Phase 1 study of MEDI3902, an investigational anti-Pseudomonas aeruginosa PcrV and Psl bispecific human monoclonal antibody, in healthy adults.

OBJECTIVES: MEDI3902 is a bivalent, bispecific human immunoglobulin G1κ monoclonal antibody that binds to both the Pseudomonas aeruginosa PcrV protein involved in host cell cytotoxicity and the Psl exopolysaccharide involved in P. aeruginosa colonization and tissue adherence. MEDI3902 is being developed for the prevention of nosocomial P. aeruginosa pneumonia in high-risk patients. METHODS: This phase 1 dose-escalation study (NCT02255760) evaluated the safety, pharmacokinetics, antidrug antibody (ADA) responses and ex vivo anticytotoxicity and opsonophagocytic killing activities of MEDI3902 after a single intravenous infusion in healthy adults aged 18 to 60 years. Fifty-six subjects were randomized in a 3:1 ratio to receive 250, 750, 1500 or 3000 mg of MEDI3902 or placebo and followed for 60 days afterwards. RESULTS: Treatment-emergent adverse events (TEAEs) were mild or moderate in severity; no serious TEAEs were observed. The most common TEAEs were infusion-related reactions. MEDI3902 exhibited approximately linear pharmacokinetics across the 250, 750 and 1500 mg doses and nonlinear pharmacokinetics between the 1500 and 3000 mg doses. One subject in the 3000 mg group tested positive for ADA on day 61 and had a lower MEDI3902 serum concentration from days 43 to 61 than ADA-negative subjects. Serum anticytotoxicity antibody concentrations and opsonophagocytic killing activity were correlated with MEDI3902 serum concentrations across all doses. CONCLUSIONS: Phase 1 study results of MEDI3902 in healthy subjects support further evaluation of its safety and efficacy in subjects at risk for P. aeruginosa pneumonia.

The Innovative Medicines Initiative's New Drugs for Bad Bugs programme: European public-private partnerships for the development of new strategies to tackle antibiotic resistance.

Antibiotic resistance (ABR) is a global public health threat. Despite the emergence of highly resistant organisms and the huge medical need for new drugs, the development of antibacterials has slowed to an unacceptable level worldwide. Numerous government and non-government agencies have called for public-private partnerships and innovative funding mechanisms to address this problem. To respond to this public health crisis, the Innovative Medicines Initiative Joint Undertaking programme has invested more than €660 million, with a goal of matched contributions from the European Commission and the European Federation of Pharmaceutical Industries and Associations, in the development of new antibacterial strategies. The New Drugs for Bad Bugs (ND4BB) programme, an Innovative Medicines Initiative, has the ultimate goal to boost the fight against ABR at every level from basic science and drug discovery, through clinical development to new business models and responsible use of antibiotics. Seven projects have been launched within the ND4BB programme to achieve this goal. Four of them will include clinical trials of new anti-infective compounds, as well as epidemiological studies on an unprecedented scale, which will increase our knowledge of ABR and specific pathogens, and improve the designs of the clinical trials with new investigational drugs. The need for rapid concerted action has driven the funding of seven topics, each of which should add significantly to progress in the fight against ABR. ND4BB unites expertise and provides a platform where the commitment and resources required by all parties are streamlined into a joint public-private partnership initiative of unprecedented scale.

[Asthma and respiratory syncytial virus. New opportunities for therapeutic intervention]. / Asma y virus respiratorio sincitial. Nuevas oportunidades de intervención terapéutica.

Numerous studies have described an association between respiratory sincticial virus (RSV) infection in infancy and the subsequent development of airway hyperresponsiveness (AHR). Besides the exaggerated immune response and the abnormal neurogenic mechanisms induced by RSV, recent studies have correlated the "persistence" of RSV in the lower respiratory tract with the development of AHR. Several investigators have evaluated whether treatment with antiviral or immunosuppressive agents could decrease the long term respiratory abnormalities induced by RSV. The RSV murine model has allowed us to study the immunopathogenesis of RSV-induced AHR. Once the airway obstruction, typical of acute disease, is resolved and no virus is longer detected by cell cultures, mice progress into a chronic phase characterized by AHR and persistent airway inflammation. The use of polymerase chain reaction assay for RSV quantitation has demonstrated, quite unexpectedly, the presence of RSV RNA in the lower respiratory tract of mice during the chronic phase of the disease. As an example of intervention, the administration of an anti-RSV neutralizing antibody (palivizumab) was associated with a significant reduction in viral replication, pulmonary inflammation and inflammatory cytokines, as well as a significant improvement in the pulmonary function both in the acute and chronic phases of the disease. Future clinical studies to determine whether therapy with palivizumab can prevent the long-term morbidity associated with RSV in children are warranted.

Asma y virus respiratorio sincitial. Nuevas oportunidades de intervención terapéutica / Asthma and respiratory syncytial virus. New opportunities for therapeutic intervention

Numerosos estudios han descrito la asociación entre la infección por virus respiratorio sincitial (VRS) en la infancia y el desarrollo posterior de hiperreactividad bronquial (HRB). Además de la respuesta inmunitaria exagerada y las alteraciones de los mecanismos neuronales,estudios recientes han relacionado la posible "persistencia" del VRS en el tracto respiratorio inferior con la patogenia de la HRB. Varios investigadores han analizado si el tratamiento de la bronquiolitis con fármacos antivirales o inmunosupresores podría disminuir las secuelas pulmonares ocasionadas por el VRS. El modelo experimental de VRS en el ratón ha permitido estudiar la inmunopatogenia de la infección por VRS. Una vez que se resuelve la fase aguda de obstrucción de la vía aérea y no se puede detectar el virus en cultivo celular, los ratones progresan hacia una fase crónica caracterizada por HRB e inflamación persistente de la vía aérea. La utilización de la reacción en cadena de polimerasa (PCR) ha permitido, de forma inesperada, la detección de ARN de VRS en el tracto respiratorio en esta fase crónica. Como ejemplo de intervención, la administración del anticuerpo neutralizante anti-VRS (palivizumab) se asoció a una reducción significativa de la replicación viral, de la inflamación pulmonary de las citocinas inflamatorias y a una mejoría significativa en las pruebas de función pulmonar en las fases aguda y crónica de la enfermedad. Estos resultados llevan a proponer la realización de estudios clínicos para evaluar el papel de palivizumab en la prevención de las secuelas pulmonares causadas por el VRS en la población pediátrica (AU)

Factors influencing the anti-inflammatory effect of dexamethasone therapy in experimental pneumococcal meningitis.

Dexamethasone (DXM) interferes with the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) and can thereby diminish the secondary inflammatory response that follows initiation of antibacterial therapy. A beneficial effect on the outcome of Haemophilus meningitis in children has been proven, but until recently the effect of DXM therapy in pneumococcal meningitis was uncertain. The aim of the present study was to evaluate factors that might influence the modulatory effect of DXM on the antibiotic-induced inflammatory response in a rabbit model of pneumococcal meningitis. DXM (1 mg/kg) was given intravenously 30 min before or 1 h after administration of a pneumococcal cell wall extract, or the first dose of ampicillin. In meningitis induced by cell wall extract, DXM therapy prevented the increase in cerebrospinal fluid (CSF) leucocyte and lactate concentrations, but only if given 30 min before the cell wall extract. In meningitis caused by live organisms, initiation of ampicillin therapy resulted in an increase in CSF TNF-alpha and lactate concentrations only in animals with initial CSF bacterial concentrations > or =5.6 log10 cfu/mL. In those animals, DXM therapy prevented significant elevations in CSF TNF-alpha [median change -184 pg/mL, -114 pg/mL versus +683 pg/mL with DXM (30 min before or 1 h after ampicillin) versus controls (no DXM), respectively, P=0.02] and lactate concentrations [median change -10.6 mmol/L, -1.5 mmol/L versus +14.3 mmol/L with DXM (30 min before or 1 h after ampicillin) versus controls (no DXM), respectively, P=0.01]. These effects were independent of the timing of DXM administration. In this model of experimental pneumococcal meningitis, an antibiotic-induced secondary inflammatory response in the CSF was demonstrated only in animals with high initial CSF bacterial concentrations (> or =5.6 log10 cfu/mL). These effects were modulated by DXM therapy whether it was given 30 min before or 1 h after the first dose of ampicillin.

Pharmacodynamics and bactericidal activity of moxifloxacin in experimental Escherichia coli meningitis.

Moxifloxacin, an 8-methoxyquinolone with broad-spectrum activity in vitro, was studied in the rabbit model of Escherichia coli meningitis. The purposes of this study were to evaluate the bactericidal effectiveness and the pharmacodynamic profile of moxifloxacin in cerebrospinal fluid (CSF) and to compare the bactericidal activity with that of ceftriaxone and meropenem therapy. After induction of meningitis, animals were given single doses of 10, 20, and 40 mg/kg or divided-dose regimens of 5, 10, and 20 mg/kg twice, separated by 6 h. After single doses, the penetration of moxifloxacin into purulent CSF, measured as percentage of the area under the concentration-time curve (AUC) in CSF relative to the AUC in plasma, was approximately 50%. After single doses of 10, 20, and 40 mg/kg, the maximum CSF concentration (C(max)) values were 1.8, 4.2, and 4.9 microg/ml, respectively; the AUC values (total drug) were 13.4, 25.4, and 27.1 microg/ml x h, respectively, and the half-life values (t(1/2)) were 6.7, 6.6, and 4.7 h, respectively. The bacterial killing in CSF for moxifloxacin, calculated as the Deltalog(10) CFU per milliliter per hour, at 3, 6, and 12 h after single doses of 10, 20, and 40 mg/kg were -5.70, -6.62, and -7.02; -7.37, -7.37, and -6.87; and -6.62, -6.62, and -6.62, respectively, whereas those of ceftriaxone and meropenem were -4.18, -5.24, and -4.43, and -3.64, -3.59, and -4.12, respectively. The CSF pharmacodynamic indices of AUC/MBC and C(max)/MBC were interrelated (r = 0.81); there was less correlation with T > MBC (r = 0.74). In this model, therapy with moxifloxacin appears to be at least as effective as ceftriaxone and more effective than meropenem therapy in eradicating E. coli from CSF.

Elevated cytokine and chemokine levels and prolonged pulmonary airflow resistance in a murine Mycoplasma pneumoniae pneumonia model: a microbiologic, histologic, immunologic, and respiratory plethysmographic profile.

Because Mycoplasma pneumoniae is hypothesized to play an important role in reactive airway disease/asthma, a comprehensive murine model of M. pneumoniae lower respiratory infection was established. BALB/c mice were intranasally inoculated once with M. pneumoniae and sacrificed at 0 to 42 days postinoculation. All mice became infected and developed histologic evidence of acute pulmonary inflammation, which cleared by 28 days postinoculation. By contrast, M. pneumoniae persisted in the respiratory tract for the entire 42 days studied. Tumor necrosis factor alpha, gamma interferon, interleukin-6 (IL-6), KC (functional IL-8), MIP-1alpha, and MCP-1/JE concentrations were significantly elevated in bronchoalveolar lavage samples, whereas IL-4 and IL-10 concentrations were not significantly elevated. Pulmonary airflow resistance, as measured by plethysmography, was detected 1 day postinoculation and persisted even after pulmonary inflammation had resolved at day 28. Serum anti-M. pneumoniae immunoglobulin G titers were positive in all mice by 35 days. This mouse model provides a means to investigate the immunopathogenesis of M. pneumoniae infection and its possible role in reactive airway disease/asthma.

Enzyme-linked immunosorbent assay to assess respiratory syncytial virus concentration and correlate results with inflammatory mediators in tracheal secretions.

OBJECTIVE: We developed an enzyme-linked immunosorbent assay (ELISA) for the quantitation of respiratory syncytial virus (RSV) in respiratory secretions in intubated patients infected with RSV. METHODS: We compared the quantitative ELISA and a standardized plaque assay in intubated children <2 years of age who were mechanically ventilated for severe RSV disease and enrolled in a randomized double blind placebo-controlled treatment trial of a monoclonal antibody to the F protein of RSV (palivizumab; Synagis). We also examined the relationship between the concentrations of virus as measured by ELISA and of three inflammatory indices in respiratory secretions (white blood cell count, myeloperoxidase and eosinophilic cationic protein). RESULTS: Quantitative ELISA and plaque assay were highly correlated for both tracheal aspirates (r = 0.67, P = 0.001) and nasal wash specimens (r = 0.75, P = 0.001). Treatment with palivizumab significantly neutralized RSV in tracheal aspirates as measured by plaque assay. In contrast quantitation of RSV by ELISA was not affected by palivizumab treatment. This finding is consistent with results that were obtained in preliminary studies of RSV-containing media treated with monoclonal antibody, where we found that the ELISA measured virus whether antibody-bound or not. The inflammatory indices were not correlated with RSV concentration measured by ELISA or plaque assay. CONCLUSIONS: We conclude that this quantitative ELISA is a potentially useful tool for measurement of RSV concentration in respiratory secretions that may help elucidate the pathophysiology of acute RSV infection. Specific antiviral strategies for the treatment of RSV disease could be evaluated by this method.

Fluoroquinolones in paediatrics.

Fluoroquinolones have a broad spectrum of activity against gram-positive, gram-negative, and mycobacterial organisms as well as anaerobes, Mycoplasma, Chlamydia, Ureaplasma, and Legionella spp. They have excellent oral bioavailability, with good tissue penetration, and long elimination half-lives. The experience with fluoroquinolones in paediatrics has been limited because of concerns about arthropathy, based on findings in animal models. However, there has not been a definitive fluoroquinolone-associated case of arthropathy described in the literature. We believe that there are a number of specific paediatric infections in which the clinical efficacy and tolerability of the fluoroquinolones should be further investigated. These include patients with cystic fibrosis who have repeated infections with Pseudomonas spp., patients with pseudomonal and other gram-negative infections such as urinary tract infections and osteomyelitis, and febrile neutropenic patients. Meningeal infections caused by multiple drug-resistant Streptococcus pneumoniae and gram-negative organisms, gastroenteritis due to enteric pathogens, and mycobacterial infections are other potential conditions where fluoroquinolones should be studied in paediatric patients.

Efficacy of gatifloxacin in experimental Escherichia coli meningitis.

The effectiveness of gatifloxacin therapy (15 mg/kg every 5 h [q5h]) was compared with that of meropenem (75 mg/kg q5h) and cefotaxime (75 mg/kg q5h) therapy in experimental meningitis caused by a beta-lactamase-producing strain of Escherichia coli. Gatifloxacin therapy was more rapidly bactericidal than cefotaxime but similar to meropenem therapy (bacterial killing rates at 5 h, 0.83 +/- 0.26, 0. 46 +/- 0.3, and 0.73 +/- 0.17 CFU/ml/h, respectively; P = 0.03 for gatifloxacin versus cefotaxime). At 10 h, seven of eight animals treated with gatifloxacin had <10 CFU/ml in their cerebrospinal fluid, compared with one of seven treated with cefotaxime therapy (P = 0.01). Gatifloxacin was at least as effective as currently available antibiotics in this model of E. coli meningitis.

Pharmacodynamics of trovafloxacin in experimental pneumococcal meningitis: basis for dosage selection in children with meningitis.

Trovafloxacin is a recently approved fluoroquinolone with excellent activity against gram-positive and gram-negative organisms that offers a potential alternative for treatment of beta-lactam-resistant pneumococcal meningitis. Using the rabbit meningitis model, we sought to characterize the pharmacodynamic properties of trovafloxacin in the cerebrospinal fluid (CSF). Animals were given single doses of trovafloxacin of 10, 15, 20 or 30 mg/kg; 1 h after Infusion mean CSF concentrations were 0.59+/-0.18, 0.74+/-0.14, 1.12+/-0.12 and 1.07+/-0.35 mg/L, respectively. The bacterial killing rate Increased with increasing dosages of trovafloxacin, indicating that its activity is concentration dependent. All three pharmacodynamic Indices (area under the concentration curve (AUC)/MBC, peak concentration (Cmax)/MBC, and time above MBC (T > MBC)) correlated with bacterial killing; however, AUC/MBC correlated best (r = 0.71). In a second experiment we found comparable bacterial killing with multiple doses of trovafloxacin given either every serum half-life or every two serum half-lives. In both experiments bacterial regrowth occurred when the concentration of trovafloxacin in CSF fell below the MBC. These data have been used in formulating an appropriate regimen for trovafloxacin treatment of bacterial meningitis in children.

Mycoplasma pneumoniae pneumonia in a mouse model.

To investigate the pathogenesis of acute Mycoplasma pneumoniae infection, BALB/c mice were anesthetized with metofane, and M. pneumoniae was introduced intranasally on days 0, 1, and 2. Mice were sacrificed on days 0-15. A histopathologic scoring system defined inflammatory changes in the lungs on a scale of 0-26 (least to most severe). Broth cultures were positive for all nasal passage and bronchoalveolar lavage (BAL) specimens. Histopathologic scores ranged from 0 to 21. The mean log10 (cfu/mL) were 4.1-6.4 on days 1-10 and >/=1.7 on days 13-15 for nasal passage and BAL specimens. Serum polymerase chain reaction was negative. ELISA for serum IgM and immunoblots for M. pneumoniae antibody were positive in 21 (62%) of 34 and 33 (97%) of 34 infected animals, respectively, at days 8-15. ELISA for IgG antibody was negative. This mouse pneumonia model can be used to study the immunologic and therapeutic responses to acute M. pneumoniae infection.

Pharmacodynamics of gatifloxacin in cerebrospinal fluid in experimental cephalosporin-resistant pneumococcal meningitis.

The purpose of this study was to evaluate the cerebrospinal fluid (CSF) pharmacodynamics of a new fluoroquinolone, gatifloxacin (AM-1155), in experimental pneumococcal meningitis. The penetration of gatifloxacin into CSF, calculated as the percentage of the area under the concentration-time curve (AUC) in CSF over the AUC in blood, was 46 to 56%. Gatifloxacin showed linear pharmacokinetics in CSF, and 1 h after intravenous dosages of 7.5, 15, or 30 mg/kg of body weight, peak CSF concentrations were 0.46 +/- 0.08 (mean +/- standard deviation), 0.94 +/- 0.16, and 1.84 +/- 0.5 microg/ml, respectively. The elimination half-life of gatifloxacin in CSF was 3. 8 to 5.6 h (compared with 2.7 to 3.2 h in blood). There was a significant interrelationship among the highest measured values of gatifloxacin in blood and CSF/minimal bactericidal concentration (Cpeak/MBC), the time antibiotic concentrations exceeded the MBC (T > MBC), and AUC/MBC (r = 0.94); in single-dose experiments, each correlated significantly with the bacterial killing rate. Divided-dose regimens, resulting in greater T > MBC values but lower Cpeak/MBC ratios, were more effective in terms of bacterial clearance compared with corresponding single-dose regimens. Gatifloxacin therapy was as effective as currently recommended regimens (e.g., a combination of ceftriaxone and vancomycin) against this highly cephalosporin-resistant pneumococcal strain. The bactericidal activity of gatifloxacin in CSF was closely related to the AUC/MBC ratio, but maximal activity was achieved only when drug concentrations exceeded the MBC for the entire dosing interval.

Application of the enzyme-linked immunoelectrotransfer blot to filter paper blood spots to estimate seroprevalence of cysticercosis in Bolivia.

An enzyme-linked immunoelectrotransfer blot (EITB) assay was used to study the prevalence of cysticercosis in rural Bolivia. Dried blood spots on filter paper from fingersticks were used as assay samples. Before the serosurvey, experiments were performed to show that samples eluted from dried whole blood on filter paper exhibited no decrease in sensitivity when compared with the more traditional serum samples used in the EITB. Fingerstick blood dried on filter paper is a convenient, economical way of transporting and storing field samples for epidemiologic surveys of cysticercosis in developing countries. This report shows the utility of this sample collection method in underdeveloped countries where refrigeration is not possible and where venipuncture is a problem. Blood was obtained from randomly selected residents in three rural regions of Bolivia: Chuquisaca (n = 1,859), Cochabamba (n = 1,516), and Tarija (n = 1,010). The estimated seroprevalence on 10% of the sample collected for the three regions were 9%, 4.5%, and 2%, respectively.