Randomized trial of a dry-powder, fibrin sealant in vascular procedures.

OBJECTIVE: Topical hemostats are important adjuncts for stopping surgical bleeding. The safety and efficacy of Fibrocaps, a dry-powder, fibrin sealant containing human plasma-derived thrombin and fibrinogen, was evaluated in patients undergoing vascular surgical procedures. METHODS: In this single-blind trial (clinicaltrials.gov: NCT01527357), adult patients were randomized 2:1 to Fibrocaps plus gelatin sponge (Fibrocaps) vs gelatin sponge alone. Results are presented for the patient subset undergoing vascular procedures with suture hole bleeding. The primary efficacy endpoint compared time to hemostasis (TTH) over 5 minutes. Safety follow-up continued to day 29. RESULTS: A total of 175 patients were randomized and treated (Fibrocaps, 117; gelatin sponge, 58). Patients were predominately male (69%) and underwent arterial bypass (81%), arteriovenous graft formation (9%), or carotid endarterectomy (9%). Fibrocaps significantly reduced TTH compared with gelatin sponge (hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.5-3.1; median TTH, 2 minutes; 95% CI, 1.5-2.5 vs 4 minutes; 95% CI, 3.0-5.0; P < .002). Significant reductions were also observed in patients receiving concomitant antiplatelet agents alone (HR, 2.8; 95% CI, 1.0-7.4; P = .03; n = 33), anticoagulants alone (HR, 2.0; 95% CI, 1.0-4.0; P = .04; n = 43), or both antiplatelet agents and anticoagulants (Fibrocaps vs gelatin sponge, HR, 2.3; 95% CI, 1.2-4.3; P = .008; n = 65). Incidences of common adverse events (procedural pain, nausea, constipation) were generally comparable between treatment arms. Anti-thrombin antibodies developed in 2% of Fibrocaps-treated patients and no-gelatin-sponge patients. CONCLUSIONS: Fibrocaps, a ready-to-use, dry-powder fibrin sealant, was well-tolerated and reduced TTH in patients undergoing vascular procedures, including those receiving antiplatelet agents and/or anticoagulants, demonstrating its safety and usefulness as an adjunct to hemostasis.

Results from a First-in-Human Trial of a Novel Vascular Sealant.

BACKGROUND: Suture hole bleeding from synthetic grafts presents a hemostatic challenge. The designs of many vascular sealants are not optimal (non-adherence to wet surfaces, excessive swelling, inflexible). PreveLeak™ (formerly ArterX ((®)) ) is a polyaldehyde-bovine serum albumin-based sealant whose efficacy, safety, and performance were evaluated in this first-in-human study. MATERIALS AND METHODS: A prospective, single-arm, multicenter study was performed in patients undergoing open vascular reconstructions with prosthetic grafts. Sealant was applied to the suture line after completion of the anastomosis. The primary endpoint was the incidence of immediate sealing (without clinically significant bleeding) upon clamp release. Secondary endpoints were time to sealing, safety, and assessment of product performance. RESULTS: Fifty-six anastomoses were performed in 32 patients. Grafts were Dacron (66% of sites), polytetrafluoroethylene (PTFE; 32%), or both Dacron and PTFE (2%). The femoral artery was the most common site of anastomosis (41% of sites). Immediate sealing after clamp release was achieved at all anastomoses (100%); 93% had no bleeding and 7% had oozing. No rebleeding occurred during 10 min of observation. The three most common adverse events were graft or bypass occlusion (n = 5 patients), infection (n = 4), and seroma (n = 3); none were device related. The sealant was considered easy to apply, quickly forming a soft gel, and adhering to tissue and grafts. CONCLUSION: PreveLeak effectively sealed anastomotic suture lines during vascular reconstruction procedures and was considered easy to use. Adverse events were consistent with those commonly observed in patients undergoing surgical procedures. These results provided the support for conducting a larger controlled clinical trial.

Safety and immunogenicity of recombinant human thrombin: a pooled analysis of results from 10 clinical trials.

STUDY OBJECTIVE: To evaluate the safety and immunogenicity of recombinant human thrombin (rThrombin), an active topical stand-alone hemostatic agent. DESIGN: Analysis of pooled data from 10 rThrombin clinical trials. PATIENTS: A total of 644 adult and pediatric patients treated with rThrombin; 609 patients were included in the immunogenicity analysis. MEASUREMENTS AND MAIN RESULTS: In all studies, rThrombin was applied during a single surgical procedure (day 1); the procedures consisted of spinal procedures, major hepatic resection, peripheral arterial bypass, arteriovenous graft formation for hemodialysis access, and synchronous burn wound excision and skin grafting. A dosage of 1000 IU/ml of rThrombin was administered for more than 99% of patients. Adverse events and clinical laboratory values were monitored through day 29. Blood samples were obtained for immunogenicity analyses before the procedure and on day 29. Adverse events were mild or moderate in severity for the majority of patients; no patients discontinued from an rThrombin study due to adverse events. The most commonly reported adverse events in the 644 patients were incision site pain (305 patients [47.4%]), procedural pain (215 patients [33.4%]), and nausea (170 patients [26.4%]). Five patients (0.8%) died during the studies; all deaths were considered unrelated to rThrombin treatment. Antibodies to the rThrombin product developed in 5 (0.8%, 95% confidence interval 0.4-2.8%) of 609 patients by day 29, approximately 1 month after treatment; these antibodies did not neutralize the activity of native human thrombin. The development of antibodies did not appear to differ substantively by type of surgical procedure, amount of rThrombin administered, or patient age. CONCLUSION: Recombinant human thrombin was well tolerated, and adverse events were consistent with those reported in the postoperative setting in the surgical populations studied. Approximately 1 month after treatment, less than 1% of the patients had developed antibodies to the rThrombin product, and these antibodies did not neutralize the activity of native human thrombin. These results support the safety of rThrombin when used as a topical aid to hemostasis in numerous surgical settings and for patients of differing ages.

Immunogenicity and safety of re-exposure to recombinant human thrombin in surgical hemostasis.

BACKGROUND: This Phase 4, open-label study evaluated the immunogenicity and safety of a second exposure to recombinant human thrombin (rThrombin) in adult patients with previous exposure to rThrombin. STUDY DESIGN: Topical rThrombin was applied as a hemostatic aid during a surgical procedure (day 1). Adverse events and clinical laboratory abnormalities were monitored to day 29 (study end). Immunogenicity samples were collected on days 1 and 29. Thirty-one patients were treated at 9 study sites; 30 patients completed the study. RESULTS: Mean age was 59.5 years; 61.3% of patients were male. Study operations types included spinal (n = 23 of 31; 74.2%), arterial reconstruction or peripheral arterial bypass (n = 4; 12.9%), arteriovenous vascular access procedure (n = 3; 9.7%), and other (n = 1; 3.2%). A median of 10 mL rThrombin (1,000 IU/mL; range 5 to 60 mL) was prepared per patient. Median elapsed time since previous rThrombin exposure was 1.3 years (range 19 days to 3.3 years). Recombinant human thrombin was not observed to be immunogenic; no patients (n = 0 of 30, 0%; 95% CI 0.0%, 11.6%) became positive for anti-rThrombin product antibodies at day 29, approximately 1 month after the second exposure to rThrombin. The most commonly reported adverse events were procedural pain (n = 23 of 31, 74.2%), constipation (n = 8, 25.8%), and nausea (n = 8, 25.8%) All adverse events and clinical laboratory abnormalities were considered unrelated to treatment. For the majority of patients, maximal severity of any adverse event was mild or moderate. CONCLUSIONS: The immunogenicity and safety results of this Phase 4 rThrombin trial suggest that patients with known previous exposure may be safely re-exposed to topical rThrombin.

Persistence of antibodies to the topical hemostat bovine thrombin.

BACKGROUND: Immunoassays that detect antibovine thrombin product antibodies are not widely available. However, knowing whether these antibodies are present preoperatively would be useful because re-exposure to bovine thrombin-containing products is contraindicated in patients with pre-existing antiproduct antibodies due to the risk of developing immune-mediated coagulopathies. In these exploratory analyses, we characterized one aspect of immune sensitization, the persistence of circulating antibodies after exposure to bovine thrombin product. STUDY DESIGN: Elapsed time since a historical surgical procedure with documented or highly likely use of bovine thrombin product was determined for 204 patients enrolled in a recently completed trial. After study completion, baseline samples were assayed for antibovine thrombin product antibodies using validated immunoassays. Antibody data were sorted by time elapsed since the historical procedure. The proportion of patients with antibovine thrombin product antibodies and 95% confidence interval (CI) were determined for each 1-year period, providing an estimate for antibody persistence. RESULTS: Antibovine thrombin product antibodies were detected in 20.7% of patients (23 of 111; 95% CI 14.2%, 29.2%) with ≤1 year since the historical surgical procedure; 6.8% of patients (3 of 44; 95% CI 1.68%, 18.9%) with 1 to <2 years; 16.1% of patients (5 of 31; 95% CI 6.62%, 33.1%) with 2 to <3 years; and 5.6% of patients (1 of 18; 95% CI 0.00%, 27.6%) with ≥3 years since the historical procedure. CONCLUSIONS: The proportion of patients with antibovine thrombin product antibodies ranged from 5.6% to 20.7% across the multiyear postoperative window. Clinicians should be aware that antibodies to bovine thrombin products may persist for years after exposure.

Evaluation of recombinant platelet-activating factor acetylhydrolase for reducing the incidence and severity of post-ERCP acute pancreatitis.

BACKGROUND: Pancreatitis is the most common major complication of diagnostic and therapeutic ERCP. Platelet-activating factor (PAF) has been implicated in the pathophysiologic events associated with acute pancreatitis. Animal and human studies suggested that recombinant PAF acetylhydrolase (rPAF-AH) might ameliorate the severity of acute pancreatitis. OBJECTIVE: Our purpose was to determine whether prophylactic rPAF-AH administration reduces the frequency or severity of post-ERCP pancreatitis in high-risk patients. DESIGN: Randomized, multicenter, double-blind, placebo-controlled study. INTERVENTIONS: Patients received rPAF-AH at a dose of either 1 or 5 mg/kg or placebo. Patients were administered a single intravenous infusion over 10 minutes of study drug or placebo <1 hour before ERCP. MAIN OUTCOME MEASUREMENTS: Standardized criteria were used to diagnose and grade the severity of post-ERCP pancreatitis. Adverse events were prospectively recorded. RESULTS: A total of 600 patients were enrolled. There were no statistically significant differences among the treatment groups with respect to patient demographics, ERCP indications, and patient and procedure risk factors for post-ERCP pancreatitis with the following exceptions: the rPAF-AH 5 mg/kg group had significantly fewer patients younger than 40 years old and scheduled to undergo a therapeutic ERCP involving the pancreatic sphincter or duct. Post-ERCP pancreatitis occurred in 17.5%, 15.9%, and 19.6% of patients receiving rPAF-AH (1 mg/kg), rPAF-AH (5 mg/kg), and placebo, respectively (P = .59 for rPAF-AH 1 mg/kg vs placebo and P = .337 for rPAF-AH 5 mg/kg vs placebo). There was no statistically significant difference between the groups with regard to the severity of pancreatitis, frequency of amylase/lipase elevation more than 3 times normal, or abdominal pain. CONCLUSIONS: There was no apparent benefit of rPAF-AH treatment compared with placebo in reducing the incidence of post-ERCP pancreatitis in subjects at increased risk.

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 (IalphaIp) 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 IalphaIp were markedly reduced to a mean value of 290+/-15 microg/mL at the onset of severe sepsis compared with normal plasma levels (617+/-197 microg/mL). Failure of IalphaIp levels to recover over the first 5 days of sepsis was associated with an unfavorable outcome (p<.001). IalphaIp levels were inversely correlated with interleukin-6 levels at study entry and over the first 5 days of management of severe sepsis. IalphaIp 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 IalphaIp levels over the course of sepsis is associated with an unfavorable outcome.

Plasma cytokine measurements augment prognostic scores as indicators of outcome in patients with severe sepsis.

Despite recent advances in the prospective identification of the patient with sepsis who may benefit from anti-inflammatory or antithrombotic therapies, successful treatment regimens have been fairly modest. We have explored whether determination of several proinflammatory cytokine or mediator concentrations can complement physiologic scoring systems to identify patients with severe sepsis who will survive or expire within 28 days. The design of the study included an exploratory analysis performed in conjunction with a prospective, randomized, double-blind, placebo-controlled, multicenter, clinical trial and involved 33 academic institutions in the United States. One hundred twenty-four patients with severe sepsis with or without septic shock were included in this analysis. Blood samples were obtained at baseline and on days 1 through 4, and were evaluated for proinflammatory and anti-inflammatory cytokine concentrations, as well as for procalcitonin and total protein C levels. Baseline concentrations and changes in the concentrations of these mediators were evaluated in relationship to the Acute Physiology and Chronic Health Evaluation (APACHE) II and multiple organ dysfunction (MOD) scores, and 28-day all-cause mortality. Using univariate logistic regression analyses, APACHE II and MOD scores, age (but not gender), and baseline plasma interleukin (IL)-6 and soluble tumor necrosis factor receptor (sTNFR) 1 (log transformed) concentrations were all predictive of increased 28-day all-cause mortality (P < 0.01). Baseline total protein C, IL-8, IL-10, TNF-alpha, and procalcitonin concentrations, and the change in plasma cytokine concentrations from baseline over the initial 4 days were not useful in predicting outcome. Selected baseline proinflammatory cytokine concentrations and APACHE II score were correlated (P < 0.01). IL-6 concentration is a strong candidate for predicting clinical outcome in patients with severe sepsis alone, or when combined with the APACHE II or MOD scores. The potential usefulness of the combination of cytokine measurements and prognostic scores to identify patients who may benefit from treatment with anti-inflammatory or antithrombotic therapies should be further evaluated.

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 microg/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.

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

OBJECTIVE: Platelet-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. DESIGN: A prospective, randomized, double-blind, placebo-controlled, multicenter, international trial. SETTING: One hundred forty-six intensive care units from nine countries. PATIENTS: Approximately 2,522 patients were planned to be enrolled < or =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 RESULTS: The 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. CONCLUSIONS: rPAF-AH was well tolerated and not antigenic, but did not decrease 28-day all-cause mortality in patients with severe sepsis.

Effect of IC14, an anti-CD14 antibody, on plasma and cell-associated chemokines during human endotoxemia.

To determine the role of CD14 in lipopolysaccharide (LPS)-induced release of chemokines, 16 humans were injected with LPS (4 ng/kg) preceded (-2 h) by intravenous IC14, an anti-human CD14 monoclonal antibody, or placebo. LPS elicited increases in interleukin (IL)-8 concentrations in plasma and in lysates of red blood cell (RBC), polymorphonuclear cell and mononuclear cell fractions, which were all reduced by IC14. LPS also induced rises in the plasma and RBC levels of monocyte chemoattractant protein (MCP)-1, which were diminished by IC14. Macrophage inflammatory protein (MIP)-1alpha and MIP-1beta, chemokines that in contrast to IL-8 and MCP-1 can not bind to the Duffy antigen receptor for chemokines on RBCs, were only detected in plasma. IC14 attenuated the LPS-induced release of MIP-1beta, but not of MIP-1alpha. IL-8 and MCP-1, but not MIP-1alpha and MIP-1b, circulate in RBC-associated form during endotoxemia. LPS-induced chemokine release is, in part, mediated by an interaction with CD14.

Molecular characterization of the acute inflammatory response to infections with gram-negative versus gram-positive bacteria.

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-1beta, 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-1beta 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.

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.

Treatment with an anti-CD14 monoclonal antibody delays and inhibits lipopolysaccharide-induced gene expression in humans in vivo.

CD14 is a receptor important for activation of cells by lipopolysaccharide (LPS). Treatment with the CD14 antibody IC14 was previously found to attenuate the release of proinflammatory cytokines and some chemokines into the circulation of healthy humans intravenously injected with LPS. To determine the role of circulating leukocytes in CD14-dependent gene expression, 16 healthy volunteers received LPS preceded by either IC14 or placebo. At different time points, mRNA was isolated from whole blood and gene expression was determined by multiplex ligation-dependent probe amplification (MLPA). LPS induced MIP-1alpha, MIP-1beta, IL-8, IL-1beta, and IL-1Ra mRNA production, which was delayed by 1 hr and reduced twofold by IC14 treatment. TNFR1 was unresponsive, whereas other investigated cytokines remained undetectable. Further, LPS showed differential effects on NFkappaB gene expression. LPS induced IkappaBalpha production, whereas p50 was unresponsive and p65 and p49/p100 remained undetectable. LPS induced IkappaBalpha expression was delayed (1 hr) and reduced by IC14. Gene expression profiles in blood cells corresponded poorly with observed changes in plasma levels. These data suggest that peripheral blood cells are of negligible importance in LPS-induced production of inflammatory mediators in vivo and that LPS may activate genes via a CD14-independent pathway that is slower and less efficient.

Effects of IC14, an anti-CD14 antibody, on coagulation and fibrinolysis during low-grade endotoxemia in humans.

To determine the role of CD14 in lipopolysaccharide (LPS)-induced effects on coagulation and fibrinolysis in humans, 16 healthy subjects received an intravenous injection of LPS preceded by intravenous IC14, a recombinant chimeric monoclonal antibody against human CD14, or placebo. LPS-induced coagulation activation (tissue-factor mRNA in whole blood cells and plasma concentrations of F1+2) was not influenced by IC14, whereas the antibody reduced the increase in thrombin-antithrombin complexes and soluble fibrin. LPS injection also was associated with an early activation of fibrinolysis (plasma concentrations of tissue-type plasminogen activator and plasmin-alpha(2)-antiplasmin complexes), followed by an inhibitory response (plasminogen activator inhibitor type 1), which were attenuated by IC14. Furthermore, LPS reduced thrombin-activatable fibrinolysis-inhibitor antigen levels and increased soluble thrombomodulin levels, which were not influenced by IC14. These results suggest that different hemostatic responses during endotoxemia may proceed via CD14-dependent and -independent pathways.

An overview of clinical studies in healthy subjects and patients with severe sepsis with IC14, a CD14-specific chimeric monoclonal antibody.

An overview and discussion of clinical studies with IC14, a chimeric monoclonal antibody directed against human CD14 is presented. These studies include phase 1 trials in: (i) healthy subjects; (ii) healthy subjects challenged with lipopolysaccharide (LPS); and (iii) patients with severe sepsis. The results from clinical studies of IC14 demonstrate this chimeric monoclonal antibody diminishes the systemic inflammatory response directed against LPS and may have potential as a treatment to prevent organ dysfunction in patients with severe sepsis. Furthermore, IC14 treatment was generally well-tolerated in both healthy subjects and severe sepsis patients and did not increase the incidence of secondary infections. Analysis of pharmacology data indicate that higher doses of IC14 are required to saturate membrane-bound CD14 receptors effectively in patients with severe sepsis than in healthy subjects. Finally, the results of non-clinical studies indicate that IC14 should only be administered with concurrent antimicrobial therapy in patients with infection.