WS13.4 Efficacy and safety of lumacaftor/ivacaftor (LUM/IVA) in patients (pts) aged 6–11 years (yrs) with cystic fibrosis (CF) homozygous for F508del-CFTR: a randomized placebo (PBO)-controlled phase 3 trial

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.

Brazilian guidelines for the pharmacological treatment of the pulmonary symptoms of cystic fibrosis. Official document of the Sociedade Brasileira de Pneumologia e Tisiologia (SBPT, Brazilian Thoracic Association)

Cystic fibrosis (CF) is a genetic disease that results in dysfunction of the CF transmembrane conductance regulator (CFTR) protein, which is a chloride and bicarbonate channel expressed in the apical portion of epithelial cells of various organs. Dysfunction of that protein results in diverse clinical manifestations, primarily involving the respiratory and gastrointestinal systems, impairing quality of life and reducing life expectancy. Although CF is still an incurable pathology, the therapeutic and prognostic perspectives are now totally different and much more favorable. The purpose of these guidelines is to define evidence-based recommendations regarding the use of pharmacological agents in the treatment of the pulmonary symptoms of CF in Brazil. Questions in the Patients of interest, Intervention to be studied, Comparison of interventions, and Outcome of interest (PICO) format were employed to address aspects related to the use of modulators of this protein (ivacaftor, lumacaftor+ivacaftor, and tezacaftor+ivacaftor), use of dornase alfa, eradication therapy and chronic suppression of Pseudomonas aeruginosa, and eradication of methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex. To formulate the PICO questions, a group of Brazilian specialists was assembled and a systematic review was carried out on the themes, with meta-analysis when applicable. The results obtained were analyzed in terms of the strength of the evidence compiled, the recommendations being devised by employing the GRADE approach. We believe that these guidelines represent a major advance to be incorporated into the approach to patients with CF, mainly aiming to favor the management of the disease, and could become an auxiliary tool in the definition of public policies related to CF.

Experience of using lumacaftor/ivacaftor in children with cystic fibrosis in the Astrakhan region

Background. Targeted therapy in patients with cystic fibrosis, which aims to restore the function of the cystic fibrosis transmembrane conductance regulator protein, is currently revolutionary in the treatment of the disease. The first drug available in Russia for the treatment of patients with this genetic disease is lumacaftor/ivacaftor (Orkambi®), which was registered on December 2, 2020.

The aim. To study the efficacy of lumacaftor/ivacaftor during 12 weeks of administration in children in Astrakhan region.

Materials and methods. This article presents the clinical experience of Orkambi medicine use in 3 children with F508del/F508del genotype and a severe course of cystic fibrosis for 12 weeks. According to the study design, such indices as body mass index, indexes of external respiratory function, character of respiratory tract microbiota, level of chloride in sweat fluid and pancreatic elastase in feces, dynamics of biochemical blood indexes were evaluated. The study was performed within the time periods specified in the study protocol, namely, before the start of therapy, 2, 4, and 12 weeks of treatment.

Results. Two patients had a decrease in sweat test values by 11 and 19 mmol/l from the baseline, a significant increase in forced vital capacity of lungs. One patient had an adverse event in the form of hepatobiliary disorders manifested by increased liver transaminase activity, which was the reason for discontinuing the drug.

Conclusions. The short-term experience of using pathogenetic therapy with lumacaftor/ ivacaftor in children in the Astrakhan region demonstrated both the expected effect on chlorine channel function and the possibility of side effects, including severe ones, that can lead to withdrawal of the drug.

Trends in Growth and Maturation in Children with Cystic Fibrosis Throughout Nine Decades

Since cystic fibrosis (CF) was first described in 1938, there have been many discoveries and innovations in the field, each having a profound impact on survival, growth and quality of life. For example, the introduction of enteric-coated pancreatic enzyme microspheres increased fat absorption and improved nutritional status. Early detection of CF through newborn screening facilitated prompt nutritional intervention for infants at high risk of malnutrition. Use of anti-pseudomonal therapy, such as inhaled tobramycin, increased weight gain and pulmonary function in addition to reducing pulmonary exacerbations. Similarly, DNAse and hypertonic saline improved pulmonary function and reduced exacerbations. The identification of the CFTR gene and its protein product were fundamental in understanding the pathophysiology of CF and paved the way for advances in both diagnosis and management. In fact, CFTR modulator therapies have revolutionized the care for individuals with CF. Here, we examine the impact of these interventions on the nutritional status, growth and pubertal maturation of children and adolescents with CF.

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.

An 8 week open-label interventional multicenter study to explore the lung clearance index as endpoint for clinical trials in cystic fibrosis patients ≥8 years of age, chronically infected with Pseudomonas aeruginosa

BACKGROUND

Forced expiratory volume in 1 second (FEV₁) is the only parameter currently recognized as a surrogate endpoint in cystic fibrosis (CF) trials. However, FEV₁ is relatively insensitive to changes in the small airways of patients with milder lung disease. This pilot study aimed to explore the lung clearance index (LCI) as a marker for use in efficacy trials with inhaled antibiotics in CF.

METHODS

This open-label, single-arm study enrolled CF patients with Pseudomonas aeruginosa infection, who were treated with tobramycin (28-day on/off regime). FEV₁, LCI and bacterial load in sputum (CFU) were assessed at baseline, after 1, 4 and 8 weeks of treatment.

RESULTS

All patients (n = 17) showed elevated LCI of > 11 despite 3 patients having normal FEV₁ (> 90% predicted) at baseline. Overall, LCI improved in 8 (47%) patients and FEV₁ in 9 (53%) patients. At week 4, LCI improved by 0.88, FEV₁ increased by 0.52%, and P. aeruginosa reduced by 30,481.3 CFU/mL. These changes were however statistically non-significant. Six adverse events occurred in 5/17 (29.4%) patients, most of which were mild-to-moderate in severity.

CONCLUSIONS

Due to the low evaluable sample size, no specific trend was observed related to the changes between LCI, FEV₁ and CFU. Based on the individual data from this study and from recently published literature, LCI has been shown to be a more sensitive parameter than FEV₁ for lung function. LCI can be hypothesized to be an appropriate endpoint for efficacy trials in CF patients if the heterogeneity in lung function is limited by enrolling younger patients or patients with more milder lung disease and thus, limiting the ventilation inhomogeneities.

TRIAL REGISTRATION

The study is registered with ClinicalTrials.gov, identifier: NCT02248922.

Correctors (specific therapies for class II CFTR mutations) for cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a common life-shortening condition caused by mutation in the gene that codes for that codes for the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which functions as a salt transporter. F508del, the most common CFTR mutation that causes CF, is found in up to 80% to 90% of people with CF. In people with this mutation, a full length of protein is transcribed, but recognised as misfolded by the cell and degraded before reaching the cell membrane, where it needs to be positioned to effect transepithelial salt transport. This severe mutation is associated with no meaningful CFTR function. A corrective therapy for this mutation could positively impact on an important proportion of the CF population.

OBJECTIVES

To evaluate the effects of CFTR correctors on clinically important outcomes, both benefits and harms, in children and adults with CF and class II CFTR mutations (most commonly F508del).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Cystic Fibrosis Trials Register. We also searched reference lists of relevant articles and online trials registries. Most recent search: 24 February 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) (parallel design) comparing CFTR correctors to placebo in people with CF with class II mutations. We also included RCTs comparing CFTR correctors combined with CFTR potentiators to placebo.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data, assessed risk of bias and quality of the evidence using the GRADE criteria. Study authors were contacted for additional data.

MAIN RESULTS

We included 13 RCTs (2215 participants), lasting between 1 day and 24 weeks. Additional safety data from an extension study of two lumacaftor-ivacaftor studies were available at 96 weeks (1029 participants). We assessed monotherapy in seven RCTs (317 participants) (4PBA (also known as Buphenyl), CPX, lumacaftor or cavosonstat) and combination therapy in six RCTs (1898 participants) (lumacaftor-ivacaftor or tezacaftor-ivacaftor) compared to placebo. Twelve RCTs recruited individuals homozygous for F508del, one RCT recruited participants with one F508del mutation and a second mutation with residual function.Risk of bias varied in its impact on the confidence we have in our results across different comparisons. Some findings were based on single RCTs that were too small to show important effects. For five RCTs, results may not be applicable to all individuals with CF due to age limits of recruited populations (i.e. adults only, children only) or non-standard design of converting from monotherapy to combination therapy.Monotherapy versus placeboNo deaths were reported and there were no clinically relevant improvements in quality of life in any RCT. There was insufficient evidence available from individual studies to determine the effect of any of the correctors examined on lung function outcomes.No placebo-controlled study of monotherapy demonstrated a difference in mild, moderate or severe adverse effects; however, it is difficult to assess the clinical relevance of these events with the variety of events and the small number of participants.Combination therapy versus placeboNo deaths were reported during any RCT (moderate- to high-quality evidence). The quality of life scores (respiratory domain) favoured combination therapy (both lumacaftor-ivacaftor and tezacaftor-ivacaftor) compared to placebo at all time points. At six months lumacaftor (600 mg once daily or 400 mg once daily) plus ivacaftor improved Cystic Fibrosis Questionnaire (CFQ) scores by a small amount 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 size was observed for twice-daily lumacaftor (200 mg) plus ivacaftor (250 mg) although the quality of evidence was low (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). Lung function measured by relative change in forced expiratory volume in one second (FEV₁) % predicted improved with both combination therapies compared to placebo at six months, by 5.21% with once daily lumacaftor-ivacaftor (95% CI 3.61% to 6.80%; 504 participants; high-quality evidence) and by 2.40% with twice-daily lumacaftor-ivacaftor (95% CI 0.40% to 4.40%; 204 participants; low-quality evidence). One study reported an increase in FEV₁ with tezacaftor-ivacaftor of 6.80% (95% CI 5.30 to 8.30%; 520 participants; moderate-quality evidence).More participants receiving the lumacaftor-ivacaftor combination reported early transient breathlessness, odds ratio 2.05 (99% CI 1.10 to 3.83; 739 participants; high-quality evidence). In addition, participants allocated to the 400 mg twice-daily dose of lumacaftor-ivacaftor experienced a rise in blood pressure over the 120-week period of the initial studies and the follow-up study of 5.1 mmHg (systolic blood pressure) and 4.1 mmHg (diastolic blood pressure) (80 participants; high-quality evidence). These adverse effects were not reported in the tezacaftor-ivacaftor studies.The rate of pulmonary exacerbations decreased for participants receiving and 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).

AUTHORS' CONCLUSIONS

There is insufficient evidence that monotherapy with correctors has clinically important effects in people with CF who have two copies of the F508del mutation.Combination therapies (lumacaftor-ivacaftor and tezacaftor-ivacaftor) each result in similarly small improvements in clinical outcomes in people with CF; specifically improvements quality of life (moderate-quality evidence), in respiratory function (high-quality evidence) and lower pulmonary exacerbation rates (moderate-quality evidence). Lumacaftor-ivacaftor is associated with an increase in early transient shortness of breath and longer-term increases in blood pressure (high-quality evidence). These adverse effects were not observed for tezacaftor-ivacaftor. Tezacaftor-ivacaftor has a better safety profile, although data are not available for children younger than 12 years. In this age group, lumacaftor-ivacaftor had an important impact on respiratory function with no apparent immediate safety concerns, but this should be balanced against the increase in blood pressure and shortness of breath seen in longer-term data in adults when considering this combination for use in young people with CF.