TREATMENT OF VIRAL RESPIRATORYINFECTIONS
Erik DE CLERCQRega Institute for Medical Research, K.U.Leuven
B-3000 Leuven, Belgium
RESPIRATORY TRACT VIRUS INFECTIONS
ADENOVIRIDAE : Adenoviruses
HERPESVIRIDAE : Cytomegalovirus, Varicella-zoster virus
PICORNAVIRIDAE : Enteroviruses (Coxsackie B, ECHO) Rhinoviruses
CORONAVIRIDAE : Coronaviruses
ORTHOMYXOVIRIDAE : Influenza (A, B, C) viruses
PARAMYXOVIRIDAE : Parainfluenza viruses Respiratory syncytial virus “SARS (Severe Acute Respiratory
Disease) virus”
RESPIRATORY TRACT VIRAL DISEASES
Adenoviruses: Adenoiditis, Pharyngitis, Bronchopneumonitis
Cytomegalovirus: Interstitial pneumonitis
Varicella-zoster virus: Pneumonitis
Enteroviruses (Coxsackie B, ECHO): URTI (Upper Respiratory Tract Infections)
Rhinoviruses: Common cold
Coronaviruses: Common cold
Influenza viruses: Influenza (upper and lower respiratory tract infections)
Parainfluenza viruses: Parainfluenza (laryngitis, tracheitis)
Respiratory syncytial virus: Bronchopneumonitis
INFLUENZA VIRUS
Influenza virus
Electron micrographs of purified influenza virions. Hemagglutinin (HA ) and neuraminidase (NA) can be seen on the envelope of viral particles. Ribonucleoproteins (RNPs) are located inside the virions.
http://www.virology.net/Big_Virology/BVRNAortho.html
Layne et al., Science 293: 1729 (2001)
Influenza
NA (neuraminidase)
M1 (membrane protein)
M2 (ion channel)
Transcriptase complex(PB1, PB2 and PA)
Lipid bilayer
RNPs (RNA, NP)
HA (hemagglutinin)
McClellan and Perry, Drugs 61: 263-283 (2001)
Simplified representation of the influenza virion showing the neuraminidase(NA) glycoprotein, the hemagglutinin (HA) glycoprotein and the matrix M2
protein
M2
Distribution of influenza A hemagglutinin (H) subtypes in nature
Figure adapted from Murphy & Webster. Orthomyxoviruses.
http://www.brown.edu/Courses/Bio_160/Projects1999/flu/mechanism.html
Distribution of influenza A hemagglutinins in nature
http://www.brown.edu/Courses/Bio_160/Projects1999/flu/mechanism.html
Distribution of influenza A neuraminidases in nature
http://www.brown.edu/Courses/Bio_160/Projects1999/flu/mechanism.html
Amantadine/rimantadine: mechanism of action limited to influenza A viruses
H
H
H
NH2.HCl
Amantadine
Symmetrel®
H
H
H
CH3
NH2.HCl
Rimantadine
Flumadine®
The tetrameric M2 helix bundle
Sansom & Kerr, Protein Eng. 6: 65-74 (1993)
Neuraminidase (NA):
Cleaves sialic acid from cell-surface glycoprotein
Glycoproteins and neuraminidase
Sialic acid
Galactose
N-acetyl-glucosamine
Core sugars
protein
Galactose
N-acetyl-glucosamine
Core sugars
protein
Sialic acid
2,3
1,4
Influenza virus neuraminidase
Functions:• removes terminal sialic acid residues• promotes release of virus particles from the
cells• destroys cellular receptors recognized by
hemagglutinin• prevents virus aggregation at the cell surface• prevents viral inactivation by respiratory mucus
NEURAMINIDASE INHIBITORS
GG167
4-Guanidino-Neu5Ac2en
Zanamivir
Relenza®
GS4104, Ro64-0796
Ethyl ester of GS4071
Oseltamivir
Tamiflu®
Sialic acidN-Acetylneuraminic acid (NANA)
OHN
HO
HO OH
H
HO
H3C
O
OH
O
OH
influenza
neuraminidase
Sialyl -glycosideR = glycoprotein
Transition state
+
-
O
HO
OH
HO
HN
O
OHO
R
HOH
H3C
O
Abdel-Magid et al., Curr. Opin. Drug Discov. Dev. 4: 776-791 (2001)
O
HO
OH
HO
HN
O
OHO
R
HOH
H3C
O
H2O
Transition state Sialic acid
R-O- R-OH
O
HO
OH
HO
HN
O
OH
HOH
H3C
O
O
HO
OH
HO
HN
HOH
H3C
O
Abdel-Magid et al., Curr. Opin. Drug Discov. Dev. 4: 776-791 (2001)
DANA
O
HO
OH
HO
HN
HOH
H3C
O
Abdel-Magid et al., Curr. Opin. Drug Discov. Dev. 4: 776-791 (2001)
FANA
O
HO
OH
HO
HN
HOH
FF
F
O
Abdel-Magid et al., Curr. Opin. Drug Discov. Dev. 4: 776-791 (2001)
ZanamivirRelenza®
O
HO
OH
HN
HN
HOH
H2N
NH
H3C
O
Oseltamivir phosphateTamiflu®
NO
HN
H3C O
O
H3C
H3C
CH3H2
PHO O
HO OH
Oseltamivir = GS4104 = oral prodrug (ethyl ester) form of GS4071
GS4071
NO
HN
H3C
C
OH
O
H3C
H3C O
H2
GS4071 bound to influenza neuraminidase
Kim et al., J. Am. Chem. Soc. 119: 681-690 (1997)
GS4071 bound to influenza neuraminidase
Zanamivir (Relenza®)
• active against both influenza A and B• IC50 : 0.21-2.6 ng/ml for influenza neuraminidase• efficacy demonstrated in mouse and ferret models for influenza
(upon topical administration)• has to be administered by inhalation : 10 mg bid• therapeutically effective (5 days) : significant reduction in
duration of illness• prophylactically effective (4 weeks) : significant reduction in
number of ill subjects• well tolerated : clinical adverse events not different from placebo• no evidence for emergence of drug-resistant virus
Oseltamivir (Tamiflu®)
• active against both influenza A and B• IC50 : < 1 ng/ml for influenza neuraminidase• efficacy demonstrated in mouse and ferret models for influenza
(upon oral administration)• can be administered orally : 75 or 150 mg bid• therapeutically effective (5 days) : significant reduction in
duration of illness• prophylactically effective (6 weeks) : significant reduction in
number of ill subjects• well tolerated : clinical adverse events not different from placebo• no evidence for emergence of drug-resistant virus
RESISTANCE MUTATIONS TO NEURAMINIDASE INHIBITORS
Neuraminidase119 Glu Gly:• specific for zanamivir;• Glu 119 interacts with guanidinium group of zanamivir
292 Arg Lys:• found for zanamivir; cross-resistance to oseltamivir• Arg 292 interacts with carboxylic acid group of zanamivir
and oseltamivirHemagglutininSome mutations (i.e. 198 Thr Ile) diminish affinity of
hemagglutinin for its receptor
McKimm-Breschkin, Antiviral Res. 47: 1-17 (2000)
Benefits offered by neuraminidase inhibitors
Therapeutically:• Reduction in illness duration by 1-2 days• Reduction in risk-virus transmission to household or
healthcare contacts• Reduction in complications (sinusitis, bronchitis)• Reduction in use of antibiotics
Prophylactically:• Seasonal prevention of infection
RWJ-270201
OH
O
HN
H3C
CH3
CH3
HN
H2N NHO
OH
H
Smee et al., Antimicrob. Agents Chemother. 45: 743-748 (2001)Sidwell et al., Antimicrob. Agents Chemother. 45: 749-757 (2001)
A-192558
Wang et al., J. Med. Chem. 44: 1192-1201 (2001)
NH2
N
HO
O
O
F
F FO N CH3
H3C CH3
A-315675
DeGoey et al., J. Org. Chem. 67: 5445-5453 (2002)Hanessian et al., J. Am. Chem. Soc. 124: 4716-4721 (2002)
NH
O
OHHN
H3C O
CH3
H
CH3
H3C
HO
T-705
Furuta et al., Antimicrob. Agents Chemother. 46: 977-981 (2002)
T-705 showed potent inhibitory activity against influenza A, B, and C viruses, with 50% effective inhibitory concentrations of 0.013 to 0.48 µg/ml, while it showed no cytotoxicity at concentrations up to 1,000 µg/ml. T-705 was also active against a neuraminidase inhibitor-resistant virus and amantadine-resistant viruses.
N
N OH
NH2F
O
HUMAN RHINOVIRUS (HRV)
HRV 14Human rhinovirus type 14
Antirhinoviral targets for therapy
Agents can (a) prevent viral attachment to host-cell receptors (ICAM-1 and the low density lipoprotein receptor), (b) inhibit viral uncoating or (c) inhibit viral protein synthesis by blocking 3C viral protease.
McKinlay, Curr. Opin. Pharmacol. 1: 477-481 (2001)
PhenoxyalkyldiketoneArildone
WIN38020
OH3C O (CH2)6 CH
C
C
C2H5
C2H5
O
O
De Clercq, In: Antiviral Agents and Human Viral Diseases. Galasso, Whitley & Merigan, eds. Lippincott-Raven Publishers, pp 1-44 (1997)
IsoxazoleDisoxaril
WIN 51711
N
O
O(CH2)7
ON
H3C
De Clercq, In: Antiviral Agents and Human Viral Diseases. Galasso, Whitley & Merigan, eds. Lippincott-Raven Publishers, pp 1-44 (1997)
PyridazinamineR61837
NN
N NOH3C
CH3
De Clercq, In: Antiviral Agents and Human Viral Diseases. Galasso, Whitley & Merigan, eds. Lippincott-Raven Publishers, pp 1-44 (1997)
PhenoxypyridazinaminePirodavirR77975
NN
N (CH2)2 O C OH3C C2H5
O
De Clercq, In: Antiviral Agents and Human Viral Diseases. Galasso, Whitley & Merigan, eds. Lippincott-Raven Publishers, pp 1-44 (1997)
Interaction of WIN 52035 with VP1 of human rhinovirus (HRV-14)
Andries, In: Antiviral Chemotherapy. Jeffries & De Clercq, eds. John Wiley & Sons, Chichester, pp 287-319 (1995)
Interaction of R61837 with VP1 of human rhinovirus (HRV-14)
Andries, In: Antiviral Chemotherapy. Jeffries & De Clercq, eds. John Wiley & Sons, Chichester, pp 287-319 (1995)
Pleconaril (VP-63843)
NO
O
NO
N CF3
Romero, Exp. Opin. Invest. Drugs 10: 369-379 (2001)
BTA188
Hayden et al., Antiviral Res. 50: A127 (2001)
BTA showed potent in vitro activity against 87 of 100 rhinovirus serotypeswith a median EC50 of 10 ng/ml, superior to pleconaril.BTA188 is targeted at the hydrophobic pocket in the core of VP1.
H3C
N N
N
O
ON CH2 CH3
Benzothiazole
Benzothiazole targeted at hydrophobic pocket in the core of VP1.EC50 against HRV-14 in cell culture: 0.8 µM.
Tsang et al., Chem. Biol. 8: 33-45 (2001)
N
S
S S
N
N
H3C
Ruprintrivir
Inhibitor of human rhinovirus C3 protease, currently undergoing clinicalevaluation for the prevention and treatment of the common cold.
Hsyu et al., Antimicrob. Agents Chemother. 46: 392-397 (2002)
N
NH
O
NH
O
O
F
O
NH
O
H3C
O
OCH2
CH3
Pyridone
Human rhinovirus (HRV) 3C protease inhibitor showed an average EC50
of 45 nM across 15 serotypes of HRV.
Dragovich et al., J. Med. Chem. 45: 1607-1623 (2002)
N
NH
O
NNH
O
O
F
O
NH
O
H3C
F
O
OCH
CH3
CH3
RESPIRATORY SYNCYTIAL VIRUS (RSV)
Hall, N. Engl. J. Med. 344: 1917-1928 (2001)
Respiratory Syncytial Virus (RSV) and Parainfluenza Virus (PIV)
Characteristics of the proteins of respiratory syncytial virus and parainfluenza virus
Protein Molecular mass Functions
Respiratory syncytial virus
Parainfluenza virus
kilodaltons
Structural protein
Surface
Fusion (F) 68 60 Penetration; major protection antigen
Attachment (G) 90 —a Viral attachment; major protective antigen
Hemagglutinin neuraminidase (HN)
— a 69 Viral attachment and release; major protective antigen
Small hydrophobic (SH [1A]) 4.8 – 30b — a Unknown
Matrix
Matrix (M) 28
22b
40
— a
Mediates attachment of nucleocapsid to envelope
Small envelope (M2) Transcriptional regulation; unique to pneumoviruses
Nucleocapsid-associated
Nucleoprotein (N, NP) 44 58 Major RNA-binding nucleocapsid protein
Phosphoprotein (P) 37 60 Major phosphorylated protein; RNA-dependent RNA polymerase activity
Large polymerase complex (L) 200 250 Large nucleocapsid-associated protein; major polymerase subunit; RNA-dependent RNA polymerase activity
aNot present in the virus.bThere are four glycosylated and nonglycosylated forms with molecular masses of 4.8, 7.5, 13 to 15, and 21 to 30 kd.
Hall, N. Engl. J. Med. 344: 1917-1928 (2001)
Hall, N. Engl. J. Med. 344: 1917-1928 (2001)
Nu
mb
er o
f ca
ses
or
iso
late
s
1993 1994 1995 1996 1997 1998
Epidemiologic pattern of infections with respiratory syncytial virusin relation to the occurrence of bronchiolitis from 1993 through 1998
Zambon et al., Lancet 358: 1410-1416 (2001)
Proportion of samples taken from cases of influenza-like illness positive forinfluenza or respiratory syncytial virus in 0-5-year-olds during 1996-1997
Zambon et al., Lancet 358: 1410-1416 (2001)
Proportion of samples taken from cases of influenza-like illness positive forinfluenza or respiratory syncytial virus in 0-5-year-olds during 1996-1997
Ribavirin
Virazole®
OHO
HO OH
H2N
N
N
N
O
RFI-641
Nikitenko et al., Bioorg. Med. Chem. Lett. 11: 1041-1044 (2001)Razinkov et al., Chem. Biol. 8: 645-659 (2001)
RFI-641 inhibits RSV fusion mediated by F (Fusion) protein, but also interfereswith the attachment (G) protein
SO
O
N
O
NH2
O
NH2
NH
N
N
N
NH
HN
HN
NaO3S
SO3Na
N
N
N
NH
HN
SN
H2N
O
O
H2N
O
O
SN
O
H2N
O
H2N
OO
SN
NH2
O
O
NH2
O O
Huntley et al., Antimicrob. Agents Chemother. 46: 841-847 (2002)
Morphology of CV-1 cells treated with RFI-641
(A) Noninfected, nontreated CV-1 cells; (B) RSV-infected, untreated CV-1 cells; (C) RSV-infected, RFI-641 (> 8 h)-treated CV-1 cells
Huntley et al., Antimicrob. Agents Chemother. 46: 841-847 (2002)
Therapeutic efficacy of RFI-641 after intranasal administration to RSV-infected African green monkeys
RFI-164 was administered intranasally, daily, starting 1 day after virus infection
R-170591 interferes with RSV fusion
Andries et al., 40th ICAAC, Toronto, Canada, 17-20 September 2000, Abstract H-1160
N
N
NH
N NH2CH3
N CH3
HO
Benzodithiin (RD3-0028)
Sudo et al., Microbiol. Immunol. 45: 531-537 (2001)
RD3-0028 inhibits RSV replication by interfering with intracellular processing of the RSV fusion protein, leading to loss of infectivity
S
S
PARAMYXOVIRIDAE
• Paramyxovirinae
• Respirovirus/Paramyxovirus (Sendai virus, Parainfluenza 1 and 3)
• Rubulavirus (Mumps virus, Parainfluenza 2, 4a and 4b)
• Morbillivirus (Measles virus)
• Megamyxovirus (Hendra and Nipah virus)
• Pneumovirinae
• Pneumovirus (Pneumovirus, Respiratory Syncytial Virus)• Metapneumovirus (Human metapneumovirus)
PHYLOGENY OF THE PARAMYXOVIRINAE
Genus Respirovirus/
Paramyxovirus
Genus Morbillivirus
Tentative new genus Megamyxovirus
Genus Rubulavirus
HPIV-1Sendai
HPIV-3
CDVPDV
RPVMeasles
PPRVDMV
Tupaia
HendraNipah
HPIV-4b
HPIV-4a
Mumps
SV5HPIV-2
MapueraNDV
OUTBREAK-INSPIRED HUNT FOR VIRUSES
• Hendra virus(1994, Megamyxovirus)
•Australian bat lyssavirus (1996, Rhabdoviridae)
•Menangle virus (1997, Rubulavirus)
•Tupaia virus (1999, Paramyxovirus)
• Nipah virus (1999, Megamyxovirus)
• Tioman virus (2000, Rubulavirus)
•Dolphin, porpoise and cetacean morbillivirus (1991, Morbillivirus)
•Salem virus (2000, not yet classified)
DIFFERENCES BETWEEN
HENDRA & NIPAH VIRUS OTHER PARAMYXOVIRINAE
Multiple host species
Reservoir host : • fruit bats (flying foxes) ?
Clinical hosts : • horse, pig, man,...
Experimental hosts : • guinea pig, cat
Not very contagious
No human-to-human spread, but infection is very lethal
Host specific : human
and
Highly contagious
Human-to-human spread, droplet infection
CONCLUSIONAPPROVED ANTIVIRAL DRUGS FOR THE TREATMENT OF
THE MAJOR RESPIRATORY TRACT VIRUS INFECTIONS
Adenoviruses : nonePicornaviruses
Entero : noneRhino : none
OrthomyxovirusesInfluenza : Neuraminidase inhibitors: zanamivir, oseltamivir
: Amantadine and rimantadine (for influenza A only)
ParamyxovirusesParainfluenza : noneRespiratory syncytial virus : RibavirinSARS virus : none