Meta-analysis of published clinical trials of a ribosomal vaccine (ribomunyl) in prevention of respiratory infections

Prevention of New Respiratory Episodes in Children with Recurrent Respiratory Infections: An Expert Consensus Statement

In healthy infants and young children, the development of respiratory tract infections (RTIs) is extremely common. In this paper, we present an international consensus of the available approaches for the prevention of recurrent RTIs in children, including the atopic/allergic ones as well as those with asthma. Few convincing measures for reducing the frequency and clinical relevance of recurrent respiratory episodes in RTI-prone children have been developed until now. Among the most recently suggested measures, immunotherapy is attractive, but only for OM-85 is there a sufficient number of well-conducted clinical trials confirming efficacy in RTIs prevention with an adequate safety profile. In the case of probiotics, it is not clear which bacteria can offer the best results and which dosage and schedule of administration are the most effective. The problems of dosage and the schedule of administration are not solved also for vitamin D, despite some promising efficacy results. While we wait for new knowledge, the elimination or reduction as much as possible of the environmental factors that favor RTIs, vaccination when available and/or indicated, and the systematic application of the traditional methods for infection prevention, such as hand washing, remain the best measures to prevent recurrent infections in RTI-prone children.

Role of ribomunyl((r)) in the prevention of recurrent respiratory tract infections in adults : overview of clinical results

Recurrent respiratory tract infections (RRTIs) in adults are the result of an imbalance between lung defense mechanisms, and bacterial burden. Antibacterial treatments can temporarily restore the equilibrium between host and bacterial load, but do not prevent recurrence of infection. An alternative approach to prevent recurrence of infection is treatment with an immunostimulant, which provides immune protection against repeated bacterial and viral infection. All immunostimulant products are bacterial in origin: lysates (first generation immunostimulants), or bacterial extracts, like bacterial ribosomes, or membrane proteoglycans. This review highlights the current state of knowledge regarding the use of immunostimulants in adults with RRTIs, taking the ribosomal immunostimulant Ribomunyl((R)) as an example. Many studies are available on the mechanism of action and clinical efficacy in prevention of RRTIs in adults treated with Ribomunyl((R)). The effect of this immunostimulant on anti-infectious responses is explained by a stimulation of both nonspecific (innate) and specific (adaptive) immunity. In order to obtain a global overview of the therapeutic efficacy of Ribomunyl((R)) the most pertinent trials were selected from the literature based on adequate patient numbers and good methodology. Results of double-blind placebo-controlled trials using Ribomunyl((R)) for the treatment of different upper or lower RRTIs have demonstrated a statistically significant reduction in the number of infectious episodes and as a consequence, a decrease in antibacterial consumption, after 3 and 6 months of treatment. The tolerance profile of Ribomunyl((R)) was good in all studies. Economic evaluations suggest that savings can be made in healthcare expenditure, in patients with recurrent episodes of infection. It is concluded that Ribomunyl((R)) is effective in preventing and reducing upper and lower respiratory tract infections in adults. The product may also have an impact on reducing the development of bacterial resistance, as a result of fewer courses of antibacterials required to treat patients with RRTIs.

Different treatment benefits were estimated by clinical trials performed in adults compared with those performed in children

OBJECTIVE

Our main objective was to see whether the therapeutic benefit observed in placebo controlled randomized controlled trials (RCTs) is different between adults and children.

STUDY DESIGN AND SETTING

We searched three electronic databases for meta-analyses that included double-blind, placebo-controlled RCTs with separate results for adults and children. The selected reviews were classified according to disease and drug used. The heterogeneity of treatment response between adults and children was measured using ratio of odds ratios (RORs).

RESULTS

We selected 89 meta-analyses and calculated RORs for 124 drugs. Heterogeneity in the direction of the treatment effect was observed in one drug and heterogeneity in the quantity of the treatment effect for 13 drugs, indicating significantly different treatment effect in adults when compared with children. RORs were not significantly different from 1 for 110 drugs. For 36 of these drugs, the treatment effect was confirmed in both populations.

CONCLUSION

We found different treatment benefits estimated by clinical trials performed in adults compared with those performed in children for 14 of 124 drugs. Data on dose adjustment and child age groups from RCTs were not adequately reported to investigate their influence on the treatment benefit dissimilarities.

[Immunoprophylaxis of infections of the upper respiratory tract in the frequently ill children]

The review of the clinical studies designed to evaluate the prophylactic effectiveness of ribosomal immunization is presented. It is shown that the application of the ribosomal vaccine ribomunyl causes a significant reduction in the occurrence of acute respiratory infections in the frequently ill children, lowers the frequency of exacerbation of chronic diseases of the upper respiratory tract, and allows to decrease the use of antibiotics. The authors emphasize the high therapeutic effectiveness and safety of preventive measures against respiratory infections in the frequently ill children with the use of the anti-influenza vaccine in combination with ribosomal immunization.

Monocyte-derived DC primed with TLR agonists secrete IL-12p70 in a CD40-dependent manner under hyperthermic conditions

Fever is an evolutionarily conserved mechanism to improve survival during infection. Previous studies have shown that feverlike temperatures directly enhance the function of murine bone marrow-derived dendritic cells (DCs). In the present study, we examined the response of human monocyte-derived DC to 39.5 degrees C hyperthermia. When primed with toll-like receptor agonists or bacterial extract but not proinflammatory cytokines, hyperthermia specifically enhanced secretion of interleukin (IL)-12p70 by DC, without altering the secretion of IL-10, tumor necrosis factor alpha or IL-1beta. These DC induced significantly higher levels of T-cell proliferation and interferon gamma production in assays of antigen presentation and MLR. Endogenous heat-sock protein 70 colocalized with CD40 in DC exposed to hyperthermic conditions. Recombinant CD40-Fc fusion protein blocked the increase in IL-12p70 secretion by DC primed with bacterial extract and hyperthermia. Thus, DC primed with toll-like receptor-agonists respond to hyperthermia with increased IL-12p70 secretion, mediated by heat-shock protein binding and activation of CD40. The data have important applications for clinical immunotherapy and the mechanism of fever.

Immunostimulants for preventing respiratory tract infection in children

BACKGROUND

Acute respiratory tract infections (ARTIs) are a major cause of childhood morbidity and mortality. Immunostimulants (IS) may reduce the incidence of ARTIs.

OBJECTIVES

To determine the efficacy and safety of IS in preventing ARTIs in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2005); MEDLINE (January 1966 to January 2006); and EMBASE (January 1990 to January 2006); PASCAL (up to January 2006); SciSearch (up to January 2006); and IPA (up to January 2006) for reports of trials. Investigators in the field were also contacted. Ongoing studies were searched in the trial registration web site, metaRegister of Controlled Trials.

SELECTION CRITERIA

All comparative trials which enrolled patients less than 18 years of age were included. The intervention of interest was the use of an IS medication administered by any method for preventing ARTIs. Clinical trials using random or quasi-random allocation and comparing IS medication or medications to placebo were included.

DATA COLLECTION AND ANALYSIS

The outcome on ARTIs was analyzed both as the mean number of ARTIs by group and as a percent change in the rate of ARTIs. Meta-analysis was undertaken using a random-effects model and results were presented as weighted mean differences (WMD) with 95% confidence intervals (CI). The trials search, quality assessment and data extraction were undertaken independently by two authors. A funnel plot suggested there may be publication bias in the trials identified.

MAIN RESULTS

Thirty-four placebo controlled trials (3877 participants) provided data in a form suitable for inclusion in the meta-analysis. When compared with placebo, the use of IS was shown to reduce ARTIs measured as the total numbers of ARTIs (WMD -1.27; 95% CI -1.58 to -0.97) and the difference in ARTIs rates (WMD -39.68%; 95% CI -47.27% to -32.09%). The trial quality was generally poor and a high level of statistical heterogeneity was evident. The subgroup analysis of bacterial IS studies produced similar results, with lower heterogeneity. No difference in adverse events was evident between the placebo and IS groups

AUTHORS' CONCLUSIONS

This review showed that IS reduces the incidence of ARTIs in children, by 40% on average. However, due to significant heterogeneity and the poor quality of the trials this positive result should be interpreted with caution. The safety profile of IS appears to be good. Further high-quality trials are needed and we encourage national health authorities to conduct large, multicenter, double-blind, placebo-controlled trials on the role of IS in the prevention of ARTIs.

Immunostimulants revisited: focus on the pharmacology of Ribomunyl

Ribomunyl is an immunostimulant that was developed and commercialized in the 1980s in France and has subsequently been made available in a large number of countries. The formulation is composed of proteoglycans from Klebsiella pneumoniae and of ribosomes from four of the most commonly encountered bacterial strains in recurrent respiratory tract infections. While it is obviously difficult to present a thorough summary of all historical data, here we revisit the mode of action of this immunostimulant and present a perspective in the context of the most recent data and hypotheses on the mechanisms of the antibacterial immune responses. We provide various examples of these mechanisms in innate immunity (phagocytosis, cell adhesion, dendritic cell maturation, Toll-like receptors, interferon production, proinflammatory cytokines, activation of natural killer cells), as well as in adaptative immunity (polyclonal activation of T and B cells, specific immunoglobulin A immune response in an integrated view of the mucosal immune system, and T helper type 1/type 2 [Th1/Th2] regulation and balance). The effect of this immunostimulant on anti-infectious responses can be explained, not only by a stimulation of the antibacterial defense directly assumed by innate immunity, but also by a stimulation of the specific (adaptative) immune response related to the activation of dendritic cells, of which the pivotal role in T-cell differentiation is already well known. This supports the potential of bacterial immunostimulants such as Ribomunyl in anti-infective therapy.

Ribosomal immunotherapy for recurrent respiratory tract infections in children

Recurrent respiratory tract infections are common in children. They reflect the immaturity of the immune system in its encounter with environmental antigens. Little or no specific protective immune response has yet been established. These infections represent an important public health problem in terms of both treatment (anti-inflammatory or antibacterial drugs for children) and economy. Immunotherapy has been proposed as a means of preventing these recurrent infections by providing children with small doses of inactive bacterial antigens liable to trigger specific and protective immune responses. Among such drugs, ribosomal preparations (to which this review is limited) appear to be not only well tolerated, but also ideally targeted to induce mucosal responses. One preparation of ribosomal mucosal vaccine is commercially available in several countries. Numerous clinical trials in the world have confirmed the positive role of this mucosal ribosomal bacterial vaccine in significantly reducing the number of infections, courses of antibacterials, and absenteeism. In vitro and ex vivo investigations have confirmed that such vaccines indeed trigger protective specific immune responses.

Meta-analysis of randomized trials of terazosin in the treatment of benign prostatic hyperplasia

OBJECTIVES

To determine the effectiveness of the long-acting alpha(1)-adrenergic receptor blocking agent terazosin compared with placebo on lower urinary tract symptoms and peak urinary flow rate in men with clinical benign prostatic hyperplasia.

METHODS

A formal meta-analysis of all nine randomized trials of terazosin using both an Empirical Bayes and a fully Bayesian approach was conducted. A pooled analysis was conducted on those studies in which patients had a baseline assessment of prostate volume by transrectal ultrasonography.

RESULTS

No evidence of heterogeneity was found in the estimated effects of terazosin on the change in peak flow rates in the studies. Terazosin treatment was associated with an increase in the peak flow rate of 1.4 mL/s (95% confidence interval [1.0, 1.7]) compared with placebo. Terazosin resulted in an average reduction of 2.2 points over placebo (95% confidence interval [1.6, 3.0]) regarding the common symptom score (range 0 to 36 points). A mild heterogeneity was found across the studies, with the decrease in symptom score slightly greater with longer treatment duration. No evidence was found that the baseline prostate volume influenced the effect of terazosin.

CONCLUSIONS

Terazosin was effective and superior to placebo in reducing symptoms and increasing the peak urinary flow rate. The effect of terazosin on the peak urinary flow rate was apparent in studies as short as 8 weeks. Most importantly, the effect of terazosin on symptoms and peak urinary flow rate was independent of the baseline prostate size for the range of prostate volumes reported.