Efficacy of Delafloxacin versus Moxifloxacin against Bacterial Respiratory Pathogens in Adults with Community-Acquired Bacterial Pneumonia (CABP): Microbiology Results from the Delafloxacin Phase 3 CABP Trial.

Delafloxacin is a novel fluoroquinolone with activity against Gram-positive, Gram-negative, and atypical pathogens, including fluoroquinolone-nonsusceptible methicillin-resistant Staphylococcus aureus (MRSA). The microbiological results of a phase 3 clinical trial in adults with community-acquired pneumonia (CAP) comparing delafloxacin (300 mg intravenously [i.v.] with the option to switch to 450 mg orally every 12 h) to moxifloxacin (400 mg i.v. with the option to switch to 400 mg orally once a day [QD]) were determined. Patients from 4 continents, predominately Europe but also South America and Asia, were enrolled. The microbiological intent-to-treat (MITT) population included 520 patients, and 60.5% of these patients had a bacterial pathogen identified. Multiple diagnostic methods were employed, including culture, serology, PCR, and urinary antigen tests. Based on baseline MIC90 values, delafloxacin exhibited at least 16-fold greater activity than moxifloxacin for Gram-positive and fastidious Gram-negative pathogens. Delafloxacin retained activity against resistant phenotypes found in Streptococcus pneumoniae (penicillin-, macrolide-, and multiple-drug resistant), Haemophilus species (ß-lactamase producing and macrolide nonsusceptible), and S. aureus (MRSA and fluoroquinolone-nonsusceptible methicillin-susceptible S. aureus [MSSA]). The microbiological success rates were 92.7% for S. pneumoniae (87.5% for penicillin-resistant S. pneumoniae [PRSP]), 92.6% for S. aureus (100% for MRSA), 100% for Escherichia coli, 82.4% for Klebsiella pneumoniae, 100% for Klebsiella oxytoca, 100% for Moraxella catarrhalis, 91.7% for Haemophilus influenzae, 88.6% for Haemophilus parainfluenzae, 96.7% for Mycoplasma pneumoniae, 93.1% for Legionella pneumophila, and 100% for Chlamydia pneumoniae There was little correlation between MICs and outcomes, with a high proportion of favorable outcomes observed across all delafloxacin baseline MIC values. Delafloxacin may be considered a treatment option as monotherapy for CAP in adults, where broad-spectrum coverage including MRSA activity is desirable.

A Comparison of the Efficacy and Safety of Intravenous Followed by Oral Delafloxacin With Vancomycin Plus Aztreonam for the Treatment of Acute Bacterial Skin and Skin Structure Infections: A Phase 3, Multinational, Double-Blind, Randomized Study.

Background: Delafloxacin is an intravenous (IV)/oral anionic fluoroquinolone with activity against gram-positive (including methicillin-resistant Staphylococcus aureus [MRSA]), gram-negative, atypical, and anaerobic organisms. It is approved in the United States for acute bacterial skin and skin structure infections (ABSSSIs) caused by designated susceptible gram-positive and gram-negative organisms, and is in development for the treatment of community-acquired bacterial pneumonia. Methods: A multicenter, randomized, double-blind trial of 850 adults with ABSSSI compared delafloxacin 300 mg IV every 12 hours for 3 days with a switch to 450 mg oral delafloxacin, to vancomycin 15 mg/kg IV with aztreonam for 5-14 days. The primary endpoint was objective response at 48-72 hours. Investigator-assessed response based on resolution of signs and symptoms at follow-up (day 14 ± 1), and late follow-up (day 21-28) were secondary endpoints. Results: In the intent-to-treat analysis set, the objective response was 83.7% in the delafloxacin arm and 80.6% in the comparator arm. Investigator-assessed success was similar at follow-up (87.2% vs 84.4%) and late follow-up (83.5% vs 82.2%). Delafloxacin was comparable to vancomycin + aztreonam in eradication of MRSA at 96.0% vs 97.0% at follow-up. Frequency of treatment-emergent adverse events between the groups was similar. Treatment-emergent adverse events leading to study drug discontinuation was higher in the vancomycin + aztreonam group (1.2% vs 2.4%). Conclusions: In ABSSSI patients, IV/oral delafloxacin monotherapy was noninferior to IV vancomycin + aztreonam combination therapy for both the objective response and the investigator-assessed response at follow-up and late follow-up. Delafloxacin was well tolerated as monotherapy in treatment of ABSSSIs. Clinical Trials Registration: NCT01984684.

Efficacy of delafloxacin versus moxifloxacin against atypical bacterial respiratory pathogens in adults with community-acquired bacterial pneumonia (CABP): Data from the Delafloxacin Phase 3 CABP Trial.

OBJECTIVES: To report atypical pathogens from clinical trial data comparing delafloxacin to moxifloxacin in the treatment of adults with community-acquired bacterial pneumonia (CABP). METHODS: Multiple diagnostic methods were employed to diagnose atypical infections including culture, serology, and urinary antigen. RESULTS: The microbiological intent-to-treat (MITT) population included 520 patients; 30% had an atypical bacterial pathogen identified (156/520). Overall, 13.1% (68/520) had a monomicrobial atypical infection and 2.3% (12/520) had polymicrobial all-atypical infections. Among patients with polymicrobial infections, Streptococcus pneumoniae was the most frequently occurring co-infecting organism and Chlamydia pneumoniae was the most frequently occurring co-infecting atypical organism. For Mycoplasma pneumoniae and Legionella pneumophila, serology yielded the highest number of diagnoses. Delafloxacin and moxifloxacin had similar in vitro activity against M. pneumoniae and delafloxacin had greater activity against L. pneumophila. Two macrolide-resistant M. pneumoniae isolates were recovered. No fluoroquinolone-resistant M. pneumoniae were isolated. The rates of microbiological success (documented or presumed eradication) at test-of-cure were similar between the delafloxacin and moxifloxacin groups. There was no evidence of a correlation between minimum inhibitory concentration (MIC) and outcome; a high proportion of favorable outcomes was observed across all delafloxacin baseline MICs. CONCLUSIONS: Delafloxacin may be considered a treatment option as monotherapy for CABP in adults, where broad-spectrum coverage including atypical activity is desirable.

A Phase 3 Study to Compare Delafloxacin With Moxifloxacin for the Treatment of Adults With Community-Acquired Bacterial Pneumonia (DEFINE-CABP).

BACKGROUND: The clinical and economic burden of community-acquired bacterial pneumonia (CABP) is significant and is anticipated to increase as the population ages and pathogens become more resistant. Delafloxacin is a fluoroquinolone antibiotic approved in the United States for the treatment of adults with acute bacterial skin and skin structure infections. Delafloxacin's shape and charge profile uniquely impact its spectrum of activity and side effect profile. This phase 3 study compared the efficacy and safety of delafloxacin with moxifloxacin for the treatment of CABP. METHODS: A randomized, double-blind, comparator-controlled, multicenter, global phase 3 study compared the efficacy and safety of delafloxacin 300 mg twice daily or moxifloxacin 400 mg once daily in adults with CABP. The primary end point was early clinical response (ECR), defined as improvement at 96 (±24) hours after the first dose of study drug. Clinical response at test of cure (TOC) and microbiologic response were also assessed. RESULTS: In the intent-to-treat analysis population (ITT), ECR rates were 88.9% in the delafloxacin group and 89.0% in the moxifloxacin group. Noninferiority of delafloxacin compared with moxifloxacin was demonstrated. At TOC in the ITT population, the success rates were similar between groups. Treatment-emergent adverse events that were considered at least possibly related to the study drug occurred in 65 subjects (15.2%) in the delafloxacin group and 54 (12.6%) in the moxifloxacin group. CONCLUSIONS: Intravenous/oral delafloxacin monotherapy is effective and well tolerated in the treatment of adults with CABP, providing coverage for Gram-positive, Gram-negative, and atypical pathogens. CLINICALTRIALSGOV IDENTIFIER: NCT03534622.

Delafloxacin Pharmacokinetics in Subjects With Varying Degrees of Renal Function.

Delafloxacin, a fluoroquinolone, has activity against gram-positive organisms including methicillin-resistant Staphylococcus aureus and fluoroquinolone-susceptible and -resistant gram-negative organisms. This study was conducted to determine delafloxacin pharmacokinetics after a single intravenous infusion or oral dose administration in subjects with varying degrees of renal function. The study was an open-label, parallel-group crossover study in subjects with normal renal function or with mild, moderate, or severe renal impairment. Subjects received 300 mg delafloxacin intravenously, placebo intravenously, and 400 mg delafloxacin orally in 3 periods separated by ≥14-day washouts. Blood and urine pharmacokinetic parameters were calculated using noncompartmental methods. Delafloxacin total clearance decreased with decreasing renal function, with a corresponding increase in AUC0-∞ . After intravenous administration, mean total clearance was 13.7 and 7.07 L/h, and mean AUC0-∞ was 22.6 and 45.0 µg·h/mL in normal and severe renal subjects, respectively. Mean renal clearance as determined by urinary excretion was 6.03 and 0.44 L/h in normal and severe renal impairment subjects, respectively. Total clearance exhibited linear relationships to eGFR and CLCR . Similar observations were found after oral administration of delafloxacin. Single doses of delafloxacin 300 mg intravenously and 400 mg orally were well tolerated in all groups. In conclusion, renal insufficiency has an effect on delafloxacin clearance; a dosing adjustment for intravenous dosing is warranted for patients with severe renal impairment (eGFR < 30 mL/min).

Clinical Pharmacokinetics of Sulfobutylether-ß-Cyclodextrin in Patients With Varying Degrees of Renal Impairment.

Delafloxacin, a fluoroquinolone, has activity against Gram-positive organisms including methicillin-resistant S aureus and fluoroquinolone-susceptible and -resistant Gram-negative organisms. The intravenous formulation of delafloxacin contains the excipient sulfobutylether-ß-cyclodextrin (SBECD), which is eliminated by renal filtration. This study examined the pharmacokinetics and safety of SBECD after single intravenous (IV) infusions in subjects with renal impairment. The study was an open-label, parallel-group, crossover study in subjects with normal renal function or mild, moderate, or severe renal impairment, and those with end-stage renal disease undergoing hemodialysis. Subjects received 300 mg delafloxacin IV or placebo IV, containing 2400 mg SBECD, in 2 periods separated by ≥14-day washouts. SBECD total clearance decreased with decreasing renal function, with a corresponding increase in area under the concentration-time curve (AUC0-∞ ). After IV delafloxacin 300 mg administration, SBECD mean total clearance was 6.28 and 1.24 L/h, mean AUC0-∞ was 387 and 2130 h·µg/mL, and mean renal clearance was 5.36 and 1.14 L/h in normal and severe renal subjects, respectively. Similar values were obtained after IV placebo administration. In subjects with end-stage renal disease, delafloxacin 300 mg IV produced mean SBECD AUC0-48 values of 2715 and 7861 h·µg/mL when dosed before and after hemodialysis, respectively. Total SBECD clearance exhibited linear relationships to estimated glomerular filtration rate and creatinine clearance. Single doses of IV delafloxacin 300 mg and IV placebo were well tolerated in all groups. In conclusion, decreasing renal function causes reduced SBECD clearance and increased exposures, but SBECD continues to exhibit a good safety and tolerability profile in IV formulations.

Pharmacokinetics of Intravenous Delafloxacin in Patients With End-Stage Renal Disease.

This was an open-label, parallel-group, crossover study that examined the pharmacokinetics and safety of delafloxacin, an anionic fluoroquinolone, after a single intravenous infusion in subjects with end-stage renal disease (ESRD; creatinine clearance <15 mL/min) undergoing hemodialysis compared with healthy subjects. Subjects received 300 mg delafloxacin containing sulfobutylether-ß-cyclodextrin in 2 periods separated by ≥14-day washouts. Blood and urine samples were collected, and pharmacokinetic parameters were calculated using noncompartmental methods. The mean total exposure (area under the curve) of delafloxacin was about 2.1 and 2.6 higher for subjects with ESRD compared to healthy subjects when dosed 1 hour before or 1 hour after hemodialysis, respectively. Compared to subjects with normal renal function, the maximum exposure to delafloxacin was 13% and 33% higher for ESRD subjects given delafloxacin 1 hour before and 1 hour after hemodialysis, respectively. The mean clearance was 13.7 L/h for healthy subjects and was lower for subjects with ESRD when given before (7.39 L/h) or after (5.69 L/h) hemodialysis. The clearance of delafloxacin in dialysate was 4.74 L/h with about 19.2% of the delafloxacin dose recovered after a 4-hour dialysis session. Delafloxacin was well tolerated in both healthy and ESRD subjects, with diarrhea being the most reported treatment-emergent adverse event.

The Pharmacokinetics of the CYP3A Substrate Midazolam After Steady-state Dosing of Delafloxacin.

PURPOSE: Delafloxacin is a novel anionic fluoroquinolone in Phase III development for the treatment of serious skin infections. The objective of this study was to evaluate the effects of delafloxacin on the pharmacokinetics of midazolam, a cytochrome P450 (CYP) 3A substrate. METHODS: CYP3A activity using midazolam as a probe was assessed before and after multiple doses of delafloxacin to reach steady state. In this nonrandomized, open-label, single-sequence, Phase I study, 22 healthy male and female subjects were administered a single 5-mg oral dose of midazolam on days 1 and 8, with oral delafloxacin 450 mg every 12 hours administered from days 3 to 8. Full pharmacokinetic profiles were obtained on days 1 and 8 (midazolam and 1-hydroxymidazolam) and days 3 and 7 (delafloxacin). FINDINGS: The geometric mean ratios (90% CIs) for AUC0-∞ and Cmax of midazolam coadministered with delafloxacin versus midazolam alone were 89.4 (83.2-96.0) and 93.6 (83.7-104.6). Similarly, the geometric ratio for the AUC0-∞ of 1-hydroxymidazolam, the primary metabolite of midazolam, was 105.7 (97.7-114.3); the ratio of Cmax was not equivalent at 116.1 (101.7-132.4), which was outside the CI of 80% to 125%. Multiple doses of oral delafloxacin for 6 days were generally well tolerated. IMPLICATIONS: Steady-state dosing of delafloxacin produced no significant changes in midazolam pharmacokinetics, except for a small but not clinically relevant change in the Cmax of 1-hydroxymidazolam. ClinicalTrials.gov identifier: NCT02505997.

Clinical Pharmacology of Delafloxacin in Patients With Hepatic Impairment.

Delafloxacin is a novel anionic fluoroquinolone with robust activity against Gram-positive, Gram-negative, atypical, and anaerobic bacteria, including methicillin-resistant S aureus. Delafloxacin is currently being studied for the treatment of acute bacterial skin and skin structure infections and community-acquired pneumonia. This was a phase 1, open-label pharmacokinetic and safety study of a single intravenous dose of 300 mg delafloxacin in subjects with mild, moderate, and severe hepatic impairment (Child-Pugh class A, B, and C, respectively) compared with matched healthy controls. The effects of hepatic impairment were assessed by ANOVA of log-transformed values for AUC0-∞ , Cmax , and systemic clearance, with hepatic group as a fixed effect. Mean AUC0-∞ and Cmax in each impairment group were not significantly different from those of the pooled healthy subjects (P > 0.05). The 90% confidence interval (CI) of the percentage ratios of least-squares means of AUC0-∞ did not indicate significant differences between the impairment groups and pooled healthy controls: Child-Pugh class A (mild) 114.4 (CI: 95.6, 137.0), Child-Pugh class B (moderate) 114.8 (CI: 95.9, 137.4), and Child-Pugh class C (severe) 115.1 (CI: 96.1, 137.8). A single IV infusion of delafloxacin was generally well tolerated in all treatment groups. The exposure and clearance of delafloxacin in subjects with mild, moderate, or severe hepatic impairment did not significantly differ from those of pooled, matched healthy subjects. Based on these pharmacokinetic data, dose adjustment of delafloxacin in the presence of hepatic impairment is not needed.