A phase I, randomized, double-blind, placebo-controlled, ascending single- and multiple-dose study of the pharmacokinetics, safety, and tolerability of oral ceftibuten in healthy adult subjects.

This was a phase I, randomized, double-blind, placebo-controlled, ascending single- and multiple-dose study of oral ceftibuten to describe the pharmacokinetics (PK) of cis-ceftibuten (administered form) and trans-ceftibuten (metabolite), and to describe safety and tolerability at higher than licensed doses. Subjects received single 400, 600, or 800 mg doses of ceftibuten on Days 1 and 4, followed by 7 days of twice-daily dosing from Days 4 to 10. Non-compartmental methods were used to describe parent drug and metabolite PK in plasma and urine. Dose proportionality was examined using C max, AUC0-12, and AUC0-INF. Accumulation was calculated as the ratio of AUC0-12 on Days 4 and 10. Adverse events (AEs) were monitored throughout the study. Following single ascending doses, mean cis- and trans-ceftibuten C max were 17.6, 24.1, and 28.1 mg/L, and 1.1, 1.5, and 2.2 mg/L, respectively; cis-ceftibuten urinary recovery accounted for 64.3%-86.9% of the administered dose over 48 h. Following multiple ascending doses, mean cis- and trans-ceftibuten C max were 21.7, 28.1, and 38.8 mg/L, and 1.4, 1.9, and 2.8 mg/L, respectively; cis-ceftibuten urinary recovery accounted for 72.2%-96.4% of the administered dose at steady state. The exposure of cis- and trans-ceftibuten increased proportionally with increasing doses. Cis- and trans-ceftibuten accumulation factor was 1.14-1.19 and 1.28-1.32. The most common gastrointestinal treatment emergent AEs were mild and resolved without intervention. Ceftibuten was well tolerated. Dose proportionality and accumulation of cis- and trans-ceftibuten were observed. These results support the ongoing development of ceftibuten at doses up to 800 mg twice-daily. (The study was registered at ClinicalTrials.gov under the identifier NCT03939429.).

In vitro potency of xeruborbactam in combination with multiple ß-lactam antibiotics in comparison with other ß-lactam/ß-lactamase inhibitor (BLI) combinations against carbapenem-resistant and extended-spectrum ß-lactamase-producing Enterobacterales.

Recently, several ß-lactam (BL)/ß-lactamase inhibitor (BLI) combinations have entered clinical testing or have been marketed for use, but limited direct comparative studies of their in vitro activity exist. Xeruborbactam (XER, also known as QPX7728), which is undergoing clinical development, is a cyclic boronate BLI with potent inhibitory activity against serine (serine ß-lactamase) and metallo-ß-lactamases (MBLs). The objectives of this study were (i) to compare the potency and spectrum of ß-lactamase inhibition by various BLIs in biochemical assays using purified ß-lactamases and in microbiological assays using the panel of laboratory strains expressing diverse serine and metallo-ß-lactamases and (ii) to compare the in vitro potency of XER in combination with multiple ß-lactam antibiotics to that of other BL/BLI combinations in head-to-head testing against recent isolates of carbapenem-resistant Enterobacterales (CRE). Minimal inhibitory concentrations (MICs) of XER combinations were tested with XER at fixed 4 or 8 µg/mL, and MIC testing was conducted in a blinded fashion using Clinical and Laboratory Standards Institute reference methods. Xeruborbactam and taniborbactam (TAN) were the only BLIs that inhibited clinically important MBLs. The spectrum of activity of xeruborbactam included several MBLs identified in Enterobacterales, e.g., and various IMP enzymes and NDM-9 that were not inhibited by taniborbactam. Xeruborbactam potency against the majority of purified ß-lactamases was the highest in comparison with other BLIs. Meropenem-xeruborbactam (MEM-XER, fixed 8 µg/mL) was the most potent combination against MBL-negative CRE with MIC90 values of 0.125 µg/mL. MEM-XER and cefepime-taniborbactam (FEP-TAN) were the only BL/BLIs with activity against MBL-producing CREs; with MEM-XER (MIC90 of 1 µg/mL) being at least 16-fold more potent than FEP-TAN (MIC90 of 16 µg/mL). MEM-XER MIC values were ≤8 µg/mL for >90% of CRE, including both MBL-negative and MBL-positive isolates, with FEP-TAN MIC of >8 µg/mL. Xeruborbactam also significantly enhanced potency of other ß-lactam antibiotics, including cefepime, ceftolozane, ceftriaxone, aztreonam, piperacillin, and ertapenem, against clinical isolates of Enterobacterales that carried various class A, class C, and class D extended-spectrum ß-lactamases and carbapenem-resistant Enterobacterales, including metallo-ß-lactamase-producing isolates. These results strongly support further clinical development of xeruborbactam combinations.

A Phase 1 Study of the Safety, Tolerability, and Pharmacokinetics of Biapenem in Healthy Adult Subjects.

The pharmacokinetics and safety of biapenem were studied in 36 healthy adult subjects in a randomized, placebo-controlled, double blind, sequential single and multiple-ascending dose study using doses from 250 to 1250 mg administered three times a day using 3-hour infusions. Maximum concentrations for biapenem were achieved at the end of the 3-hour infusion. Biapenem exposure (AUC) increased in a slightly greater than dose-proportional manner following single and multiple doses with no evidence of accumulation with multiple doses. Plasma AUCs increased from 18 mg*h/L at 250 mg to 150 mg*h/L at 1250 mg. Urinary recovery ranged from 14.2% at 250 mg to 42.3% at 1250 mg. Biapenem was well tolerated up to 1000 mg administered every 8 hours by 3-hour infusion for 7 days; however, a higher incidence of nausea, vomiting, and rash was reported at 1250 mg. There were no serious adverse events (SAEs) reported following either single or multiple doses of biapenem and all AEs were mild or moderate in severity.

QPX7728, An Ultra-Broad-Spectrum B-Lactamase Inhibitor for Intravenous and Oral Therapy: Overview of Biochemical and Microbiological Characteristics.

QPX7728 is a novel ß-lactamase inhibitor (BLI) that belongs to a class of cyclic boronates. The first member of this class, vaborbactam, is a BLI in the recently approved Vabomere (meropenem-vaborbactam). In this paper we provide the overview of the biochemical, structural and microbiological studies that were recently conducted with QPX7728. We show that QPX7728 is an ultra-broad-spectrum ß-lactamase inhibitor with the broadest spectrum of inhibition reported to date in a single BLI molecule; in addition to potent inhibition of clinically important serine ß-lactamases, including Class A and D carbapenemases from Enterobacterales and notably, diverse Class D carbapenemases from Acinetobacter, it also inhibits many metallo ß-lactamases. Importantly, it is minimally affected by general intrinsic resistance mechanisms such as efflux and porin mutations that impede entry of drugs into gram-negative bacteria. QPX7728 combinations with several intravenous (IV) ß-lactam antibiotics shows broad coverage of Enterobacterales, Acinetobacter baumannii and Pseudomonas aeruginosa, including strains that are resistant to other IV ß-lactam-BLI combinations, e.g., ceftazidime-avibactam, ceftolozane-tazobactam, meropenem-vaborbactam and imipenem-relebactam that were recently approved for clinical use. Based on studies with P. aeruginosa, different partner ß-lactams in combination with QPX7728 may be optimal for the coverage of susceptible organisms. This provides microbiological justification for a stand-alone BLI product for co-administration with different ß-lactams. QPX7728 can also be delivered orally; thus, its ultra-broad ß-lactamase inhibition spectrum and other features could be also applied to oral QPX7728-based combination products. Clinical development of QPX7728 has been initiated.

In Vitro Activity of the Ultrabroad-Spectrum Beta-Lactamase Inhibitor QPX7728 in Combination with Multiple Beta-Lactam Antibiotics against Pseudomonas aeruginosa.

QPX7728 is an ultrabroad-spectrum beta-lactamase inhibitor with potent inhibition of key serine and metallo beta-lactamases. QPX7728 enhances the potency of multiple beta-lactams in beta-lactamase-producing Enterobacterales and Acinetobacter spp. In this study, we evaluated the in vitro activity of QPX7728 (QPX; 8 µg/ml) combined with multiple beta-lactams against clinical isolates of Pseudomonas aeruginosa with various beta-lactam resistance mechanisms. Seven hundred ninety clinical isolates were included in this study; 500 isolates, termed a "representative panel," were selected to be representative of the MIC distribution of meropenem (MEM), ceftazidime-avibactam (CAZ-AVI), and ceftolozane-tazobactam (TOL-TAZ) resistance for clinical isolates according to 2017 SENTRY surveillance data. An additional 290 selected isolates ("challenge panel") that were either nonsusceptible to MEM or were resistant to TOL-TAZ or CAZ-AVI were also tested; 61 strains carried metallo-beta-lactamases (MBLs), 211 strains were defective in the carbapenem porin OprD, and 185 strains had the MexAB-OprM efflux pump overproduced based on a phenotypic test. Against the representative panel, susceptibility for all QPX7728/beta-lactam combinations was >90%. For the challenge panel, QPX-ceftolozane (TOL) was the most active combination (78.6% susceptible) followed by equipotent QPX-piperacillin (PIP) and QPX-cefepime (FEP), restoring susceptibility in 70.3% of strains (CLSI breakpoints for the beta-lactam compound alone). For MBL-negative strains, QPX-TOL and QPX-FEP restored the MIC values to susceptibility rates in ∼90% and ∼80% of strains, respectively, versus 68% to 70% for QPX-MEM and QPX-PIP and 63% to 65% for TOL-TAZ and CAZ-AVI, respectively. For MBL-positive strains, QPX-PIP restored the MIC to susceptibility values for ∼70% of strains versus 2% to 40% for other combinations. Increased efflux and impaired OprD had various effect on QPX7728 combination depending on the partner beta-lactam tested. QPX7728 enhanced the potency of multiple beta-lactams against P. aeruginosa, with varied results according to beta-lactamase production and other intrinsic resistance mechanisms.

Effect and Safety of Meropenem-Vaborbactam versus Best-Available Therapy in Patients with Carbapenem-Resistant Enterobacteriaceae Infections: The TANGO II Randomized Clinical Trial.

INTRODUCTION: Treatment options for carbapenem-resistant Enterobacteriaceae (CRE) infections are limited and CRE infections remain associated with high clinical failure and mortality rates, particularly in vulnerable patient populations. A Phase 3, multinational, open-label, randomized controlled trial (TANGO II) was conducted from 2014 to 2017 to evaluate the efficacy/safety of meropenem-vaborbactam monotherapy versus best available therapy (BAT) for CRE. METHODS: A total of 77 patients with confirmed/suspected CRE infection (bacteremia, hospital-acquired/ventilator-associated bacterial pneumonia, complicated intra-abdominal infection, complicated urinary tract infection/acute pyelonephritis) were randomized, and 47 with confirmed CRE infection formed the primary analysis population (microbiologic-CRE-modified intent-to-treat, mCRE-MITT). Eligible patients were randomized 2:1 to meropenem-vaborbactam (2 g/2 g over 3 h, q8h for 7-14 days) or BAT (mono/combination therapy with polymyxins, carbapenems, aminoglycosides, tigecycline; or ceftazidime-avibactam alone). Efficacy endpoints included clinical cure, Day-28 all-cause mortality, microbiologic cure, and overall success (clinical cure + microbiologic eradication). Safety endpoints included adverse events (AEs) and laboratory findings. RESULTS: Within the mCRE-MITT population, cure rates were 65.6% (21/32) and 33.3% (5/15) [95% confidence interval (CI) of difference, 3.3% to 61.3%; P = 0.03)] at End of Treatment and 59.4% (19/32) and 26.7% (4/15) (95% CI of difference, 4.6% to 60.8%; P = 0.02) at Test of Cure;.Day-28 all-cause mortality was 15.6% (5/32) and 33.3% (5/15) (95% CI of difference, - 44.7% to 9.3%) for meropenem-vaborbactam versus BAT, respectively. Treatment-related AEs and renal-related AEs were 24.0% (12/50) and 4.0% (2/50) for meropenem-vaborbactam versus 44.0% (11/25) and 24.0% (6/25) for BAT. Exploratory risk-benefit analyses of composite clinical failure or nephrotoxicity favored meropenem-vaborbactam versus BAT (31.3% [10/32] versus 80.0% [12/15]; 95% CI of difference, - 74.6% to - 22.9%; P < 0.001). CONCLUSIONS: Monotherapy with meropenem-vaborbactam for CRE infection was associated with increased clinical cure, decreased mortality, and reduced nephrotoxicity compared with BAT. CLINICAL TRIALS REGISTRATION: NCT02168946. FUNDING: The Medicines Company.

Ex Vivo Characterization of Effects of Renal Replacement Therapy Modalities and Settings on Pharmacokinetics of Meropenem and Vaborbactam.

The combination product meropenem-vaborbactam, with activity against KPC-producing carbapenem-resistant Enterobacteriaceae, is likely to be used during renal replacement therapy. The aim of this work was to describe the extracorporeal removal (adsorption and clearance) of meropenem-vaborbactam during continuous venovenous hemofiltration (CVVH). An ex vivo model was used to examine the effects of a matrix of operational settings. Vaborbactam did not adsorb to AN69 (acrylonitrile and sodium methallylsulfonate copolymer) ST100 (surface area, 1 m2) hemofilter; the mean (±standard deviation [SD]) meropenem adsorption was 9% (±1%). The sieving coefficients (mean ± SD) with AN69 ST100 and ST150 (surface area, 1.5 m2) filters ranged from 0.97 ± 0.16 to 1.14 ± 0.12 and from 1.13 ± 0.01 to 1.53 ± 0.28, respectively, for meropenem and from 0.64 ± 0.39 to 0.90 ± 0.14 and 0.78 ± 0.18 to 1.04 ± 0.28, respectively, for vaborbactam. At identical settings, vaborbactam sieving coefficients were 25% to 30% lower than for meropenem. Points of dilution, blood flow rates, or effluent flow rates did not affect sieving coefficients for either drug. However, doubling the effluent flow rate resulted in >50 to 100% increases in filter clearance for both drugs. Postfilter dilution resulted in 40 to 80% increases in filter clearance at a high effluent flow rate (4,000 ml/h), compared with ∼15% increases at a low effluent flow rate (1,000 ml/h) for both drugs. For all combinations of setting and filters tested, vaborbactam clearance was lower than that of meropenem by ∼20 to 40%. Overall, meropenem-vaborbactam is efficiently cleared in CVVH mode.

Effect of Meropenem-Vaborbactam vs Piperacillin-Tazobactam on Clinical Cure or Improvement and Microbial Eradication in Complicated Urinary Tract Infection: The TANGO I Randomized Clinical Trial.

Importance: Meropenem-vaborbactam is a combination carbapenem/beta-lactamase inhibitor and a potential treatment for severe drug-resistant gram-negative infections. Objective: To evaluate efficacy and adverse events of meropenem-vaborbactam in complicated urinary tract infection (UTI), including acute pyelonephritis. Design, Setting, and Participants: Phase 3, multicenter, multinational, randomized clinical trial (TANGO I) conducted November 2014 to April 2016 and enrolling patients (≥18 years) with complicated UTI, stratified by infection type and geographic region. Interventions: Eligible patients were randomized 1:1 to receive meropenem-vaborbactam (2g/2g over 3 hours; n = 274) or piperacillin-tazobactam (4g/0.5g over 30 minutes; n = 276) every 8 hours. After 15 or more doses, patients could be switched to oral levofloxacin if they met prespecified criteria for improvement, to complete 10 days of total treatment. Main Outcomes and Measures: Primary end point for FDA criteria was overall success (clinical cure or improvement and microbial eradication composite) at end of intravenous treatment in the microbiologic modified intent-to-treat (ITT) population. Primary end point for European Medicines Agency (EMA) criteria was microbial eradication at test-of-cure visit in the microbiologic modified ITT and microbiologic evaluable populations. Prespecified noninferiority margin was -15%. Because the protocol prespecified superiority testing in the event of noninferiority, 2-sided 95% CIs were calculated. Results: Among 550 patients randomized, 545 received study drug (mean age, 52.8 years; 361 [66.2%] women; 374 [68.6%] in the microbiologic modified ITT population; 347 [63.7%] in the microbiologic evaluable population; 508 [93.2%] completed the trial). For the FDA primary end point, overall success occurred in 189 of 192 (98.4%) with meropenem-vaborbactam vs 171 of 182 (94.0%) with piperacillin-tazobactam (difference, 4.5% [95% CI, 0.7% to 9.1%]; P < .001 for noninferiority). For the EMA primary end point, microbial eradication in the microbiologic modified ITT population occurred in 128 of 192 (66.7%) with meropenem-vaborbactam vs 105 of 182 (57.7%) with piperacillin-tazobactam (difference, 9.0% [95% CI, -0.9% to 18.7%]; P < .001 for noninferiority); microbial eradication in the microbiologic evaluable population occurred in 118 of 178 (66.3%) vs 102 of 169 (60.4%) (difference, 5.9% [95% CI, -4.2% to 16.0%]; P < .001 for noninferiority). Adverse events were reported in 106 of 272 (39.0%) with meropenem-vaborbactam vs 97 of 273 (35.5%) with piperacillin-tazobactam. Conclusions and Relevance: Among patients with complicated UTI, including acute pyelonephritis and growth of a baseline pathogen, meropenem-vaborbactam vs piperacillin-tazobactam resulted in a composite outcome of complete resolution or improvement of symptoms along with microbial eradication that met the noninferiority criterion. Further research is needed to understand the spectrum of patients in whom meropenem-vaborbactam offers a clinical advantage. Trial Registration: clinicaltrials.gov Identifier: NCT02166476.

Phase 1 Study of the Safety, Tolerability, and Pharmacokinetics of Vaborbactam and Meropenem Alone and in Combination following Single and Multiple Doses in Healthy Adult Subjects.

Meropenem-vaborbactam is a fixed combination of the novel ß-lactamase inhibitor vaborbactam and the carbapenem antibiotic meropenem, developed for the treatment of serious infections caused by drug-resistant Gram-negative bacteria. The safety, tolerability, and pharmacokinetics (PK) of vaborbactam and meropenem following single and multiple ascending doses of each study drug administered alone or combined were evaluated in 76 healthy adult subjects in a randomized, placebo-controlled, double-blind study. Subjects were enrolled in 1 of 5 dose cohorts (receiving 250 to 2,000 mg vaborbactam and/or 1,000 to 2,000 mg meropenem) alone or in combination. No subjects discontinued the study due to adverse events (AEs), and no serious AEs were observed. The pharmacokinetics of meropenem and vaborbactam were similar when given alone or in combination; all evaluated plasma PK exposure measures (peak plasma concentration, area under the plasma concentration-time curve [AUC] from time zero to the last measurable concentration area under the plasma concentration-time curve, and AUC from time zero to infinity) were similar for the study drugs alone versus those in combination, indicating no pharmacokinetic interaction between meropenem and vaborbactam. Across all treatments, 47 to 64% of an administered meropenem dose and 75 to 95% of vaborbactam was excreted unchanged in the urine over 48 h postdose. Meropenem and vaborbactam, when given alone or in combination, have similar pharmacokinetic properties, with no plasma or urine PK drug-drug interactions, and are well tolerated. These findings supported further clinical investigation of the combination product. (This study is registered at ClinicalTrials.gov under registration no. NCT01897779.).

Single-Dose Pharmacokinetics and Safety of Meropenem-Vaborbactam in Subjects with Chronic Renal Impairment.

Vaborbactam is a member of a new class of ß-lactamase inhibitors with inhibitory activity against serine carbapenemases (e.g., Klebsiella pneumoniae carbapenemase) that has been developed in combination with meropenem. The pharmacokinetics of the combination was evaluated in 41 subjects with chronic renal impairment in a phase 1, open-label, single-dose study. Subjects were assigned to one of five groups based on renal function: normal (creatinine clearance of ≥90 ml/min), mild (estimated glomerular filtration rate [eGFR] of 60 to 89 ml/min/1.73 m2), moderate (eGFR of 30 to <60), or severe (eGFR of <30) impairment plus end-stage renal disease (ESRD) patients on hemodialysis. Subjects received a single intravenous dose of 1 g of meropenem plus 1 g of vaborbactam by 3-h infusion. The ESRD group received two doses (on and off dialysis) separated by a washout. Pharmacokinetic parameters were estimated by standard noncompartmental methods. For both meropenem and vaborbactam, the area under the concentration-time curve was larger and the elimination half-life was longer with decreasing renal function. Meropenem and vaborbactam total plasma clearance (CLt) rates were similar and decreased with decreasing renal function. Slopes of the linear relationship between eGFR and CLt were similar, indicating a similar proportional reduction in CLt with decreasing renal function. Hemodialysis significantly increased drug clearance of meropenem (mean of 2.21-fold increase in CLt, P < 0.001) and vaborbactam (mean of 5.11-fold increase, P = 0.0235) relative to drug administration off dialysis, consistent with dose recovery rates of 38.3% and 52.9% for meropenem and vaborbactam, respectively, in dialysate. Plasma clearance of meropenem and vaborbactam is reduced with renal impairment, requiring dose adjustment. Hemodialysis removes both drugs. (This study has been registered at ClinicalTrials.gov under identifier NCT02020434.).

Single Intravenous Dose of Oritavancin for Treatment of Acute Skin and Skin Structure Infections Caused by Gram-Positive Bacteria: Summary of Safety Analysis from the Phase 3 SOLO Studies.

Oritavancin is a lipoglycopeptide with bactericidal activity against Gram-positive organisms. Its rapid concentration-dependent bactericidal activity and long elimination half-life allow single-dose treatment of acute bacterial skin and skin structure infections (ABSSSI). SOLO I and SOLO II were randomized, double-blind studies evaluating the efficacy and safety of a single 1,200-mg intravenous (i.v.) dose of oritavancin versus twice-daily i.v. vancomycin for 7 to 10 days in ABSSSI patients. Safety data from both studies were pooled for safety analysis. The database comprised pooled safety data for 976 oritavancin-treated patients and 983 vancomycin-treated patients. The incidences of adverse events, serious adverse events, and discontinuations due to adverse events were similar for oritavancin (55.3, 5.8, and 3.7%, respectively) and vancomycin (56.9, 5.9, and 4.2%, respectively). The median time to onset (3.8 days versus 3.1 days, respectively) and the duration (3.0 days for both groups) of adverse events were also similar between the two groups. The most frequently reported events were nausea, headache, and vomiting. Greater than 90% of all events were mild or moderate in severity. There were slightly more infections and infestations, abscesses or cellulitis, and hepatic and cardiac adverse events in the oritavancin group; however, more than 80% of these events were mild or moderate. Subgroup analyses did not identify clinically meaningful differences in the incidence of adverse events attributed to oritavancin. A single 1,200-mg dose of oritavancin was well tolerated and had a safety profile similar to that of twice-daily vancomycin. The long elimination half-life of oritavancin compared to that of vancomycin did not result in a clinically meaningful delay to the onset or prolongation of adverse events. (This study has been registered at ClinicalTrials.gov under registration no. NCT01252719 and NCT01252732.).

Carbapenem-Resistant Enterobacteriaceae Infections: Results From a Retrospective Series and Implications for the Design of Prospective Clinical Trials.

BACKGROUND: The increasing incidence of multidrug-resistant Gram negatives, such as carbapenem-resistant Enterobacteriaceae (CRE), has resulted in a critical need for new antimicrobials. Most studies of new antimicrobials have been performed in patients with nondrug-resistant pathogens. We performed a retrospective analysis of patients with CRE infections to inform the design of phase 3 clinical trials. METHODS: This was a retrospective study at 22 centers in 4 countries. Baseline data, treatment, and outcomes were collected in patients with complicated urinary tract infection (cUTI)/acute pyelonephritis (AP), hospital-acquired bacterial pneumonia (HABP), ventilator-associated bacterial pneumonia (VABP), and bacteremia due to CRE. RESULTS: Two hundred fifty-six cases of CRE infection were identified: 75 cUTI/AP, 21 HABP, 20 VABP, and 140 bacteremia. The patient population had significant comorbidities: 32.8% had chronic renal insufficiency, and 26.2% were immunocompromised. Illness severity at presentation was high: 29.3% presented with septic shock. Treatment regimens varied widely; however, a majority of patients received combination therapy. Outcomes were universally poor (28-day mortality was 28.1%) across all sites of infection, particularly in dialysis patients and those with sepsis. CONCLUSIONS: The CRE infections occured in patients with substantial comorbidities and were associated with high mortality and low rates of clinical cure with available antibiotics. Patients with these comorbidities are often excluded from enrollment in clinical trials for registration of new drugs. These results led to changes in the inclusion/exclusion criteria of a phase 3 trial to better represent the patient population with CRE infections and enable enrollment. Observational studies may become increasingly important to guide clinical trial design, inform on the existing standard of care, and provide an external control for subsequent trials.

Effects of Oritavancin on Coagulation Tests in the Clinical Laboratory.

Previous studies have shown that some lipoglycopeptide and lipopeptide antimicrobial agents may cause falsely elevated values for some phospholipid-dependent coagulation tests. The effect of oritavancin, a lipoglycopeptide antibiotic, on coagulation test results was explored using pooled human plasma samples spiked with drug and in a clinical study after an infusion of a single 1,200-mg intravenous dose of oritavancin in normal healthy volunteers. Pooled plasma with oritavancin added ex vivo showed concentration-dependent prolongation of prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), and dilute Russell viper venom time (DRVVT) test results. In contrast, oritavancin had no effect on the activated protein C resistance assay, chromogenic anti-factor Xa assay (anti-FXa), thrombin time, and an immunoassay for the laboratory diagnosis of heparin-induced thrombocytopenia. In participants that received a single dose of oritavancin, elevations in PT/INR result, aPTT, DRVVT, activated clotting time, and silica clotting time occurred, with the maximum times to resolution of test interference determined to be 12, 120, 72, 24, and 18 h, respectively. The anti-FXa assay was unaffected, whereas transient elevations in D dimer levels were observed in 30% of participants, with a maximum time to resolution of 72 h. Although oritavancin has no impact on the coagulation system in vivo, a single dose of oritavancin can produce falsely elevated values of some coagulation tests used to monitor hemostasis. The interference of oritavancin on affected tests is transient, and the test results revert to normal ranges within specified times after dosing.

Phase 1 Study of the Safety, Tolerability, and Pharmacokinetics of the ß-Lactamase Inhibitor Vaborbactam (RPX7009) in Healthy Adult Subjects.

Vaborbactam (formerly RPX7009) is a member of a new class of ß-lactamase inhibitor with pharmacokinetic properties similar to those of many ß-lactams, including carbapenems. The pharmacokinetics and safety of vaborbactam were evaluated in 80 healthy adult subjects in a first-in-human randomized, placebo-controlled, double-blind, sequential single- and multiple-ascending-dose study. A total of 10 dose cohorts were enrolled in the study, with 6 subjects randomized to receive 250 to 2,000 mg of vaborbactam and 2 subjects randomized to receive placebo in each cohort. Maximum concentrations for vaborbactam were achieved at the end of the 3-h infusion. Vaborbactam exposure (Cmax and area under the concentration-time curve [AUC]) increased in a dose-proportional manner following multiple doses. There was no evidence of accumulation with multiple doses, consistent with the terminal half-life of ∼2 h. Both the volume of distribution (Vss) and plasma clearance were independent of dose. For the 2,000-mg dose, the plasma clearance was 0.17 ± 0.03 liters/h, the AUC from 0 h to infinity (AUC0-∞) was 144.00 ± 13.90 mg · h/liter, and the Vss was 21.80 ± 2.26 mg · h/liter. Urinary recovery was 80% or greater over 48 h across all dose groups. No subjects discontinued the study due to adverse events (AEs), and no serious AEs (SAEs) were observed. All AEs were mild to moderate and similar among the vaborbactam- and placebo-treated subjects, with mild lethargy as the only unique AE reported with the high dose of vaborbactam. Overall, this study revealed the safety, tolerability, and pharmacokinetic profile of vaborbactam and formed the basis for advancement into patient studies in combination with meropenem, including treatment of patients with carbapenem-resistant Enterobacteriaceae (CRE) infections. (This study is registered at ClinicalTrials.gov under identifier NCT01751269.).

Safety and efficacy of prolonged levofloxacin inhalation solution (APT-1026) treatment for cystic fibrosis and chronic Pseudomonas aeruginosa airway infection.

BACKGROUND: Levofloxacin inhalation solution (LIS) is the first aerosolized fluoroquinolone licensed for treatment of patients with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa lung infection. This study evaluated the safety and efficacy of extended LIS treatment. METHODS: Patients completing a multinational, randomized study comparing LIS and tobramycin inhalation solution (TIS) were enrolled in an open-label extension in which all patients received three additional cycles of 28days of LIS 240mg twice daily followed by 28days off drug. Endpoints included mean relative change in percent predicted forced expiratory volume in 1s (FEV1), time to pulmonary exacerbation, and patient-reported quality of life. RESULTS: Extended treatment with LIS in 88 patients was well tolerated with no new safety signals and evidence of positive effects on FEV1 and quality of life. CONCLUSION: Patients receiving extended LIS treatment continued to show favorable efficacy with no additional safety concerns.

A phase 3, multi-center, multinational, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of levofloxacin inhalation solution (APT-1026) in stable cystic fibrosis patients.

RATIONALE: For patients with cystic fibrosis (CF), the use of inhaled antibiotics has become standard of care to suppress chronic Pseudomonas airways infection. There are limited antibiotic options formulated and approved for inhaled use and antibiotic efficacies attenuate over time, making additional inhaled antibiotic classes desirable. APT-1026 (levofloxacin inhalation solution, LIS) is a fluoroquinolone in development for management of chronic P. aeruginosa airways infection in patients with CF. OBJECTIVES: To compare the safety and efficacy of a 28-day course of treatment with LIS 240mg or placebo BID in persons ≥12years old with CF and chronic P. aeruginosa infection. METHODS: A multinational, randomized (2:1), double-blinded study of LIS and placebo over 28days in CF patients ≥12years with chronic P. aeruginosa infection. Time to exacerbation was the primary endpoint. FEV1 (% predicted) and patient-reported quality of life were among secondary endpoints. MAIN RESULTS: Baseline demographics for 330 subjects (LIS=220) were similar although significantly more patients randomized to LIS had experienced multiple exacerbations in the year prior to study entry. There was no statistically significant difference in protocol-defined pulmonary exacerbations between treatment arms. Relative change in FEV1% predicted from baseline was significantly greater for patients randomized to LIS compared to those randomized to placebo (mean difference 1.31%, p=0.01 [95% CI 0.27, 2.34%]). LIS was well-tolerated, with dysguesia the most frequent adverse event. CONCLUSIONS: LIS did not demonstrate a difference in time to next exacerbation when compared to placebo. Reasons for this result are discussed but may be due to an imbalance in the frequency of prior pulmonary exacerbations between the two groups. An improvement in FEV1 (% predicted) at 28days was observed and LIS was well tolerated. LIS is safe and has a potential role in the management of CF patients with chronic P. aeruginosa.

A phase 3, open-label, randomized trial to evaluate the safety and efficacy of levofloxacin inhalation solution (APT-1026) versus tobramycin inhalation solution in stable cystic fibrosis patients.

BACKGROUND: Inhaled antibiotics are standard of care for persons with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa airway infection. APT-1026 (levofloxacin inhalation solution, LIS) is fluoroquinolone in development. We compared the safety and efficacy of LIS to tobramycin inhalation solution (TIS) in persons ≥12 years old with CF and chronic P. aeruginosa infection. METHODS: This multinational, randomized (2:1), non-inferiority study compared LIS and TIS over three 28-day on/off cycles. Day 28 FEV(1) % predicted relative change was the primary endpoint. Time to exacerbation and patient-reported quality of life were among secondary endpoints. RESULTS: Baseline demographics for 282 subjects were comparable. Non-inferiority was demonstrated (1.86% predicted mean FEV(1) difference [95% CI -0.66 to 4.39%]). LIS was well-tolerated, with dysgeusia (taste distortion) as the most frequent adverse event. CONCLUSIONS: LIS is a safe and effective therapy for the management of CF patients with chronic P. aeruginosa infection.

Levofloxacin inhalation solution (MP-376) in patients with cystic fibrosis with Pseudomonas aeruginosa.

RATIONALE: Lower respiratory tract infection with Pseudomonas aeruginosa (PA) is associated with increased morbidity in patients with cystic fibrosis (CF). Current treatment guidelines for inhaled antibiotics are not universally followed due to the perception of decreased efficacy, increasing resistance, drug intolerance, and high treatment burden with current aerosol antibiotics. New treatment options for CF pulmonary infections are needed. OBJECTIVES: This study assessed the efficacy and safety of a novel aerosol formulation of levofloxacin (MP-376, Aeroquin) in a heavily treated CF population with PA infection. METHODS: This study randomized 151 patients with CF with chronic PA infection to one of three doses of MP-376 (120 mg every day, 240 mg every day, 240 mg twice a day) or placebo for 28 days. The primary efficacy endpoint was the change in sputum PA density. Secondary endpoints included changes in pulmonary function, the need for other anti-PA antimicrobials, changes in patient-reported symptom scores, and safety monitoring. MEASUREMENTS AND MAIN RESULTS: All doses of MP-376 resulted in reduced sputum PA density at Day 28, with MP-376 240 mg twice a day showing a 0.96 log difference compared with placebo (P = 0.001). There was a dose-dependent increase in FEV(1) for MP-376, with a difference of 8.7% in FEV(1) between the 240 mg twice a day group and placebo (P = 0.003). Significant reductions (61-79%) in the need for other anti-PA antimicrobials were observed with all MP-376 treatment groups compared with placebo. MP-376 was generally well tolerated relative to placebo. CONCLUSIONS: Nebulized MP-376was well tolerated and demonstrated significant clinical efficacy in heavily treated patients with CF with PA lung infection. Clinical trial registered with www.clinicaltrials.gov (NCT00677365).

Pharmacokinetics and safety of MP-376 (levofloxacin inhalation solution) in cystic fibrosis subjects.

The pharmacokinetics and tolerability of nebulized MP-376 (levofloxacin inhalation solution [Aeroquin]) were determined in cystic fibrosis (CF) subjects. Ten CF subjects received single 180-mg doses of two formulations of MP-376, followed by a multiple-dose phase of 240 mg once daily for 7 days. Serum and expectorated-sputum samples were assayed for levofloxacin content. Safety was evaluated following the single- and multiple-dose study phases. Nebulized MP-376 produced high concentrations of levofloxacin in sputum. The mean maximum plasma concentration (C(max)) ranged between 2,563 and 2,932 mg/liter for 180-mg doses of the 50- and 100-mg/ml formulations, respectively. After 7 days of dosing, the mean C(max) for the 240-mg dose was 4,691 mg/liter. The mean serum levofloxacin C(max) ranged between 0.95 and 1.28 for the 180-mg doses and was 1.71 for the 240-mg dose. MP-376 was well tolerated. Nebulized MP-376 produces high sputum and low serum levofloxacin concentrations. The pharmacokinetics, safety, and tolerability were similar for the two formulations. MP-376 240 mg (100 mg/ml) is being advanced into late-stage clinical development.

Pharmacokinetics, safety, and tolerability of ascending single intravenous doses of oritavancin administered to healthy human subjects.

Oritavancin (LY333328 diphosphate) is a novel glycopeptide antimicrobial agent with potent microbiological activity in vitro against Gram-positive bacteria. A single-dose, open-label, noncontrolled, dose-escalation study in 11 healthy human subjects was carried out to evaluate the safety and pharmacokinetics of oritavancin. One subject at each dose level received a single intravenous dose of 0.02, 0.03, 0.05, 0.08, 0.125, 0.20, and 0.325 mg/kg infused over 1 hour and four subjects each received a single-dose of 0.5 mg/kg. Safety and tolerability were evaluated by monitoring adverse events and laboratory parameters. Oritavancin pharmacokinetics were assessed by blood, urine, and fecal sampling. The plasma concentrations of oritavancin after the end of infusion followed a multiexponential decline over a 2-week period. Median (range) C(max) for the 0.5 mg/kg dose group was 6.5 (4.7-7.6) microg/mL. In every subject, plasma concentrations declined to < or =10% of the C(max) within 24 hours. Following a short, constant-rate infusion, the pharmacokinetics of oritavancin were linear across a total dose range from 3.66-44.6 mg. Renal clearance was approximately 0.457 mL/min. The mean (range) plasma terminal half-life of oritavancin was 195.4 (135.8-273.8) hours across all dose levels from 0.05-0.5 mg/kg. Less than 5% and 1% of administered drug were recovered in the urine and feces, respectively, after 7 days. This first time in man evaluation of oritavancin revealed that single doses of oritavancin of up to and including 0.5 mg/kg were safe and well tolerated. Although no clinically relevant changes in renal, hepatic and hematologic indices from baseline were observed, five subjects did manifest asymptomatic and transient elevations of hepatic transaminase concentrations. Because this study was not placebo-controlled and enrolled a small number of subjects, the safety and pharmacokinetic profiles of oritavancin need to be confirmed in additional studies.