John P. Pribble

Confirmatory interleukin-1 receptor antagonist trial in severe sepsis: a phase III, randomized, double-blind, placebo-controlled, multicenter trial. The Interleukin-1 Receptor Antagonist Sepsis Investigator Group.

OBJECTIVE To determine the therapeutic efficacy and safety of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) in the treatment of patients with severe sepsis. DESIGN Prospective, randomized, double-blind, placebo-controlled, multicenter trial with a planned, midstudy, interim analysis. SETTING Ninety-one academic medical center intensive care units in North America and Europe. PATIENTS Patients with severe sepsis or septic shock (n = 696) received standard supportive care and antimicrobial therapy for sepsis, in addition to rhIL-1ra or placebo. INTERVENTIONS Patients were randomized to receive either rhIL-1ra (100 mg) or placebo (vehicle) by intravenous bolus, followed by a 72-hr continuous intravenous infusion of either rhIL-1ra (2.0 mg/kg/hr) or placebo. MEASUREMENTS AND MAIN RESULTS The study was terminated after an interim analysis found that it was unlikely that the primary efficacy end points would be met. The 28-day, all-cause mortality rate was 33.1% (116/350) in the rhIL-1ra treatment group, while the mortality rate in the placebo group was 36.4% (126/346), yielding a 9% reduction in mortality rate (p = .36). The patients were well matched at the time of study entry; 52.9% of placebo-treated patients were in shock while 50.9% of rhIL-1ra-treated patients were in shock at the time of study entry (p = .30). The mortality rate did not significantly differ between treatment groups when analyzed on the basis of site of infection, infecting microorganism, presence of bacteremia, shock, organ dysfunction, or predicted risk of mortality at the time of study entry. No excess number of adverse reactions or microbial superinfections were attributable to rhIL-1ra treatment in this study. CONCLUSIONS A 72-hr, continuous intravenous infusion of rhIL-1ra failed to demonstrate a statistically significant reduction in mortality when compared with standard therapy in this multicenter clinical trial. If rhIL-1ra treatment has any therapeutic activity in severe sepsis, the incremental benefits are small and will be difficult to demonstrate in a patient population as defined by this clinical trial.

initial evaluation of human recombinant interleukin-1 receptor antagonist in the treatment of sepsis syndrome: A randomized, open-label, placebocontrolled multicenter trial

Objectives: To evaluate the safety, pharmacokinetics, and efficacy of human recombinant interleukin‐1 receptor antagonist (IL‐lra) in the treatment of patients with sepsis syndrome. Design: Prospective, open‐label, placebo‐controlled, phase II, multicenter clinical trial using three different doses of human recombinant ILlra. Setting: Twelve academic medical center intensive care units in the United States. Patients: Ninety‐nine patients with sepsis syndrome or septic shock who received standard supportive care and antimicrobial therapy, in addition to infusion with escalating doses of ILlra or placebo. Interventions: Patients received an intravenous loading dose of either human recombinant IL‐lra (100 mg) or placebo, followed by a 72‐hr intravenous infusion of either one of three doses of BL‐lra (17, 67, or 133 mg/hr) or placebo. All patients were evaluated for 28‐day, all‐cause mortality. Measurements and Main Results: A dosedependent, 28‐day survival benefit was associated with IL‐lra treatment (p = .015), as indicated by the following mortality rates: 11 (44%) deaths among 25 placebo patients; eight (32%) deaths among 25 patients receiving IL‐lra 17 mg/hr; six (25%) deaths among 24 patients receiving IL‐lra 67 mg/hr; and four (16%) deaths among 25 patients receiving IL‐lra 133 mg/hr. A dose‐related survival benefit was observed with infusion of IL‐lra in patients with septic shock at study entry (n = 65; p = .002) and in patients with Gram‐negative infection (n = 45; p = .04). Patients with an increased circulating interleukin‐6 (IL‐6) concentration of >100 pg/ mL at study entry demonstrated a dose‐related survival benefit with IL‐lra treatment (p = .009). In patients with an increased IL‐6 concentration at study entry, the magnitude of the decrease in IL‐6 concentration 24 hrs after the initiation of therapy was correlated with increasing the IL‐lra treatment dose (p = .052). A significant dose‐related reduction in the Acute Physiology and Chronic Health Evaluation (APACHE II) score was achieved by the end of infusion (p = .038). A renal elimination mechanism for IL‐lra was suggested by the positive correlation between IL‐lra plasma clearance and estimated creatinine clearance (p = .001; r2 = .51). Human recombinant IL‐lra was well tolerated. Conclusions: This initial evaluation suggests that human recombinant IL‐lra is safe and may provide a dose‐related survival advantage to patients with sepsis syndrome. A larger, definitive clinical trial is needed to confirm these findings. (Crit Care Med 1994; 22:12‐21)

Relationship between plasma levels of lipopolysaccharide (LPS) and LPS- binding protein in patients with severe sepsis and septic shock

Plasma endotoxin and lipopolysaccharide-binding protein (LBP) levels were measured in a group of 253 patients at the onset of severe sepsis and/or septic shock. Endotoxin levels were significantly greater than control levels (n=33; mean +/- SD, 5.1+/-7.3 pg/mL) in 78.3% of patients. Median endotoxin levels in patients with sepsis were 300 pg/mL (25%-75% interquartile range, 110-726 pg/mL). LBP levels were elevated in 97% of patients compared with normal control values of 4.1+/-1.65 microgram/mL. Median LBP levels in patients with sepsis were 31.2 microgram/mL (interquartile range, 22.5-47.7 microgram/mL). Median endotoxin levels at study entry were more highly elevated (515 vs. 230 pg/mL; P<.01), and LBP levels were less highly elevated (28.0 vs. 33.2 microgram/mL; P<.05) in nonsurvivors than survivors over the 28-day study period. No correlation was found between endotoxin and LBP levels. The quantitative level of both endotoxin and LBP may have prognostic significance in patients with severe sepsis.

Molecular Characterization of the Acute Inflammatory Response to Infections with Gram-Negative versus Gram-Positive Bacteria

ABSTRACT Sepsis caused by gram-negative bacteria and that caused by gram-positive bacteria often manifest similar clinical features. We investigated plasma proinflammatory cytokine profiles in patients with sepsis due to gram-positive and gram-negative bacteria and studied the cytokine production and differential gene regulation of leukocytes stimulated ex vivo with Escherichia coli lipopolysaccharide or heat-killed Staphylococcus aureus. Concentrations of tumor necrosis factor alpha, interleukin 1 receptor antagonist (IL-1Ra), IL-8, IL-10, IL-18 binding protein, procalcitonin, and protein C in plasma did not differ between patients with sepsis due to gram-negative and gram-positive bacteria. However, plasma IL-1β, IL-6, and IL-18 concentrations were significantly higher in patients with sepsis due to gram-positive bacteria. Ex vivo stimulation of whole blood with heat-killed S. aureus markedly increased IL-1β and IL-18 levels more than E. coli lipopolysaccharide stimulation. Microarray analysis revealed at least 359 cross-validated probe sets (genes) significant at the P < 0.001 level whose expression discriminated among gram-negative-organism-stimulated, gram-positive-organism-stimulated, and unstimulated whole-blood leukocytes. The host inflammatory responses to gram-negative and gram-positive stimuli share some common response elements but also exhibit distinct patterns of cytokine appearance and leukocyte gene expression.

Pharmacokinetics, safety and immunomodulatory effects of human recombinant interleukin-1 receptor antagonist in healthy humans

A phase I study of human recombinant interleukin-1 receptor antagonist (IL-1ra) was conducted in healthy males between the ages of 18 and 30. Twenty-five volunteers received a single, 3 h continuous intravenous infusion of doses ranging between 1 mg/kg and 10 mg/kg IL-1ra. At 3 h into the infusion, plasma IL-1ra levels were 3.1 micrograms/ml and 29 micrograms/ml for the 1 mg/kg and 10 mg/kg doses, respectively. Post-infusion plasma IL-1ra levels declined rapidly, exhibiting an initial half-life of 21 min and a terminal half-life of 108 min. Clinical, hematological, biochemical, endocrinological and immunomodulatory effects were monitored over 72 h and compared to those of four subjects receiving a 3 h infusion of saline. There were no clinically significant differences between the drug and saline groups in symptoms, physical examinations, complete blood counts, mononuclear cell phenotypes, blood chemistry profiles, serum iron and serum cortisol levels. Peripheral blood mononuclear cells (PBMC) obtained after completion of the IL-1ra infusion synthesized significantly less interleukin 6 ex vivo than PBMC from saline-injected controls. These data suggest that transient blockade of interleukin 1 receptors is safe and does not significantly affect homeostasis.

Recombinant human platelet-activating factor acetylhydrolase for treatment of severe sepsis: Results of a phase III, multicenter, randomized, double-blind, placebo-controlled, clinical trial

ObjectivePlatelet-activating factor (PAF) and structurally-related oxidized phospholipids are proinflammatory mediators in systemic inflammatory states such as severe sepsis. The enzyme platelet-activating factor acetylhydrolase (PAF-AH) rapidly degrades PAF and oxidized phospholipids into inactive metabolites. Reduced PAF-AH activity has been observed in patients with severe sepsis and may contribute to their systemic inflammatory response and organ dysfunction. A previous clinical trial with recombinant human PAF-AH (rPAF-AH, Pafase) suggested that this treatment may decrease 28-day all-cause mortality in patients with severe sepsis. The current study was undertaken to confirm this result. DesignA prospective, randomized, double-blind, placebo-controlled, multicenter, international trial. SettingOne hundred forty-six intensive care units from nine countries. PatientsApproximately 2,522 patients were planned to be enrolled ≤12 hrs after the onset of severe sepsis. Eligible patients were randomized to receive either rPAF-AH 1.0 mg/kg or placebo administered intravenously once daily for five consecutive days. Measurements and Main ResultsThe study was terminated based on the recommendation of an independent data and safety monitoring committee after the second of three planned interim analyses, and the enrollment of 1,425 patients. rPAF-AH treatment was well tolerated among the 1,261 patients included in the interim analysis (643 rPAF-AH and 618 placebo), but did not decrease 28-day all-cause mortality compared with placebo (25% for rPAF-AH vs. 24% for placebo; relative risk, 1.03; 95% confidence interval, 0.85–1.25; p = .80). There were no statistically significant differences between treatment groups in any of the secondary efficacy end points. The overall incidence of adverse events was similar among rPAF-AH and placebo-treated patients, and no rPAF-AH-treated patients developed antibodies to PAF-AH. ConclusionsrPAF-AH was well tolerated and not antigenic, but did not decrease 28-day all-cause mortality in patients with severe sepsis.

Recombinant platelet-activating factor acetylhydrolase to prevent acute respiratory distress syndrome and mortality in severe sepsis: Phase IIb, multicenter, randomized, placebo-controlled, clinical trial.

OBJECTIVE Platelet-activating factor (PAF) is a potent proinflammatory mediator implicated in the pathogenesis of both severe sepsis and acute respiratory distress syndrome. One of the regulatory pathways for PAF involves degradation to the inactive metabolite lyso-PAF by the enzyme PAF acetylhydrolase (PAF-AH). Because reduced concentrations of the natural form of PAF-AH have been reported in septic patients, the present study was conducted to determine whether treatment with recombinant human PAF-AH (rPAF-AH, Pafase) was safe when administered after the onset of severe sepsis and whether it decreases the prevalence of acute respiratory distress syndrome and 28-day all-cause mortality. DESIGN A prospective, randomized, double-blind, placebo-controlled, multicenter trial. SETTING Thirty-three medical and surgical intensive care units located in the United States. PATIENTS A total of 127 patients with severe sepsis, but without established acute respiratory distress syndrome, were enrolled in the study. Randomization occurred within 12 hrs of the onset of severe sepsis. Patients then received 1.0 mg/kg rPAF-AH (n = 45), 5.0 mg/kg rPAF-AH (n = 39), or placebo (n = 43) administered intravenously, once daily, for five consecutive days. MEASUREMENTS AND MAIN RESULTS Demographic and baseline clinical characteristics of the three treatment groups were similar, except for a significantly higher prevalence of respiratory tract infections as the cause of severe sepsis in patients treated with 1.0 mg/kg rPAF-AH. There were no treatment-related deaths, and the overall prevalence of adverse events was similar among rPAF-AH-treated and placebo-treated patients. There were no significant differences in the prevalence of acute respiratory distress syndrome among the three treatment groups. However, 28-day all-cause mortality was 21% in the 1.0 mg/kg rPAF-AH group, 28% in the 5.0 mg/kg rPAF-AH group, and 44% in the placebo group (overall chi-square p =.07; 1.0 mg/kg rPAF-AH vs. placebo, p =.03). A trend toward reduced multiple organ dysfunction also was observed in the 1.0 mg/kg rPAF-AH group compared with the placebo group (p =.11). CONCLUSION The results from this study indicate that rPAF-AH was well tolerated and should be pursued as a potential new treatment to decrease mortality in patients with severe sepsis.

CD14 receptor occupancy in severe sepsis: Results of a phase I clinical trial with a recombinant chimeric CD14 monoclonal antibody (IC14)

Objective:Binding of bacterial cell wall components to CD14 and co-receptors on myeloid cells results in cellular activation and production of proinflammatory mediators. A recombinant anti-CD14 monoclonal antibody (IC14) has been shown to decrease lipopolysaccharide-induced responses in animal and human models of endotoxemia. This study was performed to evaluate the safety, pharmacokinetics, pharmacodynamics, and clinical pharmacology of IC14 in patients with severe sepsis. Design:Randomized, double-blind, placebo-controlled, dose-ranging, multiple-center trial. Setting:Six medical and surgical intensive care units located in Germany and the Netherlands. Patients:Forty patients with severe sepsis. Interventions:IC14 was administered intravenously to eight patients/cohort as single (1 mg/kg or 4 mg/kg) or multiple doses (4 mg/kg daily for 4 days, or 4 mg/kg on day 1 followed by 2 mg/kg daily for 3 days). A placebo group (two patients/cohort) was also included. Measurements and Main Results:The overall incidence and types of adverse events were similar among treatment groups. One patient in the group receiving multiple-dose IC14 4 mg/kg daily for 4 days experienced an anaphylactic reaction after receiving the first dose of study drug. IC14 did not induce antibody formation or increase the incidence of secondary bacterial infection. A mean IC14 serum concentration of approximately 1 μg/mL was required to achieve 50% of maximum membrane-bound CD14 receptor occupancy on peripheral blood monocytes. The pattern of proinflammatory and anti-inflammatory cytokines, chemokine, soluble receptor, soluble E-selectin, and acute phase proteins in response to treatment was highly variable by patient and IC14 treatment group. Conclusions:Single and multiple doses of IC14 were generally well tolerated and did not induce antibody formation or increase the incidence of secondary bacterial infection. The results suggest that CD14 blockade with IC14 warrants further clinical investigation to determine its ability to attenuate the proinflammatory response due to infection.

Longitudinal studies of inter-alpha inhibitor proteins in severely septic patients: a potential clinical marker and mediator of severe sepsis.

Objective:To determine the clinical relevance and prognostic significance of serial measurement of inter-alpha inhibitor proteins (I&agr;Ip) in severely septic patients. Design:A laboratory-based study of serial plasma samples over the first 5 days of severe sepsis from a prospective clinical trial. Setting:Small business and academic medical center research laboratories. Patients:Two hundred sixty-six patients with severe sepsis from a multiple-center phase III clinical trial. Interventions:None. Measurements and Main Results:Inter-alpha inhibitor proteins serve as endogenous serine protease inhibitors in human plasma. The levels of I&agr;Ip were markedly reduced to a mean value of 290 ± 15 &mgr;g/mL at the onset of severe sepsis compared with normal plasma levels (617 ± 197 &mgr;g/mL). Failure of I&agr;Ip levels to recover over the first 5 days of sepsis was associated with an unfavorable outcome (p < .001). I&agr;Ip levels were inversely correlated with interleukin-6 levels at study entry and over the first 5 days of management of severe sepsis. I&agr;Ip levels were significantly lower in women, with increased age, in the presence of multiple organ failure and in patients with intra-abdominal sources of sepsis. Conclusions:Inter-alpha inhibitor proteins are markedly reduced in severe sepsis, and failure of recovery of I&agr;Ip levels over the course of sepsis is associated with an unfavorable outcome.

3346 Evaluation of recombinant human plateletactivating factor acetylhydrolase (rpaf-ah) for reducing the incidence and severity of post-ercp acute pancreatitis (ap).

ERCP provides the opportunity to administer prophylactic therapy to reduce the incidence and severity of post-ERCP AP. Platelet activating factor (PAF) is a pro-inflammatory mediator that has been implicated in the pathogenesis of AP. PAF-AH is a naturally occurring human enzyme that degrades PAF to an inactive metabolite. Aim: To determine if the prophylactic administration of rPAF-AH decreases the incidence and severity of post-ERCP AP. Methods: Eligible patients had ≥ 1 of the following risk factors for post-ERCP AP: age ≤ 40 years; failed prior ERCP; history of unexplained, recurrent pancreatitis; scheduled to undergo pancreatic therapeutic ERCP, sphincter of Oddi manometry, or ERCP for presumed sphincter of Oddi dysfunction (SOD). Patients were randomized to receive an IV infusion of placebo or rPAF-AH (1 or 5 mg/kg) ≤ 1 hour prior to ERCP. Standard criteria were used to determine the presence and severity of post-ERCP AP (GI Endosc 1991;37:383). Results: A total of 600 patients (79% female) were enrolled. Results are summarized below: Conclusion: In this high-risk patient population, prophylactic administration of rPAF-AH resulted in a reduction in the incidence and possibly the severity of post-ERCP AP, but not to a statistically significant degree.