Safety and dose relationship of recombinant human activated protein C for coagulopathy in severe sepsis.

OBJECTIVES: To assess the safety and effect on coagulopathy of a range of doses of recombinant human activated protein C (rhAPC). To determine an effective dose and duration of rhAPC for use in future clinical trials. DESIGN: Double-blind, randomized, placebo-controlled, multicenter, dose-ranging (sequential), phase II clinical trial. SETTING: Forty community or academic medical institutions in United States and Canada. PATIENTS: One hundred thirty-one adult patients with severe sepsis. INTERVENTIONS: Intravenous infusion of rhAPC (12, 18, 24, or 30 microg/kg/hr) or placebo for 48 or 96 hrs. MEASUREMENTS AND MAIN RESULTS: No significant differences in incidence of serious bleeding events (4% rhAPC, 5% placebo, p >.999) or incidence of serious adverse events (39% rhAPC, 46% placebo, p = 0.422) between rhAPC- and placebo-treated patients were observed. One of 53 rhAPC-treated patients with suitable immunogenicity samples had a low level, transient, non-neutralizing anti-APC antibody response not associated with any clinical adverse event. Significant dose-dependent decreases in both D-dimer (p <0.001) and end of infusion interleukin 6 levels (p =.021) were demonstrated. No statistically significant effects on fibrinogen or platelet counts were observed. A nonstatistically significant 15% relative risk reduction in 28-day all-cause mortality was observed between rhAPC- and placebo-treated patients. CONCLUSIONS: rhAPC was safe and well-tolerated and demonstrated a dose-dependent reduction in D-dimer and interleukin 6 levels relative to placebo. The dose of 24 microg/kg/hr for 96 hrs was selected for use in future clinical studies.

Design and methods of the Raloxifene Use for The Heart (RUTH) study.

Raloxifene is a selective estrogen receptor modulator that lowers total and low-density lipoprotein (LDL) cholesterol, reduces the risk of vertebral fracture, and is associated with a reduced incidence of invasive breast cancer in postmenopausal women with osteoporosis. The Raloxifene Use for The Heart (RUTH) trial is designed to determine whether raloxifene 60 mg/day compared with placebo: (1) lowers the risk of the coronary events (coronary death, nonfatal myocardial infarction [MI], or hospitalized acute coronary syndromes other than MI); and (2) reduces the risk of invasive breast cancer in women at risk for a major coronary event. RUTH is a double-blind, placebo-controlled, randomized clinical trial of 10,101 postmenopausal women aged > or =55 years from 26 countries. Women are eligible for randomization if they are postmenopausal and have documented coronary heart disease (CHD), peripheral arterial disease, or multiple risk factors for CHD. Use of estrogen within the previous 6 months is an exclusion factor. The study will be terminated after a minimum of 1,670 participants experience a primary coronary end point. Secondary end points include cardiovascular death, myocardial revascularization, noncoronary arterial revascularization, stroke, all-cause hospitalization, all-cause mortality, all breast cancers, clinical fractures, and venous thromboembolic events, in addition to the individual components of the composite primary coronary end point. RUTH will provide important information about the risk-benefit ratio of raloxifene in preventing acute coronary events and invasive breast cancer, as well as information about the natural history of CHD in women at risk of major coronary events.

Low levels of protein C are associated with poor outcome in severe sepsis.

STUDY OBJECTIVE: To investigate whether protein C levels predict 30-day mortality rate, shock status, duration of ICU stay, and ventilator dependence in patients with sepsis. DESIGN: Retrospective analysis of a subset of a previously published, prospective, randomized, double-blind, placebo-controlled trial ("Effects of Ibuprofen on the Physiology and Survival of Patients With Sepsis" [ISS]). SETTING: A multicenter study performed in the United States and Canada (seven sites). PATIENTS: Seventy hospitalized patients with acute severe sepsis and failure in one or more organs at entry into the ISS trial. MEASUREMENTS AND MAIN RESULTS: Blood samples were obtained from all patients at baseline and at 20, 44, 72, and 120 h after the initiation of study drug (ibuprofen or placebo) infusion. Data obtained at these times included platelet count, prothrombin time, and partial thromboplastin time. The results described in this article are based on a subset of the total ISS population for whom additional coagulation assays were performed on the blood samples obtained at baseline and 44 h. These assays included protein C antigen, D-dimer, and fibrinogen levels. A total of 63 of the 70 patients (90%) studied in this report had acquired protein C deficiency at entry to the ISS trial (baseline). The presence and severity of acquired protein C deficiency were associated with poor clinical outcome, including lower survival rate, higher incidence of shock, and fewer ICU-free and ventilator-free days. CONCLUSIONS: Acquired protein C deficiency may be useful in predicting clinical outcome in patients with sepsis. Clinical studies are warranted to determine whether the replacement of protein C in sepsis patients may improve outcome.

Efficacy and safety of recombinant human activated protein C for severe sepsis.

BACKGROUND: Drotrecogin alfa (activated), or recombinant human activated protein C, has antithrombotic, antiinflammatory, and profibrinolytic properties. In a previous study, drotrecogin alfa activated produced dose-dependent reductions in the levels of markers of coagulation and inflammation in patients with severe sepsis. In this phase 3 trial, we assessed whether treatment with drotrecogin alfa activated reduced the rate of death from any cause among patients with severe sepsis. METHODS: We conducted a randomized, double-blind, placebo-controlled, multicenter trial. Patients with systemic inflammation and organ failure due to acute infection were enrolled and assigned to receive an intravenous infusion of either placebo or drotrecogin alfa activated (24 microg per kilogram of body weight per hour) for a total duration of 96 hours. The prospectively defined primary end point was death from any cause and was assessed 28 days after the start of the infusion. Patients were monitored for adverse events; changes in vital signs, laboratory variables, and the results of microbiologic cultures; and the development of neutralizing antibodies against activated protein C. RESULTS: A total of 1690 randomized patients were treated (840 in the placebo group and 850 in the drotrecogin alfa activated group). The mortality rate was 30.8 percent in the placebo group and 24.7 percent in the drotrecogin alfa activated group. On the basis of the prospectively defined primary analysis, treatment with drotrecogin alfa activated was associated with a reduction in the relative risk of death of 19.4 percent (95 percent confidence interval, 6.6 to 30.5) and an absolute reduction in the risk of death of 6.1 percent (P=0.005). The incidence of serious bleeding was higher in the drotrecogin alfa activated group than in the placebo group (3.5 percent vs. 2.0 percent, P=0.06). CONCLUSIONS: Treatment with drotrecogin alfa activated significantly reduces mortality in patients with severe sepsis and may be associated with an increased risk of bleeding.

Application of automatic image segmentation to tibiae and vertebrae from ovariectomized rats.

Automatic contextual segmentation algorithms were developed to objectively identify bone compartments in pQCT images of tibiae, femora, and vertebrae. Principal advantages of this approach over existing techniques such as histomorphometry are as follows: (a) the algorithms can be implemented in a fast, uniform, nonsubjective manner across many images, allowing unbiased comparisons of therapeutic efficacy; (b) much larger volumes in the region of interest can be analyzed to derive true volumetric parameters for trabecular and cortical bone compartments; and (c) pQCT can be used to quantitate bone effects longitudinally in vivo. An automatic contextual segmentation algorithm was used to analyze over 600 scans of proximal tibiae, distal femora, and L-4 vertebrae from studies with ovariectomized rats. Accuracy and precision analyses were performed, and correlation to histomorphometry parameters showed that pQCT trabecular bone density correlates to Tb.N with r = 0.93, while BV/TV correlates to Tb.N with r = 0.95. In other words, pQCT correlates as well to histomorphometry as histomorphometry does to itself. We conclude that the developed automatic segmentation algorithm provides fast, precise, and objective quantitation of bone compartments that are highly correlated with histomorphometry measurements.

One-pixel-wide closed boundary identification.

An appropriate space of one-pixel-wide closed (OPWC) boundary configurations is explicitly defined and an automatic algorithm to obtain OPWC contour estimates from a segmented image is presented. The motivation is to obtain a reasonable starting estimate for a Markov chain Monte Carlo-based (McMC-based) boundary optimization algorithm.