Efficacy and safety of lascufloxacin for nursing- and healthcare-associated pneumonia: A single-arm, open-label clinical trial.

BACKGROUND: Nursing- and healthcare-associated pneumonia (NHCAP) constitutes most of the pneumonia in elderly patients including aspiration pneumonia in Japan. Lascufloxacin (LSFX) possesses broad antibacterial activity against respiratory pathogens, such as Streptococcus spp. And anaerobes inside the oral cavity. However, the efficacy and safety of LSFX in NHCAP treatment remains unknown. We aimed to evaluate the efficacy and safety of LSFX tablets in the treatment of patients with NHCAP. METHODS: In this single-arm, open-label, uncontrolled study, LSFX was administered to patients with NHCAP at 24 facilities. The study participants were orally administered 75 mg LSFX once daily for 7 days. The primary endpoint was the clinical efficacy at the time of test of cure (TOC). The secondary endpoints included clinical efficacy at the time of end of treatment (EOT), early clinical efficacy, microbiological efficacy, and safety analysis. RESULT: During the study period, 75 patients provided written informed consent to participate and were included. Finally, 56 and 71 patients were eligible for clinical efficacy and safety analyses, respectively. The median age of the patients was significantly high at 86 years. All patients were classified as having moderate disease severity using the A-DROP scoring system. LSFX tablets demonstrated high efficacy rates of 78.6 % at TOC and 89.3 % at EOT. The risk factors for resistant bacteria or aspiration pneumonia did not affect clinical efficacy. No severe adverse events associated with the study drugs were observed. CONCLUSION: Oral LSFX is an acceptable treatment option for moderate NHCAP in elderly patients who can take oral medications.

Three cases of hospitalized Legionella pneumonia patients successfully treated with lascufloxacin.

Legionella pneumonia is one of the major causes of severe pneumonia, in which treatment delay might lead to a poor prognosis. Therefore, as far as possible, early diagnosis and treatment of Legionella pneumonia is essential. Regarding the antimicrobials for Legionella pneumonia, fluoroquinolones, such as levofloxacin, or macrolides, such as azithromycin (AZM), are recommended in Japan and other countries. Lascufloxacin (LSFX), the newest fluoroquinolone developed in Japan, has been in use in daily clinical practice since January 2020. However, there are only few reports of Legionella pneumonia cases treated with LSFX. Here, we report three cases of hospitalized Legionella pneumonia patients that were successfully treated using LSFX. All three patients were admitted to the medical ward on admission, although one patient was subsequently transferred to the ICU for mechanical ventilatory management due to worsening of the pneumonia on day 3. All patients improved and were discharged following LSFX treatment (the patient admitted to the ICU was treated using LSFX + AZM combination therapy) without any severe adverse events. LSFX might be considered to be the first antibiotic choice for Legionella pneumonia, similar to levofloxacin. However, further data regarding the treatment of Legionella pneumonia cases using LSFX are needed to evaluate its efficacy and safety.

Temporal effects of lascufloxacin on human gut and salivary microbiota: Analysis using next-generation sequencing method.

INTRODUCTION: Antimicrobial treatment disrupts human microbiota. The effects of lascufloxacin (LSFX), a new fluoroquinolone, on human microbiota remains unknown. Therefore, in this study, we aimed to evaluate the effects of LSFX administration on the gut and salivary microbiota of healthy participants and those with pneumonia. METHODS: LSFX (75 mg, once a day, orally) was administered to healthy adults (healthy group) and adult patients with pneumonia (pneumonia group), and fecal and saliva samples were collected at five time points (Days 0, 3, 7, 14, and 28). Using the collected samples, α- and ß-diversity indices, as well as bacterial composition of the gut microbiota and salivary microbiota were analyzed using next-generation sequencing. RESULTS: In the healthy group, α-diversity indices of the gut and salivary microbiota were reduced and the lowest values on Day 3. For the gut microbiota, the Chao1 index (richness) recovered on Day 28, whereas the Shannon index (evenness) did not. In the salivary microbiota, the Chao1 and Shannon indices did not recover within the 28 day period. The ß-diversity indices changed after LSFX administration and subsequently recovered on Day 28. After LSFX administration, the abundance of the Lachnospiraceae family decreased in the gut microbiota, and the abundance of Granulicatella, Streptococcus, Prevotella, Absconditabacteriales(SR1), and Saccharimonadales decreased in the salivary microbiota. In the pneumonia group, the α-diversity indices were lowest on Day 14 after LSFX administration. CONCLUSIONS: We elucidated that LSFX administration differentially affected the gut and salivary microbiota; however, the richness and beta diversity recovered within 28 days.

Bactericidal effect of lascufloxacin on HEp-2 cell-internalized group A Streptococcus.

INTRODUCTION: Although amoxicillin (AMPC) is recommended as first-line therapy for acute pharyngotonsillitis caused by group A streptococci (GAS), it often fails to eradicate infections. Internalization and subsequent intracellular survival of GAS are considered major mechanisms for penicillin therapeutic failure. It is, therefore, desirable to administer drugs that exert bactericidal effects on extracellular and intracellular GAS. In this study, we aim to investigate the bactericidal effects of lascufloxacin (LSFX) on internalized GAS in HEp-2 cells. MATERIALS AND METHODS: The GAS strain M1 and clinical isolate strain #2 were used in this study. Following treatment of GAS-infected human pharyngeal carcinoma epithelial HEp-2 cells with LSFX or AMPC, internalized GAS cells were recovered. The concentrations of LSFX and AMPC were equivalent to 1 × and 2 × MIC for strain M1. Culture medium was used as a control. Time-lapse and fluorescence images of GAS invading HEp-2 cell were obtained. LIVE/DEAD fluorescence staining was used to confirm the viability of internalized GAS. RESULTS: LSFX significantly reduced the number of cell-internalized M1 and #2 GAS strains compared to the control (p < 0.01) in a dose-dependent manner. However, AMPC did not reduce this in both strains. Both live and dead intracellular GAS were confirmed in HEp-2 cells exposed to LSFX. In contrast, intracellular GAS survived in HEp-2 cells exposed to AMPC and in the control. CONCLUSION: LSFX elicits significant bactericidal effects on cell-internalized GAS, hence it may represent a potent therapeutic option for patients with acute pharyngotonsillitis in whom AMPC treatment has failed.

In vitro activities and spectrum of lascufloxacin（KRP-AM1977）against anaerobes.

The in vitro antibacterial spectra and activities of five antimicrobial agents, including lascufloxacin (LSFX) and two quinolones, were investigated against 69 species of anaerobes in 31 genera and 188 strains in 9 genera, respectively. In this study, minimum inhibitory concentrations (MICs) of lascufloxacin against the reference strains associated with respiratory and head and neck infections. LSFX inhibited the growth of 33 gram-positive and gram-negative reference strains at ≤0.015-2 µg/mL, except for Leptotrichia buccalis. MICs ranges of LSFX against the clinical isolates of 44 Porphyromonas spp., 45 Prevotella spp., 25 Fusobacterium spp., 7 Leptotrichia spp., 25 Parvimonas micra, 25 other gram-positive anaerobic cocci, and 17 Veillonella spp., were ≤0.015-4, 0.125-4, 0.06-0.5, 2, 0.25-16, ≤0.015-2, ≤0.015-16 µg/mL, respectively. LSFX demonstrated potent antibacterial efficacy against a wide range of species isolated from specimens involved in respiratory as well as head and neck infections.

In vivo pharmacodynamics of lascufloxacin and levofloxacin against Streptococcus pneumoniae and Prevotella intermedia in a pneumonia mixed-infection mouse model.

This study aimed to evaluate the antimicrobial activity of a new quinolone, lascufloxacin, for the treatment of complicated pneumonia caused by Streptococcus pneumoniae and Prevotella intermedia using a neutropenic mice pneumonia mixed-infection model. In this study, one S. pneumoniae and four P. intermedia isolates were utilized. Antimicrobial efficacy was calculated for each isolate as the reduction of the bacterial count comparatively to the non-treated mice (log10 colony forming units (cfu)/mL) obtained in the lungs of the treated mice after 24 h. Consequently, the bacterial densities of S. pneumoniae (KY-9) and P. intermedia (335) in the lungs of control animals were 8.20 ± 0.19 log10 cfu/mL and 5.26 ± 1.50 log10 cfu/mL, respectively. At human-simulated doses, lascufloxacin and levofloxacin showed high antimicrobial activities against not only S. pneumoniae (lascufloxacin: 1.88 ± 0.43 log10 cfu/mL, p < 0.001; levofloxacin 4.30 ± 0.75 log10 cfu/mL, p < 0.001), but also P. intermedia (lascufloxacin: 1.54 ± 0.57 log10 cfu/mL, p < 0.001; levofloxacin: 2.79 ± 0.55 log10 cfu/mL, p = 0.0102). Additionally, levofloxacin demonstrated attenuated antimicrobial efficacies against S. pneumoniae in the mixed-infection model compared with that in the single infection model. In contrast, lascufloxacin showed enhanced antimicrobial activities against S. pneumoniae and P. intermedia in the mixed-infection model. In conclusion, lascufloxacin resulted in enhanced efficacies against S. pneumoniae and P. intermedia, in both the single and mixed-infection models used. These data support the clinical utility of lascufloxacin for use against S. pneumoniae and P. intermedia in the treatment of pneumonia.

Pharmacokinetic study of lascufloxacin in non-elderly healthy men and elderly men.

We conducted this phase I clinical study to examine the pharmacokinetic profiles and safety of lascufloxacin (LSFX), a novel quinolone antibacterial agent, in non-elderly Japanese healthy men and the effects of aging on LSFX pharmacokinetics in elderly Japanese healthy men. 1. After single-dose oral administration of LSFX 100-800 mg (capsules) to six healthy adults in fasting state, the Cmax and AUClast roughly increased in proportion to the doses. 2. After multiple-dose oral administration of LSFX 75 mg (tablets) once daily for 7 days to six healthy adults, plasma LSFX reached the steady state by Day 7. The cumulative factor of LSFX on Day 7 to Day 1 was 1.65 for the Cmax and 1.96 for the AUCtau. 3. Regarding pharmacokinetic parameters of plasma LSFX after single-dose administration of LSFX 75 mg tablets (final product) to 24 healthy adults in fed state, the Cmax was somewhat higher, 1.28 times more than that in fasting state, whereas no changes were found in the AUClast. We therefore proposed that food effects of LSFX on absorption were negligible. 4. No clinically significant safety problems of LSFX were found in a series of studies involving healthy adults conducted this time. 5. After single-dose oral administration of LSFX 200 mg (capsules) to six elderly people in fasting state, its pharmacokinetic parameters were similar to those in non-elderly people, with no significant safety concerns. Therefore, adjustment of dosage and administration was considered to be unnecessary for LSFX administration to elderly individuals.

In Vitro Mechanistic Study of the Distribution of Lascufloxacin into Epithelial Lining Fluid.

The present study aimed to clarify the mechanism underlying the high distribution of lascufloxacin in epithelial lining fluid (ELF). Involvement of transporters was examined by transcellular transport across Calu-3 and transporter-overexpressing cells; the binding of lascufloxacin to ELF components was examined by an organic solvent-water partitioning system that employed pulmonary surfactant and phospholipids. Transcellular transport across the transporter-overexpressing cells indicated lascufloxacin to be a substrate of both P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP); therefore, its transport across Calu-3 cells was inhibited by P-gp and BCRP inhibitors. However, permeability and efflux ratios of lascufloxacin were similar to those of the other quinolones with relatively low ELF distribution, indicating the existence of another mechanism for lascufloxacin distribution in ELF. Amongst pulmonary surfactants, which are a primary component of ELF, lascufloxacin preferentially bound to phosphatidylserine (PhS) from several phospholipids, and the binding was significantly greater than that for other quinolones. This binding was saturable with two apparent classes of binding sites and inhibited by some weakly basic drugs, indicating the presence of an ionic bond. In conclusion, the results of this study suggest that the binding of lascufloxacin to PhS in the pulmonary surfactant is the major mechanism of the high distribution of lascufloxacin in the ELF.

In Vitro Activity of Lascufloxacin against Streptococcus pneumoniae with Mutations in the Quinolone Resistance-Determining Regions.

Lascufloxacin showed potent activity against Streptococcus pneumoniae with a GyrA or ParC mutation (first-step mutant). The frequency of selecting resistant strains tended to be lower for lascufloxacin than for levofloxacin and garenoxacin after drug exposure in first-step mutants but was similar in the comparison between lascufloxacin and moxifloxacin. The increase in MIC was smaller for lascufloxacin than for levofloxacin, garenoxacin, and moxifloxacin when clinical strains with only ParC mutations were exposed to the corresponding drug.

Intrapulmonary Pharmacokinetics of Lascufloxacin in Healthy Adult Volunteers.

This study was performed to investigate the intrapulmonary penetration of lascufloxacin in humans. Thirty healthy adult male Japanese subjects, allocated into five groups, received lascufloxacin in a single oral dose of 75 mg. Bronchoalveolar lavage and blood sampling were performed simultaneously in each subject at 1, 2, 4, 6, or 24 h after administration, and lascufloxacin concentrations in plasma, epithelial lining fluid, and alveolar macrophages were determined. Lascufloxacin was rapidly distributed to the epithelial lining fluid with a time to maximum drug concentration (Tmax) of 1 h, which was identical to that in plasma. The maximum concentration of drug (Cmax) values in plasma, epithelial lining fluid, and alveolar macrophages were 0.576, 12.3, and 21.8 µg/ml, respectively. The corresponding area under the concentration-time curve from 0 to 24 h (AUC0-24) values were 7.67, 123, and 325 µg · h/ml. The mean drug concentrations in the epithelial lining fluid and alveolar macrophages were much higher than those in plasma at all time points examined, and the average site-to-free plasma concentration ratios fell within the ranges of 57.5 to 86.4 and 71.0 to 217, respectively. Drug levels in epithelial lining fluid and alveolar macrophages exceeded the MIC90 values for common respiratory pathogens. (This study was registered at JAPIC under registration number JapicCTI-142547.).

In vitro activity of lascufloxacin, a novel fluoroquinolone antibacterial agent, against various clinical isolates of anaerobes and Streptococcus anginosus group.

The in vitro activities of lascufloxacin were evaluated by comparison with seven reference compounds using 412 clinical isolates of anaerobes and Streptococcus anginosus group. Lascufloxacin showed potent and broad antibacterial activities greater than those of existing quinolones against the clinical isolates used in this study.

Molecular and phenotypic characterization of Streptococcus pneumoniae isolates in a Japanese tertiary care hospital.

This study aimed to investigate the bacterial characteristics of pneumococcal isolates obtained from a tertiary care hospital in Japan. We analyzed the antimicrobial susceptibility, possession of macrolide resistance genes, pneumococcal serogroup/serotype, and sequence type (ST) of pneumococcal isolates from patients aged 15 years or older between 2011 and 2020 at Nagasaki University Hospital. Of the 73 isolates analyzed, 86.3% showed resistance to macrolides, and 28.8%, 46.6%, and 11.0% harbored mefA, ermB, and both, respectively. Of the isolates possessing ermB, 97.6% showed high levels of macrolide resistance [minimal inhibitory concentration (MIC) range, > 16 µg/mL]. Solithromycin (MIC range, 0.03-0.25 µg/mL), regardless of the presence of macrolide resistance genes, and lascufloxacin (MIC range, 0.06-0.5 µg/mL) showed potent in vitro activity against pneumococci. Serotype 19A was the most prevalent (six isolates), followed by serotypes 10A, 15A, and 15B/C (five isolates each). Four serotypes (11A, 19A, 22F, and 23B) and five STs (36, 99, 433, 558, and 3111) were significantly correlated with the presence of macrolide resistance genes. All four isolates with serotype 11A/ST99 and three isolates with serotype 19A/ST3111 harbored both mefA and ermB. No macrolide resistance genes were detected in either of the two isolates with serotype 22F/ST433, while all ten isolates with serogroup 15 (serotypes 15A and 15B/C, five isolates each) possessed ermB alone. Our study revealed the bacterial characteristics of the pneumococcal isolates obtained from our hospital. In vitro activity of solithromycin and lascufloxacin against these isolates was confirmed.

Effectiveness of Drip Infusion of Lascufloxacin, a Novel Fluoroquinolone Antibiotic, for Patients with Pneumonia Including Chronic Lung Disease Exacerbations and Lung Abscesses.

Background: Lascufloxacin (LSFX), a novel fluoroquinolone antibacterial agent, has recently been used as a drip infusion for treating pneumonia, apparently with good effectiveness against various bacteria, including anaerobes, and good intrapulmonary penetration. Methods: The clinical effectiveness of LSFX was retrospectively investigated for the 55 patients admitted to our hospital with pneumonia, including chronic lung disease exacerbations and lung abscesses, from May 2021 to July 2023. Results: The median age of the 55 patients was 76.1 (34.1-93.1) years, 45 (81.8%) were male, and 48 (87.5%) patients had underlying disease. Community-acquired pneumonia was seen in 47 (85.5%) patients, including 9 (16.4%) with lung abscess, and the other 8 (14.5%) had nursing and healthcare-associated pneumonia/hospital-acquired pneumonia. Moderate pneumonia was present in 33 (61.8%) of 55 patients, and LSFX was used as a second-line treatment for 28 (50.9%) patients in whom first-line antibiotics were ineffective. The median duration of intravenous LSFX administration was 9 (2.0-49) days. Streptococcus pneumoniae and methicillin-susceptible Staphylococcus aureus were isolated from 3 (7.1%) and 2 (4.8%) patients, respectively. Of the 55 patients, 45 (81.5%) improved clinically with intravenous LSFX administration; 20 (95.2%) of 21 community-acquired pneumonia cases, including 9 (100.0%) of 9 bacterial pneumonia cases, were improved by LSFX as first-line treatment, and 8 (88.9%) of 9 lung abscess patients also showed clinical improvement with LSFX as a second-line treatment. There were no severe adverse effects in any of the 55 patients. Conclusion: Based on these data, intravenous administration of LSFX seems effective for bacterial pneumonia, including chronic lung disease exacerbations and lung abscesses, and it appears to have broad antimicrobial activity and good tissue penetration into the lung.

Clostridium paraputrificum Bacteremia in a Patient with Rectal Cancer after Receiving Antibiotic Therapy for Acute Pharyngolaryngitis.

Clostridium paraputrificum bacteremia is very rare, and its clinical importance is poorly understood. An 86-year-old man was receiving lascufloxacin therapy for acute pharyngolaryngitis before presenting to our emergency department with a recurrent fever. Two sets of blood cultures on admission revealed C. paraputrificum. A stool culture showed a reduced presence of intestinal commensal bacteria. After admission, the patient's fever resolved without antibiotics. Colonoscopy revealed a rectal tumor. Rectal tumor and microbial substitutions caused by antibiotics may have led to bacteremia. When treating C. paraputrificum bacteremia, physicians should be mindful of coexisting gastrointestinal disorders and a history of antibiotic administration.

Overview of Side-Effects of Antibacterial Fluoroquinolones: New Drugs versus Old Drugs, a Step Forward in the Safety Profile?

Antibacterial fluoroquinolones (FQs) are frequently used in treating infections. However, the value of FQs is debatable due to their association with severe adverse effects (AEs). The Food and Drug Administration (FDA) issued safety warnings concerning their side-effects in 2008, followed by the European Medicine Agency (EMA) and regulatory authorities from other countries. Severe AEs associated with some FQs have been reported, leading to their withdrawal from the market. New systemic FQs have been recently approved. The FDA and EMA approved delafloxacin. Additionally, lascufloxacin, levonadifloxacin, nemonoxacin, sitafloxacin, and zabofloxacin were approved in their origin countries. The relevant AEs of FQs and their mechanisms of occurrence have been approached. New systemic FQs present potent antibacterial activity against many resistant bacteria (including resistance to FQs). Generally, in clinical studies, the new FQs were well-tolerated with mild or moderate AEs. All the new FQs approved in the origin countries require more clinical studies to meet FDA or EMA requirements. Post-marketing surveillance will confirm or infirm the known safety profile of these new antibacterial drugs. The main AEs of the FQs class were addressed, highlighting the existing data for the recently approved ones. In addition, the general management of AEs when they occur and the rational use and caution of modern FQs were outlined.

Lascufloxacin hydrochloride to treat bacterial infection.

Lascufloxacin hydrochloride (AM-1977) is a novel 8-methoxy fluoroquinolone antibacterial agent with a unique pharmacophore at the 1st and 7th positions of the quinoline nucleus developed by Kyorin Pharmaceutical Co., Ltd. (Tokyo, Japan). It has been approved by the Japanese Ministry of Health, Labour and Welfare (MHLW) for treatment of respiratory tract and ear, nose and throat infections including community-acquired pneumonia and otorhinolaryngological infections, and shows great promise against fluoroquinolone-resistant strains of major pathogens which infect the respiratory tract. It is suitable for treating infections caused by Staphylococcus, Streptococcus, Pneumococcus, Moraxella (Branhamella) catarrhalis, Klebsiella, Enterobacter, Haemophilus influenzae, Legionella pneumophila, Prevotella and Mycoplasma pneumoniae that are sensitive to this drug.