Transcript Significant Strides in the Treatment of Cystic Fibrosis

Significant Strides in the
Treatment of Cystic Fibrosis
Rebekah F. Brown, MD
Center Director, Cystic Fibrosis
Center at Vanderbilt
Objectives
1. At the end of this presentation, participants
will have an understanding of the
pathophysiology of cystic fibrosis and targets
of treatment for children and adults with
cystic fibrosis.
2. Provide an overview of the advancements in
treatment of children and adults with cystic
fibrosis.
What is Cystic Fibrosis?
• Autosomal recessive
• Most common life shortening inherited
disease in Caucasians
– 1 in 2500-3000 births
• CF Transmembrane Regulator (Cl- channel)
defect
– Affects lungs, GI tract, liver, pancreas, sweat
glands, vas deferens
Davies J et al. 2007
Rowe S et al. 2005
Historical Perspective
• “The child will soon die whose forehead tastes
salty when kissed”—17th century
German Children’s Songs and Games from Switzerland
• 1938 -- CF of the pancreas
– Dr. Dorothy Andersen (pathologist)
• 1943 “mucoviscidosis”
– Dr. Sydney Farber (pathologist)
Historical Perspective
• 1948 heat wave in New York
– Dr. Paul di Sant’Agnese
– Hyponatremic dehydration – CF
– Sweat with excessive salt content (1953)sweat
chloride as diagnostic test for CF
Joseph Levy Memorial Lecture & Ettore Rossi Medal Lecture at European CF Conference in Birmingham
in 2004 by Dr. Jim Littlewood
Historical Perspective
• 1980s Improved Survival
– Acid resistant pancreatic enzymes
– Fat soluble vitamin replacement
– Nasal potential difference—Knowles 1981
• Late 1980s
– CF defect noted on Chromosome 7
Historical Perspective
• 1989
– CFTR (CF transmembrane conductance regulator)
gene
– Delta F508 mutation—most common
• > 1700 mutations
www.genet.sickkids.on.ca/cftr
STILL NO CURE…YET
CFTR Models of Disease in CF
Simplified Diagram
Airway lumen—Normal function
Na+
NaCl
NaCl
Inhibits
Cl-
H2O
CFTR
NaCl
NaCl
ENaC
Na+
H2O
intracellular
Without Cystic Fibrosis
Airway Lumen
Mucus
cilia
Airway
surface fluid
Cilia have room to beat back and forth--clear the airway of
particles, bacteria, etc.
Plenty of fluid to allow inflammatory cells to find and kill
bacteria, viruses, etc.
CFTR Models of Disease in CF
Simplified Diagram
Airway lumen—CF
Inhibits
H2O
ClCFTR
Cl-
ENaC
Na+
H2O
intracellular
Cystic Fibrosis
Airway lumen—patient with CF
Mucus
cilia
Airway
surface fluid
Cilia matted down in thick mucus and cannot rid airway of
foreign particles.
Necrosis of neutrophils releases DNA and actin thick,
tenacious mucus
What does this mean for a patient?
CF Clinical Disease
• Sinopulmonary
– Chronic Sinusitis and Nasal polyposis
– Bronchiectasis, Reduced lung function
– Respiratory Failure
• GI
–
–
–
–
–
Pancreatic insufficiency
Failure to Thrive/Malnutrition
Meconium ileus/Distal Intestinal Obstruction Syndrome
Liver Disease
CF Related Diabetes
CF with
Mosaicism
CF with
Pneumothorax,
bronchiectasis,
mucous
plugging
Right Lower Lobe—non-CF patient
Right Lower Lobe in Cystic Fibrosis
Right Upper Lobe in Cystic Fibrosis
CF Related Liver Disease
Treatment of Pulmonary Disease
• Daily, maintenance airway clearance
• Early and aggressive treatment of
exacerbations
• Treatment of Pseudomonas colonization
• Elimination of smoke exposure
Treatment of GI Disease
• Pancreatic enzyme replacement therapy
• Fat soluble vitamin supplementation
– A, D, E, and K
• Early and aggressive treatment of constipation
and malabsorption
• Nutritional supplementation
Cystic Fibrosis Patient Registry 2011
Other Manifestations of CF
• Absence of the vas deferens
– Men diagnosed at infertility clinics
• Sweat
– Risk for hyponatremic, hypochloremic dehydration
Treatment of Cystic Fibrosis
Airway Clearance Medications
Airway Clearance
“Be Happy”
•
•
•
•
•
•
B
H
A
P
I
I
bronchodilator
hypertonic saline
airway clearance
pulmozyme
inhaled corticosteroid
inhaled antibiotic
Hypertonic Saline (7% Normal
Saline)
• Increase 1 hour rates of mucus clearance
• Increase 24 hour rates of mucus clearance
compared to baseline
• Improved FEV1 (mean 4-6%)
• Bronchospasm—bronchodilator pretreatment
• Infants: no improvement compared to
isotonic saline in one study
Elkins MR, et al. 2006
Donaldson SH, et al. 2006
Rosenfeld M, et al. 2012
Dornase Alfa (Pulmozyme,
recombinant human DNAse1,
rhDNAse)
• Cleaves DNA in mucus
– Possible action in cleaving DNA in biofilm of
bacteria improving sensitivity to antibiotics
• Reduced risk of exacerbations by 28%
Shak S, et al. 1995
Jones AP, et al. 2010
Wagener JS, et al. 2012
Kaplan JB, et al. 2012
Sawicki GS, et al. 2012
Dornase Alfa (Pulmozyme,
recombinant human DNAse1,
rhDNAse)
• Lung function improvement sustained at least
2 years
• Chronic use associated with 15% reduction in
odds of subsequent year mortality
Shak S, et al. 1995
Jones AP, et al. 2010
Wagener JS, et al. 2012
Kaplan JB, et al. 2012
Sawicki GS, et al. 2012
Inhaled Antibiotics
• Usually inhaled tobramycin
• Alternate month on/month off to reduce
antibiotic resistance
• Only available in nebulized form—time
consuming
• Also use aztreonam, vancomycin,
colistimethate
Airway Clearance Devices
• Vibrate secretions off airway wall
– Patient performs huff cough to mobilize secretions
out of airway
• Manual Chest Percussion
• Vest physiotherapy
• Patient effort dependent devices: variable or
fixed positive expiratory pressure
DAY IN THE LIFE OF A CF PATIENT
Be Happy
•
•
•
•
•
•
•
Bronchodilator (5–15 min)
Wait 15 min
Hypertonic saline (15-20 min)
Airway Clearance (30 min)
Dornase alfa (5 min)
Inhaled Corticosteroids (5-15 min)
Inhaled Antibiotic (15-20 min)
Total 1 ½ hours
CF Patient’s Day When Well
•
•
•
•
•
Airway clearance = 100 minutes x 2
Pancreatic enzymes with every meal, snack, etc.
Vitamins, acid blockers, ursodiol (liver disease)
Eat, eat, eat to maintain good nutrition
Go to school +/- work +/- extracurricular
activities
• Have a life!
Inflammation in Cystic Fibrosis
Inflammation in Cystic Fibrosis
• Begins in early infancy
– Bronchoalveolar lavage fluid from infants with
increased neutrophils, proinflammatory mediators
in airways and neutrophil elastase
– Inflammation excessive to bacterial burden
• Neutrophil dominated phenotype of
inflammation
Khan TZ, et al. 1995
Balough K, et al. 1995
MW, et al. 1997
• Infection with specific bacteria Konstan
Armstrong DS, et al. 1997
Noah TL, et al. 1997
Muhlebach MS, et al. 1999
Sly PD, et al. 2009
Stick SM, et al. 2009
Anti-Inflammatory Medications
• Ideal medication
– Start early
– Prevent disease progression
– Minimal side effects
– Minimal effects on bacterial burden or
colonization
Corticosteroids
• Systemic
– Improved lung function
– Significant side effects—impaired glucose
tolerance, growth impairment, cataracts
• Continued even after steroids discontinued
• Discontinuation of steroids lead to quicker rate of FEV1
declineno longer significantly different from placebo
group
– Other risks: osteopenia/osteoporosis
Auerbach HS, et al. 1985
Matthews WJ, et al. 1980
Rosenstein BJ, et al. 1991
Lai HC, et al. 2000
Corticosteroids
• Inhaled
– Inhibit NFĸB activation, decreased LPS-induced
release of IL-6 and IL-8
– No benefit demonstrated when given to CF
patients
• Insufficient evidence to determine if beneficial or
harmful
– Discontinuation CF patients in UK—no significant
harm during short observation
Escotte S, et al. 2003
Escotte S, et al. 2002
– Used if asthma + CF
Ren CL, et al. 2002
Balfour-Lynn IM, et al. 2006
Ibuprofen
• High dose ibuprofen based on
pharmacokinetics for peak plasma
concentrations 50-100 micrograms/ml
– Doses typically 20-30 mg/kg
• Less decline in lung function, less weight loss,
fewer hospitalizations, less CXR findings
• 5-13 y/o—annual rate of decline of FEV1
Konstan MW, et al. 1995
reduced by 88%
Lands LC, et al. 2007
Konstan MW, et al. 2007
Oermann CM, et al. 1999
Konstan MW, et al. 2008
Ibuprofen
• Less than 10% of CF patients on ibuprofen
• Why?
– Pharmacokinetics not locally available
– Side effects/safety
• GI hemorrhage requiring hospitalization higher
• Renal failure
• Recommendation to consider in CF patients
with mild disease
Konstan MW, et al. 1995
Lands LC, et al.
Konstan MW, et al.
Oermann CM, et al.
Konstan MW, et al.
2007
2007
1999
2008
Azithromycin
• Decreases rate of pulmonary exacerbations
• Improves lung function
• Question of use in absence of Pseudomonas
• Anti-inflammatory properties felt to be
secondary to both antimicrobial and
Jaffe A, et al. 1998
Wolter J, et al. 2002
immunomodulatory effects
Equi A, et al. 2002
Saiman L, et al.
Hoffmann N, et al.
Clement A, et al.
Southern KW, et al.
2003
2007
2006
2012
New Categories of Therapies in CF
Human Genetics
Nucleus: mRNA transcription and splicing
ER: translation and folding
Golgi: protein maturation
Vesicles: protein transport
Cell Surface Membrane
Human Genetics—Types of Mutations
Normal gene: DURING THE LECTURE PEOPLE SLEPT UNTIL THE END
Missense mutation: DURING THE LECTURE PEOPLE SWEPT UNTIL THE END
Nonsense (stop codon) mutation: DURING THE LECTURE PEOPX
Deletion: DURING THE LECTURE SLEPT UNTIL THE END
Insertion: DURING THE LECTURE PEOPLE SLEPT QUIETLY UNTIL THE END
Frameshift: DURING THE LECTURE PEOPLE SEPTU NTILTH EEN D
Classes of CFTR Defects
IV
VI
III
Golgi
II
Proteosome
ER
I
V
I—absence
II—premature
degradation
III—disordered
regulation
IV—defective Cl
conductance or
channel gating
V—reduced number
VI—accelerated
turnover
Adapted from Rowe S et al. NEJM. 2005; 352.
Two Broad Categories of CFTR
Mutations
• Mutations affect
1. Quantity
– Little to no protein (Classes I and II)
– Some protein (Classes V and VI)
2. Function
– Gating defect (Class III)—channel does not open
– Conductance defect (Class IV)—”narrow
channel” opens but not as much Cl transported
Mutation Class Specific
Medications: The Future of CF
Treatment
• Treat the underlying defect
• How much CFTR function is needed?
– Carriers mostly asymptomatic with 50% function
– <10%--absence of vas deferens
– <5%--Other CF manifestations
– Increase CFTR function to 20-25%therapeutic
Zhang L, et al. 2009
effects?
Pettit RS, 2012
Hanrahan JW, et al. 2012
Potentiators
• Potentiators activate the CFTR channel that is
already present at the plasma membrane
• FDA approved 2/2012—ivacaftor (VX-770)
– Greater than 6 y/o with G551D mutation (gating
defect)
– Improvement in pulmonary function, weight gain,
sweat chloride, decreased pulmonary
exacerbation rate
Ramsey BW, et al. 2011
McKone EF, et al. 2011
Pettit RS, 2012
Hanrahan JW, et al. 2012
Correctors
• Correct the trafficking – moves the CFTR
channel out to the cell surface
– Help the most common mutation, F508del
• Example: VX-809 Studies ongoing in
combination with ivacaftor/VX-770
• Phase 2 study
– Decreased sweat chloride
– No significant change in spirometry (lack of
Clancy JP, et al. 2012
power)
Van Goor F, et al. 2011
Boyle MP, et al. 2011
Pettit RS, 2012
Hanrahan JW, et al. 2012
Medications that Read Through
mRNA Premature Stop Codons
• Applications also in other diseases such as
Duchenne’s muscular dystrophy
• Initially found gentamicin, but side effects
• Ataluren (PTC-126) studies ongoing
– CFTR function (NPD) improved
– Trends toward increased pulmonary function
– Trends toward increased weight
Pettit R, 2012
Wilschanski M, et al. 2011
Kerern E, et al. 2008
Hirawat S, et al. 2007
References
•
•
•
•
•
•
1.
Armstrong DS, Grimwood K, Carlin JB, et al. Lower airway inflammation in infants and young
children with cystic fibrosis. American journal of respiratory and critical care medicine 1997;156:1197-204.
2.
Auerbach HS, Williams M, Kirkpatrick JA, Colten HR. Alternate-day prednisone reduces morbidity
and improves pulmonary function in cystic fibrosis. Lancet 1985;2:686-8.
3.
Balfour-Lynn IM, Lees B, Hall P, et al. Multicenter randomized controlled trial of withdrawal of
inhaled corticosteroids in cystic fibrosis. American journal of respiratory and critical care medicine
2006;173:1356-62.
4.
Balough K, McCubbin M, Weinberger M, Smits W, Ahrens R, Fick R. The relationship between
infection and inflammation in the early stages of lung disease from cystic fibrosis. Pediatric pulmonology
1995;20:63-70.
5.
Chmiel JF, Konstan MW. Inflammation and anti-inflammatory therapies for cystic fibrosis. Clinics in
chest medicine 2007;28:331-46.
6.
Clancy JP, Jain M. Personalized medicine in cystic fibrosis: dawning of a new era. American journal
of respiratory and critical care medicine 2012;186:593-7.
References
•
•
•
•
•
•
•
7.
Clancy JP, Rowe SM, Accurso FJ, et al. Results of a phase IIa study of VX-809, an investigational
CFTR corrector compound, in subjects with cystic fibrosis homozygous for the F508del-CFTR mutation.
Thorax 2012;67:12-8.
8.
Clement A, Tamalet A, Leroux E, Ravilly S, Fauroux B, Jais JP. Long term effects of azithromycin in
patients with cystic fibrosis: A double blind, placebo controlled trial. Thorax 2006;61:895-902.
9.
Cory TJ, Birket SE, Murphy BS, Mattingly C, Breslow-Deckman JM, Feola DJ. Azithromycin increases
in vitro fibronectin production through interactions between macrophages and fibroblasts stimulated with
Pseudomonas aeruginosa. The Journal of antimicrobial chemotherapy 2012.
10.
Davies JC, Alton EW, Bush A. Cystic fibrosis. Bmj 2007;335:1255-9.
11.
Donaldson SH, Bennett WD, Zeman KL, Knowles MR, Tarran R, Boucher RC. Mucus clearance and
lung function in cystic fibrosis with hypertonic saline. The New England journal of medicine 2006;354:24150.
12.
Elkins MR, Bye PT. Inhaled hypertonic saline as a therapy for cystic fibrosis. Current opinion in
pulmonary medicine 2006;12:445-52.
13.
Elkins MR, Robinson M, Rose BR, et al. A controlled trial of long-term inhaled hypertonic saline in
patients with cystic fibrosis. The New England journal of medicine 2006;354:229-40.
References
•
•
•
•
•
14.
Equi A, Balfour-Lynn IM, Bush A, Rosenthal M. Long term azithromycin in children with cystic
fibrosis: a randomised, placebo-controlled crossover trial. Lancet 2002;360:978-84.
15.
Escotte S, Danel C, Gaillard D, et al. Fluticasone propionate inhibits lipopolysaccharide-induced
proinflammatory response in human cystic fibrosis airway grafts. The Journal of pharmacology and
experimental therapeutics 2002;302:1151-7.
16.
Escotte S, Tabary O, Dusser D, Majer-Teboul C, Puchelle E, Jacquot J. Fluticasone reduces IL-6 and
IL-8 production of cystic fibrosis bronchial epithelial cells via IKK-beta kinase pathway. The European
respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
2003;21:574-81.
17.
Hanrahan JW, Sampson HM, Thomas DY. Novel pharmacological strategies to treat cystic fibrosis.
Trends in pharmacological sciences 2013;34:119-25.
18.
Hoffmann N, Lee B, Hentzer M, et al. Azithromycin blocks quorum sensing and alginate polymer
formation and increases the sensitivity to serum and stationary-growth-phase killing of Pseudomonas
aeruginosa and attenuates chronic P. aeruginosa lung infection in Cftr(-/-) mice. Antimicrobial agents and
chemotherapy 2007;51:3677-87.
References
•
•
•
•
•
•
•
•
19.
Jaffe A, Francis J, Rosenthal M, Bush A. Long-term azithromycin may improve lung function in
children with cystic fibrosis. Lancet 1998;351:420.
20.
Jones AP, Wallis C. Dornase alfa for cystic fibrosis. Cochrane database of systematic reviews
2010:CD001127.
21.
Kaplan JB, LoVetri K, Cardona ST, et al. Recombinant human DNase I decreases biofilm and
increases antimicrobial susceptibility in staphylococci. The Journal of antibiotics 2012;65:73-7.
22.
Khan TZ, Wagener JS, Bost T, Martinez J, Accurso FJ, Riches DW. Early pulmonary inflammation in
infants with cystic fibrosis. American journal of respiratory and critical care medicine 1995;151:1075-82.
23.
Konstan MW. Ibuprofen therapy for cystic fibrosis lung disease: revisited. Current opinion in
pulmonary medicine 2008;14:567-73.
24.
Konstan MW, Berger M. Current understanding of the inflammatory process in cystic fibrosis:
onset and etiology. Pediatric pulmonology 1997;24:137-42; discussion 59-61.
25.
Konstan MW, Byard PJ, Hoppel CL, Davis PB. Effect of high-dose ibuprofen in patients with cystic
fibrosis. The New England journal of medicine 1995;332:848-54.
26.
Konstan MW, Schluchter MD, Xue W, Davis PB. Clinical use of Ibuprofen is associated with slower
FEV1 decline in children with cystic fibrosis. American journal of respiratory and critical care medicine
2007;176:1084-9.
References
•
•
•
•
•
•
27.
Lai HC, FitzSimmons SC, Allen DB, et al. Risk of persistent growth impairment after alternate-day
prednisone treatment in children with cystic fibrosis. The New England journal of medicine 2000;342:8519.
28.
Lands LC, Milner R, Cantin AM, Manson D, Corey M. High-dose ibuprofen in cystic fibrosis:
Canadian safety and effectiveness trial. The Journal of pediatrics 2007;151:249-54.
29.
Lands LC, Stanojevic S. Oral non-steroidal anti-inflammatory drug therapy for cystic fibrosis.
Cochrane database of systematic reviews 2007:CD001505.
30.
Matthews WJ, Jr., Williams M, Oliphint B, Geha R, Colten HR. Hypogammaglobulinemia in patients
with cystic fibrosis. The New England journal of medicine 1980;302:245-9.
31.
Muhlebach MS, Stewart PW, Leigh MW, Noah TL. Quantitation of inflammatory responses to
bacteria in young cystic fibrosis and control patients. American journal of respiratory and critical care
medicine 1999;160:186-91.
32.
Nichols DP, Konstan MW, Chmiel JF. Anti-inflammatory therapies for cystic fibrosis-related lung
disease. Clinical reviews in allergy & immunology 2008;35:135-53.
References
•
•
•
•
•
•
•
33.
Noah TL, Black HR, Cheng PW, Wood RE, Leigh MW. Nasal and bronchoalveolar lavage fluid
cytokines in early cystic fibrosis. The Journal of infectious diseases 1997;175:638-47.
34.
Oermann CM, Sockrider MM, Konstan MW. The use of anti-inflammatory medications in cystic
fibrosis: trends and physician attitudes. Chest 1999;115:1053-8.
35.
Pettit RS. Cystic fibrosis transmembrane conductance regulator-modifying medications: the future
of cystic fibrosis treatment. The Annals of pharmacotherapy 2012;46:1065-75.
36.
Ramsey BW, Davies J, McElvaney NG, et al. A CFTR potentiator in patients with cystic fibrosis and
the G551D mutation. The New England journal of medicine 2011;365:1663-72.
37.
Ren CL. Use of modulators of airways inflammation in patients with CF. Clinical reviews in allergy &
immunology 2002;23:29-39.
38.
Rosenfeld M, Ratjen F, Brumback L, et al. Inhaled hypertonic saline in infants and children younger
than 6 years with cystic fibrosis: the ISIS randomized controlled trial. JAMA : the journal of the American
Medical Association 2012;307:2269-77.
39.
Rosenstein BJ, Eigen H. Risks of alternate-day prednisone in patients with cystic fibrosis. Pediatrics
1991;87:245-6.
References
•
•
•
•
•
•
•
40.
Rowe SM, Miller S, Sorscher EJ. Cystic fibrosis. The New England journal of medicine
2005;352:1992-2001.
41.
Saiman L, Marshall BC, Mayer-Hamblett N, et al. Azithromycin in patients with cystic fibrosis
chronically infected with Pseudomonas aeruginosa: a randomized controlled trial. JAMA : the journal of
the American Medical Association 2003;290:1749-56.
42.
Sampson HM, Lam H, Chen PC, et al. Compounds that correct F508del-CFTR trafficking can also
correct other protein trafficking diseases: an in vitro study using cell lines. Orphanet journal of rare
diseases 2013;8:11.
43.
Sawicki GS, Ayyagari R, Zhang J, et al. A pulmonary exacerbation risk score among cystic fibrosis
patients not receiving recommended care. Pediatric pulmonology 2012.
44.
Shak S. [rhDNase: scientific background, cloning and production]. Archives de pediatrie : organe
officiel de la Societe francaise de pediatrie 1995;2:666-9.
45.
Shak S. Aerosolized recombinant human DNase I for the treatment of cystic fibrosis. Chest
1995;107:65S-70S.
46.
Sly PD, Brennan S, Gangell C, et al. Lung disease at diagnosis in infants with cystic fibrosis detected
by newborn screening. American journal of respiratory and critical care medicine 2009;180:146-52.
References
•
•
•
•
•
•
•
47.
Southern KW, Barker PM, Solis-Moya A, Patel L. Macrolide antibiotics for cystic fibrosis. Cochrane
database of systematic reviews 2012;11:CD002203.
48.
Stick SM, Brennan S, Murray C, et al. Bronchiectasis in infants and preschool children diagnosed
with cystic fibrosis after newborn screening. The Journal of pediatrics 2009;155:623-8 e1.
49.
Van Goor F, Hadida S, Grootenhuis PD, et al. Correction of the F508del-CFTR protein processing
defect in vitro by the investigational drug VX-809. Proceedings of the National Academy of Sciences of the
United States of America 2011;108:18843-8.
50.
Wagener JS, Kupfer O. Dornase alfa (Pulmozyme). Current opinion in pulmonary medicine
2012;18:609-14.
51.
Wilschanski M, Kerem E. New drugs for cystic fibrosis. Expert opinion on investigational drugs
2011;20:1285-92.
52.
Wilschanski M, Miller LL, Shoseyov D, et al. Chronic ataluren (PTC124) treatment of nonsense
mutation cystic fibrosis. The European respiratory journal : official journal of the European Society for
Clinical Respiratory Physiology 2011;38:59-69.
53.
Wolter J, Seeney S, Bell S, Bowler S, Masel P, McCormack J. Effect of long term treatment with
azithromycin on disease parameters in cystic fibrosis: a randomised trial. Thorax 2002;57:212-6.
References
•
•
•
•
•
54.
Wolter JM, Seeney SL, McCormack JG. Macrolides in cystic fibrosis: is there a role? American
journal of respiratory medicine : drugs, devices, and other interventions 2002;1:235-41.
55.
Kerern E, Hirawat S, Armoni S, et al. Effectiveness of PTC124 treatment of cystic fibrosis caused by
nonsense mutations: a prospective phase II trial. Lancet 2008; 372:719-27.
56.
Boyle MP, et al. Abstract. Pediatr Pulmonol 2011; suppl 34: 287.
57.
McKone EF, et al. Abstract. Pediatr Pulmonol 201; suppl 34: 284.
58.
Hirawat S, Welch EM, Elfring GL, et al. Safety, tolerability, and pharmacokinetics of PTC124, a
nonaminoglycoside nonsense mutation suppressor, following single- and multiple-dose administration to
healthy male and female adult volunteers. J Clin Pharmacol 2007; 47: 430-44.