Treatment response in COPD: does FEV1 say it all? A post hoc analysis of the CRYSTAL study.

The association between clinically relevant changes in patient-reported outcomes (PROs) and forced expiratory volume in 1 s (FEV1) in patients with chronic obstructive pulmonary disease (COPD) has rarely been investigated. Using CRYSTAL, a 12-week open-label study in symptomatic, nonfrequently exacerbating patients with moderate COPD, we assessed at baseline the correlations between several PROs (Baseline Dyspnoea Index, modified Medical Research Council dyspnoea scale, COPD Assessment Test (CAT) and Clinical COPD Questionnaire (CCQ)), and between FEV1 and PROs. Associations between clinically relevant responses in FEV1, CAT, CCQ and Transition Dyspnoea Index (TDI) at week 12 were also assessed. Using data from 4324 patients, a strong correlation was observed between CAT and CCQ (rs=0.793) at baseline, with moderate or weak correlations between other PROs, and no correlation between FEV1 and any PRO. At week 12, 2774 (64.2%) patients were responders regarding TDI, CAT or CCQ, with 583 (13.5%) responding using all three measures. In comparison, 3235 (74.8%) were responders regarding FEV1, TDI, CAT or CCQ, with 307 (7.1%) responding concerning all four parameters. Increases in lung function were accompanied by clinically relevant improvements of PROs in a minority of patients. Our results also suggest that PROs are not interchangeable. Thus, the observed treatment success in a clinical trial may depend on the selected parameters.

Dual bronchodilation vs triple therapy in the "real-life" COPD DACCORD study.

Background: No observational studies have evaluated the "real-world" effectiveness of dual bronchodilation comprising a long-acting ß2-agonist plus a long-acting muscarinic antagonist vs that of triple therapy (long-acting ß2-agonist plus long-acting muscarinic antagonist plus inhaled corticosteroid) in COPD. Materials and methods: DACCORD is a non-interventional, observational clinical study that recruited patients following COPD maintenance therapy initiation or change in maintenance therapy between or within therapeutic class. Given the non-interventional nature of the study, the decision to initiate or change medication had to be made by the patients' physicians prior to inclusion in DACCORD. We used a matched-pairs analysis to compare disease progression in two patient groups: those receiving dual bronchodilation vs those receiving triple therapy (each group n=1,046). Results: In two subgroups of patients matched according to a broad range of demographic and disease characteristics, over 1 year, fewer patients receiving dual bronchodilation exacerbated than those receiving triple therapy (15.5% vs 26.6%; P<0.001), with a greater improvement from baseline in COPD Assessment Test total score at 1 year (mean±SD -2.9±5.8 vs -1.4±5.5;P<0.001). When analyzed according to prior therapy, the highest rate of exacerbations was in patients on triple therapy prior to the study who remained on triple therapy. Those changing from mono-bronchodilator to dual bronchodilation had the greatest COPD Assessment Test total score improvement. Conclusion: In this "real-life" cohort of patients with COPD, most of whom had not exacerbated in the 6 months prior to entry, triple therapy did not seem to improve outcomes compared with dual bronchodilation in terms of either exacerbations or health status. Our analyses clearly demonstrate the potential impact of prior medication on study results, something that should be taken into account when interpreting the results even of controlled clinical trials.

Indacaterol/glycopyrronium reduces the risk of clinically important deterioration after direct switch from baseline therapies in patients with moderate COPD: a post hoc analysis of the CRYSTAL study.

PURPOSE: COPD is a progressive disease characterized by exacerbations and a decline in health status and lung function. Clinically important deterioration (CID) is a composite endpoint used to evaluate treatment efficacy. This analysis evaluated the impact of a direct switch to once-daily indacaterol/glycopyrronium 110/50 µg (IND/GLY) from previous monotherapy with a long-acting ß2-agonist (LABA) or long-acting muscarinic antagonist (LAMA) or with an LABA and an inhaled corticosteroid (LABA + ICS) on reducing CID. METHODS: CRYSTAL was a 12-week, prospective, multicenter, randomized, open-label study conducted in clinical practice settings. Three definitions of CID (D1-D3) were used, including: 1) ≥100 mL decrease in trough forced expiratory volume in 1 second (FEV1), 2) ≥1 point decrease in transition dyspnea index (TDI) and/or ≥0.4 points increase in clinical COPD questionnaire score (CCQ), or 3) an acute moderate/severe exacerbation (AECOPD). In D1 and D2, either TDI or CCQ was evaluated along with FEV1 and AECOPD, whereas in D3, all 4 parameters were included. ClinicalTrials.gov number: NCT01985334. RESULTS: Of the 2,159 patients analyzed, 1,622 switched to IND/GLY and 537 continued their baseline treatments. The percentage of patients with a CID was significantly lower after a direct switch to IND/GLY versus LABA or LAMA using all 3 CID definitions (D1: odds ratio [OR] 0.41 [95% CI: 0.30-0.55]; D2: OR 0.41 [95% CI: 0.31-0.55]; D3: OR 0.39 [95% CI: 0.29-0.52]). Compared with LABA + ICS, IND/GLY also reduced the risk of CID (D1: OR 0.76 [95% CI: 0.56-1.02]; D2: OR 0.75 [95% CI: 0.56-1.00]; D3: OR 0.67 [95% CI: 0.51-0.89]). CONCLUSION: In this analysis, IND/GLY reduced the risk of a CID in moderate COPD patients after direct switch from LABA + ICS or LABA or LAMA in real-life clinical practice.

GOLD 2017 treatment pathways in 'real life': An analysis of the DACCORD observational study.

INTRODUCTION: The 2017 update to the Global Initiative for Obstructive Lung Disease (GOLD) strategy document includes recommendations for treatment intensification or step-down in chronic obstructive pulmonary disease (COPD), although recognises that limited supporting information is available. DACCORD is an ongoing observational, non-interventional study, recruiting patients following COPD maintenance treatment change or initiation, a subset of whom were receiving a long-acting ß2-agonist (LABA) plus a long-acting muscarinic antagonist (LAMA) fixed-dose combination (FDC) on entry. Since there were no requirements in terms of prior medication (and no washout before commencing LABA/LAMA FDC), this provides an opportunity to generate 'real world' data to test the GOLD 2017 recommendations. METHODS: To reduce heterogeneity, the current analyses include patients receiving indacaterol/glycopyrronium at baseline, and who, prior to the study, were receiving no COPD maintenance medication ('none'), LABA or LAMA monotherapy ('mono'), LABA plus inhaled corticosteroid (ICS; 'LABA/ICS'), or triple therapy ('triple'). At the baseline visit, data collected included: demographic and disease characteristics; COPD Assessment Test (CAT); and exacerbations in the 6 months prior to entry. At 3, 6, 9 and 12 months data on exacerbations were collected, with CAT recorded at 3 and 12 months. RESULTS: A total of 2724 patients were included in the baseline analyses: 795, 954, 598 and 377 in the 'none', 'mono', 'LABA/ICS' and 'triple' subgroups, respectively. There were no clinically relevant differences in baseline demographics between the four groups. In terms of disease characteristics, the 'triple' group had the highest proportion of patients with a disease duration of more than 1 year since diagnosis and with severe/very severe airflow limitation, but a similar percentage of non-exacerbators compared to the 'none' group. Over the 1-year follow-up, the majority of patients in all four subgroups did not exacerbate (exacerbation rates 0.16, 0.19, 0.21, and 0.26 in the 'none', 'mono', 'LABA/ICS' and 'triple' groups, respectively). At 12 months, 61.4%, 65.0%, 71.0% and 52.4% of patients had a clinically relevant improvement in CAT score. CONCLUSIONS: Overall, the results support the GOLD recommendations in suggesting that a switch from a mono-bronchodilator or LABA plus ICS to LABA/LAMA FDC is a valid treatment option for patients with COPD. The results also validate the use of a LABA/LAMA FDC as initial maintenance treatment for COPD, and provide first 'real world' evidence to support the newly added 'step down' recommendation (from triple to LABA/LAMA FDC).

A two-year evaluation of the 'real life' impact of COPD on patients in Germany: The DACCORD observational study.

INTRODUCTION: DACCORD is an observational, non-interventional study being conducted in German primary and secondary care centres. The study aims to describe the impact of disease (including exacerbations) and treatments over 2 years on 'real-life' patients with chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: Patients had a clinical and spirometry diagnosis of COPD, were aged ≥40 years and, on recruitment, were initiating or changing COPD maintenance medication. The only exclusion criteria were asthma and randomised clinical trial participation. Exacerbations data were collected every 3 months. COPD medication, COPD Assessment Test (CAT) and forced expiratory volume in 1 s (FEV1) were recorded at baseline and after 1 and 2 years. RESULTS: A total of 6122 patients were recruited, 3137 (51.2%) of whom completed the 2-year visit. The mean age of these patients was 65.6 years, 59% were male, 69% had mild or moderate airflow limitation, and their mean COPD Assessment Test (CAT) total score was 20.3. Overall, there was a trend towards decreasing COPD exacerbation rates over the 2-year follow-up period, with rates of 0.390 during Year 1 and 0.347 during Year 2. Rates were lower in patients with no exacerbation during the 6 months prior to entry (0.263 and 0.251 during Years 1 and 2, respectively), with 51.6% of patients having no exacerbation during the 6 months prior to entry and over the 2-year follow-up. Approximately 50% of the overall population experienced a clinically relevant improvement from baseline in CAT total score at Year 1 and 2. When assessed by treatment class (or classes), persistence to medication was high (77.8% in Year 1 and 71.4% in Year 2). CONCLUSIONS: Overall, the 2-year follow-up data from DACCORD suggest that for most patients with COPD exacerbations are a rare event. For the majority of patients, the focus should be on managing symptoms, and the impact that these symptoms have on their daily lives. Even for those patients who do exacerbate, although prevention of exacerbations is an important factor, management of symptoms should be a key consideration. DACCORD also suggests that COPD disease progression is not inevitable - providing patients are receiving pharmacological treatment.

"Real-life" inhaled corticosteroid withdrawal in COPD: a subgroup analysis of DACCORD.

Many patients with chronic obstructive pulmonary disease (COPD) receive inhaled corticosteroids (ICSs) without a clear indication, and thus, the impact of ICS withdrawal on disease control is of great interest. DACCORD is a prospective, noninterventional 2-year study in the primary and secondary care throughout Germany. A subgroup of patients were taking ICS prior to entry - 1,022 patients continued to receive ICS for 2 years; physicians withdrew ICS on entry in 236 patients. Data from these two subgroups were analyzed to evaluate the impact of ICS withdrawal. Patients aged ≥40 years with COPD, initiating or changing COPD maintenance medication were recruited, excluding patients with asthma. Demographic and disease characteristics, prescribed COPD medication, COPD Assessment Test, exacerbations, and lung function were recorded. There were few differences in baseline characteristics; ICS withdrawn patients had shorter disease duration and better lung function, with 74.2% of ICS withdrawn patients not exacerbating, compared with 70.7% ICS-continued patients. During Year 1, exacerbation rates were 0.414 in the withdrawn group and 0.433 in the continued group. COPD Assessment Test total score improved from baseline in both groups. These data suggest that ICS withdrawal is possible with no increased risk of exacerbations in patients with COPD managed in the primary and secondary care.

Coevolution of the ATPase ClpV, the sheath proteins TssB and TssC, and the accessory protein TagJ/HsiE1 distinguishes type VI secretion classes.

The type VI secretion system (T6SS) is a bacterial nanomachine for the transport of effector molecules into prokaryotic and eukaryotic cells. It involves the assembly of a tubular structure composed of TssB and TssC that is similar to the tail sheath of bacteriophages. The sheath contracts to provide the energy needed for effector delivery. The AAA(+) ATPase ClpV disassembles the contracted sheath, which resets the systems for reassembly of an extended sheath that is ready to fire again. This mechanism is crucial for T6SS function. In Vibrio cholerae, ClpV binds the N terminus of TssC within a hydrophobic groove. In this study, we resolved the crystal structure of the N-terminal domain of Pseudomonas aeruginosa ClpV1 and observed structural alterations in the hydrophobic groove. The modification in the ClpV1 groove is matched by a change in the N terminus of TssC, suggesting the existence of distinct T6SS classes. An accessory T6SS component, TagJ/HsiE, exists predominantly in one of the classes. Using bacterial two-hybrid approaches, we showed that the P. aeruginosa homolog HsiE1 interacts strongly with ClpV1. We then resolved the crystal structure of HsiE1 in complex with the N terminus of HsiB1, a TssB homolog and component of the contractile sheath. Phylogenetic analysis confirmed that these differences distinguish T6SS classes that resulted from a functional co-evolution between TssB, TssC, TagJ/HsiE, and ClpV. The interaction of TagJ/HsiE with the sheath as well as with ClpV suggests an alternative mode of disassembly in which HsiE recruits the ATPase to the sheath.

A visual assay to monitor T6SS-mediated bacterial competition.

Type VI secretion systems (T6SSs) are molecular nanomachines allowing Gram-negative bacteria to transport and inject proteins into a wide variety of target cells(1,2). The T6SS is composed of 13 core components and displays structural similarities with the tail-tube of bacteriophages(3). The phage uses a tube and a puncturing device to penetrate the cell envelope of target bacteria and inject DNA. It is proposed that the T6SS is an inverted bacteriophage device creating a specific path in the bacterial cell envelope to drive effectors and toxins to the surface. The process could be taken further and the T6SS device could perforate other cells with which the bacterium is in contact, thus injecting the effectors into these targets. The tail tube and puncturing device parts of the T6SS are made with Hcp and VgrG proteins, respectively(4,5). The versatility of the T6SS has been demonstrated through studies using various bacterial pathogens. The Vibrio cholerae T6SS can remodel the cytoskeleton of eukaryotic host cells by injecting an "evolved" VgrG carrying a C-terminal actin cross-linking domain(6,7). Another striking example was recently documented using Pseudomonas aeruginosa which is able to target and kill bacteria in a T6SS-dependent manner, therefore promoting the establishment of bacteria in specific microbial niches and competitive environment(8,9,10). In the latter case, three T6SS-secreted proteins, namely Tse1, Tse2 and Tse3 have been identified as the toxins injected in the target bacteria (Figure 1). The donor cell is protected from the deleterious effect of these effectors via an anti-toxin mechanism, mediated by the Tsi1, Tsi2 and Tsi3 immunity proteins(8,9,10). This antimicrobial activity can be monitored when T6SS-proficient bacteria are co-cultivated on solid surfaces in competition with other bacterial species or with T6SS-inactive bacteria of the same species(8,11,12,13). The data available emphasized a numerical approach to the bacterial competition assay, including time-consuming CFU counting that depends greatly on antibiotic makers. In the case of antibiotic resistant strains like P. aeruginosa, these methods can be inappropriate. Moreover, with the identification of about 200 different T6SS loci in more than 100 bacterial genomes(14), a convenient screening tool is highly desirable. We developed an assay that is easy to use and requires standard laboratory material and reagents. The method offers a rapid and qualitative technique to monitor the T6SS-dependent bactericidal/bacteriostasis activity by using a reporter strain as a prey (in this case Escherichia coli DH5α) allowing a-complementation of the lacZ gene. Overall, this method is graphic and allows rapid identification of T6SS-related phenotypes on agar plates. This experimental protocol may be adapted to other strains or bacterial species taking into account specific conditions such as growth media, temperature or time of contact.

The HsiB1C1 (TssB-TssC) complex of the Pseudomonas aeruginosa type VI secretion system forms a bacteriophage tail sheathlike structure.

Protein secretion systems in Gram-negative bacteria evolved into a variety of molecular nanomachines. They are related to cell envelope complexes, which are involved in assembly of surface appendages or transport of solutes. They are classified as types, the most recent addition being the type VI secretion system (T6SS). The T6SS displays similarities to bacteriophage tail, which drives DNA injection into bacteria. The Hcp protein is related to the T4 bacteriophage tail tube protein gp19, whereas VgrG proteins structurally resemble the gp27/gp5 puncturing device of the phage. The tube and spike of the phage are pushed through the bacterial envelope upon contraction of a tail sheath composed of gp18. In Vibrio cholerae it was proposed that VipA and VipB assemble into a tail sheathlike structure. Here we confirm these previous data by showing that HsiB1 and HsiC1 of the Pseudomonas aeruginosa H1-T6SS assemble into tubules resulting from stacking of cogwheel-like structures showing predominantly 12-fold symmetry. The internal diameter of the cogwheels is ~100 Å, which is large enough to accommodate an Hcp tube whose external diameter has been reported to be 85 Å. The N-terminal 212 residues of HsiC1 are sufficient to form a stable complex with HsiB1, but the C terminus of HsiC1 is essential for the formation of the tubelike structure. Bioinformatics analysis suggests that HsiC1 displays similarities to gp18-like proteins in its C-terminal region. In conclusion, we provide further structural and mechanistic insights into the T6SS and show that a phage sheathlike structure is likely to be a conserved element across all T6SSs.

The archetype Pseudomonas aeruginosa proteins TssB and TagJ form a novel subcomplex in the bacterial type VI secretion system.

In Pseudomonas aeruginosa three type VI secretion systems (T6SSs) coexist, called H1- to H3-T6SSs. Several T6SS components are proposed to be part of a macromolecular complex resembling the bacteriophage tail. The T6SS protein HsiE1 (TagJ) is unique to the H1-T6SS and absent from the H2- and H3-T6SSs. We demonstrate that HsiE1 interacts with a predicted N-terminal α-helix in HsiB1 (TssB) thus forming a novel subcomplex of the T6SS. HsiB1 is homologous to the Vibrio cholerae VipA component, which contributes to the formation of a bacteriophage tail sheath-like structure. We show that the interaction between HsiE1 and HsiB1 is specific and does not occur between HsiE1 and HsiB2. Proteins of the TssB family encoded in T6SS clusters lacking a gene encoding a TagJ-like component are often devoid of the predicted N-terminal helical region, which suggests co-evolution. We observe that a synthetic peptide corresponding to the N-terminal 20 amino acids of HsiB1 interacts with purified HsiE1 protein. This interaction is a common feature to other bacterial T6SSs that display a TagJ homologue as shown here with Serratia marcescens. We further show that hsiE1 is a non-essential gene for the T6SS and suggest that HsiE1 may modulate incorporation of HsiB1 into the T6SS.

Structure-function analysis of HsiF, a gp25-like component of the type VI secretion system, in Pseudomonas aeruginosa.

Bacterial pathogens use a range of protein secretion systems to colonize their host. One recent addition to this arsenal is the type VI secretion system (T6SS), which is found in many Gram-negative bacteria. The T6SS involves 12-15 components, including a ClpV-like AAA(+) ATPase. Moreover, the VgrG and Hcp components have been proposed to form a puncturing device, based on structural similarity to the tail spike components gp5/gp27 and the tail tube component gp19 of the T4 bacteriophage, respectively. Another T6SS component shows similarity to a T4 phage protein, namely gp25. The gp25 protein has been proposed to have lysozyme activity. Other T6SS components do not exhibit obvious similarity to characterized T4 phage components. The genome of Pseudomonas aeruginosa contains three T6SS gene clusters. In each cluster a gene encoding a putative member of the gp25-like protein family was identified, which we called HsiF. We confirmed this similarity by analysing the structure of the P. aeruginosa HsiF proteins using secondary and tertiary structure prediction tools. We demonstrated that HsiF1 is crucial for the T6SS-dependent secretion of Hcp and VgrG. Importantly, lysozyme activity of HsiF proteins was not detectable, and we related this observation to the demonstration that HsiF1 localizes to the cytoplasm of P. aeruginosa. Finally, our data showed that a conserved glutamate, predicted to be required for proper HsiF folding, is essential for its function. In conclusion, our data confirm the central role of HsiF in the T6SS mechanism, provide information on the predicted HsiF structure, and call for reconsideration of the function of gp25-like proteins.

Type VI secretion system in Pseudomonas aeruginosa: secretion and multimerization of VgrG proteins.

Pseudomonas aeruginosa is a Gram-negative bacterium causing chronic infections in cystic fibrosis patients. Such infections are associated with an active type VI secretion system (T6SS), which consists of about 15 conserved components, including the AAA+ ATPase, ClpV. The T6SS secretes two categories of proteins, VgrG and Hcp. Hcp is structurally similar to a phage tail tube component, whereas VgrG proteins show similarity to the puncturing device at the tip of the phage tube. In P. aeruginosa, three T6SSs are known. The expression of H1-T6SS genes is controlled by the RetS sensor. Here, 10 vgrG genes were identified in the PAO1 genome, among which three are co-regulated with H1-T6SS, namely vgrG1a/b/c. Whereas VgrG1a and VgrG1c were secreted in a ClpV1-dependent manner, secretion of VgrG1b was ClpV1-independent. We show that VgrG1a and VgrG1c form multimers, which confirmed the VgrG model predicting trimers similar to the tail spike. We demonstrate that Hcp1 secretion requires either VgrG1a or VgrG1c, which may act independently to puncture the bacterial envelope and give Hcp1 access to the surface. VgrG1b is not required for Hcp1 secretion. Thus, VgrG1b does not require H1-T6SS for secretion nor does H1-T6SS require VgrG1b for its function. Finally, we show that VgrG proteins are required for secretion of a genuine H1-T6SS substrate, Tse3. Our results demonstrate that VgrG proteins are not only secreted components but are essential for secretion of other T6SS substrates. Overall, we emphasize variability in behavior of three P. aeruginosa VgrGs, suggesting that, although very similar, distinct VgrGs achieve specific functions.

The Salmonella SPI-2 effector SseJ exhibits eukaryotic activator-dependent phospholipase A and glycerophospholipid : cholesterol acyltransferase activity.

Intracellular replication of Salmonella enterica serovar Typhimurium within membrane-bound compartments, called Salmonella-containing vacuoles, depends on the activities of several effector proteins translocated by the Salmonella pathogenicity island 2 (SPI-2)-encoded type III secretion system. The SPI-2 effector protein SseJ shows similarity at the amino acid level to several GDSL lipases with glycerophospholipid : cholesterol acyltransferase (GCAT) activity. In this study, we show that catalytic serine-dependent phospholipase A (PLA) and GCAT activity of recombinant SseJ is potentiated by factor(s) present in HeLa cells, RAW macrophages and Saccharomyces cerevisiae. SseJ activity was enhanced with increasing amounts of, or preincubation with, eukaryotic cell extracts. Analysis of the activating factor(s) shows that it is soluble and heat- and protease-sensitive. We conclude that PLA and GCAT activities of SseJ are potentiated by proteinaceous eukaryotic factor(s).