High-dose etoposide and cyclophosphamide without bone marrow transplantation for resistant hematologic malignancy

Seventy-five patients with resistant acute leukemia or lymphoma received high-dose cyclophosphamide and etoposide to explore the activity of this combination in resistant hematologic malignancies, and to determine the maximum doses of these drugs that can be combined without bone marrow transplantation. Etoposide was administered over 29 to 69 hours by continuous infusion corresponding to total doses of 1.8 g/m2 to 4.8 g/m2. Cyclophosphamide, 50 mg/kg/d, was administered on 3 or 4 consecutive days total 150 to 200 mg/kg ideal body weight). At all dose levels myelosuppression was severe but reversible. Mucosal toxicity was dose-limiting with the maximum tolerated dose level combining etoposide 4.2 g/m2 with cyclophosphamide 200 mg/kg. Continuous etoposide infusion produced stable plasma levels that were lower than would be achieved after administration by short intravenous infusion, and this could explain our ability to escalate etoposide above the previously reported maximum tolerated dose. There were 28 complete (35%) and 12 partial (16%) responses. Median duration of complete response (CR) was 3.5 months (range 1.1 to 20+). Seventeen of 40 patients (42%) with acute myelogenous leukemia (AML) achieved CR, including 6 of 20 (30%) with high-dose cytosine arabinoside resistance. We conclude that bone marrow transplantation is not required after maximum tolerated doses of etoposide and cyclophosphamide. This regimen is active in resistant hematologic neoplasms, and the occurrence of CR in patients with high-dose cytosine arabinoside-resistant AML indicates a lack of complete cross-resistance between these regimens.     

Identification of glycoprotein Ib as a target for autoantibody in idiopathic (autoimmune) thrombocytopenic purpura

An antibody (DIL) from a patient with idiopathic thrombocytopenic purpura (ITP) was shown to have autospecificity on the basis of reactions with autologous platelets that were identical to those obtained with platelets from normal subjects. DIL antibody also reacted strongly in an immunofluorescence test with platelets from a patient with Glanzmann's thrombasthenia, but failed to react with platelets from a patient with the Bernard-Soulier syndrome who was known to be deficient in glycoprotein Ib (GPIb). Purified GPIb and control platelets, but not Bernard-Soulier platelets, inhibited the lytic activity of DIL. Using the GPIb-specific monoclonal antibody AP1 and one-dimensional rocket electrophoresis into gels containing rabbit antihuman platelet membrane antibody, it was shown that staphylococcal protein A-Sepharose beads coated with DIL antibody selectively remove GPIb from solubilized platelet preparations. By crossed immunoelectrophoresis it was found that DIL recognizes a determinant on GPIb on the membrane side of the cleavage site of the platelet calcium- activated protease (calpain). These studies provide direct evidence for binding of a platelet autoantibody to a determinant on GPIb relatively close to the site of insertion of this protein into the platelet membrane.     

Designing Clinical Trials for Dystonia

With advances in the understanding of the pathophysiology of dystonia, novel therapeutics are being developed. Such therapies will require clinical investigation ranging from exploratory studies to examine safety, tolerability, dosage selection, and preliminary efficacy to confirmatory studies to evaluate efficacy definitively. As dystonia is a rare and complex disorder with clinical and etiological heterogeneity, clinical trials will require careful consideration of the trial design, including enrollment criteria, concomitant medication use, and outcome measures. Given the complexities of designing and implementing efficient clinical trials, it is important for clinicians and statisticians to collaborate closely throughout the clinical development process and that each has a basic understanding of both the clinical and statistical issues that must be addressed. To facilitate designing appropriate clinical trials in this field, we review important general clinical trial and regulatory principles, and discuss the critical components of trials with an emphasis on considerations specific to dystonia. Additionally, we discuss designs used in early exploratory, late exploratory, and confirmatory phases, including adaptive designs.     

Radiotherapy for melanotic freckles

Five patients who received radiotherapy (RT) for 7 melanotic freckles (MF, also known as Hutchinson's freckles, lentigo maligna) were reviewed 8 to 37 months after their treatment by RT. Local control and a favourable cosmetic result occurred in all patients. Treatment toxicity was minimal. Few reports about the use of RT for MF exist. Many other treatments including observation alone have been associated with high rates of recurrence, and in some cases conversion to invasive melanoma has occurred. RT appears to be a safe and effective treatment for this condition, providing that doses equivalent to 44 Gy in 11 fractions or more are given.     

Self-biting induced by activation of L-type calcium channels in mice: serotonergic influences

The L-type calcium channel activator +/-Bay K 8644 has recently been shown to provoke self-injurious biting in young mice. Since the serotonergic systems have been implicated in the expression of self-injurious behavior in both humans and animals, the present studies tested whether drugs influencing serotonin systems could modify the ability of +/-Bay K 8644 to cause this behavior. The ability of +/-Bay K 8644 to provoke self-biting behavior was increased by the serotonin uptake inhibitor fluoxetine or the monoamine oxidase inhibitor clorgyline. On the other hand, the ability of +/-Bay K 8644 to provoke self-biting was decreased by depletion of serotonin with p-chlorophenylalanine or 5,7-dihyroxytryptamine. These results suggest that the ability of +/-Bay K 8644 to provoke self-injurious behaviors may be mediated by serotonergic influences.