Flexible selection of a single treatment incorporating short‐term endpoint information in a phase II/III clinical trial

Seamless phase II/III clinical trials in which an experimental treatment is selected at an interim analysis have been the focus of much recent research interest. Many of the methods proposed are based on the group sequential approach. This paper considers designs of this type in which the treatment selection can be based on short‐term endpoint information for more patients than have primary endpoint data available. We show that in such a case, the familywise type I error rate may be inflated if previously proposed group sequential methods are used and the treatment selection rule is not specified in advance. A method is proposed to avoid this inflation by considering the treatment selection that maximises the conditional error given the data available at the interim analysis. A simulation study is reported that illustrates the type I error rate inflation and compares the power of the new approach with two other methods: a combination testing approach and a group sequential method that does not use the short‐term endpoint data, both of which also strongly control the type I error rate. The new method is also illustrated through application to a study in Alzheimer's disease. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.     

Analytical and between-subject variation of thrombin generation measured by calibrated automated thrombography on plasma samples*

Background: The Calibrated Automated Thrombography (CAT) is an in vitro thrombin generation (TG) assay that holds promise as a valuable tool within clinical diagnostics. However, the technique has a considerable analytical variation, and we therefore, investigated the analytical and between-subject variation of CAT systematically. Moreover, we assess the application of an internal standard for normalization to diminish variation.

Methods: 20 healthy volunteers donated one blood sample which was subsequently centrifuged, aliquoted and stored at ?80?°C prior to analysis. The analytical variation was determined on eight runs, where plasma from the same seven volunteers was processed in triplicates, and for the between-subject variation, TG analysis was performed on plasma from all 20 volunteers. The trigger reagents used for the TG assays included both PPP reagent containing 5?pM tissue factor (TF) and PPPlow with 1?pM TF. Plasma, drawn from a single donor, was applied to all plates as an internal standard for each TG analysis, which subsequently was used for normalization.

Results: The total analytical variation for TG analysis performed with PPPlow reagent is 3–14% and 9–13% for PPP reagent. This variation can be minimally reduced by using an internal standard but mainly for ETP (endogenous thrombin potential). The between-subject variation is higher when using PPPlow than PPP and this variation is considerable higher than the analytical variation.

Conclusion: TG has a rather high inherent analytical variation but considerable lower than the between-subject variation when using PPPlow as reagent.     

Selective Na+/H+ exchange inhibition by cariporide reduces liver fibrosis in the rat

The aim of this study was to evaluate the effect of cariporide, a selective Na(+)/H(+) exchange inhibitor, on isolated and cultured hepatic stellate cells (HSCs) and in 2 in vivo models of rat liver fibrosis. Platelet-derived growth factor (PDGF)-induced HSC proliferation, evaluated by measuring the percentage of bromodeoxyuridine-positive cells, was significantly inhibited by cariporide, with a maximal effect at 10 micromol/L. Incubation with cariporide did not inhibit PDGF-induced extracellular-regulated kinase 1/2 (ERK1/2), Akt (a downstream component of the phosphatidylinositol [PI]-3 kinase pathway), and protein kinase C (PKC) activation but reduced PDGF-induced activation of the Na(+)/H(+) exchanger, with a maximal effect at 10 micromol/L. Rats treated with dimethylnitrosamine (DMN; 10 mg/kg) for 1 and 5 weeks received a diet with or without 6 ppm cariporide. Treatment with cariporide reduced the degree of liver injury, as determined by alanine aminotransferase (ALT) values, also when administered after the induction of hepatic damage. This was associated with reduced HSC activation and proliferation and reduced collagen deposition, as determined by morphometric evaluation of alpha-smooth muscle actin (SMA)/proliferating cell nuclear antigen-positive cells and percentage of Sirius red-positive parenchyma, respectively. Moreover, cariporide was also able to reduce alpha(1)I procollagen messenger RNA (mRNA) expression. Similar effects were observed in bile duct-ligated (BDL) rats. In conclusion, selective inhibition of the Na(+)/H(+) exchanger by cariporide may represent an effective therapeutic strategy in the treatment of hepatic fibrosis.     

Analysis of late risk of systemic blood pressures <120/80 mm Hg

We studied categories of blood pressure (BP) <120/80 mm Hg as predictors of hypertension 10 to 22 years later by logistic regression analyses with 6 covariates. There was progressively increased risk for subjects with systolic BP 100 to 109 and 110 to 119 mm Hg (vs <100 mm Hg) or diastolic BP 70 to 74 and 75 to 79 mm Hg (vs <70 mm Hg). These relations were similar in men, women, and several ethnic groups but stronger in subjects <40 years old. These data suggest a definition of optimal BP of <100/70 mm Hg, similar to usual BP levels in children <10 years old.     

“Pinopodes” and Implantation

Reviews in Endocrine and Metabolic Disorders -     

Experiences with the human tumor colony-forming assay in gynecologic malignancies

Summary Tumor samples from 74 patients with gynecologic malignancies including breast cancer were processed in a soft agar colony-forming assay. None of the samples resulted in a pure single cell suspension. Of the 10 samples meeting our criteria of evaluability for chemosensitivity testing, only 5 samples showed in vitro sensitivity to any drug. Of the 3 evaluable correlations between in vitro and in vivo results, 2 were correct. Due to the low rate of evaluable samples the assay has only limited value in the assignment of chemotherapeutic drugs for patients treated at our institution.This work was supported in part by the Gesellschaft zur Bekämpfung der Krebskrankheiten Nordrhein-Westfalen     

Immunophenotypic characterization of myelomonocytic cells in patients with myelodysplastic syndrome

Summary. Infections, an important determinating factor in the clinical course of myelodysplastic syndromes (MDS), result in activation of myelomonocytic cells. In this study we demonstrate activation-associated immunophenotypic changes of cell surface antigens on monocytes and granulocytes observed in two groups of MDS patients, one with low and another one with high clinical risk, and compared them to healthy individuals. Significantly changed expression of the complement receptors 1 (CD35) and 3 (CD11b), the Fcγ receptor I (CD64), the leucocyte-homing receptor (CD44) and the activation associated membrane proteins CD67 and M5 were found on monocytes and/or granulocytes of MDS patients. In low-risk MDS patients we observed activation-associated phenotypic changes only in monocytes, whereas in high-risk MDS patients, both monocytes and granulocytes showed such changes. Additionally, we performed respiratory burst experiments and observed an impaired response of monocytes and granulocytes derived from MDS patients. Despite the fact that all patients were free of infection by clinical criteria, cell surface phenotyping as well as the reduced respiratory burst capacity of myelomonocytic cells suggests in vivo preactivation of these cells.