Effect of ivacaftor treatment in patients with cystic fibrosis and the G551D-CFTR mutation: patient-reported outcomes in the STRIVE randomized, controlled trial

Allergic Bronchopulmonary Aspergillosis (ABPA) in the Era of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Modulators

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity disease caused by Aspergillus fumigatus (Af), prevalent in persons with cystic fibrosis (CF) or asthma. In ABPA, Af proteases drive a T-helper cell-2 (Th2)-mediated allergic immune response leading to inflammation that contributes to permanent lung damage. Corticosteroids and antifungals are the mainstays of therapies for ABPA. However, their long-term use has negative sequelae. The treatment of patients with CF (pwCF) has been revolutionized by the efficacy of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy. Pharmacological improvement in CFTR function with highly effective elexacaftor/tezacaftor/ivacaftor (ETI) provides unprecedented improvements in lung function and other clinical outcomes of pwCF. The mechanism behind the improvement in patient outcomes is a continued topic of investigation as our understanding of the role of CFTR function evolves. As ETI therapy gains traction in CF management, understanding its potential impact on ABPA, especially on the allergic immune response pathways and Af infection becomes increasingly crucial for optimizing patient outcomes. This literature review aims to examine the extent of these findings and expand our understanding of the already published research focusing on the intersection between ABPA therapeutic approaches in CF and the rapid impact of the evolving CFTR modulator landscape. While our literature search yielded limited reports specifically focusing on the role of CFTR modulator therapy on CF-ABPA, findings from epidemiologic and retrospective studies suggest the potential for CFTR modulator therapies to positively influence pulmonary outcomes by addressing the underlying pathophysiology of CF-ABPA, especially by decreasing inflammatory response and Af colonization. Thus, this review highlights the promising scope of CFTR modulator therapy in decreasing the overall prevalence and incidence of CF-ABPA.

Drug-drug interactions involving CFTR modulators: a review of the evidence and clinical implications

INTRODUCTION

Cystic fibrosis (CF) is characterized by mucus accumulation impairing the lungs, gastrointestinal tract, and other organs. Cystic fibrosis transmembrane conductance regulator (CFTR) modulators (ivacaftor, tezacaftor, elexacaftor, and lumacaftor) significantly improve lung function and nutritional status; however, they are substrates, inhibitors, and/or inducers of certain CYP enzymes and transporters, raising the risk of drug-drug interactions (DDI) with common CF medications.

AREAS COVERED

A literature search was conducted for DDIs involving CFTR modulators by reviewing new drug applications, drug package inserts, clinical studies, and validated databases of substrates, inhibitors, and inducers. Clinically, CYP3A inducers and inhibitors significantly decrease and increase systemic concentrations of elexacaftor/tezacaftor/ivacaftor, respectively. Additionally, lumacaftor and ivacaftor alter concentrations of CYP3A and P-gp substrates. Potential DDIs without current clinical evidence include ivacaftor and elexacaftor's effect on CYP2C9 and OATP1B1/3 substrates, respectively, and OATP1B1/3 and P-gp inhibitors' effect on tezacaftor. A literature review was conducted using PubMed.

EXPERT OPINION

Dosing recommendations for CFTR modulators with DDIs are relatively comprehensive; however, recommendations on timing of dosing transition of CFTR modulators when CYP3A inhibitors are initiated or discontinued is incomplete. Certain drug interactions may be managed by choosing an alternative treatment to avoid/minimize DDIs. Next generation CFTR modulator therapies under development are expected to provide increased activity with reduced DDI risk.

Safety of elexacaftor/tezacaftor/ivacaftor dose reduction: Mechanistic exploration through physiologically based pharmacokinetic modeling and a clinical case series

INTRODUCTION

Elexacaftor/tezacaftor/ivacaftor (ETI) treatment is associated with significant improvement in lung function in people with cystic fibrosis (pwCF); however, some patients experience adverse effects (AEs) including hepatotoxicity. One potential strategy is dose reduction in ETI with the goal of maintaining therapeutic efficacy while resolving AEs. We report our experience of dose reduction in individuals who experienced AEs following ETI therapy. We provide mechanistic support for ETI dose reduction by exploring predicted lung exposures and underlying pharmacokinetics-pharmacodynamics (PK-PD) relationships.

METHOD

Adults prescribed ETI who underwent dose reduction due to the AEs were included in this case series, and their percent predicted forced expiratory volume in 1 s (ppFEV₁ ) and self-reported respiratory symptoms were collected. The full physiologically based pharmacokinetic (PBPK) models of ETI were developed incorporating physiological information and drug-dependent parameters. The models were validated against available pharmacokinetic and dose-response relationship data. The models were then used to predict lung concentrations of ETI at steady-state.

RESULTS

Fifteen patients underwent dose reduction in ETI due to AEs. Clinical stability without significant changes in ppFEV₁ after dose reduction was observed in all patients. Resolution or improvement of AEs occurred in 13 of the 15 cases. The model-predicted lung concentrations of reduced dose ETI exceeded the reported half maximal effective concentration (EC₅₀ ) from measurement of in vitro chloride transport, providing a hypothesis as to why therapeutic efficacy was maintained.

CONCLUSION

Albeit in a small number of patients, this study provides evidence that reduced ETI doses in pwCF who have experienced AEs may be effective. The PBPK models enable exploration of a mechanistic basis for this finding by simulating target tissue concentrations of ETI that can be compared with drug efficacy in vitro.

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.

CFTR modulator therapies - Effect on life expectancy in people with cystic fibrosis

CFTR modulators have dramatically changed the clinical course of CF in those fortunate enough to receive them. Inevitably, randomised controlled trials during the development of these drugs are too short to use mortality as an outcome. Evidence for their effect on life expectancy are best gained from real world registry studies specifically looking at mortality, but these are only available for ivacaftor to date. Therefore, indirect evidence must be obtained by looking at outcomes known to affect mortality and seeing the effect of these drugs on those outcomes.

Airway clearance and exercise for people with cystic fibrosis: Balancing longevity with life

Airway clearance has been an integral part of cystic fibrosis (CF) care for almost as long as CF has been identified as a condition. From diagnosis as a neonate through to end-of-life care, airway clearance is an everyday aspect of life, adding a considerable treatment burden to the lives of people with CF. There are many different techniques used for airway clearance which have evolved over time with an aim to improve effectiveness, support adherence and, more recently, to consider the impact of burden. A popular thought is whether airway clearance could be replaced by exercise. With new precision therapies in the form of CFTR modulators available, the CF landscape is rapidly changing, raising the question of whether certain treatments are needed at all. Depending on factors such as CFTR mutation, age, and pre-existing lung damage before starting a CFTR modulator, individuals with CF may need different levels of intensity and type of maintenance treatment. Precision medicine is likely to lead to the need for increased precision and individualized management around other maintenance therapies such as airway clearance.

Ethical Dilemma: Elexacaftor-Tezacaftor-Ivacaftor or Lung Transplantation in Cystic Fibrosis and End-Stage Lung Disease?

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). Novel, highly effective, modulator therapies correcting and potentiating CFTR function are changing the course of this disease. We present an ethical dilemma involving an 11-year-old child with CF and end-stage lung disease. Shortly after starting treatment with elexacaftor-tezacaftor-ivacaftor, the family received notification that a matched donor lung had been allocated. Clinical decision-making in this case is challenging as definitive data to medically support one treatment option over the other are limited. A survey of CF center team members was conducted for the purpose of this article. Ethical principles that may guide us in these situations are discussed. Overall, results of the survey present a lack of agreement as to the best approach in this situation. Physicians, when compared with other team members, are more likely to provide a specific recommendation vs presenting the information to the family and letting them decide (OR, 4.0; 95% CI, 1.2-12.8; P = .021). A shared decision-making model, stressing our moral obligation as physicians to respect autonomy by appreciating family values, while offering to participate in the decision-making process and ensuring nonmaleficence, is presented. In summary, CFTR modulators affect the outcomes of CF disease and influence clinical decision-making. The current lack of data on long-term outcomes, in young patients with CF receiving effective modulator therapy, should not preclude CF team participation in decision-making. Shared decision-making, which is focused on respecting autonomy, is our preferred approach in these situations.

Treatment patterns in people with cystic fibrosis: have they changed since the introduction of ivacaftor?

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Longitudinal treatment patterns among the ivacaftor-treated cystic fibrosis population in the UK differ from those seen in a contemporary cohort of individuals untreated due to their genotype, despite minimal differences between the genotype groups prior to the introduction of ivacaftor.

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People who are treated with ivacaftor were less likely to continue other treatments such as inhaled antibiotics, dornase alfa, hypertonic saline, chronic oral antibiotics and supplementary feeding, compared to people who are not treated with ivacaftor.

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The differences in use of dornase alfa and hypertonic saline solution between ivacaftor-treated and non-ivacaftor-treated people, are larger for people with higher lung function.

Background

In late 2012, ivacaftor became available in the UK for people with cystic fibrosis (CF) aged 6 years and over with a G551D mutation. Long-term changes in treatment patterns have not previously been reported. We investigated long-term treatment patterns in people with CF with a G551D mutation who took ivacaftor and compared these with non-ivacaftor-treated cohorts using the UK Cystic Fibrosis Registry.

Methods

Using 2007-2018 data we compared treatment patterns between four cohorts: 1: ivacaftor-treated; 2: ivacaftor era (2013-2018), ineligible genotype (no G551D mutation); 3: pre-ivacaftor era (2007-2012), eligible genotype (G551D mutation); 4: pre-ivacaftor era, ineligible genotype. Treatments included: inhaled antibiotics, dornase alfa, hypertonic saline, chronic oral antibiotics and supplementary feeding.

Results

Up to 2012 the percentages of people taking each treatment were similar between the two cohorts defined by genotype and tended to increase by year with a similar slope. Once ivacaftor was introduced, the use of other treatments tended to decrease or remain stable by year for the ivacaftor-treated cohort, whereas it remained stable or increased in the non-ivacaftor-treated cohort. This led to differences in treatment use between the two cohorts in the ivacaftor-era, which became more marked over time.

Conclusions

We have shown a clear divergence in treatment patterns since the introduction of ivacaftor in a number of key treatments widely used in CF. Further research is needed to investigate whether the differences in treatment patterns are associated with changes in health outcomes.

Real-world use of ivacaftor in Canada: A retrospective analysis using the Canadian Cystic Fibrosis Registry

BACKGROUND

Ivacaftor is a CFTR potentiator with demonstrated efficacy in clinical trials and has been rapidly adopted within the CF community. Given the uptake of ivacaftor in eligible people, identifying a comparator group not on modulators to measure effectiveness is difficult. We evaluated health outcomes in individuals with G551D and non-G551D genotypes on ivacaftor using real-world longitudinal data.

METHODS

This population-based observational study compared clinical trajectories pre-post ivacaftor using the Canadian CF Registry from 2006 to 01-01 through 2018-12-31. Piece-wise linear mixed-effects models were used to compare lung function, nutritional status, pulmonary exacerbations, and Pseudomonas colonization pre- and post-ivacaftor. Multivariable models were used to adjust for confounding factors.

RESULTS

Forced expiratory volume in 1 second (FEV1) increased significantly by 5.7 percent predicted (95% confidence interval (CI) 3.9, 7.5; p<0.001) after initiation of ivacaftor. FEV1 decline rate was attenuated to -0.30% (95% CI -0.9, 0.29; p = 0.32) predicted/year post-ivacaftor, compared with -0.75% (95% CI -1.12, -0.37; p<0.001) predicted/year pre-ivacaftor, although this difference did not reach statistical significance. BMI percentiles also increased post-ivacaftor (6.57 percentiles, 95% CI 3.91, 9.24; p<0.001). Pulmonary exacerbations showed a nonsignificant reduction of 18% (RR 0.82, 95% CI 0.61, 1.11; p = 0.19) and the odds of a positive sputum culture for Pseudomonas aeruginosa decreased in the post-ivacaftor period (odds ratio 0.44, 95% CI 0.30, 0.63; p<0.001).

CONCLUSIONS

This real-world, observational study demonstrated improvement in health outcomes in a broad population of people with CF. Additional studies are needed to evaluate the impact of ivacaftor on quality of life and survival.

Decreasing patient-reported burden of treatment: A systematic review of quantitative interventional studies

Objectives

To describe and analyse studies aiming at quantitatively assessing the impact of interventions on patient-reported burden of treatment as an outcome (primary or secondary).

Methods

The aim of the search strategy was to identify all publications describing a medical intervention intended to reduce patient-reported burden of treatment in adult patients with long-term conditions, from January 1, 2008 to July 15, 2019. Four databases (Medline, PsycINFO, the “Trials” section of the Cochrane-Library, and OpenGrey) were searched in English, French, Spanish, Italian and Portuguese. Each identified article was reviewed and the risk of bias was assessed using a tool adapted from the Cochrane Collaboration recommendations.

Results

Of 641 articles retrieved, 11 were included in this review. There were nine randomized controlled trials, one non-randomized controlled trial, and one before-and-after study. The sample sizes ranged from 55 to 1,546 patients. Eight out of the eleven studies reported significant positive outcomes of the studied interventions. Reducing dosing frequency, improving background therapy, offering home care or providing easier-to-use medical devices were associated with positive outcomes.

Conclusions

Only a few studies have specifically focused on decreasing the subjective burden of treatment. Small trials conducted in patients with a single specific disorder have reported positive outcomes. However, a large, high-quality study assessing the impact of a change in care process in patients with multiple morbidities did not show such results. Further studies are needed to implement this aspect of patient-centred care.

Exercise testing for children with cystic fibrosis: A systematic review

BACKGROUND

Exercise testing is routinely used to measure exercise capacity in children with cystic fibrosis (CF). Various tests are available, however the psychometric properties of these measures have not been systematically reviewed for this population.

METHOD

A systematic search of electronic databases (PubMed, Web of Science, Medline, CINHAL, Cochrane, and PEDro) was performed to identify papers that: (a) reported original psychometric data, (b) examined a measure of exercise capacity, (c) examined children with CF aged eight to 18 years; and (d) were published in English after 1950. The level of psychometric evidence was evaluated using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist.

RESULTS

Searches identified 1025 papers. Forty-six papers were included, covering 15 tests: incremental cardiopulmonary exercise test using a cycle ergometer (CPET(cycle)) or treadmill (CPET(treadmill)), 6 minute walk test (6MWT), modified shuttle test (MST), 3-minute step test (3MST), 2 minute walk test (2MWT), Bratteby walk test, intermittent sprint test, speed ramp test, incremental step test, forward-backwards jump test (FBJT), astride jump test (AJT), motor quotient test, Munich fitness test, and Glittre ADL test.

CONCLUSION

There is a plethora of exercise tests available with varying psychometric robustness. The CPET, 6MWT, and MST have fair to good psychometric properties, but each with their clinical advantages and limitations. Thus, a Selection Guide was developed to assist clinicians and researchers in selecting the most appropriate exercise test for various situations.

The Cystic Fibrosis Impact Questionnaire: qualitative development and cognitive evaluation of a new patient-reported outcome instrument to assess the life impacts of cystic fibrosis

BACKGROUND

Patients with cystic fibrosis (CF) experience significant disease burden, including progressive pulmonary decline and reduced survival. This multicenter qualitative study was conducted to develop a new patient-reported outcome (PRO) measure to assess the impact of CF on patients' quality of life: the Cystic Fibrosis Impact Questionnaire (CF-IQ). Semi-structured qualitative concept elicitation (CE) interviews with patients and caregivers documented CF-related symptoms, impacts, and treatment experiences. Coded interview data were considered alongside existing PROs, published literature, and expert opinion to develop an initial scale. Three rounds of cognitive interviews evaluated respondent comprehension and facilitated refinement of the CF-IQ.

RESULTS

Adult (N = 20) and pediatric (N = 22) patients with CF and their parents/caregivers (N = 22) completed CE interviews at 7 US clinics. The sample included patients aged 6-58 years, 57% females, and represented a broad range of disease severity (forced expiratory volume in 1 s range: 22%-127% predicted). Interviews identified 59 unique CF-related impact concepts in domains, including activity limitations (physical, social, leisure), functional limitations (school, work), vulnerability/lack of control, emotional impact, treatment burden, and future outlook. Concept saturation was achieved, and a draft questionnaire was developed. Findings from the cognitive interviews (n = 18) confirmed that instructions, items, and response scales were relevant and clear, and interpreted as intended by patients.

CONCLUSION

The CF-IQ is a 40-item novel PRO scale assessing a comprehensive set of patient-relevant concepts to characterize the multifaceted nature of CF. Qualitative interview data support the content validity of the CF-IQ, which is currently undergoing additional psychometric evaluation in patients with CF.

CFTR Modulators: The Changing Face of Cystic Fibrosis in the Era of Precision Medicine

Cystic fibrosis (CF) is a lethal inherited disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which result in impairment of CFTR mRNA and protein expression, function, stability or a combination of these. Although CF leads to multifaceted clinical manifestations, the respiratory disorder represents the major cause of morbidity and mortality of these patients. The life expectancy of CF patients has substantially lengthened due to early diagnosis and improvements in symptomatic therapeutic regimens. Quality of life remains nevertheless limited, as these individuals are subjected to considerable clinical, psychosocial and economic burdens. Since the discovery of the CFTR gene in 1989, tremendous efforts have been made to develop therapies acting more upstream on the pathogenesis cascade, thereby overcoming the underlying dysfunctions caused by CFTR mutations. In this line, the advances in cell-based high-throughput screenings have been facilitating the fast-tracking of CFTR modulators. These modulator drugs have the ability to enhance or even restore the functional expression of specific CF-causing mutations, and they have been classified into five main groups depending on their effects on CFTR mutations: potentiators, correctors, stabilizers, read-through agents, and amplifiers. To date, four CFTR modulators have reached the market, and these pharmaceutical therapies are transforming patients' lives with short- and long-term improvements in clinical outcomes. Such breakthroughs have paved the way for the development of novel CFTR modulators, which are currently under experimental and clinical investigations. Furthermore, recent insights into the CFTR structure will be useful for the rational design of next-generation modulator drugs. This review aims to provide a summary of recent developments in CFTR-directed therapeutics. Barriers and future directions are also discussed in order to optimize treatment adherence, identify feasible and sustainable solutions for equitable access to these therapies, and continue to expand the pipeline of novel modulators that may result in effective precision medicine for all individuals with CF.

Patient-reported outcomes in patients with cystic fibrosis with a G551D mutation on ivacaftor treatment: results from a cross-sectional study

Background

Clinical studies demonstrate that ivacaftor (IVA) improves health-related quality of life (HRQoL) in patients aged ≥6 years with cystic fibrosis (CF). The real-world impact of IVA and standard of care (SOC) in groups of patients with G551D and F508del mutations, respectively, was assessed using a survey comprising disease-specific and generic HRQoL measures.

Methods

Patients with CF aged ≥12 years, or aged 6–11 years with caregiver support, with either (1) a G551D mutation and receiving IVA (G551D/IVA) for ≥3 months, or (2) homozygous for F508del and receiving SOC before lumacaftor/IVA availability (F508del/SOC), were eligible to participate in a cross-sectional survey. Demographic and clinical characteristics, and HRQoL measures were compared between patient groups, and multiple regression analyses were conducted.

Results

After differences in patient demographic and clinical characteristics were controlled for, significantly better scores were observed in the G551D/IVA group than in the F508del/SOC group on multiple domains of the validated Cystic Fibrosis Questionnaire-Revised and the EuroQol 5-dimensions 5-level questionnaire.

Conclusions

G551D/IVA patients reported better HRQoL than F508del/SOC patients on generic and disease-specific measures in a real-world setting.

GLPG1837, a CFTR potentiator, in p.Gly551Asp (G551D)-CF patients: An open-label, single-arm, phase 2a study (SAPHIRA1)

BACKGROUND

Investigation of novel cystic fibrosis transmembrane conductance regulator (CFTR) potentiators, such as GLPG1837, for CF patients with gating mutations is challenging as trials require patients to withhold ivacaftor, the current standard of care. This study explored the feasibility of such a study and the impact of one-week ivacaftor withdrawal.

METHODS

This open-label, single-arm study aimed to enrol 32 adults ≥18 years of age with CF and at least one p.Gly551Asp (G551D) mutation. Patients received three increasing GLPG1837 dosages twice-daily for two 7-day and one 14-day period following a one-week ivacaftor washout. The primary outcome was safety; secondary outcomes were changes in sweat chloride concentration, spirometry outcomes, and pharmacokinetics.

RESULTS

Twenty-six patients enrolled; 24 completed the study. Adverse events were reported by 53.8-76.9% of patients (dosage-dependent), with respiratory adverse events most common. Mean sweat chloride concentrations decreased from 97.7 mmol/L (baseline) to 68.7 mmol/L (end of GLPG1837 treatment). In ivacaftor-pre-treated patients, mean sweat chloride concentrations rose from 42.5 mmol/L at screening to 98.5 mmol/L after ivacaftor washout. Levels were decreased following GLPG1837 treatment (to 68.8 mmol/L at treatment end). Percent predicted forced expiratory volume in 1 s declined from 73.3% at screening to 68.5% after ivacaftor washout but returned to screening level at treatment end (73.1%).

CONCLUSIONS

Patient willingness to participate in the study suggests that the need for a short period of ivacaftor withdrawal may not be a barrier to development of novel potentiators, such as GLPG1837. A one-week ivacaftor washout was generally well tolerated, but resulted in a decline in lung function, which was reversed with GLPG1837 treatment to pre-washout levels. Combined with the concentration-dependent decrease in sweat chloride concentration, results show that GLPG1837 increases CFTR activity in G551D-CF patients. FUND: This work was supported by Galapagos NV.

CLINICAL TRIAL REGISTRATION NUMBERS

NCT02707562; EudraCT 2015-003291-77.

A Review on the Use of Cystic Fibrosis Transmembrane Conductance Regulator Gene Modulators in Pediatric Patients

The literature surrounding the use of cystic fibrosis transmembrane conductance regulator-targeted pharmacotherapies in pediatric patients continues to evolve. These therapies represent a departure from symptom management and infection prevention, which have been the mainstay of cystic fibrosis management in pediatrics, to targeting the genetic defect present within these patients. This article reviews the clinical studies evaluating the safety and efficacy of ivacaftor, ivacaftor/lumacaftor, and ivacaftor/tezacaftor. These medications were initially studied in adults and adolescents but have begun to be studied in younger populations. Further investigation into the use of these drugs with different CFTR mutations and in younger age groups will continue to expand the number of patients who can benefit from these therapies.

CyFiT telehealth: protocol for a randomised controlled trial of an online outpatient physiotherapy service for children with cystic fibrosis

BACKGROUND

Telehealth and telemonitoring is an emerging area of study in people with cystic fibrosis (CF), with the potential of increasing access to care, and minimising infection control risks to patients without compromising their health outcomes. To date, limited evidence is available to support the use of telehealth in paediatric population with CF in a clinical setting. This study aims to investigate the utility of a multimodal telehealth-based outpatient physiotherapy service and assess its effect on quality of life, functional exercise capacity, hospital admission and intravenous antibiotic requirements, lung function, processes of care, participation in activities of daily living, and health economics associated with operating an innovative service.

METHOD

This single centre, prospective, parallel, randomised, controlled, non-inferiority trial aims to recruit 110 children with CF between the ages 8 to 18 years of age. Participants will be randomised to the Usual Outpatient Physiotherapy Service group (Usual OPS) or the telehealth intervention group (CyFiT OPS). Quality of life, participation in activity of daily living, functional exercise capacity and patient perception of care will be examined every six months using the Cystic Fibrosis Questionnaire-Revised (CFQ-R), Children's Assessment of Participation and Enjoyment (CAPE), Preferences for Activities of Children (PAC) questionnaire, Modified Shuttle Test-25 (MST25), and Measure of Process of Care (MPOC-20) questionnaire. Physiological measurements collected during routine clinical visits such as spirometry, body weight and height, information will be retrospectively retrieved via a chart review at the end of the study.

DISCUSSION

We anticipate that this multi-modal telehealth service will deliver a comparable service to traditional face-to-face models. An alternative to existing outpatient physiotherapy services may potentially increase patient options for access to care and patient-orientated outcomes such as quality of life. If deemed appropriate, the new model of care can be integrated into clinical practice immediately.

TRIAL REGISTRATION

This trial is registered with the Australian and New Zealand Clinical Trial Registry ( ACTRN12617001035314 ) last updated 17th July 2018.

Precision Medicine In Action: The Impact Of Ivacaftor On Cystic Fibrosis-Related Hospitalizations

Cystic fibrosis is a life-threatening genetic disease that causes severe damage to the lungs. Ivacaftor, the first drug that targeted the underlying defect of the disease caused by specific mutations, is a sterling example of the potential of precision medicine. Clinical trial and registry studies showed that ivacaftor improved outcomes and reduced hospitalizations. Our study used US administrative claims data to assess the real-world effectiveness of ivacaftor. Comparing twelve-month rates before and after starting the use of ivacaftor among people who initiated therapy during 2012-2015, we found that overall and cystic fibrosis-related inpatient admissions fell by 55 percent and 81 percent, respectively. There was a comparable reduction in inpatient spending. Ivacaftor appears to be effective for multiple mutations that cause the disease, as suggested by the fact that during the study period, ivacaftor's use was extended to nine additional mutations in 2014. Examination of evidence from clinical trial, clinical care, and administrative data sources is important for understanding the real-world effectiveness of precision medicines such as ivacaftor.

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

BACKGROUND

Cystic fibrosis (CF) is the commonest inherited life-shortening illness in white populations, 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 mainly affects the airways where excess salt absorption dehydrates the airway lining leading to impaired mucociliary clearance. Consequently, thick, sticky mucus accumulates making the airway prone to chronic infection and progressive inflammation; respiratory failure often ensues. Other complications include malnutrition, diabetes and subfertility.Increased understanding of the condition has allowed pharmaceutical companies to design mutation-specific therapies targeting the underlying molecular defect. CFTR potentiators target mutation classes III and IV and aim to normalise airway surface liquid and mucociliary clearance, which in turn impacts on the chronic infection and inflammation. This is an update of a previously published review.

OBJECTIVES

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

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, reviews and online clinical trial registries. Last search: 21 November 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of parallel design comparing CFTR potentiators to placebo in people with CF. A separate review examines trials combining CFTR potentiators with other mutation-specific therapies.

DATA COLLECTION AND ANALYSIS

The authors independently extracted data, assessed the risk of bias in included trials and used GRADE to assess evidence quality. Trial authors were contacted for additional data.

MAIN RESULTS

We included five RCTs (447 participants with different mutations) lasting from 28 days to 48 weeks, all assessing the CFTR potentiator ivacaftor. The quality of the evidence was moderate to low, mainly due to risk of bias (incomplete outcome data and selective reporting) and imprecision of results, particularly where few individuals experienced adverse events. Trial design was generally well-documented. All trials were industry-sponsored and supported by other non-pharmaceutical funding bodies.F508del (class II) (140 participants)One 16-week trial reported no deaths, or changes in quality of life (QoL) or lung function (either relative or absolute change in forced expiratory volume in one second (FEV1) (moderate-quality evidence). Pulmonary exacerbations and cough were the most reported adverse events in ivacaftor and placebo groups, but there was no difference between groups (low-quality evidence); there was also no difference between groups in participants interrupting or discontinuing treatment (low-quality evidence). Number of days until the first exacerbation was not reported, but there was no difference between groups in how many participants developed pulmonary exacerbations. There was also no difference in weight. Sweat chloride concentration decreased, mean difference (MD) -2.90 mmol/L (95% confidence interval (CI) -5.60 to -0.20).G551D (class III) (238 participants)The 28-day phase 2 trial (19 participants) and two 48-week phase 3 trials (adult trial (167 adults), paediatric trial (52 children)) reported no deaths. QoL scores (respiratory domain) were higher with ivacaftor in the adult trial at 24 weeks, MD 8.10 (95% CI 4.77 to 11.43) and 48 weeks, MD 8.60 (95% CI 5.27 to 11.93 (moderate-quality evidence). The adult trial reported a higher relative change in FEV1 with ivacaftor at 24 weeks, MD 16.90% (95% CI 13.60 to 20.20) and 48 weeks, MD 16.80% (95% CI 13.50 to 20.10); the paediatric trial reported this at 24 weeks, MD 17.4% (P < 0.0001)) (moderate-quality evidence). These trials demonstrated absolute improvements in FEV1 (% predicted) at 24 weeks, MD 10.80% (95% CI 8.91 to 12.69) and 48 weeks, MD 10.44% (95% CI 8.56 to 12.32). The phase 3 trials reported increased cough, odds ratio (OR) 0.57 (95% CI 0.33 to 1.00) and episodes of decreased pulmonary function, OR 0.29 (95% CI 0.10 to 0.82) in the placebo group; ivacaftor led to increased dizziness in adults, OR 10.55 (95% CI 1.32 to 84.47). There was no difference between groups in participants interrupting or discontinuing treatment (low-quality evidence). Fewer participants taking ivacaftor developed serious pulmonary exacerbations; adults taking ivacaftor developed fewer exacerbations (serious or not), OR 0.54 (95% CI 0.29 to 1.01). A higher proportion of participants were exacerbation-free at 24 weeks with ivacaftor (moderate-quality evidence). Ivacaftor led to a greater absolute change from baseline in FEV1 (% predicted) at 24 weeks, MD 10.80% (95% CI 8.91 to 12.69) and 48 weeks, MD 10.44% (95% CI 8.56 to 12.32); weight also increased at 24 weeks, MD 2.37 kg (95% CI 1.68 to 3.06) and 48 weeks, MD 2.75 kg (95% CI 1.74 to 3.75). Sweat chloride concentration decreased at 24 weeks, MD -48.98 mmol/L (95% CI -52.07 to -45.89) and 48 weeks, MD -49.03 mmol/L (95% CI -52.11 to -45.94).R117H (class IV) (69 participants)One 24-week trial reported no deaths. QoL scores (respiratory domain) were higher with ivacaftor at 24 weeks, MD 8.40 (95% CI 2.17 to 14.63), but no relative changes in lung function were reported (moderate-quality evidence). Pulmonary exacerbations and cough were the most reported adverse events in both groups, but there was no difference between groups; there was no difference between groups in participants interrupting or discontinuing treatment (low-quality evidence). Number of days until the first exacerbation was not reported, but there was no difference between groups in how many participants developed pulmonary exacerbations. No changes in absolute change in FEV1 or weight were reported. Sweat chloride concentration decreased, MD -24.00 mmol/L (CI 95% -24.69 to -23.31).

AUTHORS' CONCLUSIONS

There is no evidence supporting the use of ivacaftor in people with the F508del mutation. Both G551D phase 3 trials demonstrated a clinically relevant impact of ivacaftor on outcomes at 24 and 48 weeks in adults and children (over six years of age) with CF. The R117H trial demonstrated an improvement in the respiratory QoL score, but no improvement in respiratory function.As new mutation-specific therapies emerge, it is important that trials examine outcomes relevant to people with CF and their families and that adverse events are reported robustly and consistently. Post-market surveillance is essential and ongoing health economic evaluations are required.

Ivacaftor improves rhinologic, psychologic, and sleep-related quality of life in G551D cystic fibrosis patients

BACKGROUND

Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator that improves pulmonary function in cystic fibrosis (CF) patients with at least 1 copy of the G551D CFTR mutation. The purpose of this study is to evaluate the impact of ivacaftor on chronic rhinosinusitis (CRS) symptoms in this population.

METHODS

The G551D Observational (GOAL) study was a multicenter prospective cohort study enrolling CF patients ≥6 years with at least 1 G551D mutation. Subjects were provided 20-item Sino-Nasal Outcome Test (SNOT-20) questionnaires prior to ivacaftor therapy and at 1, 3, and 6 months afterward. The impact on rhinologic (R), psychological (P), sleep (S), and ear/facial (E) quality of life (QOL) domains was evaluated separately.

RESULTS

Of 153 subjects, 129 (84%) completed all questionnaires. Typical baseline symptom burden was low (75% with scores <1) and degree of improvement (ie, reduced scores) was greater with higher baseline scores. SNOT-20 decreased, reflecting improvement, at all follow-up intervals (1 month: [mean change ± standard deviation] -0.25 ± 0.53, p < 0.01; 3 months; -0.29 ± 0.58, p < 0.01; 6 months: -0.21 ± 0.58, p = 0.02), but less than the prespecified minimal clinically important difference (0.8). Significant improvement was observed at 1, 3, and 6 months in the R domain (1 month: -0.24, p < 0.01; 3 months: -0.34, p < 0.01; 6 months: -0.25, p < 0.01) and P domain (1 month: -0.25, p < 0.01; 3 months: -0.32, p < 0.01; 6 months: -0.26, p < 0.01), and 1 and 3 months in the S domain (1 months: -0.35, p < 0.01; 3 months: -0.32, p < 0.01; 6 months: -0.18, p = 0.07). There was no improvement in the E domain at any time point.

CONCLUSION

Ivacaftor improves QOL in the R, P, and S domains in G551D CF patients, although QOL instruments validated for CRS may not translate well to CF CRS patients because symptom burden was surprisingly low.

Energy Balance and Mechanisms of Weight Gain with Ivacaftor Treatment of Cystic Fibrosis Gating Mutations

OBJECTIVE

To determine if ivacaftor treatment results in weight gain and improved pulmonary function in people with cystic fibrosis transmembrane conductance regulator gating mutations.

STUDY DESIGN

Children and adults with cystic fibrosis and at least 1 cystic fibrosis transmembrane conductance regulator gating mutation were evaluated in this observational study before and after 3 months of ivacaftor treatment. Body size and composition, total energy expenditure, resting energy expenditure (REE%) as percent predicted, coefficient of fat absorption (CFA%), fecal calprotectin, fecal elastase, and quality of life were assessed. Some outcomes were explored by pancreatic status.

RESULTS

There were 23 patients (5-61 years of age) who completed the study; 70% had pancreatic insufficiency (PI). Patients gained 2.5 ± 2.2 kg (P < .001) with increased (P < .05) fat-free mass (0.9 ± 1.9 kg) and fat mass (1.6 ± 1.5 kg). REE% decreased by 5.5 ± 12.0% (P < .05), fecal calprotectin decreased by 30 ± 40 µg/g stool (P < .01), and total energy expenditure was unchanged. Improvements were greater for PI than patients who were pancreatic-sufficient. CFA% increased significantly only with PI. The change (Δ) in weight was positively correlated with the percent change in forced expiratory volume at 1 second (r = 0.46; P = .028) and ΔCFA% (r = 0.47; P = .032) and negatively with ΔREE% (r = -0.50; P = .017). Together, ΔREE%, ΔCFA%, and the percent change in forced expiratory volume at 1 second explained 58% of the variance in weight gain (adjusted R² = 0.579; P = .0007). Growth status and muscle strength improved, as did quality of life in several domains. Fecal elastase increased in most patients with pancreatic sufficiency, with no change in those with PI.

CONCLUSIONS

Mechanisms identified for ivacaftor-associated weight gain were decreased REE, gut inflammation, and fat malabsorption (CFA).

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02141464.

Approach to chronic abdominal pain in Cystic Fibrosis

Abdominal pain in individuals with CF is challenging for the patient as well as the physician, as the differential diagnosis can be complex. Most gastrointestinal manifestations of CF present with regional abdominal pain. Pain localization, which requires knowledge of gut development and innervation, is crucial to understanding the pathophysiology of abdominal pain in CF. The location of the pain, together with the clinical presentation, shapes the differential diagnosis and thus guides the evaluation and management.

Germline genetic variants with implications for disease risk and therapeutic outcomes

Genetic testing has multiple clinical applications including disease risk assessment, diagnosis, and pharmacogenomics. Pharmacogenomics can be utilized to predict whether a pharmacologic therapy will be effective or to identify patients at risk for treatment-related toxicity. Although genetic tests are typically ordered for a distinct clinical purpose, the genetic variants that are found may have additional implications for either disease or pharmacology. This review will address multiple examples of germline genetic variants that are informative for both disease and pharmacogenomics. The discussed relationships are diverse. Some of the agents are targeted for the disease-causing genetic variant, while others, although not targeted therapies, have implications for the disease they are used to treat. It is also possible that the disease implications of a genetic variant are unrelated to the pharmacogenomic implications. Some of these examples are considered clinically actionable pharmacogenes, with evidence-based, pharmacologic treatment recommendations, while others are still investigative as areas for additional research. It is important that clinicians are aware of both the disease and pharmacogenomic associations of these germline genetic variants to ensure patients are receiving comprehensive personalized care.

Ivacaftor for the p.Ser549Arg (S549R) gating mutation - The Israeli experience

BACKGROUND

Ivacaftor is a drug that increases the probability of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel remaining open. Information about the efficacy of ivacaftor in patients carrying the rare p.Ser549Arg (S549R) CFTR mutation is sparse.

AIM

Efficacy of ivacaftor treatment in patients carrying the p.Ser549Arg (S549R) CFTR mutation.

METHODS

Data obtained from CF patients receiving ivacaftor for one year.

RESULTS

Eight CF patients, mean age 21 ± 10 years, received ivacaftor. After one year, significant improvement was found in FEV₁, increasing from 74% to 88% (p < 0.001), FVC, 89% to 101% (p = 0.019), and FEF_25-75, 59%-76% (p = 0.019). Sweat chloride concentration decreased from 116 ± 8 mmol/L to 51 ± 17 mmol/L (p < 0.001), and BMI increased from 20 ± 3 to 22 ± 4 (p = 0.003). Glucose tolerance improved in five patients. There was no significant change in bacterial colonization.

CONCLUSIONS

Ivacaftor therapy resulted in significant clinical improvement in patients carrying the p.Ser549Arg (S549R) CFTR mutation.

CFTR Modulators: Shedding Light on Precision Medicine for Cystic Fibrosis

Cystic fibrosis (CF) is the most common life-threatening monogenic disease afflicting Caucasian people. It affects the respiratory, gastrointestinal, glandular and reproductive systems. The major cause of morbidity and mortality in CF is the respiratory disorder caused by a vicious cycle of obstruction of the airways, inflammation and infection that leads to epithelial damage, tissue remodeling and end-stage lung disease. Over the past decades, life expectancy of CF patients has increased due to early diagnosis and improved treatments; however, these patients still present limited quality of life. Many attempts have been made to rescue CF transmembrane conductance regulator (CFTR) expression, function and stability, thereby overcoming the molecular basis of CF. Gene and protein variances caused by CFTR mutants lead to different CF phenotypes, which then require different treatments to quell the patients' debilitating symptoms. In order to seek better approaches to treat CF patients and maximize therapeutic effects, CFTR mutants have been stratified into six groups (although several of these mutations present pleiotropic defects). The research with CFTR modulators (read-through agents, correctors, potentiators, stabilizers and amplifiers) has achieved remarkable progress, and these drugs are translating into pharmaceuticals and personalized treatments for CF patients. This review summarizes the main molecular and clinical features of CF, emphasizes the latest clinical trials using CFTR modulators, sheds light on the molecular mechanisms underlying these new and emerging treatments, and discusses the major breakthroughs and challenges to treating all CF patients.

Ivacaftor in cystic fibrosis adults: Czech experience with six years of follow-up

AIMS

Ivacaftor is a revolutionary treatment option for cystic fibrosis (CF) patients with G551D and other gating mutations. The aim of this study was to evaluate the clinical status of patients on ivacaftor who were followed for up to 6 years together with an evaluation of ivacaftor therapy in one patient with an initial FEV1 less than 40% of predicted value.

METHODS

Data on development of clinical status and sinopulmonary-related therapies were obtained from patient health records during ivacaftor treatment lasting for up to six years and were compared with an equivalent period before ivacaftor administration.

RESULTS

Five CF adults with a median age 28.6 years (range 21.4-35.6 years) with median FEV1 45% pred. (range 16-85% pred.) were included in the study. Four subjects were also participants in the STRIVE and PERSIST studies. Altogether, twenty-four patient-years of ivacaftor treatment were analyzed. The median FEV1 decline per year decreased from -4.5 to -0.9% pred. (P = 0.043). Reduction in number of days on antibiotic treatment and hospital stays was 21% (P < 0.001) and 75% (P = 0.003), respectively. Improvement and stabilization of lung function was observed for up to six years of treatment. In a patient with severe airway obstruction, an increase in the FEV1 value (30.4% from baseline) was documented during the first twelve months of treatment.

CONCLUSION

Ivacaftor therapy resulted in improved and stabilized lung function in up to six years of treatment with a reduction in number of days on antibiotic treatment and hospital stays. Its efficiency was also displayed in a patient with severe airway obstruction.

Impact of pulmonary exacerbations and lung function on generic health-related quality of life in patients with cystic fibrosis

BACKGROUND

The analysis aimed to examine the impact of pulmonary exacerbations (PEs) and lung function on generic measures of HRQL in patients with cystic fibrosis (CF) using trial-based data.

METHODS

In a 48-week randomized, placebo-controlled study of ivacaftor in patients ≥12 years with CF and a G551D-CFTR mutation the relationship between PEs, PE-related hospitalizations and percent predicted forced expiratory volume in one second (ppFEV1) with EQ-5D measures (index and visual analog scale [VAS]) was examined in post-hoc analyses. Multivariate mixed-effects models were employed to describe the association of PEs, PE-related hospitalizations, and ppFEV1 on EQ-5D measures.

RESULTS

One hundred sixty one patients (age: mean 25.5 [SD 9.5] years; baseline ppFEV1: 63.6 [16.4]) contributed 1,214 observations (ppFEV1: no lung dysfunction [n = 157], mild [n = 419], moderate [n = 572], severe [n = 66]). Problems were most frequently reported on pain/discomfort, anxiety/depression, and usual activities EQ-5D items. The mean (SE) EQ-5D index nominally decreased (worsened) with worsening severity of lung dysfunction (P = 0.070): 0.931 (0.023); mild: 0.923 (0.021); moderate: 0.904 (0.018); severe: 0.870 (0.020). 146 PEs were experienced by 72 patients, including 52 PEs (35.6 %) that required hospitalization. Mean EQ-5D index and VAS scores were lowest (worst) within 1 week (before or after PE start) for PEs requiring hospitalization. Pulmonary exacerbations, PE-related hospitalizations, and ppFEV1 were significant predictors of EQ-5D index and VAS.

CONCLUSIONS

In a clinical study of patients with CF (≥12 years of age and a G551D-CFTR mutation), PEs, primarily those requiring hospitalization, were associated with low EQ-5D index and VAS scores. The impact of ppFEV1 was relatively smaller. Reducing PEs, in particular those requiring hospitalization, would likely improve HRQL among these patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00909532 ; URL: clinicaltrials.gov, May 26, 2009.