denufosol-tetrasodium and Cystic-Fibrosis

Our current understanding of the pathogenesis of cystic fibrosis (CF) lung disease stresses the importance of the physical and chemical properties of the airway surface liquid (ASL). In particular, the loss of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel function in CF reduces the volume and fluidity of the ASL, thus impairing mucociliary clearance and innate antimicrobial mechanisms. Besides direct approaches to restoring mutant CFTR function, alternative therapeutic strategies may also be considered to correct the basic defect of impaired salt and water transport. Such alternative strategies are focused on the restoration of mucociliary transport by (1) reducing sodium and fluid absorption by inhibiting the ENaC channel; (2) activating alternative chloride channels; and (3) increasing airway surface hydration with osmotic agents. Therapeutic approaches directed at targets other than CFTR are attractive because they are potentially useful to all patients irrespective of their genotype. Clinical trials are underway to test the efficacy of these approaches.

Topics: Anoctamin-1; Bacteriocins; Chloride Channels; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deoxycytosine Nucleotides; Diuretics, Osmotic; Epithelial Cells; Epithelial Sodium Channel Blockers; Epithelial Sodium Channels; Humans; Mannitol; Mucociliary Clearance; Neoplasm Proteins; Peptides; Sodium; Uridine

The aims of this article are to summarize existing knowledge regarding the pathophysiology of small airways disease in cystic fibrosis (CF), to speculate about additional mechanisms that might play a role, and to consider the available or potential options to treat it. In the first section, we review the evidence provided by pathologic, physiologic, and imaging studies suggesting that obstruction of small airways begins early in life and is progressive. In the second section we discuss how the relationships between CF transmembrane conductance regulator (CFTR), ion transport, the volume of the periciliary liquid layer and airway mucus might lead to defective mucociliary clearance in small airways. In addition, we discuss how chronic endobronchial bacterial infection and a chronic neutrophilic inflammatory response increase the viscosity of CF secretions and exacerbate the clearance problem. Next, we discuss how the mechanical properties of small airways could be altered early in the disease process and how remodeling can contribute to small airways disease. In the final section, we discuss how established therapies impact small airways disease and new directions that may lead to improvement in the treatment of small airways disease. We conclude that there are many reasons to believe that small airways play an important role in the pathophysiology of (early) CF lung disease. Therapy should be aimed to target the small airways more efficiently, especially with drugs that can correct the basic defect at an early stage of disease.

Topics: Administration, Inhalation; Airway Obstruction; Airway Remodeling; Anti-Inflammatory Agents; Child; Child, Preschool; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deoxycytosine Nucleotides; Humans; Infant; Ion Transport; Mannitol; Mucociliary Clearance; Mucus; Neutrophils; Pneumonia, Bacterial; Pulmonary Alveoli; Radiography; Respiratory Mucosa; Sodium Channel Blockers; Uridine; Young Adult

Among the most promising of the new therapies being developed for the treatment of Cystic Fibrosis (CF) are those targeted at increasing mucosal hydration on the surface of the airways. One of these therapies, P2Y(2) receptor agonists, bypasses the defective CFTR chloride channel, and activates an alternative chloride channel. This activation results in an increase in airway surface epithelial hydration, and through these actions and effects on cilia beat frequency, increases mucociliary clearance. The pharmacology of P2Y(2) agonists has been confirmed in several preclinical and clinical studies. Denufosol tetrasodium is a novel second-generation, metabolically stable, selective P2Y(2) receptor agonist currently in Phase 3 clinical development. In radiolabelled deposition studies of P2Y(2) agonists in healthy non-smokers and smokers, approximately 7mg of a 40-mg nebulizer (PARI LC Star) load was deposited in the lungs. In a pharmacokinetic study in healthy volunteers, very limited systemic exposure was observed when doses of 200mg of denufosol were nebulized. Thus, it appears that high concentrations of denufosol can be achieved in the airways with very low systemic absorption. Denufosol has been generally well-tolerated in healthy volunteers and patients with CF. The most common adverse events were in the respiratory system, with cough having the highest frequency. Doses of 20-60mg have been evaluated in Phase 2 trials of up to 28 days duration, and superiority relative to placebo on FEV1 has been observed in patients with relatively normal lung function (FEV1 greater than or equal to 75% of predicted). The first Phase 3 trial is a comparison of denufosol 60mg and placebo in 350 patients with CF with FEV1 at study entry greater than or equal to 75% of predicted.

Topics: Administration, Inhalation; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Cystic Fibrosis; Deoxycytosine Nucleotides; Female; Forced Expiratory Volume; Humans; Male; Polyphosphates; Purinergic P2 Receptor Agonists; Receptors, Purinergic P2Y2; Uracil Nucleotides; Uridine

Although cystic fibrosis (CF) patients display multiorgan dysfunction (e.g. pancreas, gut, and lung) it is lung disease that is the leading cause of premature death in these patients. CF lung disease is characterized by persistent pulmonary infection and mucus plugging of the airways initiated by the failure of solute transport across the airway epithelium. Many drug therapies aim to alleviate the secondary characteristics of CF lung disease; however, new therapies in development are targeted at correcting the ion transport deficiency of CF. The goal is to hydrate airway surfaces by stimulating secretion (through activation of the CF transmembrane conductance regulator and calcium-activated chloride channels), and/or inhibiting absorption (through the epithelial sodium channel) thereby stimulating healthy mucociliary clearance. If mucociliary clearance can be stimulated sufficiently from an early age, then there is the possibility that secondary lung infection may be eradicated from the syndrome of CF disease.

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deoxycytosine Nucleotides; Humans; Ion Transport; Lung; Mannitol; Peptides, Cyclic; Saline Solution, Hypertonic; Sodium Channel Blockers; Uridine

P2Y(2) receptor agonists are a new class of compounds that are being evaluated as a treatment for the pulmonary manifestations of Cystic Fibrosis (CF). Results of preclinical research suggest that these compounds inhibit sodium absorption, restore chloride conductance and rehydrate the CF airway surface. In addition, P2Y(2) receptor agonists have been shown to enhance ciliary beat frequency and increase mucociliary clearance in animals and subjects with impaired mucociliary clearance. The normalization of airway surface liquid and enhancement of lung clearance is expected to provide a clinical benefit to CF patients. A number of P2Y(2) agonist compounds have been evaluated in healthy subjects and patients with CF. Most recently, INS37217, a metabolically stable and potent P2Y(2) agonist has been developed and studies have shown it to be well-tolerated when given via inhalation. This compound is currently being evaluated in children and adults with CF lung disease.

Topics: Administration, Inhalation; Animals; Clinical Trials as Topic; Cystic Fibrosis; Deoxycytosine Nucleotides; Epithelium; Humans; Mucociliary Clearance; Ophthalmic Solutions; Polyphosphates; Purinergic P2 Receptor Agonists; Receptors, Purinergic P2Y2; Uracil Nucleotides; Uridine

Denufosol stimulates chloride secretion independent of the chloride channel which is dysfunctional in cystic fibrosis (CF) and therefore has the potential to benefit CF patients regardless of genotype.. To assess the efficacy of denufosol in CF patients with mild lung function impairment age 5 years and older.. This multicenter, randomized, parallel group double-blind placebo-controlled trial was conducted at 102 CF care centers in Australia, Canada and the United States (NCT00625612) The active group (n=233) received 60 mg denufosol via inhalation three times daily The primary efficacy endpoint was change in FEV(1) in liters from Day 0 to week 48.. 685 patients were screened for the study and 466 patients (233 in each group) were randomized to study treatment. The adjusted mean change in FEV(1)was 40 mL for denufosol and 32 mL for placebo with a resulting treatment effect of 8 mL (95% CI -0.040, 0.056). The average rate of change in FEV(1) percent of predicted over 0 to 48 weeks was -3.04% for placebo vs. -2.30 for denufosol (a difference of 24% relative to placebo) among all patients. The incidence of pulmonary exacerbation was 26% vs. 21% for the placebo and denufosol groups with no differences in the time to first event. The study treatments were well tolerated and there was no evidence of systemic effects in any safety parameter assessed.. In patients with CF treatment with denufosol for 48 weeks did not improve pulmonary function or reduce the incidence of pulmonary exacerbations.

Topics: Administration, Inhalation; Adolescent; Adult; Child; Child, Preschool; Chlorides; Cystic Fibrosis; Deoxycytosine Nucleotides; Double-Blind Method; Female; Forced Expiratory Volume; Humans; Incidence; Kaplan-Meier Estimate; Lung; Lung Diseases; Male; Treatment Outcome; Uridine; Young Adult

Intervention for cystic fibrosis lung disease early in its course has the potential to delay or prevent progressive changes that lead to irreversible airflow obstruction. Denufosol is a novel ion channel regulator designed to correct the ion transport defect and increase the overall mucociliary clearance in cystic fibrosis lung disease by increasing chloride secretion, inhibiting sodium absorption, and increasing ciliary beat frequency in the airway epithelium independently of cystic fibrosis transmembrane conductance regulator genotype.. To evaluate the efficacy and safety of denufosol in patients with cystic fibrosis who had normal to mildly impaired lung function characteristic of early cystic fibrosis.. A total of 352 patients greater than or equal to 5 years old with cystic fibrosis who had FEV(1) greater than or equal to 75% of predicted normal were randomized to receive inhaled denufosol, 60 mg, or placebo three times daily in a Phase 3, randomized, double-blind, placebo-controlled, 24-week trial.. Main outcome measures included change in FEV(1) from baseline to Week 24 endpoint and adverse events. Mean change from baseline to Week 24 endpoint in FEV(1) (primary efficacy endpoint) was 0.048 L for denufosol (n = 178) and 0.003 L for placebo (n = 174; P = 0.047). No significant differences between groups were observed for secondary endpoints including exacerbation rate and other measures of lung function. Denufosol was well tolerated with adverse event and growth profiles similar to placebo.. Denufosol improved lung function relative to placebo in cystic fibrosis patients with normal to mildly impaired lung function. Clinical trial registered with www.clinicaltrials.gov (NCT00357279).

Topics: Adolescent; Adult; Analysis of Variance; Child; Child, Preschool; Cystic Fibrosis; Deoxycytosine Nucleotides; Double-Blind Method; Female; Humans; Lung; Male; Respiratory Function Tests; Severity of Illness Index; Treatment Outcome; Uridine; Young Adult

Topics: Adult; Age Factors; Child, Preschool; Cystic Fibrosis; Deoxycytosine Nucleotides; Humans; Infant; Infant, Newborn; Lung; Uridine

Centralized spirometry may significantly improve quality of spirometry and reduce variability of this outcome measure in clinical trials in cystic fibrosis (CF).. Spirometry was performed during the phase 2 randomized, placebo-controlled, double-blind clinical trial of denufosol in patients with mild to moderate CF using American Thoracic Society guidelines. Uniform spirometers were used with electronic data transmission of all the data to a reading center. Spirometry was evaluated for quality by a central reader based on start of test, cough during the test, and evidence of a plateau.. A total of 1418 spirometry values were assessed in 89 subjects during the trial. In only 5 instances did the central reading center need to give feedback to sites regarding the quality of spirometry. The study site data matched the central reading center's data for all but 78 (6%) spirometry values in 33 patients. Many of these differences were small with only 35 (3%) values differing by more than 50 mL in 26 patients.. Spirometry in this clinical trial was of high quality with low rate of significant centralized over-read.

Topics: Administration, Inhalation; Adolescent; Cystic Fibrosis; Deoxycytosine Nucleotides; Dose-Response Relationship, Drug; Double-Blind Method; Female; Follow-Up Studies; Humans; Male; Maximal Expiratory Flow Rate; Severity of Illness Index; Spirometry; Treatment Outcome; Uridine; Vital Capacity

Denufosol tetrasodium is a selective P2Y(2) agonist that enhances mucosal hydration and mucus clearance by activating Cl(-) secretion and inhibiting epithelial Na(+) transport through a non-cystic fibrosis transmembrane conductance regulator mechanism in the lung.. To examine the safety and efficacy of 28 days of treatment with denufosol compared with placebo in patients with mild cystic fibrosis.. The study was a randomized, double-blind, multi-center, 28-day, phase 2 clinical trial of denufosol tetrasodium inhalation solution (20, 40, or 60 mg) versus placebo (normal saline). Patients with screening FEV(1) >or= 75% of predicted normal value and not treated with inhaled antibiotics for the past 30 days were randomized to receive one of three doses of denufosol or placebo administered three times daily.. Eighty-nine patients were randomized and received the study drug, 94% completed the study, and 98% were compliant with dosing. All treatments were generally well tolerated, with no dose-response trends observed with respect to safety parameters. The most common adverse event was cough (52% of placebo patients and 47% of denufosol patients). Five patients discontinued early due to adverse events, two on placebo and three on denufosol. Denufosol patients (pooling active doses) had significantly higher changes from baseline in FEV(1) (P = 0.006), FEF(25%-75%) (P = 0.008), FVC (P = 0.022), and FEV(1)/FVC (P = 0.047) than placebo patients at the end of the study.. Denufosol administered three times daily for 28 days appeared to be safe and well tolerated in this population with mild cystic fibrosis and provided preliminary evidence of potential benefit in lung function.

Topics: Adolescent; Adult; Child; Cough; Cystic Fibrosis; Deoxycytosine Nucleotides; Double-Blind Method; Female; Humans; Lung Volume Measurements; Male; Middle Aged; Nebulizers and Vaporizers; Purinergic P2 Receptor Agonists; Treatment Outcome; Uridine

Denufosol tetrasodium (INS37217) is a selective P2Y(2) agonist that stimulates ciliary beat frequency and Cl(-) secretion in normal and cystic fibrosis (CF) airway epithelia, and is being investigated as an inhaled treatment for CF. The Cl(-) secretory response is mediated via a non-CFTR pathway, and the driving force for Cl(-) secretion is enhanced by the effect of P2Y(2) activation to also inhibit epithelial Na(+) transport. Denufosol is metabolically more stable and better tolerated, and may enhance mucociliary clearance for a longer period of time than previously investigated P2Y(2) agonists. The goal of this phase 1/phase 2 study was to assess the safety and tolerability of single and repeated doses of aerosolized denufosol in subjects with CF. The study was a double-blind, placebo-controlled, multicenter comparison of ascending single doses of denufosol (10, 20, 40, and 60 mg, administered by inhalation via the Pari LC Star nebulizer) vs. placebo (normal saline), followed by a comparison of twice-daily administration of the maximum tolerated dose (MTD) of denufosol or placebo for 5 days. Thirty-seven adult (18 years of age or older) and 24 pediatric (5-17 years of age) subjects with CF were evaluated in five cohorts. Subjects were randomized in a 3:1 ratio to receive either denufosol or placebo within each cohort. The percent of subjects experiencing adverse events was similar between the denufosol and placebo groups. The most common adverse event in subjects receiving denufosol was chest tightness in adult subjects (39%) and cough in pediatric subjects (56%). Three (7%) subjects receiving denufosol and one (7%) subject receiving placebo experienced a serious adverse event. Forced expiratory volume in 1 sec (FEV(1)) profiles following dosing were similar across treatment groups, with some acute, reversible decline seen in both groups, most notably in subjects with lower lung function at baseline. In conclusion, doses up to 60 mg of denufosol inhalation solution were well-tolerated in most subjects. Some intolerability was noted among subjects with lower baseline lung function. Based on the results of this phase 1/phase 2 study, the Therapeutics Development Network (TDN) of the Cystic Fibrosis Foundation (CFF) and Inspire Pharmaceuticals, Inc., recently completed a multicenter, 28-day, phase 2 safety and efficacy clinical trial of denufosol inhalation solution in CF subjects with mild lung disease.

Topics: Administration, Inhalation; Adolescent; Child; Cystic Fibrosis; Deoxycytosine Nucleotides; Double-Blind Method; Female; Forced Expiratory Volume; Humans; Male; Purinergic P2 Receptor Agonists; Receptors, Purinergic P2Y2; Uridine

Topics: Adolescent; Alleles; Child; Child, Preschool; Clinical Trials as Topic; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deoxycytosine Nucleotides; Disease Progression; Drug Design; Drug Industry; Female; Humans; Inflammation; Male; Research Design; Sputum; Time Factors; Treatment Outcome; Uridine

Topics: Administration, Inhalation; Adolescent; Adult; Child; Child, Preschool; Cystic Fibrosis; Deoxycytosine Nucleotides; Diuretics, Osmotic; Humans; Infant; Mannitol; Treatment Outcome; Uridine; Young Adult

Topics: Amiloride; Animals; Bacterial Infections; Biomarkers; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deoxycytosine Nucleotides; Disease Progression; Humans; Inflammation; Lung; Oxadiazoles; Respiratory Function Tests; Sodium Channel Blockers; Uridine

Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deoxycytosine Nucleotides; Genetic Therapy; Humans; Mannitol; Natriuretic Agents; Osmolar Concentration; Uridine

Topics: Administration, Inhalation; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deoxycytosine Nucleotides; Genetic Therapy; Humans; Mutation; Oxadiazoles; Purinergic P2 Receptor Agonists; Receptors, Purinergic P2Y2; Uridine

INS37217 [P(1)-(uridine 5')-P(4)-(2'-deoxycytidine 5')tetraphosphate, tetrasodium salt] is a deoxycytidine-uridine dinucleotide with agonist activity at the P2Y(2) receptor. In primate lung tissues, the P2Y(2) receptor mRNA was located by in situ hybridization predominantly in epithelial cells and not in smooth muscle or stromal tissue. The pharmacologic profile of INS37217 parallels that of UTP, leading to increased chloride and water secretion, increased cilia beat frequency, and increased mucin release. The combined effect of these actions was confirmed in an animal model of tracheal mucus velocity that showed that a single administration of INS37217 significantly enhanced mucus transport for at least 8 h after dosing. This extended duration of action is consistent with the ability of INS37217 to resist metabolism by airway cells and sputum enzymes. The enhanced metabolic stability and resultant increased duration of improved mucociliary clearance may confer significant advantages to INS37217 over other P2Y(2) agonists in the treatment of diseases such as cystic fibrosis.

Topics: Animals; Astrocytoma; Brain Neoplasms; Calcium; Chlorides; Cilia; Cystic Fibrosis; Deoxycytosine Nucleotides; Epithelial Cells; Humans; In Situ Hybridization; In Vitro Techniques; Indicators and Reagents; Macaca mulatta; Mucins; Mucociliary Clearance; Ophthalmic Solutions; Polyphosphates; Purinergic P2 Receptor Agonists; Receptors, Purinergic P2; Receptors, Purinergic P2Y2; Reverse Transcriptase Polymerase Chain Reaction; Sheep; Tumor Cells, Cultured; Uracil Nucleotides; Uridine

1. The defective Cl- secretion characteristic of cystic fibrosis airway epithelial cells can be bypassed by an alternative Ca2+ dependent Cl- secretory pathway that is activated by extracellular nucleotides, e.g. uridine-5'triphosphate (UTP), acting on P2U purinoceptors. Since UTP is susceptible to hydrolysis by nucleotidases and phosphatases present in the airways, the identification of stable P2U-purinoceptor agonists would be of therapeutic relevance. 2. Uridine-5'-O-(3-thiotriphosphate) (UTP gamma S) was synthesized by nucleoside diphosphate kinase-catalyzed transfer of the gamma-phosphorothioate from guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S) or adenosine-5' = O-(3-thiotriphosphate) (ATP gamma S) to UDP. Formation of UTP gamma S was illustrated by observation of transfer of 35S from [35S]-GTP gamma S and transfer of 3H from [3H]-UDP. The chemical identity of high performance liquid chromatography (h.p.l.c.)-purified UTP gamma S was confirmed by nuclear magnetic resonance analysis. 3. Human 1321N1 astrocytoma cells stably expressing the phospholipase C-coupled human P2U-purinoceptor were utilized to test the activity of UTP gamma S. UTP gamma S (EC50 = 240 nM) was essentially equipotent to UTP and ATP for stimulation of inositol phosphate formation. 4. Unlike [3H]-UTP, [3H]-UTP gamma S was not hydrolyzed by alkaline phosphatase, acid phosphatase, or apyrase. Moreover, no hydrolysis was detected during a 1 h incubation with human nasal epithelial cells. 5. UTP gamma S was equally potent and efficacious with UTP for stimulation of Cl- secretion by human nasal epithelium from both normal donors and cystic fibrosis patients. Based on its high potency and resistance to hydrolysis, UTP gamma S represents a promising compound for treatment of cystic fibrosis.

Topics: Astrocytoma; Chlorides; Cystic Fibrosis; Epithelium; Humans; Inositol Phosphates; Magnetic Resonance Spectroscopy; Membrane Potentials; Nasal Cavity; Purinergic Agonists; Thionucleotides; Tumor Cells, Cultured; Uridine Triphosphate