EFFECT OF ELEXACAFTOR/TEZACAFTOR/IVACAFTOR ON ANNUAL RATE OF LUNG FUNCTION DECLINE IN PEOPLE WITH CYSTIC FIBROSIS

Racial inequities and rare CFTR variants: Impact on cystic fibrosis diagnosis and treatment

Cystic fibrosis (CF) has been traditionally viewed as a disease that affects White individuals. However, CF occurs among all races, ethnicities, and geographic ancestries. The disorder results from mutations in the CF transmembrane conductance regulator (CFTR). Varying incidence of CF is reported among Black, Indigenous, and People of Color (BIPOC), who typically exhibit worse clinical outcomes. These populations are more likely to carry rare CFTR variants omitted from newborn screening panels, leading to disparities in care such as delayed diagnosis and treatment. In this study, we present a case-in-point describing an individual of Gambian descent identified with CF. Patient genotype includes a premature termination codon (PTC) (c.2353C>T) and previously undescribed single nucleotide deletion (c.1970delG), arguing against effectiveness of currently available CFTR modulator-based interventions. Strategies for overcoming these two variants will likely include combinations of PTC suppressors, nonsense mediated decay inhibitors, and/or alternative approaches (e.g. gene therapy). Investigations such as the present study establish a foundation from which therapeutic treatments may be developed. Importantly, c.2353C>T and c.1970delG were not detected in the patient by traditional CFTR screening panels, which include an implicit racial and ethnic diagnostic bias as these tests are comprised of mutations largely observed in people of European ancestry. We suggest that next-generation sequencing of CFTR should be utilized to confirm or exclude a CF diagnosis, in order to equitably serve BIPOC individuals. Additional epidemiologic data, basic science investigations, and translational work are imperative for improving understanding of disease prevalence and progression, CFTR variant frequency, genotype-phenotype correlation, pharmacologic responsiveness, and personalized medicine approaches for patients with African ancestry and other historically understudied geographic lineages.

Predicting lung function decline in cystic fibrosis: the impact of initiating ivacaftor therapy

BACKGROUND

Modulator therapies that seek to correct the underlying defect in cystic fibrosis (CF) have revolutionized the clinical landscape. Given the heterogeneous nature of lung disease progression in the post-modulator era, there is a need to develop prediction models that are robust to modulator uptake.

METHODS

We conducted a retrospective longitudinal cohort study of the CF Foundation Patient Registry (N = 867 patients carrying the G551D mutation who were treated with ivacaftor from 2003 to 2018). The primary outcome was lung function (percent predicted forced expiratory volume in 1 s or FEV1pp). To characterize the association between ivacaftor initiation and lung function, we developed a dynamic prediction model through covariate selection of demographic and clinical characteristics. The ability of the selected model to predict a decline in lung function, clinically known as an FEV1-indicated exacerbation signal (FIES), was evaluated both at the population level and individual level.

RESULTS

Based on the final model, the estimated improvement in FEV1pp after ivacaftor initiation was 4.89% predicted (95% confidence interval [CI]: 3.90 to 5.89). The rate of decline was reduced with ivacaftor initiation by 0.14% predicted/year (95% CI: 0.01 to 0.27). More frequent outpatient visits prior to study entry and being male corresponded to a higher overall FEV1pp. Pancreatic insufficiency, older age at study entry, a history of more frequent pulmonary exacerbations, lung infections, CF-related diabetes, and use of Medicaid insurance corresponded to lower FEV1pp. The model had excellent predictive accuracy for FIES events with an area under the receiver operating characteristic curve of 0.83 (95% CI: 0.83 to 0.84) for the independent testing cohort and 0.90 (95% CI: 0.89 to 0.90) for 6-month forecasting with the masked cohort. The root-mean-square errors of the FEV1pp predictions for these cohorts were 7.31% and 6.78% predicted, respectively, with standard deviations of 0.29 and 0.20. The predictive accuracy was robust across different covariate specifications.

CONCLUSIONS

The methods and applications of dynamic prediction models developed using data prior to modulator uptake have the potential to inform post-modulator projections of lung function and enhance clinical surveillance in the new era of CF care.

Real world study on elexacaftor-tezacaftor-ivacaftor impact on cholesterol levels in adults with cystic fibrosis

INTRODUCTION

The introduction of the highly effective modulator therapy elexacaftor-tezacaftor-ivacaftor (ETI) has revolutionized the care of persons with cystic fibrosis (PwCF) with major improvements seen in lung function and body mass index. The effects of ETI therapy in real-world cohorts on other parameters such as cholesterol levels are largely unknown.

METHODS

A single-center, retrospective chart review study was conducted to assess the change in lipid panels before and after ETI initiation. The study investigated total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride levels using both a univariate and multivariate mixed-effects model to evaluate the change after initiation of ETI in a cohort of PwCF.

RESULTS

There were 128 adult PwCF included in the analysis. Statistically significant changes were seen in both univariate and multivariate analyses for TC, LDL-C, and HDL-C. On multivariate analysis, TC increased by an average of 15.0 mg/dL after ETI initiation (p < 0.0001), LDL-C increased by an average of 9.3 mg/dL (p < 0.001), and HDL-C increased by an average of 3.8 mg/dL (p < 0.001) after ETI initiation.

CONCLUSION

In this real-world cohort of PwCF, cholesterol parameters increased after initiation with ETI therapy. Further consideration may need to be given for PwCF in regards to screening for cardiometabolic risk factors as PwCF age as well as the potential need for cholesterol-lowering therapies.

Cystic fibrosis in Europe: improved lung function and longevity - reasons for cautious optimism, but challenges remain

BACKGROUND

Prognosis and disease severity in cystic fibrosis (CF) are linked to declining lung function. To characterise lung function by the number of adults in countries with different levels of Gross National Income (GNI), data from the European Cystic Fibrosis Society Patient Registry were utilised.

METHODS

Annual data including age, forced expiratory volume in 1 s (FEV1), anthropometry, genotype, respiratory cultures and CF-related diabetes (CFRD) were retrieved between 2011 and 2021. All countries were stratified into GNI per capita to reflect differences within Europe.

RESULTS

A consistent improvement in FEV1 % pred and survival was observed among the 47 621 people with CF (pwCF), including subjects with chronic Pseudomonas aeruginosa infection, CFRD and/or undernutrition. Mean values of FEV1 % pred changed from 85% to 94.2% for children and from 63.6% to 74.7% for adults. FEV1 % pred further increased among those carrying the F508del mutation in 2021, when elexacaftor/tezacaftor/ivacaftor was available. The number of adult pwCF increased from 13 312 in 2011 to 21 168 in 2021, showing a 60% increase. PwCF living in European lower income countries did not demonstrate a significant annual increase in FEV1 % pred or in the number of adults.

CONCLUSION

This pan-European analysis demonstrates a consistent improvement in FEV1 % pred, number of adult pwCF and survival over the last decade only in European higher and middle income countries. Urgent action is needed in the lower income countries where such improvement was not observed. The notable improvement observed in pwCF carrying the F508del mutation emphasises the need to develop treatments for all CF mutations.

Efficacy and safety profile of elexacaftor-tezacaftor-ivacaftor triple therapy on cystic fibrosis: a systematic review and single arm meta-analysis

Background: Elexacaftor-Tezacaftor-Ivacaftor (ELE/TEZ/IVA) is believed to be an effective and well-tolerated treatment for cystic fibrosis (CF), but the exact efficacy and safety profile are still unknown. Objective: This study aimed to clarify the extent of functional restoration when patients are given with triple combination treatment and demonstrate the prevalence of adverse events, to evaluate the overall profile of ELE/TEZ/IVA on CF. Methods: A literature search was conducted in PubMed, Web of Science and Cochrane Library. Random effects single-arm meta-analysis was performed to decipher the basal characteristics of CF, the improvement and safety profile after ELE/TEZ/IVA treatment. Results: A total 53 studies were included in this analysis. For all the patients in included studies. 4 weeks after ELE/TEZ/IVA treatment, the increasement of percentage of predicted Forced Expiratory Volume in the first second (ppFEV1) was 9.23% (95%CI, 7.77%-10.70%), the change of percentage of predicted Forced Vital Capacity (ppFVC) was 7.67% (95%CI, 2.15%-13.20%), and the absolute change of Cystic Fibrosis Questionnaire-Revised (CFQ-R) score was 21.46 points (95%CI, 18.26-24.67 points). The Sweat chloride (SwCl) was significantly decreased with the absolute change of -41.82 mmol/L (95%CI, -44.38 to -39.25 mmol/L). 24 weeks after treatment, the increasement of ppFEV1 was 12.57% (95%CI, 11.24%-13.90%), the increasement of ppFVC was 10.44% (95%CI, 7.26%-13.63%), and the absolute change of CFQ-R score was 19.29 points (95%CI, 17.19-21.39 points). The SwCl was significantly decreased with the absolute change of -51.53 mmol/L (95%CI, -56.12 to -46.94 mmol/L). The lung clearance index2.5 (LCI2.5) was also decreased by 1.74 units (95%CI, -2.42 to -1.07 units). The body mass index increased by 1.23 kg/m2 (95%CI, 0.89-1.57 kg/m2). As for adverse events, 0.824 (95%CI, 0.769-0.879) occurred during ELE/TEZ/IVA period, while the incidence of severe adverse events was 0.066 (95%CI, 0.028-0.104). Conclusion: ELE/TEZ/IVA is a highly effective strategy and relatively safe for CF patients and needs to be sustained to achieve better efficacy. Systematic Review Registration: Identifier: CRD42023441840.

Trials and tribulations of highly effective modulator therapies in cystic fibrosis

Highly effective modulator therapies (HEMTs) have revolutionised the management approach of most patients living with cystic fibrosis (CF) who have access to these therapies. Clinical trials have reported significant improvements across multiorgan systems, with patients surviving longer. However, there are accumulating case reports and observational data describing various adverse events following initiation of HEMTs including drug-to-drug interactions, drug induced liver injury, Stevens-Johnson syndrome, and neurocognitive symptoms including psychosis and depression, which have required discontinuation of therapy. Current clinical trials are assessing efficacy in younger patients with CF, yet long-term studies are also required to better understand the safety profile in the real-world setting across all ages and the impact of HEMT dose alteration or discontinuation.

Cystic fibrosis year in review 2022

Remarkable medical advancements have been made for people with cystic fibrosis (CF) in recent years, with an abundance of research continuing to be conducted worldwide. With concern for limitations in access to highly effective CFTR modulators, as well as the recent Coronavirus Disease-19 pandemic, there has been a consistent effort to understand and improve CF screening, disease burden, diagnosis, and management. Our aim in this review is to present articles from 2022 with an emphasis on clinically relevant studies. We hope this will serve as a broad overview of the research published in the past year.

Understanding and addressing the needs of people with cystic fibrosis in the era of CFTR modulator therapy

Cystic fibrosis is a multiorgan disease caused by impaired function of the cystic fibrosis transmembrane conductance regulator (CFTR). Since the introduction of the CFTR modulator combination elexacaftor-tezacaftor-ivacaftor (ETI), which acts directly on mutant CFTR to enhance its activity, most people with cystic fibrosis (pwCF) have seen pronounced reductions in symptoms, and studies project marked increases in life expectancy for pwCF who are eligible for ETI. However, modulator therapy has not cured cystic fibrosis and the success of CFTR modulators has resulted in immediate questions about the new state of cystic fibrosis disease and clinical challenges in the care of pwCF. In this Series paper, we summarise key questions about cystic fibrosis disease in the era of modulator therapy, highlighting state-of-the-art research and clinical practices, knowledge gaps, new challenges faced by pwCF and the potential for future health-care challenges, and the pressing need for additional therapies to treat the underlying genetic or molecular causes of cystic fibrosis.

Spirometric and anthropometric improvements in response to elexacaftor/tezacaftor/ivacaftor depending on age and lung disease severity

Introduction: Triple-combination cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy with elexacaftor/tezacaftor/ivacaftor (ETI) was introduced in August 2020 in Germany for people with CF (pwCF) ≥12 years (yrs.) of age and in June 2021 for pwCF ≥6 yrs of age. In this single-center study, we analyzed longitudinal data on the percent-predicted forced expiratory volume (ppFEV1) and body-mass-index (BMI) for 12 months (mo.) after initiation of ETI by linear mixed models and regression analyses to identify age- and severity-dependent determinants of response to ETI. Methods: We obtained data on 42 children ≥6-11 yrs, 41 adolescents ≥12-17 yrs, and 143 adults by spirometry and anthropometry prior to ETI, and 3 and 12 mo. after ETI initiation. Data were stratified by the age group and further sub-divided into age-specific ppFEV1 impairment. To achieve this, the age strata were divided into three groups, each according to their baseline ppFEV1: lowest 25%, middle 50%, and top 25% of ppFEV1. Results: Adolescents and children with more severe lung disease prior to ETI (within the lowest 25% of age-specific ppFEV1) showed higher improvements in lung function than adults in this severity group (+18.5 vs. +7.5; p = 0.002 after 3 mo. and +13.8 vs. +7.2; p = 0.012 after 12 mo. of ETI therapy for ≥12-17 years and +19.8 vs. +7.5; p = 0.007 after 3 mo. for children ≥6-11 yrs). In all age groups, participants with more severe lung disease showed higher BMI gains than those with medium or good lung function (within the middle 50% or top 25% of age-specific ppFEV1). Regression analyses identified age as a predictive factor for FEV1 increase at 3 mo. after ETI initiation, and age and ppFEV1 at ETI initiation as predictive factors for FEV1 increase 12 mo. after ETI initiation. Discussion: We report initial data, which suggest that clinical response toward ETI depends on age and lung disease severity prior to ETI initiation, which argue for early initiation of ETI.

Post-approval studies with the CFTR modulators Elexacaftor-Tezacaftor—Ivacaftor

Triple combination therapy with the CFTR modulators elexacaftor (ELX), tezacaftor (TEZ) and ivacaftor (IVA) has been qualified as a game changer in cystic fibrosis (CF). We provide an overview of the body of literature on ELX/TEZ/IVA published between November 2019 and February 2023 after approval by the regulators. Recombinant ELX/TEZ/IVA-bound Phe508del CFTR exhibits a wild type conformationin vitro, but in patient’s tissue a CFTR glyoisoform is synthesized that is distinct from the wild type and Phe508del isoforms. ELX/TEZ/IVA therapy improved the quality of life of people with CF in the real-life setting irrespective of their anthropometry and lung function at baseline. ELX/TEZ/IVA improved sinonasal and abdominal disease, lung function and morphology, airway microbiology and the basic defect of impaired epithelial chloride and bicarbonate transport. Pregnancy rates were increasing in women with CF. Side effects of mental status changes deserve particular attention in the future.

Elexacaftor-Tezacaftor-Ivacaftor: A Life-Changing Triple Combination of CFTR Modulator Drugs for Cystic Fibrosis

Cystic fibrosis (CF) is a potentially fatal monogenic disease that causes a progressive multisystemic pathology. Over the last decade, the introduction of CF transmembrane conductance regulator (CFTR) modulator drugs into clinical practice has profoundly modified the lives of many people with CF (PwCF) by targeting the fundamental cause of the disease. These drugs consist of the potentiator ivacaftor (VX-770) and the correctors lumacaftor (VX-809), tezacaftor (VX-661), and elexacaftor (VX-445). In particular, the triple combination of CFTR modulators composed of elexacaftor, tezacaftor, and ivacaftor (ETI) represents a life-changing therapy for the majority of PwCF worldwide. A growing number of clinical studies have demonstrated the safety and efficacy of ETI therapy in both short- and long-term (up to two years of follow-up to date) and its ability to significantly reduce pulmonary and gastrointestinal manifestations, sweat chloride concentration, exocrine pancreatic dysfunction, and infertility/subfertility, among other disease signs and symptoms. Nevertheless, ETI therapy-related adverse effects have also been reported, and close monitoring by a multidisciplinary healthcare team remains vital. This review aims to address and discuss the major therapeutic benefits and adverse effects reported by the clinical use of ETI therapy for PwCF.