https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25164 Pseudomonas aeruginosa. The in vitro synergistic activity of polymyxin B combined with ivacaftor or lumacaftor was assessed using checkerboard and static time-kill assays against a panel of polymyxin-susceptible and polymyxin-resistant P. aeruginosa isolates from the lungs of CF patients. Polymyxin B, ivacaftor, and lumacaftor were ineffective when used individually against polymyxin-resistant (MIC ≥ 4 mg/L) isolates. However, when used together, the combination of clinically relevant concentrations of polymyxin B (2 mg/L) combined with ivacaftor (8 mg/L) or ivacaftor (8 mg/L) + lumacaftor (8 mg/L) displayed synergistic killing activity against polymyxin-resistant P. aeruginosa isolates as demonstrated by a 100-fold decrease in the bacterial count (CFU/mL) even after 24 h. The combinations also displayed excellent antibacterial activity against P. aeruginosa under CF relevant conditions in a sputum medium assay. The combination of lumacaftor (alone) with polymyxin B showed additivity against P. aeruginosa. The potential antimicrobial mode of action of the combinations against P. aeruginosa was investigated using different methods. Treatment with the combinations induced cytosolic GFP release from P. aeruginosa cells and showed permeabilizing activity in the nitrocefin assay, indicating damage to both the outer and inner Gram-negative cell membranes. Moreover, scanning and transmission electron micrographs revealed that the combinations produce outer membrane damage to P. aeruginosa cells that is distinct from the effect of each compound per se. Ivacaftor was also shown to be a weak inhibitor of the bacterial DNA gyrase and topoisomerase IV with no effect on either human type I or type IIα topoisomerases. Lumacaftor displayed the ability to increase the cellular production of damaging reactive oxygen species. In summary, the combination of polymyxin B with KALYDECO or ORKAMBI exhibited synergistic activity against highly polymyxin-resistant P. aeruginosa CF isolates and can be potentially useful for otherwise untreatable CF lung infections.]]> Thu 04 Nov 2021 10:40:12 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:28305 97%) to plasma proteins, there is the strong possibility that co-administered CF drugs may compete for the same plasma protein binding sites and impact the free drug concentration. This, in turn, could lead to drastic changes in the in vivo efficacy of ivacaftor and therapeutic outcomes. This biochemical study compares the binding affinity of ivacaftor and co-administered CF drugs for human serum albumin (HSA) and α₁-acid glycoprotein (AGP) using surface plasmon resonance and fluorimetric binding assays that measure the displacement of site-selective probes. Because of their ability to strongly compete for the ivacaftor binding sites on HSA and AGP, drug–drug interactions between ivacaftor are to be expected with ducosate, montelukast, ibuprofen, dicloxacillin, omeprazole, and loratadine. The significance of these plasma protein drug–drug interactions is also interpreted in terms of molecular docking simulations. This in vitro study provides valuable insights into the plasma protein drug–drug interactions of ivacaftor with co-administered CF drugs. The data may prove useful in future clinical trials for a staggered treatment that aims to maximize the effective free drug concentration and clinical efficacy of ivacaftor.]]> Sat 24 Mar 2018 07:27:06 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46958 40% predicted. We set out to observe the most sensitive clinical measure that would change with treatment in terms of exercise capacity or lung function in adults with severe lung disease as defined by an FEV1 < 40% predicted when clinically stable. Methods: 10 adults homozygous for the Phe508del received LUM/IVA. We assessed; six minute walk test (6MWT), spirometry, gas transfer (DLCO), plethysmography, and nitrogen multiple breath washout (MBW) at baseline, 4, 12, 24 and 52 weeks. Comparison was made with 10 matched historical controls that had been observed over 12 months. Results: There was a significant improvement in 6MWT by 4 weeks of treatment; with a mean increase of 78 m (SD 62.3) and this increased to 118.1 m (SD 80.9) (ANOVA p = 0.006) by 52 weeks. Significant improvements were also seen in the resting heart rate and the oxygen saturation (SaO2) after 6 min walking. A significant improvement was not seen in FEV1 though until 24 weeks, though this was maintained at 52 weeks (ANOVA, p = 0.0004). There were no significant differences seen in the MBW or DLCO. After 12 months treatment with LUM/IVA, in comparison to historical controls; the 6MWT increased by 118 m (SD 80.9), but fell in the controls - 61.3 m (SD 31.1). FEV1; LUM/IVA led to an increase of 0.398 L/min, compared to a fall in the controls - 0.18 (SD 0.2). Conclusion: In adults homozygous for Phe508del with severe disease, treatment with LUM/IVA results in a clinically significant improvement in 6MWT that was evident at 4 weeks and maintained at 52 weeks. Improvement in exercise tolerance is an important outcome to consider in those with more severe airways disease. Trial registration: This was an observational trial conducted on individuals who became eligible to receive LUM/IVA. All investigations were carried out as part of routine clinical care. The trial was registered in retrospect on the 13/5/2019 on the Australian New Zealand Clinical Trials registry; ACTRN12619000708156.]]> Mon 12 Dec 2022 10:01:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40051 40%. There is limited safety or efficacy data in patients with ppFEV1 < 40%. We determined whether LUM/IVA in patients with ppFEV1 < 40 would reduce the rate of pul- monary exacerbations. Methods: This was a case control study performed on patients > 12 years, homozygous for Phe508del CFTR mutation and with ppFEV1 < 40%. Control subjects were matched for age, sex and ppFEV1, and had mutations ineligible for LUM/IVA. We assessed the rate of pulmonary exacerbations requiring intravenous antibiotics, the mean rate of change in ppFEV1 over 12 months and all adverse events. Results: Data was collected from 7 Australian CF centres on 105 patients; 72 on LUM/IVA and 33 controls. LUM/IVA demonstrated a large reduction in exacerbations with an incident rate ratio of 0.455 (95%CI; 0.306 –0.676), p < 0.001 after adjusting for the number of exacerbations in the previous 12 months. LUM/IVA prolonged the time to first exacerbation and reduced the rate of decline in ppFEV1 over 12 months. Adverse events were common; chest tightness or dyspnoea was experienced by 55% and resulted in cessation of treatment in 32%. Conclusions: Treatment with LUM/IVA resulted in a substantially lower rate of pulmonary exacerbations, prolonged time to first exacerbation and slowed the rate of decline of ppFEV1 in participants with severe lung disease. Adverse reactions to LUM/IVA however were unacceptably frequent, and resulted in a very high discontinuation rate.]]> Fri 22 Jul 2022 13:27:19 AEST ]]>