Reltecimod (previously AB103 or p2TA) is a short-peptide mimetic of the CD28 costimulatory receptor on T cells that attenuates CD28/B7-2 signaling, which are responsible for the hyperinflammatory response that is observed during severe infections. A single-dose of reltecimod provides sustained survival benefit in animal models of sepsis and clinical benefit in patients with necrotizing soft tissue infections. Here, the pharmacokinetic/pharmacodynamics profile of reltecimod was evaluated to determine the basis of its sustained single-dose effect. The half-life of reltecimod was assessed using bioanalytical methods in different animals, and the biodistribution was studied in male BALB/c mice that were administered a single intravenous dose of [14C]-reltecimod. Blood partitioning was performed, and the minimal time to observe efficacy of reltecimod was evaluated in vitro. The plasma half-life of reltecimod was short in humans and all tested animal models, ranging from 1 to 8 min. Upon leaving the blood vessels, reltecimod quickly redistributed to lymphatic tissues, where T cells are produced and exposed to antigens. Lymphatic concentration of reltecimod was 22 times higher than plasma concentration by 20 min post-administration, and reltecimod was enriched in the white blood cell fraction of blood (6.8% after 2 h). Reltecimod had a rapid onset of effect (5 min) that lasted for at least 12 h based on levels of IFN-γ that were secreted by antigen-activated human peripheral blood mononuclear cells. This suggests that reltecimod’s prolonged clinical benefits are based on fast distribution to target organs and rapid intervention with signaling pathways, irrespective of its short residence time in the plasma.

Soft-tissue bacterial infection can progress to severe sepsis and septic shock as a result of a disproportionate inflammatory response, characterized by an excessive release of cytokines and influx of immune cells. Reltecimod (previously known as AB103 or p2TA), a peptide derived from the T-cell receptor CD28, modulates the host immune response by targeting the co-stimulatory pathway, which is essential for the induction of multiple pro-inflammatory cytokines. Consequently, reltecimod has demonstrated beneficial effects against different bacterial infections, their exotoxins and endotoxins, and ionizing radiation. The dosing regimen of reltecimod was evaluated in three mouse models of infection. The effect of the number of reltecimod doses with respect to survival, cytokine/chemokine levels, and blood leukocyte profiles was assessed. Overall, mice treated with a single intravenous dose of reltecimod (5 mg/kg) at 1–2 h after infection showed significantly greater survival as compared with saline-treated controls. Mice treated with a second doses demonstrated improved survival compared with saline-treated controls. However, in all models of infection, administration of a single therapeutic dose of reltecimod was superior to two or multiple doses. Further examination showed that the single therapeutic dose of reltecimod was associated with an early (within 24 h) decrease in cytokine/chemokine levels and most circulating leukocyte subpopulations. A second dose of reltecimod did not improve these early positive effects and appeared to attenuate further changes. These results provided insight into the mechanism of action of reltecimod and established a basis for the dosing regimen utilized in clinical trials, where reltecimod is administered as a single dose.

Necrotizing soft-tissue infections (NSTIs) are uncommon but devastating infections associated with significant morbidity, mortality and medical resource utilization. Unlike less severe skin infections, NSTIs involve both local and systemic disease manifestations. The systemic response is the culmination of a host response to infection that, while initially appropriate, becomes dysregulated. The augmented release of proinflammatory cytokines correlates with NSTI severity and can lead to shock, multiorgan failure and death. Currently, no therapies are specifically approved to treat NSTI. Reltecimod is a synthetic peptide antagonist of both superantigen exotoxins and the CD28 T-cell costimulatory receptor that is under development for the treatment of NSTI. In animal models of infection, it has been shown to have a broad spectrum of activity, protecting from the overproduction of cytokines. A phase II study demonstrated the safety of reltecimod in NSTI patients, and, compared to placebo, consistent improvement in clinical status across multiple endpoints. An ongoing phase III study is evaluating the efficacy of reltecimod using a composite end-point of clinical parameters resulting from NSTI. This review will focus on the pathophysiology of NSTI and the development of reltecimod as a novel treatment.

OBJECTIVE Our objective was to develop and validate a composite endpoint for patients with necrotizing soft tissue infections that incorporates: local tissue injury, systemic organ dysfunction, and mortality. METHODS The Necrotizing Infection Clinical Composite Endpoint (NICCE) was defined as follows:(i) alive at day 28, (ii) three or less debridements before day 14, (iii) no amputation beyond first debridement, (iv) modified sequential organ failure assessment score score (mSOFA) at day 14 ⩽ 1. To be considered a success, all individual criteria must be met. Several data sets were used to assess validity: (i) a retrospective data set of 198 patients treated during 2013 at 12 US trauma centers; (ii) a subset with high disease acuity, admission mSOFA score of 3 or higher (n = 69); and (iii) 40 patients from a multicenter, phase 2 randomized trial of a CD28 immunomodulator (AB103). Clinical success based on each parameter and the composite score was assessed. RESULTS Using the retrospective data set for all patients and those with high disease severity (respectively), survival rates were 92% and 84%; day 14 mSOFA 1 or lower score was 69% and 51%; three or less debridements was 84% and 77%; and no subsequent amputations were 96% and 94%. Overall, the percent meeting all success criteria for NICCE was 58% (all patients) and 33% (mSOFA > 3). NICCE success was also associated with reduced utilization of health care resources, intensive care unit–free days were median (interquartile range) of 25.3 (21.9–28) and 19.6 (4.3–25.1) days (one-sided Wilcoxon p < 0.001) and ventilator-free days were 28 (26–28) versus 25 (14–28) (p < 0.001) for NICCE success versus failure, respectively. Using the phase 2 data set, the treated group (0.5 mg/kg, n = 15) demonstrated a NICCE success rate of 73.3% versus 40% for placebo (n = 10). CONCLUSION These data demonstrate internal consistency of the components and face and criterion validity of the NICCE endpoint. NICCE offers an opportunity to demonstrate a clinically relevant treatment effect for patients enrolled in clinical trials for necrotizing soft tissue infection. Level of Evidence Prognostic/Epidemiological, level III; Therapeutic, level IV.

Bulger, Eileen; Maislin, Gregory; Dankner, Wayne; May, Addison; Edgar, Rotem; Shirvan, Anat Author Information

BACKGROUND:Necrotizing soft tissue infections (NSTI) represent a rare but devastating disease for which the systemic manifestations have been poorly characterized. In an effort to define an optimal endpoint for clinical trials in this condition, the objective of this study was to establish the pattern of organ dysfunction over time and determine the correlation between organ dysfunction and clinical outcome in patients with NSTI. METHODS:We conducted a multicenter, retrospective clinical study of patients with NSTI presenting to 12 academic medical centers in the U.S. during 2013. Patients with a diagnosis of NSTI confirmed by surgical findings were included. Organ dysfunction was assessed using a modified Sequential Organ Failure Assessment (SOFA) score (mSOFA: excluding liver) on admission and on hospital days 1, 2, 3, 7, 10, and 14. The presence of organ dysfunction on admission and resolution of organ dysfunction were correlated with clinical parameters, including intensive care unit (ICU)-free days (of 28 d), ventilator-free days, number of debridements, and mortality rate. The incidence of acute kidney injury (AKI) and recovery also were assessed. RESULTS:There were 198 patients enrolled, of whom 62% were male, the mean age was 51 years, and 40% had monomicrobial infections. The mean mSOFA score on admission was 2.4 ± 3.0, with 49% of the patients having a score ≥2 and 35% a score of ≥3. Patients typically demonstrated worsening of the mSOFA score over the first 24 h followed by gradual resolution. An mSOFA ≥3 at admission was associated with a significant decrease in ventilator-free days (mean 20.1 vs. 25.6 days; p < 0.001); ICU-free days (15.2 vs. 23.1, p < 0.001); more debridements (mean 2.3 vs. 2.0; p = 0.11); a higher mortality rate (15.9% vs. 3.1%; p = 0.003); and a higher rate of AKI (59.4 vs. 35.9%; p < 0.001). The persistence of organ dysfunction (mSOFA >1) among survivors at day 14 was associated with fewer ICU-free days (17.8 vs. 23.6; p < 0.001) and ventilator-free days (23.6 vs. 27; p = 0.001) and a lower recovery rate from AKI (38.7% vs. 81.3%; p < 0.001). CONCLUSION:Early development of systemic organ dysfunction in patients with NSTI is associated with higher morbidity and mortality rates. Failure of the resolution of organ dysfunction by day 14 forecasts a poor outcome. The mSOFA score may be a useful marker for patient selection for inclusion in interventional trials, and the resolution of organ dysfunction by day 14 may be an important clinical endpoint.

Number 3 Morbidity and Mortality Multicenter Behavior of Acute Kidney Injury. Two Decades Follow-up Nadienka Rodríguez Ramos, Lietny M Becerra Castillo, Leonel Soto León Abel Santamaria Hospital With the purpose of describing the clinical behavior of Acute Kidney injury; the morbidity and mortality of this syndrome and the detection of the aspects that are susceptible to modification to accomplish an improvement on the evolution and prognosis of these patients, was performed an analytical and longitudinal multicentre study in the western area of Cuba, in 1567 patients with age older than 19 years, classified by suffering of acute kidney injury with need of dialysis on the period of January 1992 to December 2012. Was used a data collecting card with information obtained from the review of the patient’s medical record, were assessed the clinical, humoral and prognosis variables. Were used summary measures, OR ratio and Chi-square 0,95% for p <0,05. The data was displayed on tables and graphics. The masculine sex prevailed, and the 25 – 59 age groups on both sexes in which the early diagnosis based on AKIN criteria improved a great deal the prognosis. The APACHE II was directly and proportionally associated with the presence of AKI and with its mortality. The patients with oliguric AKI have a greater possibility of dying, situation that is reduced on the ones that received treatment with hemodialysis which affected positively on a better prognosis, therefore it can be considered as a protective factor.

IMPORTANCE Necrotizing soft-tissue infections (NSTI) have high morbidity and mortality rates despite aggressive surgical debridement and antibiotic therapy. AB103 is a peptide mimetic of the T-lymphocyte receptor, CD28. We hypothesized that AB103 will limit inflammatory responses to bacterial toxins and decrease the incidence of organ failure.OBJECTIVES To establish the safety of AB103 in patients with NSTI and evaluate the potential effects on clinically meaningful parameters related to the disease.DESIGN, SETTING, AND PARTICIPANTS A prospective, randomized, placebo-controlled, double-blinded study was performed in 6 academic medical centers in the United States. Participants included adults with NSTI. Of 345 patients screened, 43 were enrolled for the intent-to-treat analysis, and 40 met criteria for the modified intent-to-treat analysis; 15 patients each were included in the high-dose and low-dose treatment arms, and 10 in the placebo arm.INTERVENTION Single intravenous dose of AB103 (0.5 or 0.25mg/kg) within 6 hours after diagnosis of NSTI.MAIN OUTCOMES AND MEASURES Change in the Sequential Organ Failure Assessment score within 28 days, intensive care unit-free and ventilator-free days, number and timing of debridements, plasma and tissue cytokine levels at 0 to 72 hours, and adverse events.RESULTS Baseline characteristics were comparable in the treatment groups. The Sequential Organ Failure Assessment score improved from baseline in both treatment groups compared with the placebo group at 14 days (change from baseline score, -2.8 in the high-dose, -2 in the low-dose, and + 1.3 in the placebo groups; P =.04). AB103-treated patients had a similar number of debridements (mean [SD], 2.2 [1.1] for the high-dose, 2.3 [1.2] for the low-dose, and 2.8 [2.1] for the placebo groups; P =.56). There were no statistically significant differences in intensive care unit-free and ventilator-free days or in plasma and tissue cytokine levels. No drug-related adverse events were detected.CONCLUSIONS AND RELEVANCE AB103 is a safe, promising new agent for modulation of inflammation after NSTI. Further study is warranted to establish efficacy.

BACKGROUND Severe gram-negative bacterial infections and sepsis are major causes of morbidity and mortality. Dysregulated, excessive proinflammatory cytokine expression contributes to the pathogenesis of sepsis. A CD28 mimetic peptide (AB103; previously known as p2TA) that attenuates CD28 signaling and T-helper type 1 cytokine responses was tested for its ability to increase survival in models of polymicrobial infection and gram-negative sepsis. METHODS Mice received AB103, followed by an injection of Escherichia coli 0111:B4 lipopolysaccharide (LPS); underwent induction E. coli 018:K1 peritonitis induction, followed by treatment with AB103; or underwent cecal ligation and puncture (CLP), followed by treatment with AB103. The effects of AB103 on factors associated with and the lethality of challenge infections were analyzed. RESULTS AB103 strongly attenuated induction of tumor necrosis factor α and interleukin 6 (IL-6) by LPS in human peripheral blood mononuclear cells. Receipt of AB103 following intraperitoneal injection of LPS resulted in survival among 73% of CD1 mice (11 of 15), compared with 20% of controls (3 of 15). Suboptimal doses of antibiotic alone protected 20% of mice (1 of 5) from E. coli peritonitis, whereas 100% (15 of 15) survived when AB103 was added 4 hours following infection. Survival among mice treated with AB103 12 hours after CLP was 100% (8 of 8), compared with 17% among untreated mice (1 of 6). In addition, receipt of AB103 12 hours after CLP attenuated inflammatory cytokine responses and neutrophil influx into tissues and promoted bacterial clearance. Receipt of AB103 24 hours after CLP still protected 63% of mice (5 of 8). CONCLUSIONS Single-dose AB103 reduces mortality in experimental models of polymicrobial and gram-negative bacterial infection and sepsis, warranting further studies of this agent in clinical trials.

The goal of this study was to elucidate the action of the CD28 mimetic peptide p2TA (AB103) that attenuates an excessive inflammatory response in mitigating radiation-induced inflammatory injuries. BALB/c and A/J mice were divided into four groups: Control (C), Peptide (P; 5 mg/kg of p2TA peptide), Radiation (R; total body irradiation with 8 Gy γ-rays), and Radiation + Peptide (RP; irradiation followed by p2TA peptide 24 h later). Gastrointestinal tissue damage was evaluated by analysis of jejunum histopathology and immunohistochemistry for cell proliferation (Cyclin D1) and inflammation (COX-2) markers, as well as the presence of macrophages (F4/80). Pro-inflammatory cytokines IL-6 and KC as well as fibrinogen were quantified in plasma samples obtained from the same mice. Our results demonstrated that administration of p2TA peptide significantly reduced the irradiation-induced increase of IL-6 and fibrinogen in plasma 7 days after exposure. Seven days after total body irradiation with 8 Gy of gamma rays numbers of intestinal crypt cells were reduced and villi were shorter in irradiated animals compared to the controls. The p2TA peptide delivery 24 h after irradiation led to improved morphology of villi and crypts, increased Cyclin D1 expression, decreased COX-2 staining and decreased numbers of macrophages in small intestine of irradiated mice. Our study suggests that attenuation of CD28 signaling is a promising therapeutic approach for mitigation of radiation-induced tissue injury.

Staphylococcus aureus and group A Streptococcus pyogenes (GAS) express superantigen (SAg) exotoxin proteins capable of inducing lethal shock. To induce toxicity, SAgs must bind not only to the major histocompatibility complex II molecule of antigen-presenting cells and the variable β chain of the T-cell receptor but also to the dimer interface of the T-cell costimulatory receptor CD28. Here, we show that the CD28-mimetic peptide AB103 (originally designated "p2TA") protects mice from lethal challenge with streptococcal exotoxin A, as well as from lethal GAS bacterial infection in a murine model of necrotizing soft-tissue infection. Administration of a single dose of AB103 increased survival when given up to 5 hours after infection, reduced inflammatory cytokine expression and bacterial burden at the site of infection, and improved muscle inflammation in a dose-dependent manner, without compromising cellular and humoral immunity. Thus, AB103 merits further investigation as a potential therapeutic in SAg-mediated necrotizing soft-tissue infection.

Disclosed are peptides and methods for the treatment of bacterial infections and associated inflammation. Effective doses and treatment protocols are disclosed.

Department of Neurology, Rabin Medical Center, Petah-Tiqva, IsraelThe last author, Ilan Ziv discovered an error in his affiliation information. The correct affiliation information should be listed as,“Aposense Ltd, Petach-Tiqva; and the Sackler School of Medicine, Tel-Aviv University, Tel-Aviv; and the Department of Neurology,Rabin Medical Center, Petach-Tiqva, Israel”.

Corrigendum to “Molecular imaging of neurodegeneration by a novel cross-disease biomarker” [Exp. Neurol. 219/1 (2009) 274–283] Anat Shirvan, Ayelet Reshef, Merav Yogev-Falach⁎, Ilan Ziv a Aposense Ltd., 5 Ha'Odem St., P.O. Box 7119, Petach-Tikva, 49170, Israel b Aposense, Ltd, Petach-Tiqva, Israel c Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel d Rabin Medical Center, Petach-Tiqva, Israel

Correction to: Cell Research (2009) 19:625–637. doi:10.1038/cr.2009.17; published online 17 February 2009 The authors apologize for missing an affiliation for this paper. The correct affliations of Ilan Ziv are as follows:1,2 1Aposense Ltd, 5-7 Ha'Odem St, Kiryat Matalon, PO Box 7119, Petach Tikva, Israel

Clinical PET of apoptosis may have substantial value in advancing patient care. We report here the first-in-humans study with 18F-labeled 2-(5-fluoropentyl)-2-methyl malonic acid (18F-ML-10), a small-molecule PET tracer for apoptosis. Presented are the dosimetry, biodistribution, stability, and safety profiles of this PET tracer in healthy human volunteers. Also reported is tracer binding to targeted apoptotic cells in testicular tissue, where a relative abundance of apoptotic cells is normally observed. Methods: 18F-ML-10 (233 ± 90 MBq) was intravenously administered to 8 healthy subjects, followed by whole-body PET/CT for 220 min. Serial blood and urine samples were collected for radioactivity measurement, and plasma tracer stability was assessed by high-performance liquid chromatography. Dosimetry calculations were performed using OLINDA/EXM software. Results: 18F-ML-10 manifested high stability in vivo and rapid distribution followed by fast clearance, with an elimination half-life of 1.3 ± 0.1 and 1.1 ± 0.2 h from the blood and from all other organs, respectively, and excretion through the urine. Dosimetry showed an average effective whole-body dose of 15.4 ± 3.7 μSv/MBq, with the urinary bladder being the dose-limiting organ. Selective accumulation and retention of the tracer in the testes was observed in all male subjects, a finding also demonstrated in mice using both small-animal PET and histopathology, confirming binding to apoptotic cells. Administration of 18F-ML-10 was safe, without adverse effects. Conclusion: 18F-ML-10 administered to healthy humans demonstrated a favorable dosimetry, biodistribution, stability, and safety profile. Binding to apoptotic sites was also demonstrated. These data support further development of this small-molecule probe for clinical PET of apoptosis.

Introduction Fibrinolytic shutdown plays a pivotalrole in the pathogenesis of multiple organ dysfunction syndrome (MODS) in disseminated intravascular coagulation (DIC).We tested the hypothesis that the levels of thrombin activatable fi brinolysis inhibitor (TAFI) are not suffi cient to overcome fi brinolytic shutdown, thus contributing to MODS and the poor prognosis in sepsis-induced DIC.Methods Fifty patients with sepsis, severe sepsis, or septic shock were enrolled in the study.The DIC was diagnosed based on the Japanese Association for Acute Medicine (JAAM) DIC criteria.The overt DIC scores based on the International Society on Thrombosis and Haemostasis (ISTH) were also calculated.On the day of sepsis diagnosis (day 1), and days 3 and 5, we measured TAFI, soluble fi brin, and global coagulation and fi brinolysis markers. ResultsThe JAAM DIC scores on day 1 and maximum JAAM DIC scores were independent predictors of patient death and MODS, respectively.The JAAM DIC patients, especially those who simultaneously met the ISTH overt DIC criteria, showed lower TAFI antigen levels and activity, and higher levels of soluble fi brin in comparison with non-DIC patients.There were diff erences in the levels of soluble fi brin and TAFI activity between the patients with and without MODS.The fi ndings of stepwise logistic regression and multiple regression analyses suggested that low TAFI activity is an independent predictor of patient death and MODS.A multiple regression analysis also indicated that soluble fi brin negatively correlated with the TAFI activity in DIC patients.Conclusion Thrombin activation results in the consumption of TAFI.Low TAFI activity is involved in the pathogenesis of DIC-induced MODS and poor prognosis. P2Anti-endotoxin immunity in abdominal sepsis patients O Butyrsky, V Starosek