Nemonoxacin (TG-873870) for treatment of community-acquired pneumonia

A multicentre, randomised, double-blind, double-dummy, parallel-controlled, phase 3 clinical trial assessing the efficacy and safety of intravenous nemonoxacin malate vs. levofloxacin for community-acquired pneumonia in adult patients

BACKGROUND

Nemonoxacin malate is a novel non-fluorinated quinolone for oral and intravenous (IV) administration. This phase 3, multicentre, randomised, double-blind, double-dummy, parallel-controlled clinical trial (NCT02205112) evaluated the efficacy and safety of IV nemonoxacin vs. levofloxacin for the treatment of community-acquired pneumonia (CAP) in adult patients.

METHODS

Eligible patients were randomised to receive 500 mg nemonoxacin or levofloxacin via IV infusion, once daily for 7-14 days. The primary endpoint was the clinical cure rate at the test-of-cure (TOC) visit in the modified intent-to-treat (mITT) population. Secondary efficacy and safety were also compared between nemonoxacin and levofloxacin.

RESULTS

Overall, 525 patients were randomised and treated with nemonoxacin (n = 349) or levofloxacin (n = 176). The clinical cure rate was 91.8% (279/304) for nemonoxacin and 85.7% (138/161) for levofloxacin in the mITT population (P > 0.05). The clinical efficacy of nemonoxacin was non-inferior to levofloxacin for treatment of CAP. Microbiological success rate with nemonoxacin was 88.8% (95/107) and with levofloxacin was 87.8% (43/49) (P > 0.05) at the TOC visit in the bacteriological mITT population. The incidence of drug-related adverse events (AEs) was 37.1% in the nemonoxacin group and 22.2% in the levofloxacin group. These AEs were mostly local reactions at the infusion site, nausea, elevated alanine aminotransferase/aspartate aminotransferase (ALT/AST), and QT interval prolongation. The nemonoxacin-related AEs were mostly mild and resolved after discontinuation of nemonoxacin.

CONCLUSIONS

Nemonoxacin 500 mg IV once daily for 7-14 days is effective and safe and non-inferior to levofloxacin for treating CAP in adult patients.

Treatment of MRSA Infection: Where are We?

Staphylococcus aureus is a leading cause of septicemia, endocarditis, pneumonia, skin and soft tissue infections, bone and joint infections, and hospital-acquired infections. In particular, methicillin-resistant Staphylococcus aureus (MRSA) is associated with high morbidity and mortality, and continues to be a major public health problem. The emergence of multidrug-resistant MRSA strains along with the wide consumption of antibiotics has made anti-MRSA treatment a huge challenge. Novel treatment strategies (e.g., novel antimicrobials and new administrations) against MRSA are urgently needed. In the past decade, pharmaceutical companies have invested more in the research and development (R&D) of new antimicrobials and strategies, spurred by favorable policies. All research articles were collected from authentic online databases, including Google Scholar, PubMed, Scopus, and Web of Science, by using different combinations of keywords, including 'anti-MRSA', 'antibiotic', 'antimicrobial', 'clinical trial', 'clinical phase', clinical studies', and 'pipeline'. The information extracted from articles was compared to information provided on the drug manufacturer's website and Clinical Trials.gov (https://clinicaltrials.gov/) to confirm the latest development phase of anti-MRSA agents. The present review focuses on the current development status of new anti-MRSA strategies concerning chemistry, pharmacological target(s), indications, route of administration, efficacy and safety, pharmacokinetics, and pharmacodynamics, and aims to discuss the challenges and opportunities in developing drugs for anti-MRSA infections.

Structural Characterization of the Millennial Antibacterial (Fluoro)Quinolones-Shaping the Fifth Generation

The evolution of the class of antibacterial quinolones includes the introduction in therapy of highly successful compounds. Although many representatives were withdrawn due to severe adverse reactions, a few representatives have proven their therapeutical value over time. The classification of antibacterial quinolones into generations is a valuable tool for physicians, pharmacists, and researchers. In addition, the transition from one generation to another has brought new representatives with improved properties. In the last two decades, several representatives of antibacterial quinolones received approval for therapy. This review sets out to chronologically outline the group of approved antibacterial quinolones since 2000. Special attention is given to eight representatives: besifloxacin, delafoxacin, finafloxacin, lascufloxacin, nadifloxacin and levonadifloxacin, nemonoxacin, and zabofloxacin. These compounds have been characterized regarding physicochemical properties, formulations, antibacterial activity spectrum and advantageous structural characteristics related to antibacterial efficiency. At present these new compounds (with the exception of nadifloxacin) are reported differently, most often in the fourth generation and less frequently in a new generation (the fifth). Although these new compounds' mechanism does not contain essential new elements, the question of shaping a new generation (the fifth) arises, based on higher potency and broad spectrum of activity, including resistant bacterial strains. The functional groups that ensured the biological activity, good pharmacokinetic properties and a safety profile were highlighted. In addition, these new representatives have a low risk of determining bacterial resistance. Several positive aspects are added to the fourth fluoroquinolones generation, characteristics that can be the basis of the fifth generation. Antibacterial quinolones class continues to acquire new compounds with antibacterial potential, among other effects. Numerous derivatives, hybrids or conjugates are currently in various stages of research.

Efficacy and Safety of Nemonoxacin in Outpatients with Community-Acquired Pneumonia

PURPOSE

To evaluate the efficacy and safety of 500 mg of nemonoxacin administered orally once daily to outpatients with community-acquired pneumonia (CAP).

PATIENTS AND METHODS

Patients with CAP who received nemonoxacin monotherapy were selected from outpatients who visited the Department of Pulmonary and Critical Care Medicine of Shengjing Hospital of China Medical University between July and December 2018. Their characteristics, pneumonia-related symptoms, treatment effects, and adverse reactions were recorded.

RESULTS

In total, 337 patients with CAP were administered 500 mg of nemonoxacin orally once daily for 8.24 ± 3.73 days. Fourteen patients were lost during the follow-up period. At the end of the follow-up period, information on 323 patients (132 males and 191 females) with a median age of 52 (P25, P75: 34, 61) years was collected. On the basis of CRB-65 scores, 273 and 50 cases were classified to have low and intermediate risks, respectively. After 3 days of treatment, the symptom improvement rate was 61.3% (198 patients). Improved symptoms or cures were evident in 98.14% (317 patients) of the patients after treatment was completed. Five (1.55%) patients were hospitalized for poor treatment efficacy, and one (0.31%) patient was diagnosed with lung cancer despite improved symptoms. During oral therapy, there were three cases of skin and three cases of gastrointestinal adverse events, an incidence of 1.86%. Based on subsequent re-examinations and telephonic follow-ups, 93.50% (302 cases) of patients were satisfied with treatment effects.

CONCLUSION

In treating outpatients with mild-to-moderate CAP, nemonoxacin can effectively control symptoms, reducing medical costs and saving patient time. Importantly, this is a safe and effective therapeutic approach as it is well tolerated with few side effects.

In vitro Activities of Nemonoxacin and Other Antimicrobial Agents Against Human Mycoplasma and Ureaplasmas Isolates and Their Defined Resistance Mechanisms

Nemonoxacin, a newly developed non-fluorinated quinolone (NFQ), selectively inhibits bacterial DNA topoisomerase activity. However, its activities against Mycoplasmas have rarely been studied to date. Herein, the activities of nemonoxacin were evaluated against clinical isolates of 50 Mycoplasma pneumoniae, 20 Mycoplasma hominis, and 77 Ureaplasma spp., and they were compared to fluoroquinolones, tetracyclines, and macrolides. Nemonoxacin MICs (μg/ml) ranged from 0.03 to 0.25 for M. pneumoniae, 0.25 to 8 for M. hominis, and 0.06 to >16 for Ureaplasma spp., and all of the ranges are similar to those of fluoroquinolones. The activity of nemonoxacin against Mycoplasmas was not affected by resistance to macrolides in the strains tested, but it seems to have the same resistant mechanism as fluoroquinolones. In addition, minimum bactericidal concentrations (MBC) of nemonoxacin to M. pneumoniae were within two dilutions of the MIC values, indicating a bactericidal effect on M. pneumoniae. Nemonoxacin merits further study for treating infections caused by these organisms.

The efficacy and safety of nemonoxacin compared with levofloxacin in the treatment of community-acquired pneumonia: a systemic review and meta-analysis of randomized controlled trials

Objectives

This meta-analysis aims to assess the clinical efficacy and safety of nemonoxacin in comparison with levofloxacin in treating community-acquired pneumonia (CAP).

Materials and methods

The Pubmed, Embase, ClinicalTrials.gov., and the Cochrane databases were searched up to September 2018. Only randomized controlled trials (RCTs) evaluating nemonoxacin and levofloxacin in the treatment of CAP were included. The primary outcome was the clinical cure rate, and the secondary outcomes included the microbiologic response rate and the risk of adverse events.

Results

Three RCTs were included. Overall, nemonoxacin and levofloxacin had similar clinical cure rates in the treatment of CAP (OR =1.05, 95% CI =0.67–1.64, I²=0%). Nemonoxacin also had a microbiologic response rate similar to levofloxacin (OR =0.89, 95% CI =0.44–1.81, I²=0%). No significant differences were found in treatment-emergent adverse events between the two drugs (OR =1.08, 95% CI =0.81–1.43, I²=0%). In subgroup analysis, the similarities in the clinical cure rate, microbiologic response rate, and risk of adverse events of these two drugs remained unchanged with the dose of nemonoxacin (500 or 750 mg) and individual pathogens.

Conclusion

The clinical and microbiologic efficacy of nemonoxacin is comparable to that of levofloxacin in the treatment of CAP, and this agent is as well tolerated as levofloxacin.

A randomized, double-blind, multicenter Phase II study comparing the efficacy and safety of oral nemonoxacin with oral levofloxacin in the treatment of community-acquired pneumonia

BACKGROUND/PURPOSE

To compare the clinical efficacy and safety of nemonoxacin with levofloxacin in treating community-acquired pneumonia (CAP) in a Phase II clinical trial.

METHODS

One hundred ninety-two patients with CAP were randomized to receive oral nemonoxacin (500 mg or 750 mg) or levofloxacin (500 mg) once daily for 7-10 days. Clinical and bacteriological responses were determined at the test of cure (TOC) visit in the full analysis set (FAS).

RESULTS

The clinical cure rate of nemonoxacin (500 mg), nemonoxacin (750 mg), and levofloxacin (500 mg) was 93.3%, 87.3%, and 88.5%, respectively, in the FAS (n = 168), and 93.0%, 93.9%, and 88.9%, respectively in the per protocol set (n = 152). At the TOC visit, nemonoxacin at 500 mg and 750 mg was proven to be noninferior to levofloxacin at 500 mg in the FAS in terms of clinical efficacy. The overall bacteriological success rate was 83.3% in both nemonoxacin groups and 80.0% in the levofloxacin 500 mg group in the bacteriological FAS. The comprehensive efficacy rate was comparable among the three groups (87.5% for the nemonoxacin 500 mg group, 93.8% for the nemonoxacin 750 mg group, and 81.3% for the levofloxacin 500 mg group). Most drug-related adverse events were mild and transient, mainly gastrointestinal symptoms such as nausea and vomiting, transient neutropenia, and elevated liver enzymes. No drug-related serious adverse events occurred.

CONCLUSION

Either 500 mg or 750 mg of oral nemonoxacin taken once daily for 7-10 days demonstrated high clinical and bacteriological success rates in Chinese adult patients with CAP. Nemonoxacin at 500 mg once daily for 7-10 days is recommended for future Phase III clinical trials. ClinicalTrials.gov identifier: NCT01537250.

Update on infections caused by Stenotrophomonas maltophilia with particular attention to resistance mechanisms and therapeutic options

Stenotrophomonas maltophilia is a Gram-negative, biofilm-forming bacterium. Although generally regarded as an organism of low virulence, S. maltophilia is an emerging multi-drug resistant opportunistic pathogen in hospital and community settings, especially among immunocompromised hosts. Risk factors associated with S. maltophilia infection include underlying malignancy, cystic fibrosis, corticosteroid or immunosuppressant therapy, the presence of an indwelling central venous catheter and exposure to broad spectrum antibiotics. In this review, we provide a synthesis of information on current global trends in S. maltophilia pathogenicity as well as updated information on the molecular mechanisms contributing to its resistance to an array of antimicrobial agents. The prevalence of S. maltophilia infection in the general population increased from 0.8-1.4% during 1997-2003 to 1.3-1.68% during 2007-2012. The most important molecular mechanisms contributing to its resistance to antibiotics include β-lactamase production, the expression of Qnr genes, and the presence of class 1 integrons and efflux pumps. Trimethoprim/sulfamethoxazole (TMP/SMX) is the antimicrobial drug of choice. Although a few studies have reported increased resistance to TMP/SMX, the majority of studies worldwide show that S. maltophilia continues to be highly susceptible. Drugs with historically good susceptibility results include ceftazidime, ticarcillin-clavulanate, and fluoroquinolones; however, a number of studies show an alarming trend in resistance to those agents. Tetracyclines such as tigecycline, minocycline, and doxycycline are also effective agents and consistently display good activity against S. maltophilia in various geographic regions and across different time periods. Combination therapies, novel agents, and aerosolized forms of antimicrobial drugs are currently being tested for their ability to treat infections caused by this multi-drug resistant organism.

Development of novel antibacterial drugs to combat multiple resistant organisms

BACKGROUND

Infections due to multidrug-resistant (MDR) bacteria are increasing both in hospitals and in the community and are characterized by high mortality rates. New molecules are in development to face the need of active compounds toward resistant gram-positive and gram-negative pathogens. In particular, the Infectious Diseases Society of America (IDSA) has supported the initiative to develop ten new antibacterials within 2020. Principal targets are the so-called ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacteriaceae).

PURPOSE

To review the characteristics and the status of development of new antimicrobials including new cephalosporins, carbapenems, beta-lactamase inhibitors, aminoglycosides, quinolones, oxazolidones, glycopeptides, and tetracyclines.

CONCLUSIONS

While numerous new compounds target resistant gram-positive pathogens and have been approved for clinical use, very few new molecules are active against MDR gram-negative pathogens, especially carbapenemase producers. New glycopeptides and oxazolidinones are highly efficient against methicillin-resistant S. aureus (MRSA), and new cephalosporins and carbapenems also display activity toward MDR gram-positive bacteria. Although new cephalosporins and carbapenems have acquired activity against MRSA, they offer few advantages against difficult-to-treat gram-negatives. Among agents that are potentially active against MDR gram-negatives are ceftozolane/tazobactam, new carbapenems, the combination of avibactam with ceftazidime, and plazomicin. Since a relevant number of promising antibiotics is currently in development, regulatory approvals over the next 5 years are crucial to face the growing threat of multidrug resistance.

The potential role of nemonoxacin for treatment of common infections

INTRODUCTION

Nemonoxacin , a novel non-fluorinated quinolone, exhibits potent activity against Gram-positive bacteria, including MRSA and fluoroquinolone-resistant MRSA, Gram-negative and atypical pathogens. This agent also has a reduced propensity for resistance development in many kinds of pathogens.

AREAS COVERED

This article reviews currently available clinical and in vitro data that support the potential role of nemonoxacin for the treatment of common infectious diseases, including community-acquired pneumonia (CAP), Clostridium difficile infections (CDIs), acute bacterial skin and skin structure infections (ABSSSIs) and sexually transmitted diseases (STDs). One recent Phase II trial comparing either 500 mg or 750 mg oral nemonoxacin with 500 mg oral levofloxacin for mild to moderate CAP demonstrated that nemonoxacin had comparable clinical success with levofloxacin. Nemonoxacin showed lower MICs against clinical C. difficile isolates than commercially available fluoroquinolones, making it a potential therapeutic agent if novel formulations are developed to maintain a higher concentration in the human gut. For STDs, nemonoxacin also showed good activity against some common pathogens, such as Chlamydia trachomatis and Neisseria gonorrhoeae.

EXPERT OPINION

Although in vitro studies have shown promising results regarding the susceptibility to nemonoxacin of common pathogens causing CDIs, ABSSSIs and STDs, further clinical trials are needed to prove its efficacy.