Therapy for cystic fibrosis--the end of the beginning?

Use of elexacaftor/tezacaftor/ivacaftor combination in pregnancy

INTRODUCTION

Management of cystic fibrosis has recently stepped forward with the introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators, although data on potential adverse effects are lacking for many categories of patients, such as pregnant women.

METHODS

We report one of the first reports on the outcome of pregnancy in a woman treated with Elexacaftor/Tezacaftor/Ivacaftor during the second and third trimester of pregnancy, showing a significant improvement of respiratory status, compared with the first trimester when the medication was discontinued due to unknown and, therefore, potential teratogenic effects. Also, we performed the review of the existing literature on the topic.

RESULTS

The course of pregnancy was uneventful, with reference to major obstetric complications, and the patient delivered a healthy neonate. These results were similar to those coming from other short series of pregnant women affected by cystic fibrosis and treated with CFTR modulators during pregnancy.

CONCLUSIONS

Thus, despite the lack of evidence on the topic, the use of Elexacaftor/Tezacaftor/Ivacaftor in pregnancy seems to be apparently not associated with major adverse events, thus opening optimistic scenarios in terms of management of these patients.

Inpatient Management of the Acutely Decompensating Lung Transplant Candidate

Lung allocation in the US changed nearly 15 years ago from time accrued on the waiting list to disease severity and likelihood of posttransplant survival, represented by the lung allocation score (LAS). Notably, the risk of death within a year plays a stronger role on the score calculation than posttransplant survival. While this change was associated with the intended decrease in waitlist mortality (most recently reported at 14.6%), it was predictable that transplant teams would have to care for increasingly older and complex candidates and recipients. This urgency-based allocation also led centers to routinely consider transplanting patients with higher acuity, often hospitalized and, not infrequently, in the intensive care unit (ICU). According to the Scientific Registry for Transplant Recipients, from 2009 to 2019, the proportion of lung recipients hospitalized and those admitted to the ICU at the time of transplant increased from 18.9% to 26.8% and from 9.2% to 16.5%, respectively..

Multicenter Surveillance of Cystic Fibrosis in Korean Children

Purpose

Methods

Results

Conclusions

Stability Prediction for Mutations in the Cytosolic Domains of Cystic Fibrosis Transmembrane Conductance Regulator

Cystic Fibrosis (CF) is caused by mutations to the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) chloride channel. CFTR is composed of two membrane spanning domains, two cytosolic nucleotide-binding domains (NBD1 and NBD2) and a largely unstructured R-domain. Multiple CF-causing mutations reside in the NBDs and some are known to compromise the stability of these domains. The ability to predict the effect of mutations on the stability of the cytosolic domains of CFTR and to shed light on the mechanisms by which they exert their effect is therefore important in CF research. With this in mind, we have predicted the effect on domain stability of 59 mutations in NBD1 and NBD2 using 15 different algorithms and evaluated their performances via comparison to experimental data using several metrics including the correct classification rate (CCR), and the squared Pearson correlation (R²) and Spearman's correlation (ρ) calculated between the experimental ΔT_m values and the computationally predicted ΔΔG values. Overall, the best results were obtained with FoldX and Rosetta. For NBD1 (35 mutations), FoldX provided R² and ρ values of 0.64 and -0.71, respectively, with an 86% correct classification rate (CCR). For NBD2 (24 mutations), FoldX R², ρ, and CCR were 0.51, -0.73, and 75%, respectively. Application of the Rosetta high-resolution protocol (Rosetta_hrp) to NBD1 yielded R², ρ, and CCR of 0.64, -0.75, and 69%, respectively, and for NBD2 yielded R², ρ, and CCR of 0.29, -0.27, and 50%, respectively. The corresponding numbers for the Rosetta's low-resolution protocol (Rosetta_lrp) were R² = 0.47, ρ = -0.69, and CCR = 69% for NBD1 and R² = 0.27, ρ = -0.24, and CCR = 63% for NBD2. For NBD1, both algorithms suggest that destabilizing mutations suffer from destabilizing vdW clashes, whereas stabilizing mutations benefit from favorable H-bond interactions. Two triple consensus approaches based on FoldX, Rosetta_lpr, and Rosetta_hpr were attempted using either "majority-voting" or "all-voting". The all-voting consensus outperformed the individual predictors, albeit on a smaller data set. In summary, our results suggest that the effect of mutations on the stability of CFTR's NBDs could be largely predicted. Since NBDs are common to all ABC transporters, these results may find use in predicting the effect and mechanism of the action of multiple disease-causing mutations in other proteins.

Cystic fibrosis transmembrane conductance regulator modulators reduce the risk of recurrent acute pancreatitis among adult patients with pancreas sufficient cystic fibrosis

BACKGROUND

Approximately 1 in 5 patients with pancreas sufficient cystic fibrosis (PS-CF) will develop acute pancreatitis (AP). It is not known whether ivacaftor alone or in combination with other CFTR (cystic transmembrane regulator) modulators (tezacaftor or lumacaftor) can reduce the risk of AP in patients with PS-CF and AP history.

METHODS

We retrospectively queried the CF registry at our institution for adult patients with PS-CF, a documented history of AP and initiation of CFTR modulators for pulmonary indications. Patient characteristics including demographics, CFTR genotype, pancreatitis risk factors, pancreatic exocrine function and other relevant laboratory, imaging parameters were obtained from the time of the sentinel AP episode through the follow-up period.

RESULTS

A total of 15 adult CF patients were identified with mean age of 44.1 years (SD ± 13.8). In the 24 months preceding CFTR modulator initiation, six of these patients had at least 1 episode of AP with median of 2 episodes [1.75, 2.5]. None of the patients had evidence of pancreatic calcifications or exocrine pancreas insufficiency at the time of CFTR modulator initiation. The mean duration of follow-up after CFTR modulator initiation was 36.7 months (SD ± 21.5). None of the patients who remained on CFTR modulators developed an episode of AP or required hospitalization for AP related abdominal pain during follow-up.

CONCLUSIONS

CFTR modulators, alone or in combination, substantially reduce the risk of recurrent AP over a mean follow-up period of 3 years in adult patients with PS-CF and a history of prior AP. These data suggest that any augmentation of CFTR function can reduce the risk of pancreatitis.

Cystic fibrosis: a clinical view

Cystic fibrosis (CF), a monogenic disease caused by mutations in the CFTR gene on chromosome 7, is complex and greatly variable in clinical expression. Airways, pancreas, male genital system, intestine, liver, bone, and kidney are involved. The lack of CFTR or its impaired function causes fat malabsorption and chronic pulmonary infections leading to bronchiectasis and progressive lung damage. Previously considered lethal in infancy and childhood, CF has now attained median survivals of 50 years of age, mainly thanks to the early diagnosis through neonatal screening, recognition of mild forms, and an aggressive therapeutic attitude. Classical treatment includes pancreatic enzyme replacement, respiratory physiotherapy, mucolitics, and aggressive antibiotic therapy. A significant proportion of patients with severe symptoms still requires lung or, less frequently, liver transplantation. The great number of mutations and their diverse effects on the CFTR protein account only partially for CF clinical variability, and modifier genes have a role in modulating the clinical expression of the disease. Despite the increasing understanding of CFTR functioning, several aspects of CF need still to be clarified, e.g., the worse outcome in females, the risk of malignancies, the pathophysiology, and best treatment of comorbidities, such as CF-related diabetes or CF-related bone disorder. Research is focusing on new drugs restoring CFTR function, some already available and with good clinical impact, others showing promising preliminary results that need to be confirmed in phase III clinical trials.

A reliable computational workflow for the selection of optimal screening libraries

Background

The experimental screening of compound collections is a common starting point in many drug discovery projects. Successes of such screening campaigns critically depend on the quality of the screened library. Many libraries are currently available from different vendors yet the selection of the optimal screening library for a specific project is challenging. We have devised a novel workflow for the rational selection of project-specific screening libraries.

Results

The workflow accepts as input a set of virtual candidate libraries and applies the following steps to each library: (1) data curation; (2) assessment of ADME/T profile; (3) assessment of the number of promiscuous binders/frequent HTS hitters; (4) assessment of internal diversity; (5) assessment of similarity to known active compound(s) (optional); (6) assessment of similarity to in-house or otherwise accessible compound collections (optional). For ADME/T profiling, Lipinski’s and Veber’s rule-based filters were implemented and a new blood brain barrier permeation model was developed and validated (85 and 74 % success rate for training set and test set, respectively). Diversity and similarity descriptors which demonstrated best performances in terms of their ability to select either diverse or focused sets of compounds from three databases (Drug Bank, CMC and CHEMBL) were identified and used for diversity and similarity assessments. The workflow was used to analyze nine common screening libraries available from six vendors. The results of this analysis are reported for each library providing an assessment of its quality. Furthermore, a consensus approach was developed to combine the results of these analyses into a single score for selecting the optimal library under different scenarios.

Conclusions

We have devised and tested a new workflow for the rational selection of screening libraries under different scenarios. The current workflow was implemented using the Pipeline Pilot software yet due to the usage of generic components, it can be easily adapted and reproduced by computational groups interested in rational selection of screening libraries. Furthermore, the workflow could be readily modified to include additional components. This workflow has been routinely used in our laboratory for the selection of libraries in multiple projects and consistently selects libraries which are well balanced across multiple parameters.Graphical abstract

Cystic Fibrosis below the Diaphragm: Abdominal Findings in Adult Patients

Cystic fibrosis (CF) is the most common lethal autosomal recessive disease in the white population. Mutation of the CF transmembrane conductance regulator gene on chromosome 7 results in production of abnormally viscous mucus and secretions in the lungs of patients with CF. A similar pathologic process occurs in the gastrointestinal tract, pancreas, and hepatobiliary system. Inspissated mucus causes luminal obstruction and resultant clinical and radiologic complications associated with the disease process. Pancreatic involvement can result in exocrine and endocrine insufficiency, pancreatic atrophy, fatty replacement, or lipomatous pseudohypertrophy. Acute and chronic pancreatitis, pancreatic calcification, cysts, and cystosis also occur. Hepatic manifestations include hepatic steatosis, focal biliary and multilobular cirrhosis, and portal hypertension. Biliary complications include cholelithiasis, microgallbladder, and sclerosing cholangitis. The entire digestive tract can be involved. Distal ileal obstruction syndrome, intussusception, appendicitis, chronic constipation, colonic wall thickening, fibrosing colonopathy, pneumatosis intestinalis, gastroesophageal reflux, and peptic ulcer disease have been described. Renal manifestations include nephrolithiasis and secondary amyloidosis. The educational objectives of this review are to reveal the abdominal manifestations of CF to facilitate focused analysis of cross-sectional imaging in adult patients. Life expectancy in patients with CF continues to improve because of a combination of aggressive antibiotic treatment, improved emphasis on nutrition and physiotherapy, and development of promising new CF transmembrane conductance regulator modulators. As lung function and survival improve, extrapulmonary conditions, including hepatic and gastrointestinal malignancy, will be an increasing cause of morbidity and mortality. Awareness of the expected abdominal manifestations of CF may assist radiologists in identifying acute inflammatory or neoplastic conditions. (©)RSNA, 2015.

Ivacaftor: a novel mutation modulating drug

Cystic fibrosis (CF) is multisystemic disorder presenting in newborn period to adulthood, predominantly affecting respiratory system. It is caused by mutation in CF transmembrane conductance regulator gene. ΔF508 is the most common mutation seen worldwide. Supportive management with bronchodilators, anti-inflammatory, mucolytics, antibiotics are the corner stone of therapy. Mutation specific drug, Ivacaftor, was recently approved USFDA in January 2012 for patients carrying G551D mutation. It is approved in patients who are six years and older in 150 mg twice daily dosing schedule with fat containing meals. It improves the lung function and other aspects of disease including weight gain. The side effects like upper respiratory infection, headache, rash, diarrhoea, stomach ache and dizziness are mild and self-limiting. This is excellent example of promise of personalised medicine - targeted drug that treat patients with specific genetic makeup.

Improving transition from paediatric to adult cystic fibrosis care: programme implementation and evaluation

BACKGROUND

The paradigm of cystic fibrosis (CF) care has changed as effective therapies extend the lives of patients well into adulthood. Preparing for and maintaining high quality CF care into the adult healthcare setting is critical for prolonged survival. Unfortunately, this transfer process from the paediatric to the adult CF centre is met with a variety of challenges.

OBJECTIVE AND METHODS

The objective of this quality improvement (QI) project was to develop, implement and evaluate a theory-based programme for transition from paediatric to adult CF care. In a multi-phase process, the paediatric and adult programmes developed a transition curriculum, addressed care standards and standardised patient transfer protocols. We evaluated the impact of this process through staff surveys, review of field notes from QI meetings, tracking transfers and responses of patients to the Transition Readiness Assessment Questionnaire (TRAQ) at the start of the programme and 18 months after initiation.

RESULTS

The collaboration between the paediatric and adult teams continued through quarterly meetings over the past 4 years. This has provided a forum that sustained our transition programme, harmonised care across CF centres and addressed other needs of our CF centre. Discussion of transition with families in the paediatric centre increased twofold (35% to 73% p<0.001), and resulted in a trend towards improved patient TRAQ self-advocacy scores and decreased in-hospital transfer.

CONCLUSIONS

We successfully created a curriculum and process for transition from paediatric to adult CF care at our centres. This collaboration shapes the communication between our paediatric and adult CF care teams and enables ongoing feedback among patients, families and providers. The impact of our transition programme on long-term patient morbidity will require future evaluation.

Nebulized hyaluronan ameliorates lung inflammation in cystic fibrosis mice

RATIONALE

Chronic lung inflammation with increased susceptibility to bacterial infections cause much of the morbidity and mortality in patients with cystic fibrosis (CF), the most common severe, autosomal recessively inherited disease in the Caucasian population. Exogenous inhaled hyaluronan (HA) can exert a protective effect against injury and beneficial effects of HA have been shown in experimental models of chronic respiratory diseases. Our objective was to examine whether exogenous administration of nebulized HA might interfere with lung inflammation in CF.

STUDY DESIGN/METHODS

F508del homozygous mice (Cftr(F508del) ) and transgenic mice overexpressing the ENaC channel β-subunit (Scnn1b-Tg) were treated with nebulized HA (0.5 mg/mouse/day for 7 days). Tumor necrosis factor-alpha (TNFα), macrophage inflammatory protein-2 (MIP-2), myeloperoxidase (MPO) levels, and macrophage infiltration were assessed on lung tissues. IB3-1 and CFBE41o-epithelial cell lines were cultured with HA (24 hr, 100 µg/ml) and Reactive Oxygen Species (ROS), Tissue Transglutaminase (TG2) SUMOylation and Peroxisome Proliferator Activated Receptor gamma (PPARγ) and phospho-p42/p44 levels were measured by dichlorodihydrofluorescein assay, or fluorescence resonance energy transfer (FRET) microscopy or immunoblots.

RESULTS

Nebulized HA reduced TNFα expression (P < 0.005); TNFα, MIP-2, and MPO protein levels (P < 0.05); MPO activity (P < 0.05); and CD68+ cells counts (P < 0.005) in lung tissues of Cftr(F508del) and Scnn1b-Tg mice, compared with saline-treated mice. HA reduced ROS, TG2 SUMOylation, TG2 activity, phospho-p42-44, and increased PPARγ protein in both IB3-1 and CFBE41o cells (P < 0.05).

CONCLUSIONS

Nebulized HA is effective in controlling inflammation in vivo in mice CF airways and in vitro in human airway epithelial cells. We provide the proof of concept for the use of inhaled HA as a potential anti-inflammatory drug in CF therapy.

Novel amino-carbonitrile-pyrazole identified in a small molecule screen activates wild-type and ΔF508 cystic fibrosis transmembrane conductance regulator in the absence of a cAMP agonist

Cystic fibrosis (CF) is caused by loss-of-function mutations in the CF transmembrane conductance regulator (CFTR) Cl⁻ channel. We developed a phenotype-based high-throughput screen to identify small-molecule activators of human airway epithelial Ca²⁺-activated Cl⁻ channels (CaCCs) for CF therapy. Unexpectedly, screening of ∼110,000 synthetic small molecules revealed an amino-carbonitrile-pyrazole, C(act)-A1, that activated CFTR but not CaCC Cl⁻ conductance. C(act)-A1 produced large and sustained CFTR Cl⁻ currents in CFTR-expressing Fisher rat thyroid (FRT) cells and in primary cultures of human bronchial epithelial (HBE) cells, without increasing intracellular cAMP and in the absence of a cAMP agonist. C(act)-A1 produced linear whole-cell currents. C(act)-A1 also activated ΔF508-CFTR Cl⁻ currents in low temperature-rescued ΔF508-CFTR-expressing FRT cells and CF-HBE cells (from homozygous ΔF508 patients) in the absence of a cAMP agonist, and showed additive effects with forskolin. In contrast, N-(2,4-di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4-dihydroquinoline-3-carboxamide (VX-770) and genistein produced little or no ΔF508-CFTR Cl⁻ current in the absence of a cAMP agonist. In FRT cells expressing G551D-CFTR and in CF nasal polyp epithelial cells (from a heterozygous G551D/Y1092X-CFTR patient), C(act)-A1 produced little Cl⁻ current by itself but showed synergy with forskolin. The amino-carbonitrile-pyrazole C(act)-A1 identified here is unique among prior CFTR-activating compounds, as it strongly activated wild-type and ΔF508-CFTR in the absence of a cAMP agonist. Increasing ΔF508-CFTR Cl⁻ conductance by an "activator," as defined by activation in the absence of cAMP stimulation, provides a novel strategy for CF therapy that is different from that of a "potentiator," which requires cAMP elevation.

Understanding the costs of care for cystic fibrosis: an analysis by age and health state

OBJECTIVES

Cystic fibrosis (CF) is an inherited disease that requires more intensive treatments as the disease progresses. Recent medical advancements have improved survival but have also increased costs. Our lack of understanding on the relationship between disease severity and lifetime health care costs is a major impediment to the timely economic assessment of new treatments.

METHODS

Using data from three waves of the Australian Cystic Fibrosis Australia Data Registry, we estimate the annual costs of CF care by age and health state. We define health states on the basis of annual lung-function scores and patient's organ transplant status. We exploit the longitudinal nature of the data to model disease progression, and we use this to estimate lifetime health care costs.

RESULTS

The mean annual health care cost for treating CF is US $15,571. Costs for patients with mild, moderate, and severe disease are US $10,151, US $25,647, and US $33,691, respectively. Lifetime health care costs are approximately US $306,332 (3.5% discount rate). The majority of costs are accounted for by hospital inpatients (58%), followed by pharmaceuticals (29%), medical services (10%), complications (2%), and diagnostic tests (1%).

CONCLUSIONS

Our study is the first of its kind using the Australian Cystic Fibrosis Data Registry, and demonstrates the utility of longitudinal registry data for the purpose of economic analysis. Our results can be used as an input to future economic evaluations by providing analysts with a better understanding of the long-term cost impact when new treatments are developed.

Targeting the Intracellular Environment in Cystic Fibrosis: Restoring Autophagy as a Novel Strategy to Circumvent the CFTR Defect

Cystic fibrosis (CF) patients harboring the most common deletion mutation of the CF transmembrane conductance regulator (CFTR), F508del, are poor responders to potentiators of CFTR channel activity which can be used to treat a small subset of CF patients who genetically carry plasma membrane (PM)-resident CFTR mutants. The misfolded F508del-CFTR protein is unstable in the PM even if rescued by pharmacological agents that prevent its intracellular retention and degradation. CF is a conformational disease in which defective CFTR induces an impressive derangement of general proteostasis resulting from disabled autophagy. In this review, we discuss how rescuing Beclin 1 (BECN1), a major player of autophagosome formation, either by means of direct gene transfer or indirectly by administration of proteostasis regulators, could stabilize F508del-CFTR at the PM. We focus on the relationship between the improvement of peripheral proteostasis and CFTR PM stability in F508del-CFTR homozygous bronchial epithelia or mouse lungs. Moreover, this article reviews recent pre-clinical evidence indicating that targeting the intracellular environment surrounding the misfolded mutant CFTR instead of protein itself could constitute an attractive therapeutic option to sensitize patients carrying the F508del-CFTR mutation to the beneficial action of CFTR potentiators on lung inflammation.

Personalizing rare disease research: how genomics is revolutionizing the diagnosis and treatment of rare disease

A decade after the complete sequencing of the human genome, combined with recent advances in throughput and sequencing costs, the genetics of rare diseases has entered a new era. There has now been an explosion in the identification and mapping of rare diseases, with over 10,000 exomes having been sequenced to date. This article surveys the progress and development of technologies to understand rare disease; it provides a historical overview of traditional techniques such as karyotyping and homozygosity mapping, reviews current methods of whole-exome and -genome sequencing, and provides a future perspective on upcoming developments such as targeted drugs and gene therapy. This article will discuss the implications of these methods for rare disease research, along with a discussion of the success stories that provide great hope and optimism for patients and scientists alike.

Targeting autophagy as a novel strategy for facilitating the therapeutic action of potentiators on ΔF508 cystic fibrosis transmembrane conductance regulator

Channel activators (potentiators) of cystic fibrosis (CF) transmembrane conductance regulator (CFTR), can be used for the treatment of the small subset of CF patients that carry plasma membrane-resident CFTR mutants. However, approximately 90% of CF patients carry the misfolded ΔF508-CFTR and are poorly responsive to potentiators, because ΔF508-CFTR is intrinsically unstable at the plasma membrane (PM) even if rescued by pharmacological correctors. We have demonstrated that human and mouse CF airways are autophagy deficient due to functional sequestration of BECN1 and that the tissue transglutaminase-2 inhibitor, cystamine, or antioxidants restore BECN1-dependent autophagy and reduce SQSTM1/p62 levels, thus favoring ΔF508-CFTR trafficking to the epithelial surface. Here, we investigated whether these treatments could facilitate the beneficial action of potentiators on ΔF508-CFTR homozygous airways. Cystamine or the superoxide dismutase (SOD)/catalase-mimetic EUK-134 stabilized ΔF508-CFTR at the plasma membrane of airway epithelial cells and sustained the expression of CFTR at the epithelial surface well beyond drug withdrawal, overexpressing BECN1 and depleting SQSTM1. This facilitates the beneficial action of potentiators in controlling inflammation in ex vivo ΔF508-CFTR homozygous human nasal biopsies and in vivo in mouse ΔF508-CFTR lungs. Direct depletion of Sqstm1 by shRNAs in vivo in ΔF508-CFTR mice synergized with potentiators in sustaining surface CFTR expression and suppressing inflammation. Cystamine pre-treatment restored ΔF508-CFTR response to the CFTR potentiators genistein, Vrx-532 or Vrx-770 in freshly isolated brushed nasal epithelial cells from ΔF508-CFTR homozygous patients. These findings delineate a novel therapeutic strategy for the treatment of CF patients with the ΔF508-CFTR mutation in which patients are first treated with cystamine and subsequently pulsed with CFTR potentiators.

Cystic fibrosis transmembrane conductance regulator-modifying medications: the future of cystic fibrosis treatment

OBJECTIVE

To review and evaluate cystic fibrosis transmembrane conductance regulator (CFTR) modulators for the treatment of cystic fibrosis (CF).

DATA SOURCES

Literature was accessed through MEDLINE (1977-January 2012), the Cochrane Library, and International Pharmaceutical Abstracts (1977-March 2012). Search terms included ivacaftor, VX-770, VX-809, ataluren, PTC 124, CFTR modulator, and cystic fibrosis.

STUDY SELECTION AND DATA EXTRACTION

All English-language articles identified from the data sources were evaluated for inclusion. Clinical trials and relevant review articles were evaluated for each CFTR modulator.

DATA SYNTHESIS

CF is caused by a mutation in the gene that encodes for the CFTR protein; mutations can be separated into 5 different classes. Ivacaftor is a new CFTR potentiator that helps the CFTR channel open properly in patients with the CFTR mutation, G551D. Patients in one study had significant decreases in sweat chloride values and increases in pulmonary function tests. Ivacaftor was approved by the Food and Drug Administration (FDA) to be taken orally at a dose of 150 mg twice a day in G551D CF patients older than 6 years. Additional studies are investigating the use of ivacaftor in other gating mutations and in younger patients. VX-809 is a CFTR corrector that modulates the folding and trafficking of CFTR. VX-809 was originally studied alone in patients with F508del mutation but is now being used in combination with ivacaftor in Phase 2 studies. Ataluren allows the read through of premature stop codons, and studies in patients with CF with nonsense mutations show an increase in chloride transportation. Ataluren requires 3 times a day dosing and is currently in a Phase 3 placebo-controlled study.

CONCLUSIONS

Three new agents, ivacaftor, VX-809, and ataluren, target the basic defects in CFTR production. Ivacaftor was recently FDA approved, while the other 2 agents are still in clinical trials. Patients with CF will benefit from personalized medicine based on their specific genotype.