopathy (TMA) is a complication that can develop directly from certain malignancies, but more often results from anticancer therapy. Currently, the incidence of cancer drug-induced TMA during the last few decades is >15%, primarily due to the introduction of anti-vascular endothelial growth factor (VEGF) agents. It is important for clinicians to understand the potential causes of cancer drug-induced TMA to facilitate successful diagnosis and treatment. In general, cancer drug-induced TMA can be classified into 2 types. Type I cancer drug-induced TMA includes chemotherapy regimens (ie, mitomycin C) that can potentially promote long-term kidney injury, as well as increased morbidity and mortality. Type II cancer drug-induced TMA includes anti-VEGF agents that are not typically associated with cumulative dose-dependent cell damage. In addition, functional recovery of kidney function often occurs after drug interruption, assuming a type I agent was not given prior to or during therapy. There are no randomized controlled trials to provide physician guidance in the management of TMA. However, previously accumulated information and research suggest that endothelial cell damage has an underlying immunologic basis. Based on this, the emerging trend includes the use of immunosuppressive agents if a refractory or relapsing clinical course that does not respond to plasmapheresis and steroids is observed.

Preemptive rituximab infusions after remission efficiently prevent relapses in acquired thrombotic thrombocytopenic purpura

In acquired thrombotic thrombocytopenic purpura (TTP), the persistence of severe ADAMTS13 deficiency (<10%) during remission is associated with more relapse. Preemptive (ie, after remission) administration of rituximab in these patients to prevent relapses remains controversial. We performed a cross-sectional analysis of 12-year follow-up data to compare the relapse incidence with or without preemptive rituximab infusion. Among 48 patients who experienced at least one episode of acquired TTP followed by severe ADAMTS13 deficiency during remission, 30 received preemptive rituximab (group 1); the other 18 did not (group 2). After a median of 17 months (interquartile range [IQR], 11-29) following rituximab, the relapse incidence decreased from 0.57 episodes/year (IQR, 0.46-0.7) to 0 episodes/year (IQR, 0-0.81) (P < .01) in group 1. ADAMTS13 activity 3 months after the first rituximab infusion increased to 46% (IQR, 30%-68%). Nine patients required additional courses of rituximab. In 5 patients, ADAMTS13 activity failed to increase durably. Four patients experienced manageable adverse effects. In group 2, the relapse incidence was higher (0.5 relapses/year; IQR, 0.12-0.5; P < .01). Relapse-free survival was longer in group 1 (P = .049). A persistent severe ADAMTS13 deficiency during TTP remission should prompt consideration of preemptive rituximab to prevent relapses.

ADAMTS13 predicts renal and cardiovascular events in type 2 diabetic patients and response to therapy

In patients with diabetes, impaired ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13) proteolysis of highly thrombogenic von Willebrand factor (VWF) multimers may accelerate renal and cardiovascular complications. Restoring physiological VWF handling might contribute to ACE inhibitors' (ACEi) reno- and cardioprotective effects. To assess how Pro618Ala ADAMTS13 variants and related proteolytic activity interact with ACEi therapy in predicting renal and cardiovascular complications, we genotyped 1,163 normoalbuminuric type 2 diabetic patients from BErgamo NEphrologic DIabetes Complications Trial (BENEDICT). Interaction between Pro618Ala and ACEi was significant in predicting both renal and combined renal and cardiovascular events. The risk for renal or combined events versus reference Ala carriers on ACEi progressively increased from Pro/Pro homozygotes on ACEi (hazard ratio 2.80 [95% CI 0.849-9.216] and 1.58 [0.737-3.379], respectively) to Pro/Pro homozygotes on non-ACEi (4.77 [1.484-15.357] and 1.99 [0.944-4.187]) to Ala carriers on non-ACEi (8.50 [2.416-29.962] and 4.00 [1.739-9.207]). In a substudy, serum ADAMTS13 activity was significantly lower in Ala carriers than in Pro/Pro homozygotes and in case subjects with renal, cardiovascular, or combined events than in diabetic control subjects without events. ADAMTS13 activity significantly and negatively correlated with all outcomes. In patients with diabetes, ADAMTS13 618Ala variant associated with less proteolytic activity, higher risk of chronic complications, and better response to ACEi therapy. Screening for Pro618Ala polymorphism may help identify patients with diabetes at highest risk who may benefit the most from early reno- and cardioprotective therapy.

Cyclosporin A therapy on idiopathic thrombotic thrombocytopenic purpura in the relapse setting: two case reports and a review of the literature

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease, characterized by microangiopathic hemolytic anemia, thrombocytopenia, fever, neurologic disturbances, and renal failure. Plasma therapy has dramatically improved prognosis of TTP, whereas recurrent acute episodes still occur in approximately 40% of patients. Moreover, patients with acquired ADAMTS13 deficiency, which is a significant factor for relapse, may require additional immunosuppressive treatment to get a durable remission.

STUDY DESIGN AND METHODS

We hereby report two patients with a history of relapsed idiopathic TTP, who both received cyclosporin A (CSA) as a prophylactic manner after the remission was achieved. We also discuss the efficacy of CSA in patients with relapsed idiopathic TTP with a review of the published literature.

RESULTS

Under CSA therapy, both patients maintained their clinical remission state, and the ADAMTS13 levels were normalized.

CONCLUSION

To conclude, CSA therapy may be useful for the prevention of relapsed idiopathic TTP in patients with a history of frequent relapses.

Rituximab therapy for autoimmune haematological diseases

Autoimmune haematological diseases are characterized by the production of antibodies against blood proteins or cells, and comprise primary immune thrombocytopenia, autoimmune haemolytic anaemia, acquired haemophilia, and thrombotic thrombocytopenic purpura. Current treatments for these disorders include corticosteroids, cytotoxic drugs and splenectomy, which may be associated with significant systemic toxicity and/or morbility. B cells play a key role in both the development and perpetuation of autoimmunity, since they produce autoantibodies but also function as antigen-presenting cells, and release immunomodulatory cytokines. Rituximab, an anti-CD20 monoclonal antibody that specifically depletes B cells, may be an effective treatment strategy for patients with autoimmune disorders. This article reviews data of the literature, showing that patients with autoimmune haematological diseases can respond to rituximab irrespective of age and number or type of prior treatments. These data suggest that rituximab provides an effective and well-tolerated treatment option for these conditions.

Rituximab therapy to prevent relapse in chronic relapsing thrombotic thrombocytopenic purpura (TTP) in a child

Our patient first developed thrombotic thrombocytopenic purpura (TTP) at age 10 years with an initial platelet count of 10,000/microL. She achieved remission with plasmapheresis (PE), but suffered 2 relapses in the next 2 years, each approximately 1 year from PE, with ADAMTS13 levels of <5%. Early in her third remission, with vincristine (weekly x 4 doses) and prednisone (for 2 weeks) her ADAMTS13 increased to 99% in 24 weeks, but decreased to <4% in the next 38 weeks. After 4 weekly doses of rituximab (375 mg/m(2)), her ADAMTS13 level reached 101% in 9 weeks and has remained consistently above 97% on bimonthly monitoring for more than a year. She remains in continuous clinical and hematologic remission with an ADAMTS13 level of 108% at 60 weeks from rituximab therapy and 124 weeks from her second relapse. This case report suggests that monitoring ADAMTS13 level at regular intervals in recurrent TTP may help us identify patients at risk for further relapse; and such a relapse may be prevented, or at least delayed with timely rituximab therapy, thus reducing morbidity from relapsed TTP and its treatment.

Sustained response with rituximab in patients with thrombotic thrombocytopenic purpura: a report of 13 cases and review of the literature

Idiopathic thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease mediated by autoantibodies directed against ADAMTS-13. A number of small series and case reports have shown promising results with rituximab in refractory or relapsed TTP. In this report, we present 13 patients with TTP treated with rituximab. Twelve of the 13 patients (92%) achieved complete response; no subsequent relapses occurred with median follow-up of 24 months (range, 13-84 months). The addition of rituximab to standard therapy appears to be effective in sustaining long-term remission in TTP. However, the optimal dosing and timing of rituximab warrant further investigation. Am. J. Hematol., 2009. (c) 2009 Wiley-Liss, Inc.

Off-label use of rituximab in a tertiary Queensland hospital

BACKGROUND

Rituximab is a monoclonal antibody directed against CD20, a pan B lymphocyte marker. It is approved in Australia for treatment of CD20-positive B cell non-Hodgkin lymphoma and rheumatoid arthritis. There is increasing off-label use of rituximab in conditions where B cells and autoantibodies play a role in the pathophysiology. Rituximab is not only expensive, but its safety in unregistered indications is uncertain.

METHODS

We performed a retrospective review of the off-label use of rituximab approved by the High Cost Drug Subcommittee at the Princess Alexandra Hospital between 2005 and 2008. Cases of post transplant lymphoproliferative disorder were excluded.

RESULTS

A total of 28 patients received rituximab for a variety of off-label indications. There were no reported cases of serious infusion reactions or other notable adverse events. The most favourable outcomes were seen in myasthenia gravis, shrinking lung syndrome, thrombotic thrombocytopenic purpura, prevention and treatment of renal transplant rejection and lupus nephritis. No benefit was observed in cases of focal segmental glomerulosclerosis (primary or post-transplant recurrence) and post-transplant recurrence of haemolytic uremic syndrome. There was limited benefit in cryoglobulinaemic vasculitis. The cost of off-label use was in excess of $210,000.

CONCLUSION

In the absence of formal clinical trials, decisions regarding off-label use of rituximab are difficult. Our cases contribute to the published literature and should help provide clinicians with greater insights into which conditions are likely to respond. As can be seen in our series, rituximab benefits people with certain conditions; longevity and cost-effectiveness are currently unknown.

Rituximab as an adjunct to plasma exchange in TTP: a report of 12 cases and review of literature

Idiopathic thrombotic thrombocytopenic purpura (TTP) is caused by the production of autoantibodies against the Von Willebrand factor cleaving enzyme. This provides a rationale for the use of rituximab in this disease. We report a retrospective review of 12 patients treated with rituximab for TTP refractory to plasma exchange. Eleven patients were treated during initial presentation, and one patient was treated for recurrent relapse. Ten patients responded to treatment. Median time to response after first dose of rituximab was 10 days (5-32). Of the 11 patients treated during initial presentation, nine remain free of relapse after a median follow-up of 57+ months (1+-79+). Two patients died during initial treatment. One patient was lost to follow-up 1 month after achieving complete response. The patient treated for recurrent disease during second relapse remained disease free for 2years, relapsed and was treated again with rituximab, and was in remission for 22 months. She relapsed again, was retreated, and has now been in remission for 21+ months. We conclude that rituximab is an useful addition to plasma exchange treatment in TTP, but its exact role and dosing need to be verified in prospective studies.

Rituximab-based therapy for gemcitabine-induced hemolytic uremic syndrome in a patient with metastatic pancreatic adenocarcinoma: a case report

PURPOSE

The purpose of this report is to describe the management and outcome of an unusual complication of a commonly used chemotherapeutic agent. Gemcitabine is a known risk factor for hemolytic uremic syndrome (HUS), which can often have a rapidly fatal clinical course despite intervention with steroids, plasmapheresis and hemodialysis.

METHODS

A retrospective report of the first case of gemcitabine-related HUS, in a patient with metastatic pancreatic adenocarcinoma, treated with a variety of standard therapies in addition to rituximab is presented. The hematologic response parameters and clinical outcomes to each of the therapies given are described.

RESULTS

Chemotherapy-induced HUS was aggressively treated with plasmapheresis, high-dose steroids, vincristine and rituximab. Platelet recovery and clinical improvement coincided with administration of rituximab. In addition, aggressive supportive measures to manage renal failure (hemodialysis) and labile hypertension, allowed this patient to have an extended survival as a result of successful therapy for this complication despite an underlying rapidly fatal malignancy.

CONCLUSION

This case highlights the importance of timely application of aggressive measures even in patients with known diagnosis of a fatal malignancy as these interventions can prolong life and be of palliative benefit.

New treatment options for immune-mediated hematological disorders

In recent years, there has been a tremendous increase in the number of clinical studies with monoclonal antibodies and small molecules in the treatment of hematological malignancies. Clinical observations have shown that some of these molecules may also aid in the treatment of immune-mediated hematological disorders. Moreover, immunotherapy has become an important treatment cornerstone in other, non-hematological, auto-immune diseases. This paper reviews the current state of the use of these new molecules in the treatment of the most frequently encountered immune-mediated hematological disorders: auto-immune hemolytic anemia (AIHA), idiopathic thrombocytopenic purpura (ITP), and thrombotic thrombocytopenic purpura (TTP).

Regional UK TTP registry: correlation with laboratory ADAMTS 13 analysis and clinical features

Thrombotic thrombocytopenic purpura (TTP) is an acute, rare, life-threatening disorder. This report presents the South East (SE) England registry for TTP, from April 2002 to December 2006, which included 176 patients and 236 acute episodes; 75% of patients were female and 25% were male, overall median age at presentation was 42 years. Mortality was 8.5%, most cases died before treatment was instigated. The main ethnic groups were Caucasian (64%) and Afro Caribbean (27%). Seventy-seven percent of cases were idiopathic, 5% were congenital and the remaining cases had a defined precipitant. Neurological features were the most prevalent, but cardiac involvement accounted for 42% of presenting features. The overall median number of plasma exchanges (PEXs) to remission was 15; between April 2002 and December 2003, the median number of PEXs was 19 and it was 12 between January 2004 and December 2006 (P < 0.0001). In the latter period, adjuvant therapies were reduced, but Rituximab was increased. ADAMTS 13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity was <10% in 74% and 95% of these cases had positive IgG antibodies to ADAMTS 13. Renal impairment and delayed normalisation of platelet count were the main differences between idiopathic and secondary TTP.

Von Willebrand factor, ADAMTS13, and thrombotic thrombocytopenic purpura

Discoveries during the past decade have revolutionized our understanding of idiopathic thrombotic thrombocytopenic purpura (TTP). Most cases in adults are caused by acquired autoantibodies that inhibit ADAMTS13, a metalloprotease that cleaves von Willebrand factor within nascent platelet-rich thrombi to prevent hemolysis, thrombocytopenia, and tissue infarction. Although approximately 80% of patients respond to plasma exchange, which removes autoantibody and replenishes ADAMTS13, one third to one half of survivors develop refractory or relapsing disease. Intensive immunosuppressive therapy with rituximab appears to be effective as salvage therapy, and ongoing clinical trials should determine whether adjuvant rituximab with plasma exchange also is beneficial at first diagnosis. A major unanswered question is whether plasma exchange is effective for the subset of patients with idiopathic TTP who do not have severe ADAMTS13 deficiency.

Thrombotic thrombocytopenic purpura is associated with a high relapse rate after plasma exchange: a single-centre experience

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a rare condition characterized by microangiopathic haemolytic anaemia, thrombocytopenia, renal and/or neurological dysfunction secondary to microvascular or macrovascular thrombosis. Despite advances in treatment, TTP remains a serious condition with significant morbidity and mortality.

METHODS

We undertook an audit of patients with TTP over 14 years to assess remission, relapse, survival and factors predictive of outcome using current therapy based on plasma exchange with fresh-frozen plasma.

RESULTS

Forty patients were identified between January 1992 and December 2005. Thirty-one (82%) achieved complete response (CR) to therapy using plasma exchange with fresh-frozen plasma (median 11 exchanges) and steroids. Twelve (37%) relapsed a median of 14 days following cessation of therapy, with multiple relapses occurring in two patients. TTP-related death occurred in four patients during their initial presentation and in two during subsequent relapse. Four patients were only partially responsive to first-line therapy. The absence of neurological features at presentation was the only factor predicting a sustained CR to first-line therapy (P = 0.027, log-rank analysis). The mean duration of inpatient treatment was 18 days (range 4-38 days) with 30% of patients requiring intensive care admission. Thirty-four per cent of patients acquired central venous line infection, with a median of two episodes of line sepsis per patient.

CONCLUSION

Our results indicate the need for better treatments to reduce the high early relapse rate and significant mortality associated with current therapy.

Cyclosporin and plasma exchange in thrombotic thrombocytopenic purpura: long-term follow-up with serial analysis of ADAMTS13 activity

We hypothesized that cyclosporin (CSA) as adjunct to plasma exchange (PE) improves the efficacy of PE in idiopathic thrombotic thrombocytopenic purpura (TTP) via suppression of the antibody inhibitor of ADAMTS13. Our preliminary findings with CSA and PE as the upfront treatment of TTP suggested that the addition of CSA to PE significantly decreased the exacerbation (disease recurrence within 30 d of the last PE) rates compared to a cohort that received corticosteroids and PE as their upfront therapy of TTP. We present an updated analysis with long-term follow-up of 18 patients with idiopathic TTP treated with concurrent CSA and PE with analysis of serial measurements of ADAMTS13 activity, antigen and inhibitor concentration in the context of clinical outcome data. Overall, 16/18 (89%) patients achieved remission, similar to historical remission rates in idiopathic TTP with PE with only one patient suffering an exacerbation. Clinical responses correlated with improvements in ADAMTS13 activity and suppression of the antibody inhibitor of ADAMTS13. These data suggest that the efficacy of CSA is at least in part related to its suppression of the antibody inhibitor of ADAMTS13 and a subsequent improvement in ADAMTS13 activity and antigen.

Translational mini-review series on complement factor H: therapies of renal diseases associated with complement factor H abnormalities: atypical haemolytic uraemic syndrome and membranoproliferative glomerulonephritis

Genetic and acquired abnormalities in complement factor H (CFH) have been associated with two different human renal diseases: haemolytic uraemic syndrome and membrano proliferative glomerulonephritis. The new genetic and pathogenetic findings in these diseases and their clinical implications for the management and cure of patients are reviewed in this paper.

Anti-CD20 antibody in thrombotic thrombocytopenic purpura refractory to plasma exchange

Thrombotic thrombocytopenic purpura is a rare condition characterized by microangiopathic haemolytic anaemia, thrombocytopenia, altered neurology, renal impairment and fever. While plasma exchange has reduced mortality from more than 90% to between 10 and 30%, a proportion of cases fail to respond. Rituximab may be efficacious in the management of refractory cases of thrombotic thrombocytopenic purpura. We present two cases in which rituximab was used with successful outcomes. Treatment resulted in resolution of severe clinical and haematological abnormalities in both patients. There has been no relapse after 16 months follow up. Our experience supports the use of rituximab in difficult cases of TTP. Ongoing evaluation of its use is in progress at our institution.

Targeting the inhibitor of ADAMTS13 in thrombotic thrombocytopenic purpura

There has clearly been an evolution in the treatment of thrombotic thrombocytopenic purpura (TTP) over the past several years based upon a better understanding of the pathophysiology of this disorder. An autoantibody inhibitor of the ADAMTS13 protease and the resulting severe deficiency of ADAMTS13 function seem to be significant risk factors for the development of TTP, a disease increasingly recognized as an autoimmune disorder. Immune-based therapy aimed at suppressing the inhibitor of ADAMTS13 has been applied to the treatment of patients with TTP who are refractory to the standard treatment of plasma exchange and to patients with multiple recurrences of TTP. More recently, immunosuppressive therapy has been used alone as prophylactic therapy to prevent recurrences of acute TTP. This review focuses on the recent developments in the use of rituximab and ciclosporin in the treatment of TTP.

A dramatic response to rituximab in a patient with resistant thrombotic thrombocytopenic purpura (TTP) who developed acute stroke

BACKGROUND

Refractory condition can occur in 10-30% of all cases of thrombotic thrombocytopenic purpura despite increased frequency of total plasma exchange. Rituximab can affect the clinical outcome of the refractory cases. However, little is known about usefulness of rituximab on central nervous system involvement mimicking acute ischemic stroke.

METHODS

We report the case of a woman with refractory thrombotic thrombocytopenic purpura who developed an acute onset right sided paralysis, dysarthria, and central facial paralysis, suggestive of cerebrovascular accident while under plasma exchange, corticosteroid, and vincristine therapy.

RESULTS

After initiation of rituximab (375 mg/m(2) weekly for 4 weeks), a dramatic response occurred and the patient's neurologic function recovered fully within days. Sustained remission was achieved, and the patient was well 1 year after her admission, while she was on azathioprine treatment.

CONCLUSION

This report suggests that rituximab can provide a good outcome of the dramatic central nervous system involvement in patients with thrombotic thrombocytopenic purpura.

Predictors of response and relapse in a cohort of adults with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: a single-institution experience

BACKGROUND

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is a diagnosis of exclusion when a patient presents with the sine qua non findings of thrombocytopenia and microangiopathic hemolytic anemia without an identifiable cause. Although most patients respond to therapeutic plasma exchange (TPE), a significant number of patients relapse. The aim was to determine if clinical, laboratory, and/or treatment features could predict response and/or relapse.

STUDY DESIGN AND METHODS

This study was a retrospective review of adults with TTP-HUS treated with TPE at our institution from January 1996 to February 2004.

RESULTS

The study population consisted of 90 patients (69% female) with mean age of 45 years and mostly obese (65%). The majority of cases were considered idiopathic. Ten patients died (11%) from the disease before achieving a response, whereas 79 percent were considered responders. Obesity and severe anemia at presentation were predictors of response to TPE (p = 0.0126 and p = 0.0071, respectively). Among the responders, 28 percent relapsed in a median of 14 months. Male sex, severe thrombocytopenia (mean +/- SD, 13 x 10(9) +/- 8 x 10(9)/L), and higher lactate dehydrogenase pre-/posttreatment ratio were associated with relapse (p values of 0.0141, 0.0199, and 0.0407, respectively). ADAMTS-13 values were not obtained on enough number of patients to provide important data.

CONCLUSION

Although patient and laboratory characteristics associated with response and relapse were identified, there was significant overlap between patient groups. Thus, our findings offer preliminary evidence and do not yet justify short- or long-term changes in the management of patients with TTP-HUS.

Rituximab therapy for thrombotic thrombocytopenic purpura: a proposed study of the Transfusion Medicine/Hemostasis Clinical Trials Network with a systematic review of rituximab therapy for immune-mediated disorders

The rationale for immunosuppressive therapy of thrombotic thrombocytopenic purpura (TTP) was established by observations that TTP may be caused by autoantibodies to ADAMTS13. Patients with high-titer autoantibodies to ADAMTS13 may have a higher mortality, and survivors may require prolonged plasma exchange therapy in spite of adjunctive glucocorticoid treatment. More intensive immunosuppressive therapy with rituximab may provide benefit for many of these patients. The Transfusion Medicine/Hemostasis Clinical Trials Network is developing a randomized, clinical trial to test the hypothesis that addition of rituximab to standard treatment of TTP with plasma exchange and glucocorticoids will decrease initial treatment failure rates as well as subsequent relapses over the following 3 years. To provide the background data for this clinical trial, a systematic review of all published reports on rituximab treatment of immune-mediated disorders was performed. Twelve articles have reported 27 patients treated with rituximab for TTP, with benefit described in 25 (93%) of the patients. Additional reports have described rituximab treatment of 37 other immune-mediated disorders, with clinical response in most patients. These observations from small uncontrolled case series provide the background and rationale for a randomized clinical trial to establish the role of rituximab in the management of patients with TTP.

Splenectomy for the treatment of thrombotic thrombocytopenic purpura

Plasma exchange is the treatment of choice for patients with thrombotic thrombocytopenic purpura (TTP) and results in remission in >80% of the cases. Treatment of patients who are refractory to plasma therapy or have relapsing disease is difficult. Splenectomy has been a therapeutic option in these conditions but its value remains controversial. We report on a series of 33 patients with TTP who were splenectomised because they were plasma refractory (n = 9) or for relapsed disease (n = 24). Splenectomy generated prompt and unmaintained remissions in all except five patients, in whom remission was delayed (n = 4) or who died with progressive disease (n = 1). Four postoperative complications occurred: one pulmonary embolism and three surgical complications. Median follow-up after splenectomy was 109 months (range 28-230 months). The overall postsplenectomy relapse rate was 0.09 relapses/patient-year and the 10-year relapse-free survival (RFS) was 70% (95% CI 50-83%). In the patients with relapsing TTP, relapse rate fell from 0.74 relapses/patient-year before splenectomy to 0.10 after splenectomy (P < 0.00001). Two patients died from first postsplenectomy relapse. Although these results are based on retrospective data and that the relapse rate may spontaneously decrease with time, we conclude that splenectomy, when performed during stable disease, has an acceptable safety profile and should be considered in cases of plasma refractoriness or relapsing TTP to reach durable remissions and to reduce or prevent future relapses.