Activity of JNJ-Q2, a new fluoroquinolone, tested against contemporary pathogens isolated from patients with community-acquired bacterial pneumonia

Investigational and Experimental Drugs for Community-Acquired Pneumonia: the Current Evidence

Community-acquired pneumonia (CAP) is a common infection with a constantly evolving etiological spectrum. This changing etiology conditions the adequate selection of optimal therapeutic regimens, both in empirical and definitive treatments. In recent years, new antimicrobials have been approved by regulatory authorities for use in CAP, although it is necessary to continue incorporating new antimicrobial agents that improve the activity profile in relation to the appearance of bacterial resistance in certain pathogens, such as pneumococcus, Staphylococcus aureus or Pseudomonas aeruginosa. Delafloxacin, omadacycline and lefamulin are the most recently approved antibiotics for CAP. These three antibiotics have shown non-inferiority to their comparators for the treatment of CAP with an excellent safety profile. However, in the 2019 ATS/IDSA guidelines, it has been considered that more information is needed to incorporate these new drugs into community-based treatment. New antimicrobials, such as solithromycin and nemonoxacin, are currently being studied in Phase III clinical trials. Both drugs have shown non-inferiority against the comparators and an acceptable safety profile; however, they have not yet been approved by the regulatory authorities. Several drugs are being tested in Phase I and II clinical trials. These include zabofloxacin, aravofloxacin, nafithromycin, TP-271, gepotidacin, radezolid, delpazolid, and CAL02. The preliminary results of these clinical trials allow us to assure that most of these drugs may play a role in the future treatment of CAP.

Investigational drugs in phase I and phase II clinical trials for the treatment of community-acquired pneumonia

INTRODUCTION

Community acquired pneumonia is one of the main infections, remaining as a global cause of considerable morbidity and mortality. Successful treatment hinges on expedient delivery of appropriate antibiotic therapy tailored to both the likely pathogens and the severity of disease. Although antibiotic resistance is increasing and pharmaceutical companies continue to debate the profitability of introducing new antibacterial agents, an encouraging number of new molecules have recently been unveiled which target multidrug-resistant bacteria. Areas covered: Herein, the authors summarize the actual situation of novel antibiotics for CAP in phase I & II of development. For each set of compounds, the medical significance and possible clinical placement are discussed. Current treatment options from the most important international guidelines are also reviewed. Expert opinion: Our review shows that the new antibiotics in the pipeline belong to existing antibiotic classes as β-lactams, macrolides, quinolones, oxazolidinones, tetracyclines, lipoglycopeptides, and cyclic lipopeptides and a few with a narrow spectrum of activity are novel compounds directed against novel targets. With rising outpatient antibiotic resistance in pneumonia, some of the compounds discussed are being considered for more rapid advancement in the pipeline, helping to increase the number of agents in later stages of development.

Proposed Pharmacokinetic-Pharmacodynamic Breakpoint of Garenoxacin and Other Quinolones

The pharmacokinetic-pharmacodynamic (PK-PD) breakpoints (BPs) of garenoxacin (GRNX) and other oral quinolones were calculated using Monte Carlo simulation (MCS) based on the distribution of changes in their plasma concentrations. PK-PD BPs of 400 mg once a day (QD) of GRNX for the free area under the curve/minimum inhibitory concentration (fAUC/MIC) for 30 strains of Streptococcus pneumoniae and 100 strains of gram-negative bacteria (G [－]) were 0.5 and 0.125 μg/mL, respectively. PK-PD BPs of other quinolones for S. pneumoniae/G (－) were 1/0.25 μg/mL for levofloxacin (LVFX) 500 mg QD, 0.5/0.125 μg/mL for moxifloxacin (MFLX) 400 mg QD, 0.0625/0.0156 μg/mL for sitafloxacin (STFX) 50 mg twice a day (BID) (100 mg QD), and 0.125/0.0313 μg/mL for STFX 100 mg BID. We also investigated the hypothetical probability of target attainments (PTAs) of fAUC/MIC for community-acquired pneumonia (CAP) using MCS, in consideration of the isolation frequencies of the three main causative pathogens of CAP: S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. For hypothetical CAP in adults, PTA of fAUC/MIC was 100% with GRNX and MFLX, 96%-97% with STFX at 100 mg BID, 45%-46% with LVFX, and 53%-58% with STFX at 100 mg QD and 50 mg BID. Based on the PK-PD BP, GRNX showed higher fAUC/MIC than the other quinolones tested against the three main pathogens of respiratory infections.

New strategies for targeting and treatment of multi-drug resistant Staphylococcus aureus

Staphylococcus aureus is a major cause of bacterial infection in humans, and has been notoriously able to acquire resistance to a variety of antibiotics. An example is methicillin-resistant S. aureus (MRSA), which despite having been initially associated with clinical settings, now is one of the key causative agents of community-acquired infections. Antibiotic resistance in S. aureus involves mechanisms ranging from drug efflux to increased expression or mutation of target proteins, and this has required innovative approaches to develop novel treatment methodologies. This review provides an overview of the major mechanisms of antibiotic resistance developed by S. aureus, and describes the emerging alternatives being sought to circumvent infection and proliferation, including new generations of classic antibiotics, synergistic approaches, antibodies, and targeting of virulence factors.

Focus on JNJ-Q2, a novel fluoroquinolone, for the management of community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections

JNJ-Q2 is a novel, fifth-generation fluoroquinolone that has excellent in vitro and in vivo activity against a variety of Gram-positive and Gram-negative organisms. In vitro studies indicate that JNJ-Q2 has potent activity against pathogens responsible for acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP), such as Staphylococcus aureus and Streptococcus pneumoniae. JNJ-Q2 also has been shown to have a higher barrier to resistance compared to other agents in the class and it remains highly active against drug-resistant organisms, including methicillin-resistant S. aureus, ciprofloxacin-resistant methicillin-resistant S. aureus, and drug-resistant S. pneumoniae. In two Phase II studies, the efficacy of JNJ-Q2 was comparable to linezolid for ABSSSI and moxifloxacin for CABP. Furthermore, JNJ-Q2 was well tolerated, with adverse event rates similar to or less than other fluoroquinolones. With an expanded spectrum of activity and low potential for resistance, JNJ-Q2 shows promise as an effective treatment option for ABSSSI and CABP. Considering its early stage of development, the definitive role of JNJ-Q2 against these infections and its safety profile will be determined in future Phase III studies.

Current therapeutics and prophylactic approaches to treat pneumonia

Bacterial pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Mycoplasma pneumoniae, and Klebsiella pneumoniae represents a frequent cause of mortality worldwide. The increased incidence of pneumococcal diseases in both developed and developing countries is alarmingly high, affecting infants and aged adult populations. The growing rate of antibiotic resistance and biofilm formation on medical device surfaces poses a greater challenge for treating respiratory infections. Over recent years, a better understanding of bacterial growth, metabolism, and virulence has offered several potential targets for developing therapeutics against bacterial pneumonia. This chapter will discuss the current and developing trends in treating bacterial pneumonia.

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.

Renaissance of antibiotics against difficult infections: Focus on oritavancin and new ketolides and quinolones

Lipoglycopeptide, ketolide, and quinolone antibiotics are currently in clinical development, with specific advantages over available molecules within their respective classes. The lipoglycopeptide oritavancin is bactericidal against MRSA, vancomycin-resistant enterococci, and multiresistant Streptococcus pneumoniae, and proved effective and safe for the treatment of acute bacterial skin and skin structure infection (ABSSSI) upon administration of a single 1200 mg dose (two completed phase III trials). The ketolide solithromycin (two phase III studies recruiting for community-acquired pneumonia) shows a profile of activity similar to that of telithromycin, but in vitro data suggest a lower risk of hepatotoxicity, visual disturbance, and aggravation of myasthenia gravis due to reduced affinity for nicotinic receptors. Among quinolones, finafloxacin and delafloxacin share the unique property of an improved activity in acidic environments (found in many infection sites). Finafloxacin (phase II completed; activity profile similar to that of ciprofloxacin) is evaluated for complicated urinary tract and Helicobacter pylori infections. The other quinolones (directed towards Gram-positive pathogens) show improved activity on MRSA and multiresistant S. pneumoniae compared to current molecules. They are in clinical evaluation for ABSSSI (avarofloxacin (phase II completed), nemonoxacin and delafloxacin (ongoing phase III)), respiratory tract infections (zabofloxacin and nemonoxacin (ongoing phase III)), or gonorrhea (delafloxacin).

The changing microbiologic epidemiology of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common infectious disease in the United States and the incidence continues to grow as the aging population increases. Overall, in-hospital patient mortality rates have been reported to be as high as 18%. Management of patients with CAP has been challenged by the evolution of resistant pathogens (particularly Streptococcus pneumoniae and Staphylococcus aureus) that have reduced susceptibility to recommended standard antimicrobial agents. Streptococcus pneumoniae continues to be the most frequently identified pathogen in CAP and recently, S. aureus has been found to be the second most often identified pathogen. Data from the SENTRY Antimicrobial Surveillance Program has shown declining susceptibility of pneumococci to penicillin, amoxicillin/clavulanate, and ceftriaxone from 1998 through 2011. In the Assessing Worldwide Resistance Evaluation (AWARE) surveillance program, > 50% of all S. aureus isolates from patient bloodstream infections, skin and skin structure infections, and pneumonia were methicillin-resistant. Stratifying risk factors to identify patients at risk for community-acquired multidrug-resistant pathogens should be considered when selecting therapy. Differences in microbiology and outcomes have been noted in patients presenting from the community with recent exposure to the health care system (eg, nursing home residents, patients with a recent hospital admission). These patients are at an increased risk of an infection caused by a multidrug-resistant pathogen. Understanding a patient's risk for drug-resistant pathogens will allow the physician to choose an appropriate empiric treatment regimen to optimize clinical outcomes.

Pipeline of Known Chemical Classes of Antibiotics

Many approaches are used to discover new antibiotic compounds, one of the most widespread being the chemical modification of known antibiotics. This type of discovery has been so important in the development of new antibiotics that most antibiotics used today belong to the same chemical classes as antibiotics discovered in the 1950s and 1960s. Even though the discovery of new classes of antibiotics is urgently needed, the chemical modification of antibiotics in known classes is still widely used to discover new antibiotics, resulting in a great number of compounds in the discovery and clinical pipeline that belong to existing classes. In this scenario, the present article presents an overview of the R&D pipeline of new antibiotics in known classes of antibiotics, from discovery to clinical trial, in order to map out the technological trends in this type of antibiotic R&D, aiming to identify the chemical classes attracting most interest, their spectrum of activity, and the new subclasses under development. The result of the study shows that the new antibiotics in the pipeline belong to the following chemical classes: quinolones, aminoglycosides, macrolides, oxazolidinones, tetracyclines, pleuromutilins, beta-lactams, lipoglycopeptides, polymyxins and cyclic lipopeptides.

Advances in antibiotic therapy for community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) is a major public health problem all over the world. The increasing number of antibiotic-resistant bacteria is a matter of concern for physicians when choosing antibiotic treatment in patients with CAP. This review focuses on the current recommendations of antibiotic treatment, recent information concerning antibiotic resistance of pathogens, and the advances in antibiotic therapy in the field of CAP.

RECENT FINDINGS

A significant increase in the frequency of resistance to the antibiotics commonly used against causative pathogens of CAP, such as β-lactams or macrolides, has been reported in recent years. At present, the prevalence of fluoroquinolone resistance in Streptococcus pneumoniae remains low. Community-acquired methicillin-resistant Staphylococcus aureus and influenza A(H1N1)pdm09 have been reported as causes of severe CAP. Several newly-developed antibiotics, including cepholosporins, ketolides and quinolones, present marked activity in vitro against the main causative pathogens of CAP. Many randomized controlled trials have demonstrated equivalent efficacy of the newer antibiotics compared with conventional antimicrobial therapy in mild-to-moderate CAP.

SUMMARY

An increase of resistance to the antibiotics used in CAP has been documented over the years. Several new antibiotics have been developed for treating CAP, with promising results. However, data regarding their efficacy and safety in patients with severe CAP are lacking.