NOVAS TERAPIAS

Lumacaftor-Ivacaftor in Patients with Cystic Fibrosis Homozygous for Phe508del CFTR.

Wainwright CE, Elborn JS, Ramsey BW, Marigowda G, Huang X, Cipolli M, Colombo C, Davies JC, De Boeck K, Flume PA, Konstan MW, McColley SA, McCoy K, McKone EF, Munck A, Ratjen F, Rowe SM, Waltz D, Boyle MP; TRAFFIC Study Group; TRANSPORT Study Group.

N Engl J Med. 2015

Abstract

BACKGROUND:

Cystic fibrosis is a life-limiting disease that is caused by defective or deficient cystic fibrosis transmembrane conductance regulator (CFTR) protein activity. Phe508del is the most common CFTR mutation.

METHODS:

We conducted two phase 3, randomized, double-blind, placebo-controlled studies that were designed to assess the effects of lumacaftor (VX-809), a CFTR corrector, in combination with ivacaftor (VX-770), a CFTR potentiator, in patients 12 years of age or older who had cystic fibrosis and were homozygous for the Phe508del CFTR mutation. In both studies, patients were randomly assigned to receive either lumacaftor (600 mg once daily or 400 mg every 12 hours) in combination with ivacaftor (250 mg every 12 hours) or matched placebo for 24 weeks. The primary end point was the absolute change from baseline in the percentage of predicted forced expiratory volume in 1 second (FEV1) at week 24.

RESULTS:

A total of 1108 patients underwent randomization and received study drug. The mean baseline FEV1 was 61% of the predicted value. In both studies, there were significant improvements in the primary end point in both lumacaftor-ivacaftor dose groups; the difference between active treatment and placebo with respect to the mean absolute improvement in the percentage of predicted FEV1 ranged from 2.6 to 4.0 percentage points (P<0.001), which corresponded to a mean relative treatment difference of 4.3 to 6.7% (P<0.001). Pooled analyses showed that the rate of pulmonary exacerbations was 30 to 39% lower in the lumacaftor-ivacaftor groups than in the placebo group; the rate of events leading to hospitalization or the use of intravenous antibiotics was lower in the lumacaftor-ivacaftor groups as well. The incidence of adverse events was generally similar in the lumacaftor-ivacaftor and placebo groups. The rate of discontinuation due to an adverse event was 4.2% among patients who received lumacaftor-ivacaftor versus 1.6% among those who received placebo.

CONCLUSIONS:

These data show that lumacaftor in combination with ivacaftor provided a benefit for patients with cystic fibrosis homozygous for the Phe508del CFTR mutation.


Potentiators (specific therapies for class III and IV mutations) for cystic fibrosis.

Patel S1, Sinha IP, Dwan K, Echevarria C, Schechter M, Southern KW.

Cochrane Database Syst Rev. 2015

Abstract

BACKGROUND:

Cystic fibrosis is the most common inherited life-shortening illness in Caucasians and caused by a mutation in the gene that codes for the cystic fibrosis transmembrane regulator protein (CFTR), which functions as a salt transporter. This mutation most notably affects the airways of people with cystic fibrosis. Excess salt absorption by defective CFTR dehydrates the airway lining and leads to defective mucociliary clearance. Consequent accumulation of thick, sticky mucus makes the airway prone to chronic infection and progressive inflammation; respiratory failure often ensues. Additionally, abnormalities with CFTR lead to systemic complications like malnutrition, diabetes and subfertility.Since the discovery of the causative gene, our understanding of the structure and function of CFTR and the impact of different mutations has increased and allowed pharmaceutical companies to design new mutation-specific therapies targeting the underlying molecular defect. Therapies targeting mutation classes III and IV (CFTR potentiators) aim to normalise airway surface liquid and help re-establish mucociliary clearance, which then has a beneficial impact on the chronic infection and inflammation that characterizes lung disease in people with cystic fibrosis. These therapies may also affect other mutations.

OBJECTIVES:

To evaluate the effects of CFTR potentiators on clinically important outcomes in children and adults with cystic fibrosis.

SEARCH METHODS:

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Last search: 05 March 2015.We searched the EU Clinical Trials Register, clinicaltrials.gov (US Clinical Trials Register) and the International Clinical Trials Registry Platform (ICTRP). Last search of clinical trial registries: 06 February 2014.

SELECTION CRITERIA:

Randomised controlled trials of parallel design comparing CFTR potentiators to placebo in people with cystic fibrosis. In a post hoc change we excluded trials combining CFTR potentiators with other mutation-specific therapies. These will be considered in a separate review.

DATA COLLECTION AND ANALYSIS:

The authors independently extracted data and assessed the risk of bias in included trials; they contacted trial authors for additional data. Meta-analyses were undertaken on outcomes at a number of time points.

MAIN RESULTS:

We included four randomised controlled trials (n = 378), lasting from 28 days to 48 weeks, comparing the potentiator ivacaftor to placebo. Trials differed in terms of design and participant eligibility criteria, which limited the meta-analyses. The phase 2 trial (n = 19) and two phase 3 trials (adult trial (n = 167), paediatric trial (n = 52)), recruited participants with the G551D mutation (class III). The fourth trial (n = 140) enrolled participants homozygous for the ΔF508 mutation (class II).Risks of bias in the trials were moderate. Random sequence generation, allocation concealment and blinding of trial personnel were well-documented. Participant blinding was less clear throughout all trials; in three trials, some participant data were excluded from the analysis. Selective outcome reporting was apparent in three trials. All trials were sponsored by industry and supported by other non-pharmaceutical funding bodies.No trial reported any deaths. Significantly higher quality of life scores in the respiratory domain were reported by the adult phase 3 G551D trial at 24 weeks, mean difference 8.10 (95% confidence interval (CI) 4.77 to 11.43) and 48 weeks, mean difference 8.60 (95% CI 5.27 to 11.93); but not by the paediatric phase 3 G551D trial. The adult phase 3 G551D trial reported improvements in relative change from baseline in forced expiratory volume at one second at 24 weeks, mean difference 16.90% (95% CI 13.60 to 20.20) and 48 weeks, mean difference 16.80% (95% CI 13.50 to 20.10); as did the paediatric G551D trial at 24 weeks, mean difference 17.4% (P < 0.0001)). No improvements in quality of life or lung function were reported in the ΔF508 participants.Combined data from both phase 3 G551D trials demonstrated increased reporting of cough, odds ratio 0.57 (95% CI 0.33 to 1.00) and increased episodes of decreased pulmonary function, odds ratio 0.29 (95% CI 0.10 to 0.82) in the placebo group. The adult phase 3 G551D trial demonstrated increased reporting of dizziness amongst the ivacaftor group, OR 10.55 (95% CI 1.32 to 84.47). No trial showed a difference between treatment arms in the number of participants interrupting or discontinuing the trial drug.In the phase 3 G551D trials, fewer participants assigned to ivacaftor developed serious pulmonary exacerbations. When considering all data for exacerbations, participants taking ivacaftor in the adult phase 3 G551D study developed fewer exacerbations, odds ratio 0.54 (95% CI 0.29 to 1.01). In the other G551D studies and in the ΔF508 study, there was no difference between groups in the number of participants who developed pulmonary exacerbations.Combined data from both phase 3 G551D trials demonstrated significant improvements in absolute change from baseline in forced expiratory volume at one second (% predicted) at 24 weeks, mean difference 10.80% (95% CI 8.91 to 12.69) and 48 weeks, mean difference 10.44% (95% CI 8.56 to 12.32); also in weight at 24 weeks, mean difference 2.37 kg (95% CI 1.68 to 3.06) and 48 weeks, mean difference 2.75 kg (95% CI 1.74 to 3.75). No improvements in these outcomes were reported in the ΔF508 participants.Significant reductions in sweat chloride concentration were reported in both G551D and ΔF508 participants: in combined data from both phase 3 G551D trials at 24 weeks, mean difference -48.98 mmol/L (95% CI -52.07 to -45.89) and 48 weeks, mean difference -49.03 mmol/L (95% CI -52.11 to -45.94); and from the ΔF508 trial at 16 weeks, mean difference -2.90 mmol/L (95% CI -5.60 to -0.20).

AUTHORS’ CONCLUSIONS:

Both G551D phase 3 trials (n = 219) demonstrated a clinically relevant impact of the potentiator ivacaftor on outcomes at 24 and 48 weeks, providing evidence for the use of this treatment in adults and children (over six years of age) with cystic fibrosis and the G551D mutation (class III). There is no evidence to support the use of ivacaftor in people with the ΔF508 mutation (class II) (n = 140). Trials on ivacaftor in people with different mutations are ongoing.


Safety, pharmacokinetics, and pharmacodynamics of ivacaftor in patients aged 2-5 years with cystic fibrosis and a CFTR gating mutation (KIWI): an open-label, single-arm study.

Davies JC1, Cunningham S2, Harris WT3, Lapey A4, Regelmann WE5, Sawicki GS6, Southern KW7, Robertson S8, Green Y9, Cooke J9, Rosenfeld M10; KIWI Study Group.

Lancet Respir Med. 2016

Abstract

BACKGROUND:

Ivacaftor has been shown to be a safe, effective treatment for cystic fibrosis in patients aged 6 years or older with a CFTR gating mutation. We aimed to assess the safety, pharmacokinetics, and pharmacodynamics of ivacaftor in children aged 2-5 years.

METHODS:

In the two-part KIWI study, we enrolled children aged 2-5 years weighing 8 kg or more with a confirmed diagnosis of cystic fibrosis and a CFTR gating mutation on at least one allele from 15 hospitals in the USA, UK, and Canada. Participants received oral ivacaftor 50 mg (if bodyweight <14 kg) or 75 mg (if bodyweight ≥14 kg) every 12 h for 4 days in part A (to establish the short-term safety of doses for subsequent assessment in part B), and then for 24 weeks in part B (to assess safety and longer-term pharmacodynamics). Children could participate in both or just one part of the study. Primary outcomes were pharmacokinetics and safety, analysed in all patients who received at least one dose of ivacaftor. Secondary outcomes were absolute change from baseline in sweat chloride concentrations and bodyweight, body-mass index (BMI), and height Z scores, and pharmacokinetic parameter estimation of ivacaftor. This study is registered with ClinicalTrials.gov, number NCT01705145.

 FINDINGS:

Between Jan 8, 2013, and March 1, 2013, nine patients were enrolled onto part A of the study, all of whom completed the 4 day treatment period, and eight of whom took part in part B. Between June 28, 2013, and Sept 26, 2013, 34 patients were enrolled in part B, 33 of whom completed the 24 week treatment period. All patients received at least one dose of ivacaftor. Results of ivacaftor pharmacokinetics suggested that exposure was similar to that reported in adults (median Cmin were 536 ng/mL for the 50 mg dose; 580 ng/mL for the 75 mg dose; median ivacaftor AUC values were 9840 ng × h/mL and 10 200 ng × h/mL, respectively). Common adverse events in part B included cough (in 19 [56%] of 34 patients) and vomiting (in ten [29%]). Five (15%) patients had liver function test (LFT) results that were more than eight times higher than the upper limit of normal, four of whom had study drug interrupted, and one of whom had study drug discontinued. Six (18%) of 34 patients had seven serious adverse events; a raised concentration of transaminases was the only serious adverse event regarded as related to ivacaftor and the only adverse event that resulted in study treatment discontinuation. At week 24, in patients for whom we had data, sweat chloride had changed from baseline by a mean of -46·9 mmol/L (SD 26·2, p<0·0001), weight Z score by 0·2 (0·3; p<0·0001), BMI Z score by 0·4 (0·4, p<0·0001), and height Z score by -0·01 (0·3; p=0·84).

 INTERPRETATION:

Ivacaftor at doses of 50 mg and 75 mg seems to be safe in children aged 2-5 years with cystic fibrosis with a gating mutation followed up for 24 weeks, although the frequency of elevated LFTs suggests that monitoring should be frequent in young children, particularly those with a history of elevated LFTs. Results of an ongoing extension study assessing durability of these effects and longer-term safety are warranted.


Ataluren for the treatment of nonsense-mutation cystic fibrosis: a randomised, double-blind, placebo-controlled phase 3 trial.

 Kerem E1, Konstan MW2, De Boeck K3, Accurso FJ4, Sermet-Gaudelus I5, Wilschanski M1, Elborn JS6, Melotti P7, Bronsveld I8, Fajac I9, Malfroot A10, Rosenbluth DB11, Walker PA12, McColley SA13, Knoop C14, Quattrucci S15, Rietschel E16, Zeitlin PL17, Barth J18, Elfring GL18, Welch EM18, Branstrom A18, Spiegel RJ18, Peltz SW18, Ajayi T18, Rowe SM19; Cystic Fibrosis Ataluren Study Group.

Lancet Respir Med. 2014

BACKGROUND:

Ataluren was developed to restore functional protein production in genetic disorders caused by nonsense mutations, which are the cause of cystic fibrosis in 10% of patients. This trial was designed to assess the efficacy and safety of ataluren in patients with nonsense-mutation cystic fibrosis.

 METHODS:

This randomised, double-blind, placebo-controlled, phase 3 study enrolled patients from 36 sites in 11 countries in North America and Europe. Eligible patients with nonsense-mutation cystic fibrosis (aged ≥ 6 years; abnormal nasal potential difference; sweat chloride >40 mmol/L; forced expiratory volume in 1 s [FEV1] ≥ 40% and ≤ 90%) were randomly assigned by interactive response technology to receive oral ataluren (10 mg/kg in morning, 10 mg/kg midday, and 20 mg/kg in evening) or matching placebo for 48 weeks. Randomisation used a block size of four, stratified by age, chronic inhaled antibiotic use, and percent-predicted FEV1. The primary endpoint was relative change in percent-predicted FEV1 from baseline to week 48, analysed in all patients with a post-baseline spirometry measurement. This study is registered with ClinicalTrials.gov, number NCT00803205.

 FINDINGS:

Between Sept 8, 2009, and Nov 30, 2010, 238 patients were randomly assigned, of whom 116 in each treatment group had a valid post-baseline spirometry measurement. Relative change from baseline in percent-predicted FEV1 did not differ significantly between ataluren and placebo at week 48 (-2.5% vs -5.5%; difference 3.0% [95% CI -0.8 to 6.3]; p=0.12). The number of pulmonary exacerbations did not differ significantly between treatment groups (rate ratio 0.77 [95% CI 0.57-1.05]; p=0.0992). However, post-hoc analysis of the subgroup of patients not using chronic inhaled tobramycin showed a 5.7% difference (95% CI 1.5-10.1) in relative change from baseline in percent-predicted FEV1 between the ataluren and placebo groups at week 48 (-0.7% [-4.0 to 2.1] vs -6.4% [-9.8 to -3.7]; nominal p=0.0082), and fewer pulmonary exacerbations in the ataluern group (1.42 events [0.9-1.9] vs 2.18 events [1.6-2.7]; rate ratio 0.60 [0.42-0.86]; nominal p=0.0061). Safety profiles were generally similar for ataluren and placebo, except for the occurrence of increased creatinine concentrations (ie, acute kidney injury), which occurred in 18 (15%) of 118 patients in the ataluren group compared with one (<1%) of 120 patients in the placebo group. No life-threatening adverse events or deaths were reported in either group.

 INTERPRETATION:

Although ataluren did not improve lung function in the overall population of nonsense-mutation cystic fibrosis patients who received this treatment, it might be beneficial for patients not taking chronic inhaled tobramycin.

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