A Canadian phase II study evaluating the efficacy of rituximab in the management of patients with relapsed/refractory thrombotic thrombocytopenic purpura.

Rituximab is a chimeric monoclonal antibody that targets the human CD-20 antigen present on malignant and normal B lymphocytes. Recent clinical studies have shown a significant response rate when this drug is given to selected patients with thrombotic thrombocytopenic purpura (TTP). Given that the clinical manifestations of TTP may be the direct result of an auto-antibody against a regulatory Von Willebrand factor enzyme (ADAMTS13), it makes biological sense to consider a therapy that has the ability to diminish or eradicate antibody-producing B cells.

Mechanism of microthrombosis in HUS.

The mechanism of formation of the microthrombi in hemolytic uremic syndrome (HUS) is not known. Plasma from five adult and six pediatric cases of HUS showed aggregation and release of adenosine triphosphate from normal platelets. When the plasma was absorbed with staphylococcal protein A and again exposed to normal platelets there was no aggregation or release, indicating that an antibody was responsible for the aggregation.

The effect of patient-controlled analgesia on coadministered red blood cells.

Background: Patient-controlled analgesia (PCA) provides effective pain control. The possibility of administrating opioids in the same line as red blood cells (RBCs) for patients with poor venous access has been entertained. The literature on this approach is not extensive, but generally cautionary.

Plasma exchange when myeloma presents as acute renal failure: a randomized, controlled trial.

Background: Two small, randomized trials provide conflicting evidence about the benefits of plasma exchange for patients with acute renal failure at the onset of multiple myeloma.

Objective: To assess the effect of 5 to 7 plasma exchanges on a composite outcome in patients with acute renal failure at the onset of multiple myeloma.

Design: Randomized, open, controlled trial, stratified by chemotherapy and dialysis dependence, conducted from 1998 to 2004.

Effect of awareness of a randomized controlled trial on use of experimental therapy.

Context: Use of experimental therapies during but outside of randomized controlled trials (RCTs) has not been studied.

Objective: To determine whether initiation of an RCT leads to increased use of the experimental therapy outside the trial.

Design And Setting: Data on national apheresis use during 3 Canadian RCTs for multiple sclerosis (1986-1988), thrombotic thrombocytopenic purpura (1982-1988), and myeloma cast nephropathy (1998-2000) were obtained from 19 major medical centers in Canada.