Natalia Popowicz

Immediate effects of lumacaftor/ivacaftor administration on lung function in patients with severe cystic fibrosis lung disease

Safety-data for lumacaftor/ivacaftor (LUM/IVA) combination therapy in patients with severe lung disease (percent predicted forced expiratory volume in 1s [ppFEV1] <40) remain limited. We report immediate post-dose respiratory-related adverse events in 12 patients with severe cystic fibrosis (CF) lung disease (median [IQR] ppFEV1: 34 [31-36]) prescribed LUM/IVA. All patients experienced a decline in ppFEV1 from baseline at 2-hours (median [IQR] relative change: -19 [-21 to -11]%, p<0.001) that persisted at 24-hours but recovered in most patients at 1-month. No pre- and post-differences in bronchodilator response were observed. Ten (83.3%) patients reported non-severe respiratory-related adverse events within 24-hours of LUM/IVA initiation. At 1-month, eight (67%) patients had persistent symptoms and six (50%) were treated for a pulmonary exacerbation. Our results highlight that LUM/IVA respiratory-related adverse events are common in patients with a ppFEV1<40. We recommend close assessment of adverse events. Further studies are required to evaluate the efficacy of LUM/IVA in patients with severe lung disease.

Dose de-escalation of intrapleural tissue plasminogen activator therapy for pleural infection the alteplase dose assessment for pleural infection therapy project

Rationale: Intrapleural therapy with a combination of tissue plasminogen activator (tPA) 10 mg and DNase 5 mg administered twice daily has been shown in randomized and open‐label studies to successfully manage over 90% of patients with pleural infection without surgery. Potential bleeding risks associated with intrapleural tPA and its costs remain important concerns. The aim of the ongoing Alteplase Dose Assessment for Pleural infection Therapy (ADAPT) project is to investigate the efficacy and safety of dose de‐escalation for intrapleural tPA. The first of several planned studies is presented here. Objectives: To evaluate the efficacy and safety of a reduced starting dose regimen of 5 mg of tPA with 5 mg of DNase administered intrapleurally for pleural infection. Methods: Consecutive patients with pleural infection at four participating centers in Australia, the United Kingdom, and New Zealand were included in this observational, open‐label study. Treatment was initiated with tPA 5 mg and DNase 5 mg twice daily. Subsequent dose escalation was permitted at the discretion of the attending physician. Data relating to treatment success, radiological and systemic inflammatory changes (blood C‐reactive protein), volume of fluid drained, length of hospital stay, and treatment complications were extracted retrospectively from the medical records. Results: We evaluated 61 patients (41 males; age, 57 ± 16 yr). Most patients (n = 58 [93.4%]) were successfully treated without requiring surgery for pleural infection. Treatment success was corroborated by clearance of pleural opacities visualized by chest radiography (from 42% [interquartile range, 22‐58] to 16% [8‐31] of hemithorax; P < 0.001), increase in pleural fluid drainage (from 175 ml in the 24 h preceding treatment to 2,025 ml [interquartile range, 1,247‐2,984] over 72 h of therapy; P < 0.05) and a reduction in blood C‐reactive protein (P < 0.05). Seven patients (11.5%) had dose escalation of tPA to 10 mg. Three patients underwent surgery. Three patients (4.9%) received blood transfusions for gradual pleural blood loss; none were hemodynamically compromised. Pain requiring escalation of analgesia affected 36% of patients; none required cessation of therapy. Conclusions: These pilot data suggest that a starting dose of 5 mg of tPA administered intrapleurally twice daily in combination with 5 mg of DNase for the treatment of pleural infection is safe and effective. This regimen should be tested in future randomized controlled trials.

Preclinical assessment of adjunctive tPA and DNase for peritoneal dialysis associated peritonitis.

A major complication of peritoneal dialysis is the development of peritonitis, which is associated with reduced technique and patient survival. The inflammatory response elicited by infection results in a fibrin and debris-rich environment within the peritoneal cavity, which may reduce the effectiveness of antimicrobial agents and predispose to recurrence or relapse of infection. Strategies to enhance responses to antimicrobial agents therefore have the potential to improve patient outcomes. This study presents pre-clinical data describing the compatibility of tPA and DNase in combination with antimicrobial agents used for the treatment of PD peritonitis. tPA and DNase were stable in standard dialysate solution and in the presence of antimicrobial agents, and were safe when given intraperitoneally in a mouse model with no evidence of local or systemic toxicity. Adjunctive tPA and DNase may have a role in the management of patients presenting with PD peritonitis.

Human pleural fluid is a potent growth medium for Streptococcus pneumoniae

Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biology of bacteria within human pleural fluid has not been studied. Streptococcus pneumoniae is the most common cause of pediatric and frequent cause of adult empyema. We investigated whether S. pneumoniae can proliferate within human pleural fluid and if growth is affected by the cellular content of the fluid and/or characteristics of pneumococcal surface proteins. Invasive S. pneumoniae isolates (n = 24) and reference strain recovered from human blood or empyema were inoculated (1.5×106CFU/mL) into sterile human malignant pleural fluid samples (n = 11). All S. pneumoniae (n = 25) strains proliferated rapidly, increasing by a median of 3009 (IQR 1063–9846) from baseline at 24hrs in all pleural effusions tested. Proliferation was greater than in commercial pneumococcal culture media and concentrations were maintained for 48hrs without autolysis. A similar magnitude of proliferation was observed in pleural fluid before and after removal of its cellular content, p = 0.728. S. pneumoniae (D39 strain) wild-type, and derivatives (n = 12), each with mutation(s) in a different gene required for full virulence were inoculated into human pleural fluid (n = 8). S. pneumoniae with pneumococcal surface antigen A (ΔpsaA) mutation failed to grow (2207-fold lower than wild-type), p<0.001, however growth was restored with manganese supplementation. Growth of other common respiratory pathogens (n = 14) across pleural fluid samples (n = 7) was variable and inconsistent, with some strains failing to grow. We establish for the first time that pleural fluid is a potent growth medium for S. pneumoniae and proliferation is dependent on the PsaA surface protein and manganese.

Aggressive versus symptom-guided drainage of malignant pleural effusion via indwelling pleural catheters (AMPLE-2): an open-label randomised trial

BACKGROUND Indwelling pleural catheters are an established management option for malignant pleural effusion and have advantages over talc slurry pleurodesis. The optimal regimen of drainage after indwelling pleural catheter insertion is debated and ranges from aggressive (daily) drainage to drainage only when symptomatic. METHODS AMPLE-2 was an open-label randomised trial involving 11 centres in Australia, New Zealand, Hong Kong, and Malaysia. Patients with symptomatic malignant pleural effusions were randomly assigned (1:1) to the aggressive (daily) or symptom-guided drainage groups for 60 days and minimised by cancer type (mesothelioma vs others), performance status (Eastern Cooperative Oncology Group [ECOG] score 0-1 vs ≥2), presence of trapped lung, and prior pleurodesis. Patients were followed up for 6 months. The primary outcome was mean daily breathlessness score, measured by use of a 100 mm visual analogue scale during the first 60 days. Secondary outcomes included rates of spontaneous pleurodesis and self-reported quality-of-life measures. Results were analysed by an intention-to-treat approach. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12615000963527. FINDINGS Between July 20, 2015, and Jan 26, 2017, 87 patients were recruited and randomly assigned to the aggressive (n=43) or symptom-guided (n=44) drainage groups. The mean daily breathlessness scores did not differ significantly between the aggressive and symptom-guided drainage groups (geometric means 13·1 mm [95% CI 9·8-17·4] vs 17·3 mm [13·0-22·0]; ratio of geometric means 1·32 [95% CI 0·88-1·97]; p=0·18). More patients in the aggressive group developed spontaneous pleurodesis than in the symptom-guided group in the first 60 days (16 [37·2%] of 43 vs five [11·4%] of 44, p=0·0049) and at 6 months (19 [44·2%] vs seven [15·9%], p=0·004; hazard ratio 3·287 [95% CI 1·396-7·740]; p=0·0065). Patient-reported quality-of-life measures, assessed with EuroQoL-5 Dimensions-5 Levels (EQ-5D-5L), were better in the aggressive group than in the symptom-guided group (estimated means 0·713 [95% CI 0·647-0·779] vs 0·601 [0·536-0·667]). The estimated difference in means was 0·112 (95% CI 0·0198-0·204; p=0·0174). Pain scores, total days spent in hospital, and mortality did not differ significantly between groups. Serious adverse events occurred in 11 (25·6%) of 43 patients in the aggressive drainage group and in 12 (27·3%) of 44 patients in the symptom-guided drainage group, including 11 episodes of pleural infection in nine patients (five in the aggressive group and six in the symptom-guided drainage group). INTERPRETATION We found no differences between the aggressive (daily) and the symptom-guided drainage regimens for indwelling pleural catheters in providing breathlessness control. These data indicate that daily indwelling pleural catheter drainage is more effective in promoting spontaneous pleurodesis and might improve quality of life. FUNDING Cancer Council of Western Australia and the Sir Charles Gairdner Research Advisory Group.

Pathogenesis of pleural infection: A complex warfare

See related Article

Unintentional intramuscular administration of tPA/DNase for pleural infection

Intrapleural tissue plasminogen activator (tPA) and deoxyribonuclease (DNase) therapy has recently been shown to improve outcomes in pleural infection in a randomized trial. Published literature, to date, consists of only ∼50 patients who had received tPA/DNase. Safety data of this regimen remain limited. Pleural contents often track along chest drains, but the effect of tPA/DNase on subcutaneous tissues is unknown. We report a patient treated in another center who was unintentionally administered up to six instillations of tPA (10 mg) and DNase (5 mg) intramuscularly via a malpositioned chest drain. The patient experienced minimal discomfort, and there were no signs of tissue inflammation or necrosis on computed tomography. No complications were detected over a 2‐month follow‐up. Upon transfer, a new pleural drain was inserted and tPA/DNase administered with clearance of his loculated complicated parapneumonic effusion. This case adds to the safety profile of intrapleural tPA/DNase therapy and highlights the importance of correct tube placement.

Bacteriology and clinical outcomes of patients with culture-positive pleural infection in Western Australia: A 6-year analysis: Empyema in Western Australia 2006-2011

Pleural infection is a clinical challenge; its microbiology can be complex. Epidemiological and outcome data of pleural infection in adult Australians are lacking. We describe the bacteriology and clinical outcomes of Australian adults with culture‐positive pleural infection (CPPI) over a 6‐year period.

Streptococcus pneumoniae potently induces cell death in mesothelial cells

Pleural infection/empyema is common and its incidence continues to rise. Streptococcus pneumoniae is the commonest bacterial cause of empyema in children and among the commonest in adults. The mesothelium represents the first line of defense against invading microorganisms, but mesothelial cell responses to common empyema pathogens, including S. pneumoniae, have seldom been studied. We assessed mesothelial cell viability in vitro following exposure to common empyema pathogens. Clinical isolates of S. pneumoniae from 25 patients with invasive pneumococcal disease and three reference strains were tested. All potently induced death of cultured mesothelial cells (MeT-5A) in a dose- and time-dependent manner (>90% at 107 CFU/mL after 24 hours). No significant mesothelial cell killing was observed when cells were co-cultured with Staphylococcus aureus, Streptococcus sanguinis and Streptococcus milleri group bacteria. S. pneumoniae induced mesothelial cell death via secretory product(s) as cytotoxicity could be: i) reproduced using conditioned media derived from S. pneumoniae and ii) in transwell studies when the bacteria and mesothelial cells were separated. No excess cell death was seen when heat-killed S. pneumoniae were used. Pneumolysin, a cytolytic S. pneumoniae toxin, induced cell death in a time- and dose-dependent manner. S. pneumoniae lacking the pneumolysin gene (D39 ΔPLY strain) failed to kill mesothelial cells compared to wild type (D39) controls, confirming the necessity of pneumolysin in D39-induced mesothelial cell death. However, pneumolysin gene mutation in other S. pneumoniae strains (TIGR4, ST3 and ST23F) only partly abolished their cytotoxic effects, suggesting different strains may induce cell death via different mechanisms.

A rapid, LC-MS/MS assay for quantification of piperacillin and tazobactam in human plasma and pleural fluid; application to a clinical pharmacokinetic study

Piperacillin, in combination with tazobactam is a common first-line antibiotic used for the treatment of pleural infection, however its pleural pharmacokinetics and penetration has not previously been reported. The objective of this work was to develop and validate a rapid and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) assay for quantification of piperacillin (PIP) and tazobactam (TAZ). PIP and TAZ were extracted from both human plasma and pleural fluid samples by protein precipitation in methanol containing the internal standards (IS) piperacillin-d5 (PIP-d5) and sulbactam (SUL). Briefly, 5 μL of sample was mixed with 125 μL of methanol containing IS, vortexed and centrifuged. Supernatant (50 μL) was diluted into 500 μL of mobile phase containing 10 mM of ammonium bicarbonate in LCMS grade water and transferred to the autosampler tray. Electrospray ionization in positive mode and multiple reaction monitoring (MRM) were used for PIP and PIP-d5 at the transitions m/z 518.2 → 143.2 and m/z 523.2 → 148.2 respectively, and electrospray ionization in negative mode and MRM were used for TAZ and SUL at the transitions m/z 299.1 → 138.1 and m/z 232.4 → 140.1. The chromatographic separation was achieved using an Acquity BEH C-18 column with gradient elution of mobile phase containing 10 mmol/L ammonium bicarbonate in water and methanol. A linear range was observed over the concentration range of 0.25-352 mg/L and 0.25-50.5 mg/L for PIP and TAZ respectively. Complete method validation was performed according to US FDA guidelines for selectivity, specificity, precision and accuracy, LLOQ, matrix effects, recovery and stability, with all results within acceptable limits. This method was successfully applied to two patients with pleural infection and is suitable for further pharmacokinetic studies and therapeutic drug monitoring.