Approaches to monitoring clinical trials.

In prospective clinical trials, safety and efficacy results should be monitored periodically. If early data provide convincing evidence of a superior therapeutic index for one of the treatments, then early trial termination would satisfy important ethical requirements and save valuable resources and time. The data obtained in these studies are often analyzed further to determine whether treatment effects differ in various subsets. In this paper we discuss the problems that can arise from frequently used inappropriate approaches to interim and subset analyses. The proper role of such analyses is then discussed, and valid and useful methods are described for deciding on early termination of negative as well as positive studies and for investigating subset effects.

Anticardiolipin antibodies and recurrent coronary events: a prospective study of 1150 patients. Thrombogenic Factors, and Recurrent Coronary Events Investigators.

BACKGROUND: The association of anticardiolipin (aCL) antibodies with coronary artery disease has been shown in several studies but remains controversial. We evaluated the association of aCL and anti-beta(2)-glycoprotein I (abeta(2)GPI) antibodies with the risk of recurrent cardiac events in postinfarction patients. METHODS AND RESULTS: The study population consisted of 1150 patients with acute myocardial infarction. Levels of IgG and IgM aCL and abeta(2)GPI antibodies were determined on sera collected before hospital discharge. There were 131 recurrent cardiac events (nonfatal myocardial infarctions or cardiac deaths) over a mean follow-up period of 24.6 months. Patients with elevated IgG aCL antibodies had a higher event rate than patients with low levels (P:=0.05). Multivariate Cox analysis after adjustment for relevant clinical covariates showed that elevated levels of IgG aCL (hazard ratio=1. 63; P:=0.01) and low levels of IgM aCL (hazard ratio of 1.76; P:=0. 02) antibodies contribute independent risks for recurrent cardiac events. Patients with elevated IgG aCL and low IgM aCL antibody levels had a 3-fold higher risk of recurrent cardiac events than patients with low IgG aCL and elevated IgM aCL antibody levels (P:<0. 001). There was no significant association of the abeta(2)GPI antibodies with recurrent cardiac events. CONCLUSIONS: In postinfarction patients, elevated IgG aCL and low IgM aCL antibodies are independent risk factors for recurrent cardiac events. Patients with both elevated IgG aCL and low IgM aCL antibodies have the highest risk. These findings shed additional light on the mechanistic role of aCL antibodies in coronary artery disease in patients without autoimmune diseases.

Analysis of factors that correlate with mucositis in recipients of autologous and allogeneic stem-cell transplants.

PURPOSE: To identify predictors of oral mucositis and gastrointestinal toxicity after high-dose therapy. PATIENTS AND METHODS: Mucositis and gastrointestinal toxicity were prospectively evaluated in 202 recipients of high-dose therapy and autologous or allogeneic stem-cell rescue. Of 10 outcome variables, three were selected as end points: the peak value for the University of Nebraska Oral Assessment Score (MUCPEAK), the duration of parenteral nutritional support, and the peak daily output of diarrhea. Potential covariates included patient age, sex, diagnosis, treatment protocol, transplantation type, stem-cell source, and rate of neutrophil recovery. The three selected end points were also examined for correlation with blood infections and transplant-related mortality. RESULTS: A diagnosis of leukemia, use of total body irradiation, allogeneic transplantation, and delayed neutrophil recovery were associated with increased oral mucositis and longer parenteral nutritional support. No factors were associated with diarrhea. Also, moderate to severe oral mucositis (MUCPEAK > or = 18 on a scale of 8 to 24) was correlated with blood infections and transplant-related mortality: 60% of patients with MUCPEAK > or = 18 had positive blood cultures versus 30% of patients with MUCPEAK less than 18 (P =.001); 24% of patients with MUCPEAK > or = 8 died during the transplantation procedure versus 4% of patients with MUCPEAK less than 18 (P =.001). CONCLUSION: Gastrointestinal toxicity is a major cause of transplant-related morbidity and mortality, emphasizing the need for corrective strategies. The peak oral mucositis score and the duration of parenteral nutritional support are useful indices of gastrointestinal toxicity because these end points are correlated with clinically significant events, including blood infections and treatment-related mortality.

Increased level of von Willebrand factor is significantly and independently associated with diabetes in postinfarction patients. THROMBO Investigators.

Diabetes is an established risk factor for reinfarction and cardiac death in postinfarction patients. Since the underlying mechanism of diabetes-related risk is not fully understood we aimed to evaluate the association between lipids, thrombogenic factors and diabetes in postinfarction patients. The study population consisted of 1,045 postinfarction patients (846 non-diabetic, 125 non-insulin- and 74 insulin-requiring diabetics) with the following blood tests performed 2 months after an index myocardial infarction: lipoprotein (a), apolipoprotein-B, apolipoprotein-A, cholesterol, HDL cholesterol, triglycerides, insulin, von Willebrand factor (vWF), fibrinogen, factor VII, D-dimer, and plasminogen activator inhibitor (PAI-1). After adjustment for relevant clinical covariates, non-insulin-requiring diabetes was significantly (p < 0.05) associated with elevated levels of (odd ratios per 1 log unit increase in parenthesis) vWF (1.74) and PAI-1 (1.42) whereas insulin requiring diabetes was associated with even more elevated levels of vWF (4.68), but not with increased levels of PAI-1. No significant differences in lipid levels were observed among three groups. In conclusion, increased level of von Willebrand factor is significantly and independently associated with diabetes in postinfarction patients, suggesting that endothelial damage is the primary mechanisms contributing to an increased occurrence of vascular and cardiac events in diabetic postinfarction patients.

Detection of a group of risk factors in coronary disease using a new carriership analysis approach.

Carriership analysis is a statistical approach for detecting the average increase in risk (hazard ratio) for adverse time-dependent events per number of prespecified phenotypic or genotypic risk factors carried by subjects in limited-sized populations. This carriership approach was applied to phenotypic risk factor analysis in a postinfarction population, and simulated genetic modeling was performed to show how carriership analysis could be used to identify a group of oligogenic factors in common polygenic disorders.

Gender-related differences in thrombogenic factors predicting recurrent cardiac events in patients after acute myocardial infarction. The THROMBO Investigators.

Thrombosis contributes to recurrent coronary events in patients after acute myocardial infarction (AMI), but prognostic significance of thrombogenic factors by gender is unknown. This study aimed to determine gender-related differences in the prognostic significance of thrombogenic factors for predicting cardiac events (nonfatal reinfarction or cardiac death) in postinfarction patients. Blood levels of the following factors were measured 2 months after AMI in 791 men and 254 women: fibrinogen, von Willebrand factor, factor VII and VIIa, plasminogen activator inhibitor, D-dimer, cholesterol, apolipoprotein A-1, apolipoprotein B, lipoprotein(a), triglycerides, and high-density lipoprotein cholesterol. After adjustment for clinical covariates, levels of apolipoprotein A, high-density lipoprotein cholesterol, fibrinogen, and factor VIIa were significantly higher in postinfarction women than men. During a mean 26-month follow-up, there were 67 cardiac events (8.5%) in men and 14 (5.5%) in women (p = 0.11). In the multivariate Cox model, elevated levels of factor VIIa were a significant predictor of cardiac events in women (p = 0.022) but not in men (p = 0.80), with significant gender-related effect (hazard ratio 2.80 vs 0.92, respectively; p <0.05). D-dimer had prognostic value in men (p = 0. 006) but not in women (p = 0.36), although the difference between hazard ratios for men and women was not significant (2.35 vs 1.58, respectively; p = 0.49). In conclusion, elevated levels of factor VIIa are associated with an increased risk of recurrent cardiac events in postinfarction women, but not in men. D-dimer is more predictive for cardiac events in postinfarction men than women. These observations indicate possible gender-related differences in the pathophysiologic mechanisms of recurrent cardiac events.

CD44-9v and CD44-10v are potential molecular markers for squamous cell carcinoma of the vulva.

OBJECTIVE: CD44 is a cell surface glycoprotein widely distributed in the extracellular matrix. CD44 isoforms arising from alternative mRNA splicing are implicated in tumor metastases. The aim of this study is to investigate the expression of CD44s and two splice variants, CD44-9v and CD44-10v, in squamous cell carcinoma (SCC) of the vulva as well as its correlation with lymph node (LN) metastases and disease-free survival. METHODS: Thirty-five SCC vulvar tumors were evaluated for CD44s, CD44-9v, and CD44-10v expression by immunocytochemistry. One nonmetastatic LN was studied also. In cases with LN metastases, the metastatic LN as well as a nonmetastatic LN from the same patient were evaluated. RESULTS: CD44s and CD44-9v were expressed in all epithelia--normal, dysplastic, and SCC. However, intensity and distribution of expression of 9v isoforms changed within the tissue containing invasive cancer. CD44-9v expression was downregulated in the most differentiated cells within the carcinoma, mainly in patients who had disease recurrence or eventually died of disease (P = .031). All metastatic tumor to LNs was immunoreactive also for CD44-9v. CD44-10v expression was present in 78% of tumors and 56% of normal epithelium. Interestingly, CD44-10v membrane expression, but not cytoplasmic expression, correlated with disease recurrence (P = .035). CONCLUSION: Our findings warrant larger multi-institutional studies to determine the potential of CD44-9v and CD44-10v as molecular markers of disease recurrence in vulvar carcinoma. We propose to test the use of anti-CD44-9v monoclonal antibody for radioimmunoimaging of occult LN metastases.

Adaptive immune responses of patients with asthma to the attachment (G) glycoprotein of respiratory synctial virus.

A history of acute bronchiolitis in infancy caused by respiratory syncytial virus is a risk factor for recurrent wheezing in early childhood. Because the attachment (G) protein sensitizes mice for pulmonary eosinophilia and because Th2 cells are central in the pathogenesis of asthma, plasma and peripheral blood mononuclear cells (PBMC) from donors with asthma and from healthy donors were evaluated for anti-G protein responses. A significant trend connecting severity of asthma with anti-G protein IgG1 and IgG2 titers was observed. The correlation between anti-F protein IgG3 titers and asthma severity approached significance. Peptide mapping studies revealed that more positive recall responses (interferon-gamma and interleukin-10 secretion) occurred after PBMC from donors with asthma were stimulated with peptides representing the nonglycosylated domain of G protein. The same peptides elicited more positive recall responses (proliferation and interferon-gamma secretion) in the PBMC of healthy donors. These data suggest that a mechanism may exist whereby adaptive immune responses against G protein contribute to wheezing.

Thrombogenic factors and recurrent coronary events.

BACKGROUND: Thrombosis is a pivotal event in the pathogenesis of coronary disease. We hypothesized that the presence of blood factors that reflect enhanced thrombogenic activity would be associated with an increased risk of recurrent coronary events during long-term follow-up of patients who have recovered from myocardial infarction. METHODS AND RESULTS: We prospectively enrolled 1045 patients 2 months after an index myocardial infarction. Baseline thrombogenic blood tests included 6 hemostatic variables (D-dimer, fibrinogen, factor VII, factor VIIa, von Willebrand factor, and plasminogen activator inhibitor-1), 7 lipid factors [cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, lipoprotein(a), apolipoprotein (apo)A-I, and apoB], and insulin. Patients were followed up for an average of 26 months, with the primary end point being coronary death or nonfatal myocardial infarction, whichever occurred first. The hemostatic, lipid, and insulin parameters were dichotomized into their top and the lower 3 risk quartiles and evaluated for entry into a Cox survivorship model. High levels of D-dimer (hazard ratio, 2.43; 95% CI, 1.49, 3.97) and apoB (hazard ratio, 1.82; 95% CI, 1.10, 3.00) and low levels of apoA-I (hazard ratio, 1.84; 95% CI, 1.10, 3.08) were independently associated with recurrent coronary events in the Cox model after adjustment for 6 relevant clinical covariates. CONCLUSIONS: Our findings indicate that a procoagulant state, as reflected in elevated levels of D-dimer, and disordered lipid transport, as indicated by low apoA-1 and high apoB levels, contribute independently to recurrent coronary events in postinfarction patients.