Corrector therapies (with or without potentiators) for people with cystic fibrosis with class II CFTR gene variants (most commonly F508del).

BACKGROUND: Cystic fibrosis (CF) is a common life-shortening genetic condition caused by a variant in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. A class II CFTR variant F508del is the commonest CF-causing variant (found in up to 90% of people with CF (pwCF)). The F508del variant lacks meaningful CFTR function - faulty protein is degraded before reaching the cell membrane, where it needs to be to effect transepithelial salt transport. Corrective therapy could benefit many pwCF. This review evaluates single correctors (monotherapy) and any combination of correctors (most commonly lumacaftor, tezacaftor, elexacaftor, VX-659, VX-440 or VX-152) and a potentiator (e.g. ivacaftor) (dual and triple therapies). OBJECTIVES: To evaluate the effects of CFTR correctors (with or without potentiators) on clinically important benefits and harms in pwCF of any age with class II CFTR mutations (most commonly F508del). SEARCH METHODS: We searched the Cochrane CF Trials Register (28 November 2022), reference lists of relevant articles and online trials registries (3 December 2022). SELECTION CRITERIA: Randomised controlled trials (RCTs) (parallel design) comparing CFTR correctors to control in pwCF with class II mutations. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data, assessed risk of bias and judged evidence certainty (GRADE); we contacted investigators for additional data. MAIN RESULTS: We included 34 RCTs (4781 participants), lasting between 1 day and 48 weeks; an extension of two lumacaftor-ivacaftor studies provided additional 96-week safety data (1029 participants). We assessed eight monotherapy RCTs (344 participants) (4PBA, CPX, lumacaftor, cavosonstat and FDL169), 16 dual-therapy RCTs (2627 participants) (lumacaftor-ivacaftor or tezacaftor-ivacaftor) and 11 triple-therapy RCTs (1804 participants) (elexacaftor-tezacaftor-ivacaftor/deutivacaftor; VX-659-tezacaftor-ivacaftor/deutivacaftor; VX-440-tezacaftor-ivacaftor; VX-152-tezacaftor-ivacaftor). Participants in 21 RCTs had the genotype F508del/F508del, in seven RCTs they had F508del/minimal function (MF), in one RCT F508del/gating genotypes, in one RCT either F508del/F508del genotypes or F508del/residual function genotypes, in one RCT either F508del/gating or F508del/residual function genotypes, and in three RCTs either F508del/F508del genotypes or F508del/MF genotypes. Risk of bias judgements varied across different comparisons. Results from 16 RCTs may not be applicable to all pwCF due to age limits (e.g. adults only) or non-standard designs (converting from monotherapy to combination therapy). Monotherapy Investigators reported no deaths or clinically relevant improvements in quality of life (QoL). There was insufficient evidence to determine effects on lung function. No placebo-controlled monotherapy RCT demonstrated differences in mild, moderate or severe adverse effects (AEs); the clinical relevance of these events is difficult to assess due to their variety and few participants (all F508del/F508del). Dual therapy In a tezacaftor-ivacaftor group there was one death (deemed unrelated to the study drug). QoL scores (respiratory domain) favoured both lumacaftor-ivacaftor and tezacaftor-ivacaftor therapy compared to placebo at all time points (moderate-certainty evidence). At six months, relative change in forced expiratory volume in one second (FEV1) % predicted improved with all dual combination therapies compared to placebo (high- to moderate-certainty evidence). More pwCF reported early transient breathlessness with lumacaftor-ivacaftor (odds ratio (OR) 2.05, 99% confidence interval (CI) 1.10 to 3.83; I2 = 0%; 2 studies, 739 participants; high-certainty evidence). Over 120 weeks (initial study period and follow-up), systolic blood pressure rose by 5.1 mmHg and diastolic blood pressure by 4.1 mmHg with twice-daily 400 mg lumacaftor-ivacaftor (80 participants). The tezacaftor-ivacaftor RCTs did not report these adverse effects. Pulmonary exacerbation rates decreased in pwCF receiving additional therapies to ivacaftor compared to placebo (all moderate-certainty evidence): lumacaftor 600 mg (hazard ratio (HR) 0.70, 95% CI 0.57 to 0.87; I2 = 0%; 2 studies, 739 participants); lumacaftor 400 mg (HR 0.61, 95% CI 0.49 to 0.76; I2 = 0%; 2 studies, 740 participants); and tezacaftor (HR 0.64, 95% CI 0.46 to 0.89; 1 study, 506 participants). Triple therapy No study reported any deaths (high-certainty evidence). All other evidence was low- to moderate-certainty. QoL respiratory domain scores probably improved with triple therapy compared to control at six months (six studies). There was probably a greater relative and absolute change in FEV1 % predicted with triple therapy (four studies each across all combinations). The absolute change in FEV1 % predicted was probably greater for F508del/MF participants taking elexacaftor-tezacaftor-ivacaftor compared to placebo (mean difference 14.30, 95% CI 12.76 to 15.84; 1 study, 403 participants; moderate-certainty evidence), with similar results for other drug combinations and genotypes. There was little or no difference in adverse events between triple therapy and control (10 studies). No study reported time to next pulmonary exacerbation, but fewer F508del/F508del participants experienced a pulmonary exacerbation with elexacaftor-tezacaftor-ivacaftor at four weeks (OR 0.17, 99% CI 0.06 to 0.45; 1 study, 175 participants) and 24 weeks (OR 0.29, 95% CI 0.14 to 0.60; 1 study, 405 participants); similar results were seen across other triple therapy and genotype combinations. AUTHORS' CONCLUSIONS: There is insufficient evidence of clinically important effects from corrector monotherapy in pwCF with F508del/F508del. Additional data in this review reduced the evidence for efficacy of dual therapy; these agents can no longer be considered as standard therapy. Their use may be appropriate in exceptional circumstances (e.g. if triple therapy is not tolerated or due to age). Both dual therapies (lumacaftor-ivacaftor, tezacaftor-ivacaftor) result in similar small improvements in QoL and respiratory function with lower pulmonary exacerbation rates. While the effect sizes for QoL and FEV1 still favour treatment, they have reduced compared to our previous findings. Lumacaftor-ivacaftor was associated with an increase in early transient shortness of breath and longer-term increases in blood pressure (not observed for tezacaftor-ivacaftor). Tezacaftor-ivacaftor has a better safety profile, although data are lacking in children under 12 years. In this population, lumacaftor-ivacaftor had an important impact on respiratory function with no apparent immediate safety concerns, but this should be balanced against the blood pressure increase and shortness of breath seen in longer-term adult data when considering lumacaftor-ivacaftor. Data from triple therapy trials demonstrate improvements in several key outcomes, including FEV1 and QoL. There is probably little or no difference in adverse events for triple therapy (elexacaftor-tezacaftor-ivacaftor/deutivacaftor; VX-659-tezacaftor-ivacaftor/deutivacaftor; VX-440-tezacaftor-ivacaftor; VX-152-tezacaftor-ivacaftor) in pwCF with one or two F508del variants aged 12 years or older (moderate-certainty evidence). Further RCTs are required in children under 12 years and those with more severe lung disease.

Corrector therapies (with or without potentiators) for people with cystic fibrosis with class II CFTR gene variants (most commonly F508del).

BACKGROUND: Cystic fibrosis (CF) is a common life-shortening genetic condition caused by a variant in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. A class II CFTR variant F508del (found in up to 90% of people with CF (pwCF)) is the commonest CF-causing variant. The faulty protein is degraded before reaching the cell membrane, where it needs to be to effect transepithelial salt transport. The F508del variant lacks meaningful CFTR function and corrective therapy could benefit many pwCF. Therapies in this review include single correctors and any combination of correctors and potentiators. OBJECTIVES: To evaluate the effects of CFTR correctors (with or without potentiators) on clinically important benefits and harms in pwCF of any age with class II CFTR mutations (most commonly F508del). SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Cystic Fibrosis Trials Register, reference lists of relevant articles and online trials registries. Most recent search: 14 October 2020. SELECTION CRITERIA: Randomised controlled trials (RCTs) (parallel design) comparing CFTR correctors to control in pwCF with class II mutations. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data, assessed risk of bias and evidence quality (GRADE); we contacted investigators for additional data. MAIN RESULTS: We included 19 RCTs (2959 participants), lasting between 1 day and 24 weeks; an extension of two lumacaftor-ivacaftor studies provided additional 96-week safety data (1029 participants). We assessed eight monotherapy RCTs (344 participants) (4PBA, CPX, lumacaftor, cavosonstat and FDL169), six dual-therapy RCTs (1840 participants) (lumacaftor-ivacaftor or tezacaftor-ivacaftor) and five triple-therapy RCTs (775 participants) (elexacaftor-tezacaftor-ivacaftor or VX-659-tezacaftor-ivacaftor); below we report only the data from elexacaftor-tezacaftor-ivacaftor combination which proceeded to Phase 3 trials. In 14 RCTs participants had F508del/F508del genotypes, in three RCTs F508del/minimal function (MF) genotypes and in two RCTs both genotypes. Risk of bias judgements varied across different comparisons. Results from 11 RCTs may not be applicable to all pwCF due to age limits (e.g. adults only) or non-standard design (converting from monotherapy to combination therapy). Monotherapy Investigators reported no deaths or clinically-relevant improvements in quality of life (QoL). There was insufficient evidence to determine any important effects on lung function. No placebo-controlled monotherapy RCT demonstrated differences in mild, moderate or severe adverse effects (AEs); the clinical relevance of these events is difficult to assess with their variety and small number of participants (all F508del/F508del). Dual therapy Investigators reported no deaths (moderate- to high-quality evidence). QoL scores (respiratory domain) favoured both lumacaftor-ivacaftor and tezacaftor-ivacaftor therapy compared to placebo at all time points. At six months lumacaftor 600 mg or 400 mg (both once daily) plus ivacaftor improved Cystic Fibrosis Questionnaire (CFQ) scores slightly compared with placebo (mean difference (MD) 2.62 points (95% confidence interval (CI) 0.64 to 4.59); 1061 participants; high-quality evidence). A similar effect was observed for twice-daily lumacaftor (200 mg) plus ivacaftor (250 mg), but with low-quality evidence (MD 2.50 points (95% CI 0.10 to 5.10)). The mean increase in CFQ scores with twice-daily tezacaftor (100 mg) and ivacaftor (150 mg) was approximately five points (95% CI 3.20 to 7.00; 504 participants; moderate-quality evidence). At six months, the relative change in forced expiratory volume in one second (FEV1) % predicted improved with combination therapies compared to placebo by: 5.21% with once-daily lumacaftor-ivacaftor (95% CI 3.61% to 6.80%; 504 participants; high-quality evidence); 2.40% with twice-daily lumacaftor-ivacaftor (95% CI 0.40% to 4.40%; 204 participants; low-quality evidence); and 6.80% with tezacaftor-ivacaftor (95% CI 5.30 to 8.30%; 520 participants; moderate-quality evidence). More pwCF reported early transient breathlessness with lumacaftor-ivacaftor, odds ratio 2.05 (99% CI 1.10 to 3.83; 739 participants; high-quality evidence). Over 120 weeks (initial study period and follow-up) systolic blood pressure rose by 5.1 mmHg and diastolic blood pressure by 4.1 mmHg with twice-daily 400 mg lumacaftor-ivacaftor (80 participants; high-quality evidence). The tezacaftor-ivacaftor RCTs did not report these adverse effects. Pulmonary exacerbation rates decreased in pwCF receiving additional therapies to ivacaftor compared to placebo: lumacaftor 600 mg hazard ratio (HR) 0.70 (95% CI 0.57 to 0.87; 739 participants); lumacaftor 400 mg, HR 0.61 (95% CI 0.49 to 0.76; 740 participants); and tezacaftor, HR 0.64 (95% CI, 0.46 to 0.89; 506 participants) (moderate-quality evidence). Triple therapy Three RCTs of elexacaftor to tezacaftor-ivacaftor in pwCF (aged 12 years and older with either one or two F508del variants) reported no deaths (high-quality evidence). All other evidence was graded as moderate quality. In 403 participants with F508del/minimal function (MF) elexacaftor-tezacaftor-ivacaftor improved QoL respiratory scores (MD 20.2 points (95% CI 16.2 to 24.2)) and absolute change in FEV1 (MD 14.3% predicted (95% CI 12.7 to 15.8)) compared to placebo at 24 weeks. At four weeks in 107 F508del/F508del participants, elexacaftor-tezacaftor-ivacaftor improved QoL respiratory scores (17.4 points (95% CI 11.9 to 22.9)) and absolute change in FEV1 (MD 10.0% predicted (95% CI 7.5 to 12.5)) compared to tezacaftor-ivacaftor. There was probably little or no difference in the number or severity of AEs between elexacaftor-tezacaftor-ivacaftor and placebo or control (moderate-quality evidence). In 403 F508del/F508del participants, there was a longer time to protocol-defined pulmonary exacerbation with elexacaftor-tezacaftor-ivacaftor over 24 weeks (moderate-quality evidence). AUTHORS' CONCLUSIONS: There is insufficient evidence that corrector monotherapy has clinically important effects in pwCF with F508del/F508del. Both dual therapies (lumacaftor-ivacaftor, tezacaftor-ivacaftor) result in similar improvements in QoL and respiratory function with lower pulmonary exacerbation rates. Lumacaftor-ivacaftor was associated with an increase in early transient shortness of breath and longer-term increases in blood pressure (not observed for tezacaftor-ivacaftor). Tezacaftor-ivacaftor has a better safety profile, although data are lacking in children under 12 years. In this population, lumacaftor-ivacaftor had an important impact on respiratory function with no apparent immediate safety concerns; but this should be balanced against the blood pressure increase and shortness of breath seen in longer-term adult data when considering lumacaftor-ivacaftor. There is high-quality evidence of clinical efficacy with probably little or no difference in AEs for triple (elexacaftor-tezacaftor-ivacaftor) therapy in pwCF with one or two F508del variants aged 12 years or older. Further RCTs are required in children (under 12 years) and those with more severe respiratory function.

Impact of indoor environment on children's pulmonary health.

INTRODUCTION: A child's living environment has a significant impact on their respiratory health, with exposure to poor indoor air quality (IAQ) contributing to potentially lifelong respiratory morbidity. These effects occur throughout childhood, from the antenatal period through to adolescence. Children are particularly susceptible to the effects of environmental insults, and children living in socioeconomic deprivation globally are more likely to breathe air both indoors and outdoors, which poses an acute and long-term risk to their health. Adult respiratory health is, at least in part, determined by exposures and respiratory system development in childhood, starting in utero. AREAS COVERED: This narrative review will discuss, from a global perspective, what contributes to poor IAQ in the child's home and school environment and the impact that indoor air pollution exposure has on respiratory health throughout the different stages of childhood. EXPERT OPINION: All children have the right to a living and educational environment without the threat of pollution affecting their health. Action is needed at multiple levels to address this pressing issue to improve lifelong respiratory health. Such action should incorporate a child's rights-based approach, empowering children, and their families, to have access to clean air to breathe in their living environment.

Cystic Fibrosis Cases Missed by Newborn Bloodspot Screening-Towards a Consistent Definition and Data Acquisition.

Repeated European surveys of newborn bloodspot screening (NBS) have shown varied strategies for collecting missed cases, and information on data collection differs among countries/regions, hampering data comparison. The ECFS Neonatal Screening Working Group defined missed cases by NBS as either false negatives, protocol-related, concerning analytical issues, or non-protocol-related, concerning pre- and post-analytical issues. A questionnaire has been designed and sent to all key workers identified in each NBS programme to assess the feasibility of collecting data on missed cases, the stage of the NBS programme when the system failed, and individual patient data on each missed case.