Iseganan HCl: a novel antimicrobial agent

Inflammation-responsive drug delivery nanosystems for treatment of bacterial-induced sepsis

Sepsis, a complication of dysregulated host immune systemic response to an infection, is life threatening and causes multiple organ injuries. Sepsis is recognized by WHO as a big contributor to global morbidity and mortality. The heterogeneity in sepsis pathophysiology, antimicrobial resistance threat, the slowdown in the development of antimicrobials, and limitations of conventional dosage forms jeopardize the treatment of sepsis. Drug delivery nanosystems are promising tools to overcome some of these challenges. Among the drug delivery nanosystems, inflammation-responsive nanosystems have attracted considerable interest in sepsis treatment due to their ability to respond to specific stimuli in the sepsis microenvironment to release their payload in a precise, targeted, controlled, and rapid manner compared to non-responsive nanosystems. These nanosystems posit superior therapeutic potential to enhance sepsis treatment. This review critically evaluates the recent advances in the design of drug delivery nanosystems that are inflammation responsive and their potential in enhancing sepsis treatment. The sepsis microenvironment's unique features, such as acidic pH, upregulated receptors, overexpressed enzymes, and enhanced oxidative stress, that form the basis for their design have been adequately discussed. These inflammation-responsive nanosystems have been organized into five classes namely: Receptor-targeted nanosystems, pH-responsive nanosystems, redox-responsive nanosystems, enzyme-responsive nanosystems, and multi-responsive nanosystems. Studies under each class have been thematically grouped and discussed with an emphasis on the polymers used in their design, nanocarriers, key characterization, loaded actives, and key findings on drug release and therapeutic efficacy. Further, this information is concisely summarized into tables and supplemented by inserted figures. Additionally, this review adeptly points out the strengths and limitations of the studies and identifies research avenues that need to be explored. Finally, the challenges and future perspectives on these nanosystems have been thoughtfully highlighted.

Mammals' humoral immune proteins and peptides targeting the bacterial envelope: from natural protection to therapeutic applications against multidrug‐resistant Gram ‐negatives

Mammalian innate immunity employs several humoral ‘weapons’ that target the bacterial envelope. The threats posed by the multidrug‐resistant ‘ESKAPE’ Gram‐negative pathogens (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) are forcing researchers to explore new therapeutic options, including the use of these immune elements. Here we review bacterial envelope‐targeting (peptidoglycan and/or membrane‐targeting) proteins/peptides of the mammalian immune system that are most likely to have therapeutic applications. Firstly we discuss their general features and protective activity against ESKAPE Gram‐negatives in the host. We then gather, integrate, and discuss recent research on experimental therapeutics harnessing their bactericidal power, based on their exogenous administration and also on the discovery of bacterial and/or host targets that improve the performance of this endogenous immunity, as a novel therapeutic concept. We identify weak points and knowledge gaps in current research in this field and suggest areas for future work to obtain successful envelope‐targeting therapeutic options to tackle the challenge of antimicrobial resistance.

Antimicrobial peptides, conventional antibiotics, and their synergistic utility for the treatment of drug-resistant infections

Antimicrobial peptides (AMPs), also known as host defense peptides (HDPs), are important effector immune defense molecules in multicellular organisms. AMPs exert their antimicrobial activities through several mechanisms; thus far, induction of drug resistance through AMPs has been regarded as unlikely. Therefore, they have great potential as new generation antimicrobial agents. To date, more than 30 AMP-related drugs are in the clinical trial phase. In recent years, studies show that some AMPs and conventional antibiotics have synergistic effects. The combined use of AMPs and antibiotics can kill drug-resistant pathogens, prevent drug resistance, and significantly improve the therapeutic effects of antibiotics. In this review, we discuss the progress in synergistic studies on AMPs and conventional antibiotics. An overview of the current understanding of the functional scope of AMPs, ongoing clinical trials, and challenges in the development processes are also presented.

Helicity Modulation Improves the Selectivity of Antimicrobial Peptoids

The modulation of conformational flexibility in antimicrobial peptides (AMPs) has been investigated as a strategy to improve their efficacy against bacterial pathogens while reducing their toxicity. Here, we synthesized a library of helicity-modulated antimicrobial peptoids by the position-specific incorporation of helix-inducing monomers. The peptoids displayed minimal variations in hydrophobicity, which permitted the specific assessment of the effect of conformational differences on antimicrobial activity and selectivity. Among the moderately helical peptoids, the most dramatic increase in selectivity was observed in peptoid 17, providing more than a 20-fold increase compared to fully helical peptoid 1. Peptoid 17 had potent broad-spectrum antimicrobial activity that included clinically isolated multi-drug-resistant pathogens. Compared to pexiganan AMP, 17 showed superior metabolic stability, which could potentially reduce the dosage needed, alleviating toxicity. Dye-uptake assays and high-resolution imaging revealed that the antimicrobial activity of 17 was, as with many AMPs, mainly due to membrane disruption. However, the high selectivity of 17 reflected its unique conformational characteristics, with differential interactions between bacterial and erythrocyte membranes. Our results suggest a way to distinguish different membrane compositions solely by helicity modulation, thereby improving the selectivity toward bacterial cells with the maintenance of potent and broad-spectrum activity.

Vitamin lipid nanoparticles enable adoptive macrophage transfer for the treatment of multidrug-resistant bacterial sepsis

Sepsis, a condition caused by severe infections, affects more than 30 million people worldwide every year and remains the leading cause of death in hospitals^1,2. Moreover, antimicrobial resistance has become an additional challenge in the treatment of sepsis³, and thus, alternative therapeutic approaches are urgently needed^2,3. Here, we show that adoptive transfer of macrophages containing antimicrobial peptides linked to cathepsin B in the lysosomes (MACs) can be applied for the treatment of multidrug-resistant bacteria-induced sepsis in mice with immunosuppression. The MACs are constructed by transfection of vitamin C lipid nanoparticles that deliver antimicrobial peptide and cathepsin B (AMP-CatB) mRNA. The vitamin C lipid nanoparticles allow the specific accumulation of AMP-CatB in macrophage lysosomes, which is the key location for bactericidal activities. Our results demonstrate that adoptive MAC transfer leads to the elimination of multidrug-resistant bacteria, including Staphylococcus aureus and Escherichia coli, leading to the complete recovery of immunocompromised septic mice. Our work provides an alternative strategy for overcoming multidrug-resistant bacteria-induced sepsis and opens up possibilities for the development of nanoparticle-enabled cell therapy for infectious diseases.

Perspectives on synthetic pharmacotherapy for the treatment of nosocomial pneumonia

Introduction: Nosocomial pneumonia is the second most common infection in hospital settings, resulting in substantial increases in morbidity, mortality, and length of hospital stay. The rapid increase in resistance of nosocomial pathogens to many antibiotics and the high dissemination of resistance genes highlight the need for innovative approaches to combat difficult-to-treat nosocomial respiratory infections. Areas covered: This review summarizes the synthetic antimicrobials that are currently in development for the treatment of nosocomial pneumonia, focusing on antibiotics in the final phases of clinical development and on the strategies employed by novel synthetic antimicrobial peptides. Expert opinion: Several novel synthetic antimicrobials are currently in the pipeline, and it appears that new antimicrobial peptides or mimetics will soon be made available, expanding the opportunities to treat nosocomial pneumonia. However, the approval process for use in the treatment of nosocomial pneumonia is arduous. Given that significant investments by pharmaceutical companies have ended in failure to obtain the approval of regulatory agencies, novel platforms for antimicrobial discovery are needed. The identification of new and fully synthetic chemical structures with activity against nosocomial pathogens needs to be followed by preclinical studies in large animals and by pharmacokinetic and pharmacodynamic studies in specific critically ill populations to assess lung penetration.

The Road from Host-Defense Peptides to a New Generation of Antimicrobial Drugs

Host-defense peptides, also called antimicrobial peptides (AMPs), whose protective action has been used by animals for millions of years, fulfill many requirements of the pharmaceutical industry, such as: (1) broad spectrum of activity; (2) unlike classic antibiotics, they induce very little resistance; (3) they act synergically with conventional antibiotics; (4) they neutralize endotoxins and are active in animal models. However, it is considered that many natural peptides are not suitable for drug development due to stability and biodisponibility problems, or high production costs. This review describes the efforts to overcome these problems and develop new antimicrobial drugs from these peptides or inspired by them. The discovery process of natural AMPs is discussed, as well as the development of synthetic analogs with improved pharmacological properties. The production of these compounds at acceptable costs, using different chemical and biotechnological methods, is also commented. Once these challenges are overcome, a new generation of versatile, potent and long-lasting antimicrobial drugs is expected.

Preventive Intervention Possibilities in Radiotherapy- and Chemotherapy-induced Oral Mucositis: Results of Meta-analyses

The aim of these meta-analyses was to evaluate the effectiveness of interventions for the prevention of oral mucositis in cancer patients treated with head and neck radiotherapy and/or chemotherapy, with a focus on randomized clinical trials. A literature search was performed for reports of randomized controlled clinical studies, published between 1966 and 2004, the aim of which was the prevention of mucositis in cancer patients undergoing head and neck radiation, chemotherapy, or chemoradiation. The control group consisted of a placebo, no intervention, or another intervention group. Mucositis was scored by either the WHO, the National Cancer Institute-Common Toxicity Criteria (NCI-CTC) score, or the absence or presence of ulcerations, or the presence or absence of grades 3 and 4 mucositis. The meta-analyses included 45 studies fulfilling the inclusion criteria, in which 8 different interventions were evaluated: i.e., local application of chlorhexidine; iseganan; PTA (polymyxin E, tobramycine, and amphotericin B); granulocyte macrophage-colony-stimulating factor/granulocyte colony-stimulating factor (GM-CSF/G-CSF); oral cooling; sucralfate and glutamine; and systemic administration of amifostine and GM-CSF/G-CSF. Four interventions showed a significant preventive effect on the development or severity of oral mucositis: PTA with an odds ratio (OR) = 0.61 (95% confidence interval [CI], 0.39–0.96); GM-CSF, OR = 0.53 (CI: 0.33–0.87); oral cooling, OR = 0.3 (CI: 0.16–0.56); and amifostine, OR = 0.37 (CI: 0.15–0.89). To date, no single intervention completely prevents oral mucositis, so combined preventive therapy strategies seem to be required to ensure more successful outcomes.

Key Residues of Outer Membrane Protein OprI Involved in Hexamer Formation and Bacterial Susceptibility to Cationic Antimicrobial Peptides

Antimicrobial peptides (AMPs) are important components of the host innate defense mechanism against invading pathogens. Our previous studies have shown that the outer membrane protein, OprI from Pseudomonas aeruginosa or its homologue, plays a vital role in the susceptibility of Gram-negative bacteria to cationic α-helical AMPs (Y. M. Lin, S. J. Wu, T. W. Chang, C. F. Wang, C. S. Suen, M. J. Hwang, M. D. Chang, Y. T. Chen, Y. D. Liao, J Biol Chem 285:8985-8994, 2010, http://dx.doi.org/10.1074/jbc.M109.078725; T. W. Chang, Y. M. Lin, C. F. Wang, Y. D. Liao, J Biol Chem 287:418-428, 2012, http://dx.doi.org/10.1074/jbc.M111.290361). Here, we obtained two forms of recombinant OprI: rOprI-F, a hexamer composed of three disulfide-bridged dimers, was active in AMP binding, while rOprI-R, a trimer, was not. All the subunits predominantly consisted of α-helices and exhibited rigid structures with a melting point centered around 76°C. Interestingly, OprI tagged with Escherichia coli signal peptide was expressed in a hexamer, which was anchored on the surface of E. coli, possibly through lipid acids added at the N terminus of OprI and involved in the binding and susceptibility to AMP as native P. aeruginosa OprI. Deletion and mutation studies showed that Cys1 and Asp27 played a key role in hexamer formation and AMP binding, respectively. The increase of OprI hydrophobicity upon AMP binding revealed that it undergoes conformational changes for membrane fusion. Our results showed that OprI on bacterial surfaces is responsible for the recruitment and susceptibility to amphipathic α-helical AMPs and may be used to screen antimicrobials.

Antimicrobial peptide-based treatment for endodontic infections--biotechnological innovation in endodontics

The presence/persistence of microorganisms in the pulp and periapical area corresponds to the maintenance of an exacerbated immune response that leads to the start of periradicular bone resorption and its perpetuation. In endodontic treatment, the available intracanal medications do not have all the desirable properties in the context of endodontic infection and apical periodontitis; they need to include not only strong antimicrobial performance but also an immunomodulatory and reparative activity, without host damage. In addition, there are various levels of resistance to root canal medications. Thus, antimicrobial agents that effectively eliminate resistant species in root canals could potentially improve endodontic treatment. In the emergence of new therapies, an increasing number of studies on antimicrobial peptides (AMPs) have been seen over the past few years. AMPs are defense biomolecules produced in response to infection, and they have a wide spectrum of action against many oral microorganisms. There are some studies that correlate peptides and oral infections, including oral peptides, neuropeptides, and bacterial, fish, bovine and synthetic peptides. So far, there are around 120 published studies correlating endodontic microbiota with AMPs but, according to our knowledge, there are no registered patents in the American patent database. There are a considerable number of AMPs that exhibit excellent antimicrobial activity against endodontic microbiota at a small inhibitory concentration and modulate an exacerbated immune response, down-regulating bone resorption. All these reasons indicate the antimicrobial peptide-based endodontic treatment as an emerging and promising option.

The antimicrobial effect of Iseganan HCl oral solution in patients receiving stomatotoxic chemotherapy: analysis from a multicenter, double-blind, placebo-controlled, randomized, phase III clinical trial

BACKGROUND

Cytotoxic chemotherapy induces changes in the oral microflora that may cause oral and systemic infections in myelosuppressed cancer patients. These complications prompted us to assess the antimicrobial activity of a topical Iseganan HCl mouthwash vs. placebo on the aerobic and facultatively anaerobic oral flora in these patients.

METHODS

Two hundred and twenty-five chemotherapy patients were recruited into a randomized, double-blind, placebo-controlled trial, conducted at multiple centers. The study compared the antimicrobial efficacy of Iseganan HCl vs. placebo (95% of the Iseganan and 97% of the control group received myeloablative chemotherapy). Iseganan HCl 9 mg/3 ml was administered as a swish and swallow solution, six times daily for 21-28 days. Microbial cultures were made before and after the daily Iseganan mouth rinse on the first and final days of chemotherapy.

RESULTS

The reduction in total microbial load after the first day of treatment was statistically significant (1.59 vs. 0.18 log10 CFU for the Iseganan HCl and placebo groups, respectively, P < 0.0001). Iseganan HCl rinse had a cumulative effect demonstrated by the significant difference between the two groups on the last day of the study (i.e. completion of Iseganan daily treatment) (P < 0.05). The reduction was mainly due to decreased densities of viridans streptococci, non-hemolytic streptococci, and yeasts. The minimal inhibitory concentration (MIC) of Iseganan HCl remained the same throughout the course of treatment.

CONCLUSIONS

Topical Iseganan HCl significantly reduces the total oral aerobic bacterial, streptococcal, and yeast load. Its potential as an oral antimicrobial agent in preventing these types of infections is clear.

The design, structures and therapeutic potential of protein epitope mimetics

Using a biologically relevant peptide or protein structure as a starting point for lead identification represents one of the most powerful approaches in modern drug discovery. Here, we focus on the protein epitope mimetic (PEM) approach, where folded 3D structures of peptides and proteins are taken as starting points for the design of synthetic molecules that mimic key epitopes involved in protein-protein and protein-nucleic acid interactions. By transferring the epitope from a recombinant to a synthetic scaffold that can be produced by parallel combinatorial methods, it is possible to optimize target affinity and specificity as well as other drug-like ADMET properties. The PEM technology is a powerful tool for target validation, and for the development of novel PEM-based drugs.

Establishing Literature-Based Items for an Oral Mucositis Assessment Tool in Children

Although there are numerous instruments for oral mucositis (OM) assessment in adults, there is a lack of validated instruments for use in children. The objectives of this systematic review were to describe literature-based items that should be considered for a pediatric mucositis scale and other issues that should be considered when assessing mucositis in children. Literature search of PubMed and bibliography searches identified articles relevant to the assessment of mucositis and mucositis assessment studies in children. The elements established from the literature were grouped under objective, subjective, and functional items. Other issues that require consideration include the conditions for the assessment of the oral cavity and the etiology of OM. The resultant list included 23 items that have been used in mucositis assessment scales. This list of items may be used as an initial step in developing a new pediatric OM scale that particularly focuses on the unique issues in children.

Severe mucositis is associated with reduced survival after autologous stem cell transplantation for lymphoid malignancies

Mucositis is a known complication of autologous stem cell transplantation (ASCT). This study retrospectively reviewed 191 patients with lymphoid malignancies undergoing ASCT following a uniform mobilising regimen of etoposide (VP-16)/granulocyte colony-stimulating factor and a uniform high-dose preparative regimen of busulfan/cyclophosphamide/VP-16. Eighty-seven patients experienced severe mucositis (modified Oral Mucositis Assessment Scale > or =1). Patient characteristics compared between mucositis groups were balanced according to disease status, prior exposure to radiation therapy, time from radiation therapy and actual body weight. Log-rank analysis revealed that severe mucositis was associated with inferior overall survival (P = 0.002). A 12-month landmark analysis showed this difference in survival occurred within 1 year post-transplant. Multivariate analysis of all-cause mortality showed lower pretransplant albumin and severe mucositis to be significant risk factors. Multivariate analysis for relapse mortality revealed severe mucositis to be a risk factor (P = 0.047), while lower pretransplant albumin was significant for non-relapse mortality (NRM; P = 0.009). Kaplan-Meier estimates of survival based on relapse and NRM were significantly worse for patients with severe mucositis. Reduced pretransplant forced expiratory volume in 1 s (FEV(1)) and carbon monoxide (CO) diffusing capacity (DLCO) were also associated with severe mucositis. Our data suggest that studies of new treatment strategies for mucositis should include relapse and survival endpoints and that pretransplant factors, such as FEV(1) and DLCO may be useful to risk-stratify patients entered onto such trials.

A Randomized Double-Blind Trial of Iseganan in Prevention of Ventilator-associated Pneumonia

RATIONALE

Iseganan, an antimicrobial peptide, is active against aerobic and anaerobic gram-positive and gram-negative bacteria as well as fungi and yeasts. The drug has shown little resistance in vitro and to be safe and well tolerated in 800 patients with cancer treated for up to 6 wk.

OBJECTIVES

To determine the efficacy of iseganan for the prevention of ventilator-associated pneumonia (VAP).

METHODS

Mechanically ventilated patients in the United States and Europe were randomized to oral topical iseganan or placebo (1:1) and treated six times per day while intubated for up to 14 d. Patients were eligible if randomized within 24 h of intubation and estimated to survive and remain mechanically ventilated for 48 h or more. The primary efficacy endpoint of the study was VAP measured among survivors at Day 14.

MEASUREMENTS AND MAIN RESULTS

A total of 709 patients were randomized and received at least one dose of study drug. The two groups were comparable at baseline except iseganan-treated patients were, on average, 3 yr older. The rate of VAP among survivors at Day 14 was 16% (45/282) in patients treated with iseganan and 20% (57/284) in those treated with placebo (p = 0.145). Mortality at Day 14 was 22.1% (80/362) in the iseganan group compared with 18.2% (63/347) in the placebo group (p = 0.206). No pattern of excess adverse events in the iseganan group compared with placebo was observed.

CONCLUSIONS

Iseganan is not effective in improving outcome in patients on prolonged mechanical ventilation.

Temporin A and related frog antimicrobial peptides use formyl peptide receptor-like 1 as a receptor to chemoattract phagocytes

Many mammalian antimicrobial peptides (AMPs) have multiple effects on antimicrobial immunity. We found that temporin A (TA), a representative frog-derived AMP, induced the migration of human monocytes, neutrophils, and macrophages with a bell-shaped response curve in a pertussis toxin-sensitive manner, activated p44/42 MAPK, and stimulated Ca(2+) flux in monocytes, suggesting that TA is capable of chemoattracting phagocytic leukocytes by the use of a G(ialpha) protein-coupled receptor. TA-induced Ca(2+) flux in monocytes was cross-desensitized by an agonistic ligand MMK-1 specific for formyl peptide receptor-like 1 (FPRL1) and vice versa, suggesting that TA uses FPRL1 as a receptor. This conclusion was confirmed by data showing that TA selectively stimulated chemotaxis of HEK 293 cells transfected with human FPRL1 or its mouse ortholog, murine formyl peptide receptor 2. In addition, TA elicited the infiltration of neutrophils and monocytes into the injection site of mice, indicating that TA is also functionally chemotactic in vivo. Examination of two additional temporins revealed that Rana-6 was also able to attract human phagocytes using FPRL1, but temporin 1P selectively induced the migration of neutrophils using a distinct receptor. Comparison of the chemotactic and antimicrobial activities of several synthetic analogues suggested that these activities are likely to rely on different structural characteristics. Overall, the results demonstrate that certain frog-derived temporins have the capacity to chemoattract phagocytes by the use of human FPRL1 (or its orthologs in other species), providing the first evidence suggesting the potential participation of certain amphibian antimicrobial peptides in host antimicrobial immunity.

Antimicrobial proteins and peptides: anti-infective molecules of mammalian leukocytes

Phagocytic leukocytes are a central cellular element of innate-immune defense in mammals. Over the past few decades, substantial progress has been made in defining the means by which phagocytes kill and dispose of microbes. In addition to the generation of toxic oxygen radicals and nitric oxide, leukocytes deploy a broad array of antimicrobial proteins and peptides (APP). The majority of APP includes cationic, granule-associated (poly)peptides with affinity for components of the negatively charged microbial cell wall. Over the past few years, the range of cells expressing APP and the potential roles of these agents have further expanded. Recent advances include the discovery of two novel families of mammalian APP (peptidoglycan recognition proteins and neutrophil gelatinase-associated lipocalin), that the oxygen-dependent and oxygen-independent systems are inextricably linked, that APP can be deployed in the context of novel subcellular organelles, and APP and the Toll-like receptor system interact. From a clinical perspective, congeners of several of the APP have been developed as potential therapeutic agents and have entered clinical trials with some evidence of benefit.

A novel carrier molecule for high-level expression of peptide antibiotics in Escherichia coli

Peptide antibiotics are often hard to express in engineered bacteria at high level. According to the properties of peptide antibiotics, a heterologous protein PaP3.30, encoded by ORF30 of Pseudomonas aeruginosa bacteriophage PaP3, was selected as a carrier molecule. The gene of the carrier molecule was constructed into the plasmid pQE-32 to give rise to the vector pQE-PaP30 for expression of peptide antibiotics in Escherichia coli. A his-tagged fusion protein was genetically constructed with a peptide antibiotic at its carboxy terminus. The novel carrier molecule was used for high-level expression of six peptide antibiotics with different sizes and isoelectric points in E. coli, which are hPAB-beta, MSI-78, Melletin, hBD-1, Cecropin A, and an ovine anion peptide. And further, one of six peptide antibiotics, hPAB-beta (an analog of a human peptide antibiotic), was taken as an example for studies of recovery of interesting products from the fusion partner, purification and antimicrobial activity evaluation. The results indicated that the expressed fusion protein existed as an inclusion body in the cytoplasm and the expression amounts of six peptide antibiotic fusions are all higher than 34% of the total cell protein. The expression products could be easily purified by Ni-NTA chromatography. Cyanogen bromide was used to cut at the methionine linker between the carrier and hPAB-beta peptide. hPAB-beta was recovered from the fusion partner and purified to homogeneity with High S cation-exchange and Bio-gel P6 gel chromatography. The bactericidal activities of the purified recombinant hPAB-beta against P. aeruginosa are 31-64 microg/ml, and against Staphylococcus aureus are > or = 128 microg/ml, being comparable to that of the chemical synthesis peptide. These results show that the carrier molecule can result in high-level expression of peptide antibiotics, and expression products can be easily recovered from their fusion partner and retain their bioactivity.

A fludarabine, topotecan, and cytarabine regimen is active in patients with refractory acute myelogenous leukemia

As fludarabine, topotecan and cytarabine (ara-C) are effective in acute myeloid leukemia (AML), a pilot study of these three agents combined (FTA) was conducted. FTA consisted of topotecan 1.25 mg/m2 by CIV days 1-5, fludarabine 15 mg/m2 and ara-C 0.5 g/m2 IV, BID, on days 2-6. Seventeen patients (6 primary resistant, 11 relapsed) with AML received 33 courses of FTA. Six patients (35%) achieved complete remission. Seven patients (41%) developed grade 3 or 4 diarrhea. FTA was effective and warrants further study in patients with refractory AML.

A phase III, randomized, double-blind, placebo-controlled, study of iseganan for the reduction of stomatitis in patients receiving stomatotoxic chemotherapy

The invasion and colonization of oral cavity mucosal tissues by microflora may contribute to the pathophysiology of ulcerative oral mucositis (UOM). Iseganan is an analog of protegrin-1, a naturally occurring peptide with broad-spectrum microbicidal activity. A randomized, double-blind, placebo-controlled study was conducted to evaluate the efficacy and safety of iseganan in preventing UOM after stomatotoxic therapy. Patients received an oral rinse, consisting of iseganan 9mg or placebo, to be swished/swallowed six times daily, starting with stomatotoxic therapy and continuing up to 21 days. Patients were assessed for stomatitis and UOM, and administered a questionnaire evaluating mouth pain and difficulty swallowing thrice weekly. The primary study efficacy endpoint was the proportion of patients who did not have peak stomatitis NCI-CTC grade >or=2. Between November 2001 and June 2002, 502 patients were randomized to receive iseganan (251) or placebo (251). Equivalent numbers of patients in both cohorts received bone marrow or peripheral blood allogeneic or autologous stem cell transplantation (SCT). Forty-three percent and 37% of iseganan and placebo patients, respectively, did not have peak stomatitis grade =2 (P = 0.182). There was no significant difference between the cohorts in stomatitis severity, incidence of UOM, peak mouth pain, peak difficulty swallowing, amount of opiate analgesics used, or adverse event type or incidence. A major impact of Iseganan on reducing stomatitis, UOM, or its clinical sequelae in patients receiving stomatotoxic therapy was not detected on this study.

A multinational, randomized phase iii trial of iseganan hcl oral solution for reducing the severity of oral mucositis in patients receiving radiotherapy for head-and-neck malignancy

PURPOSE

Oral mucositis (OM) causes significant morbidity during the course of radiotherapy (RT) treatment of head-and-neck cancer. It is hypothesized that infection plays a role in the development of OM. We tested the efficacy of iseganan HCl (iseganan), a synthetic peptide with broad-spectrum antimicrobial activity, for preventing RT-associated OM.

METHODS

A multinational, randomized, double-blind, controlled trial was performed on patients receiving primary RT, primary chemoradiotherapy or postoperative RT. Patients were randomized to receive iseganan oral solution plus standard-of-care oral hygiene (SOC), placebo plus SOC, or SOC alone throughout the RT administration period. The severity of OM was assessed by NCI-CTC scoring and clinical symptoms by patient questionnaire.

RESULTS

A total of 545 patients were randomized to the study. Nine percent of the patients in both the iseganan and placebo groups did not develop ulcerative OM (Grades 2, 3, 4) (p = 0.998) whereas only 2% of the patients receiving SOC alone remained free of oral ulceration (p = 0.049). The maximum severity of mouth pain and difficulty swallowing did not differ in patients treated with iseganan or placebo. However, patients in both intervention groups reported less mouth pain and difficulty swallowing than did patients receiving SOC alone. Nausea was the only adverse event that occurred with >/=5% increased frequency in the iseganan group than in either the placebo or SOC groups (51% vs. 42% vs. 46%). Adverse events leading to study drug discontinuation and death did not differ significantly between groups.

CONCLUSION

Iseganan oral solution was safe but did not reduce the risk for developing ulcerative OM relative to placebo. Intensified oral hygiene or the administration of the vehicle used to deliver study drug in this trial appears to have reduced the risk and severity of OM. Our results suggest that antimicrobial intervention may not meaningfully affect the pathogenesis of radiation-induced OM.

The effect of oral mucositis on morbidity and mortality in bone marrow transplant

Oral mucosal ulceration is a frequent complication in bone marrow transplantation, resulting from epithelial injury caused by cytotoxic chemotherapy and radiation conditioning, as well as from pre-existing infection. Oral mucositis causes pain, interferes with patient nutrition, and can lead to systemic infection and other complications that increase patient morbidity and mortality; this complication also markedly increases the expense of bone marrow transplantation. A variety of interventions have been assessed for preventing oral mucositis or reducing the severity of mucositis and its sequelae. These include meticulous pretransplantation and ongoing mouth care, calcium phosphate solution, near-infrared light and lower-energy laser treatment, interleukin-11, sucralfate, oral glutamine, granulocyte-macrophage colony-stimulating factor rinse, tretinoin, and keratinocyte growth factor; particularly promising results have been observed with use of the cytoprotectant/radioprotectant agent amifostine. Reduction in the severity and duration of oral mucositis and its sequelae in patients undergoing bone marrow transplantation can have a substantial impact on morbidity and mortality and cost of care. Further systematic evaluation of approaches to prevention and management of oral mucositis is necessary to define optimal strategies in the transplantation setting.

Innate immune activation as a broad-spectrum biodefense strategy: prospects and research challenges

Biodefense strategies require protection against a broad and largely unforeseen spectrum of pathogens—the forte of innate immune system defenses—that have evolved over millennia to function within moments of encountering either ancient or newly emerging pathogens. Although constitutive, the innate immune system is activated by the presence of microbes or their products, providing a rationale for a potential biodefense strategy. Both prophylactic and postexposure strategies involving innate immune stimulation have been shown to be plausible to prevent or ameliorate infections in animal models. Innate immune-activating compounds based on conserved microbial components recognized by toll-like molecules and other receptors could be synthesized and delivered like drugs by using an entirely different strategy from conventional vaccination. However, important theoretic and practical questions emerge about developing and deploying innate immune protective strategies for biodefense. This rostrum discusses prospects and problems in the overall approach itself. Important topics include microbe-specific issues about innate immune system effectiveness against highly virulent pathogens and general questions, such as whether innate immune responses will be safe and effective if used in a diverse human population of different age groups and with different genetic makeups.

Evaluation of pain associated with oral mucositis during the acute period after administration of high-dose chemotherapy

BACKGROUND

No single oral mucositis (OM) assessment scale is universally accepted; the most commonly used scales are deficient because they combine subjective and objective measures and do not capture the patient's perspective. Because pain is the hallmark symptom of OM, the authors sought to determine whether a simple measure of patient-reported pain was correlated with objective, physician-assessed measures of OM. The findings of the current study may provide a clinical context for understanding the relation between objective indicators and patients' perceptions of OM.

METHODS

Three hundred twenty-three patients receiving stomatotoxic chemotherapy and randomized to receive either iseganan or placebo for treatment of OM underwent periodic objective and subjective evaluations of OM. Objective measures included clinician scoring of stomatitis and dysphagia using the National Cancer Institute Common Toxicity Criteria scales. A subjective measure was obtained by having patients complete a questionnaire (with questions based on an 11-point numeric scale) regarding oral pain.

RESULTS

More than 90% of scheduled oral assessments were obtained. Mouth pain scores were closely related to stomatitis and dysphagia; peak mouth pain coincided with peak stomatitis and dysphagia. Analgesic use increased by 0.7 days for each unit rise on the pain scale. Patients receiving iseganan had a significantly lower level of peak mouth pain than did patients receiving placebo (P=0.041).

CONCLUSIONS

A separate measurement of patient-reported pain was useful for capturing the patient's perspective on OM and was correlated with the physician's objective assessment. These findings support the use of a simple, patient-reported rating of mouth pain as a clinically relevant and responsive endpoint in clinical trials. This rating system also may provide a straightforward method of following OM in clinical practice.

A phase III, randomized, double-blind, placebo-controlled, multinational trial of iseganan for the prevention of oral mucositis in patients receiving stomatotoxic chemotherapy (PROMPT-CT trial)

Microfloral invasion and colonization of oral cavity mucosal tissues contribute to the pathophysiology of ulcerative oral mucositis (UOM). Iseganan is an analog of Protegrin-1, a naturally occurring peptide with broad-spectrum microbicidal activity. A randomized, double-blind, placebo-controlled study was conducted to evaluate iseganan in preventing UOM after stomatotoxic therapy. Patients received an oral rinse of iseganan 9 mg or placebo, swished/swallowed 6 times daily, starting with stomatotoxic therapy and continuing for 21-28 days. One hundred sixty three and 160 patients, respectively, were randomized to receive iseganan or placebo. One hundred and two patients (32%) were affected by a drug dispensing error, caused by a flawed computerized allocation system. Among all 323 patients, analyzed according to randomization assignment, 43% and 33% of iseganan and placebo patients, respectively, did not develop UOM (P = 0.067). On an 11-point scale, iseganan patients experienced less mouth pain (3.0 and 3.8 (P = 0.041), throat pain (3.8 and 4.6 (P = 0.048)), and difficulty swallowing (3.9 and 4.7 (P = 0.074)), compared to placebo patients. On the 5-point NCI CTC scale, iseganan patients experienced lower stomatitis scores (1.6 and 2.0 (P = 0.0131). Iseganan was well tolerated; no systemic absorption was detected. Iseganan is safe and may be effective in reducing UOM and its clinical sequelae.

Mucosal injury in patients undergoing hematopoietic progenitor cell transplantation: new approaches to prophylaxis and treatment

Hematopoietic progenitor cell transplantation is often associated with severe mucosal toxicity. The need for parenteral analgesics and parenteral nutrition are evidence of the severity of the problem in individual patients. However, the increased risk for systemic infection related to bacteremia associated with the breakdown of mucosal barriers is a significant cause of morbidity and mortality as well. There is a multitude of grading scales, demonstrating the lack of consensus among clinicians in this area. Multiple agents have been used prophylactically and therapeutically to address mucositis. While efforts have been less successful in the past, the advent of newer agents including amifostine, keratinocyte growth factor, transforming growth factor beta and interleukin-11 provides hope that this toxicity will be significantly decreased in the near future.

Oral mucositis: time for more studies

Oral Mucositis (OM) is a frequent cause of severe morbidity in patients receiving chemotherapy and/or radiotherapy. The pathophysiology of OM involves direct cytotoxic effects, local inflammatory responses, and alterations in oral microflora. There are currently no approved agents for the prevention or treatment of OM. In this review we briefly describe current knowledge of the pathophysiology, clinical presentation, and management of OM. We then discuss investigational agents being studied in OM with a particular focus on local antimicrobial agents, hemopoietic growth factors, and cytokines. Measures to reduce the incidence of OM and/or alleviate its clinical sequelae should be incorporated into all chemotherapy or radiotherapy studies.