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1 1 Prof. Ruth A Karron Center for Immunization Research Johns Hopkins Bloomberg School of Public Health RSV vaccine development 2 RSV structure; Protective antigens RSV epidemiology & risk groups Goals for vaccine development Obstacles to successful vaccine development Current approaches Passive prophylaxis Subunit vaccines Live-attenuated vaccines Native RSV Vectored vaccines Replication-defective vaccines What will the next decade bring? Financial disclosures Investigator: NIH/NIAID Scientific advisory boards: Novartis, Novavax, Merck, GSK, GenVec 3 1

Respiratory syncytial virus (RSV) Discovered in 1957 (Chimpanzee coryza agent) Leading viral cause of lower respiratory illness (LRI) in infants and young children Second only to influenza as cause

stranded negative sense enveloped RNA virus Two surface glycoproteins, F (fusion) and G (attachment), elicit protective antibody Two serotypes, RSV A and RSV B F largely conserved between serotypes;

2 Respiratory syncytial virus (RSV) Discovered in 1957 (Chimpanzee coryza agent) Leading viral cause of lower respiratory illness (LRI) in infants and young children Second only to influenza as cause of viral LRI in the elderly Leading viral cause of LRI in bone marrow transplant and lung transplant patients and some children with chronic lung disease (cystic fibrosis) 4 RSV structure Single stranded negative sense enveloped RNA virus Two surface glycoproteins, F (fusion) and G (attachment), elicit protective antibody Two serotypes, RSV A and RSV B F largely conserved between serotypes; G varies Within serotypes, genetic variation occurs, but not progressive (i.e., no antigenic drift) F Fusion Matrix RNP complex 5 G Attachment Lipid membrane RSV seasonality Fall-winter-spring in temperate Northern and Southern hemisphere locations (US, Europe, Australia, Japan) Rainy season in some tropical countries Year round in other tropical countries 6 Reviewed in: Law BJ et al., Respir Med.2002; 96 Suppl B: S1-7 Crowe JE Jr and Collins PL, Fields Virology

RSV is a global pediatric pathogen In US infants and preschoolers, annual RSV epidemics lead to: 57,000 hospitalizations 500,000 ER visits 2,100,000

160,000 deaths 3 1.Hall CB. N Engl J Med. 2009; 360(6): 588-98 7 2.Leader S. Pediatr Infect Dis J. 2002; 21: 629-32 3.Nair H. Lancet.

3 RSV is a global pediatric pathogen In US infants and preschoolers, annual RSV epidemics lead to: 57,000 hospitalizations 500,000 ER visits 2,100,000 medical visits 1 Most frequent cause of hospitalization for US infants 2 Global estimates are imprecise; Annual burden is at least: 64 million cases 160,000 deaths 3 1.Hall CB. N Engl J Med. 2009; 360(6): Leader S. Pediatr Infect Dis J. 2002; 21: Nair H. Lancet. 2010; 375(9725): The spectrum of RSV illness in young children URI: fever, cough, congestion, rhinorrhea Otitis media (ear infection) LRI: bronchiolitis. & pneumonia in infancy wheezing in older children 8 Apnea: in infancy Risk factors for severe RSV disease Boyce TG et al., J Pediatr2000; 137: Karron RA et al., JID 1999; 180: 41-9 Impact Pediatrics1998; 102(3): Feltes J Peds 2003; 143: Bockova Pediatrics 2002: 110(2): e20 3

4 Healthy term infants without identifiable risk factors account for most pediatric RSV hospitalizations Of all infants hospitalized with RSV in the US each year, only about 25-33% were premature 1 In an Israeli study, only 25% of all children with RSV admitted to an intensive care unit admissions met the definition of high risk 2 1. Law BJ et al., RespirMed.2002;96 Suppl B: S Prais D Pediatrics. 2003;112(3 Pt1): Note: studies conducted prior to routine use of RSV passive prophylaxis RSV also causes illness in the elderly Detected annually in 3-7% of healthy elderly and 4-10% of high risk adults In hospitalized patients, RSV accounted for: 10.6% pneumonia 11.4% chronic obstructive pulmonary disease (COPD) 5.4% congestive heart failure (CHF) 7.2% asthma 11 Falsey AR et al., N Engl J Med. 2005; 352(17): Goal for RSV vaccines To prevent infection? 12 4

Respiratory syncytial virus can reinfect healthy young adults 100 80 % Reinfected 60 40 20 0 0 2 4 8 14 20 26

Goal for RSV vaccines To induce immunity safely and in a quantity sufficient to prevent RSV-associated lower

5 Respiratory syncytial virus can reinfect healthy young adults % Reinfected Time of challenge (months) 13 Hall CB J Infect Dis 1991; 163: Goal for RSV vaccines To induce immunity safely and in a quantity sufficient to prevent RSV-associated lower respiratory tract illness in those at risk 14 Despite its clinical importance and over 50 years of research, a vaccine for RSV does not yet exist 15 5

Obstacles to RSV vaccine development 16 1.

Hospitalized for RSV at JHH, 1993-1996 No.

10 11 12 15 18 21 Age in months Karron et al.

6 Obstacles to RSV vaccine development Peak of severe RSV disease occurs in early infancy 60 Hospitalized for RSV at JHH, No. of children (n=444) Age in months Karron et al., J Infect Dis 1999; 180(1): Heterogeneous at-risk population (young and old) Courtesy of E Walsh 18 6

3. Enhanced RSV disease Formalin-inactivated RSV (FI-RSV) developed in the early 1960 s Vaccine administered to RSV seropositive toddlers and RSV naive infants The

died 19 Kapikian et al., Am J Epidemiol1969; 89: 1699 Kim et al.

7 3. Enhanced RSV disease Formalin-inactivated RSV (FI-RSV) developed in the early 1960 s Vaccine administered to RSV seropositive toddlers and RSV naive infants The vaccine did not harm the toddlers, but when the infants later encountered wild-type (live) RSV, they experienced severe (enhanced) disease; Two (ages 14 and 16 months) died 19 Kapikian et al., Am J Epidemiol1969; 89: 1699 Kim et al., Am J Epidemiol1969; 89: Potentiation of RSV LRI following formalin inactivated vaccine 100 % of subjects enrolled at CHC Vaccinees Adapted from Kim et al., Am J Epidemiol 1969; 89: Controls What do we understand about enhanced RSV disease? 21 7

8 Mechanisms of disease enhancement: humoral Induction of non-neutralizing antibodies FI-RSV immunized children: RSV F Ab >> RSV neut Ab 1 Immune complex deposition Immune complexes were detected in lung autopsiesfrom 2 children who died after FI-RSV 2 Impaired affinity maturation In mice, FI-RSV induces low avidity antibody and lung pathology, which can be overcome by administration of LPS (TLR agonist) with FI-RSV 3 1. Murphy BR et al., J Clin Micro 1986; 24(2): Polack FP et al., J Exp Med 2002; 196: Polack FP et al., Nature Medicine2009;15: Mechanisms of disease enhancement: cellular FI-RSV associated with imbalanced cellular response: Over-stimulation of Th2 CD4+ T cells 1,2 Poor stimulation of IFNγ-producing (Th1) NK cells and CD8 T cells 1. Openshaw et al., Vaccine 2001; 20: S Johnson TR et al.,j Virol2002; 76(9): Mechanisms of disease enhancement: implications for RSV vaccine development Live vaccines are the safest alternative for RSV-naïve infants & children Enhanced RSV disease not observed in children given live attenuated vaccines 1 Non-replicating vaccines may be safely administered to those who are not RSV-naïve 24 Wright PF et al., Vaccine 2007; 25(42):

9 Passive and active prophylaxis against RSV disease 25 Passive prophylaxis Administration of RSV neutralizing antibody IV or IM can protect against severe RSV disease in high risk infants 1,2 Current licensed formulation is palivizumab (Synagis), a humanized mab directed against highly conserved region of RSV F 1. Groothuis JR et al., N Engl J Med. 1993; 329(21): IMpact-RSV study group, Pediatrics 1998; 102(3): Use of palivizumab Not a vaccine (require monthly dosing) In some countries, administered during RSV season to highest risk infants Proof-of-concept that high titers of passively acquired RSV neutralizing antibody can protect young infants against RSV LRI 27 9

10 Passive RSV prophylaxis is not an alternative to RSV vaccination Palivizumab costs $ (USD)/dose wholesale (2011 data) 1 Even wealthy countries limit indications for palivizumab use 2 Even if less expensive, monthly dosing means that passive prophylaxis could never be a global strategy Committee on Infectious Diseases, Pediatrics. 2009;124(6): Active prophylaxis: RSV vaccines 29 Subunit RSV vaccines 30 10

11 RSV F glycoprotein is the primary target for subunit vaccines Most neutralizing antibodies directed against RSV F Little antigenic variation in RSV F (unlike RSV G) Previously RSV F vaccine candidates (PFP-1, 2, 3; RSV F/G/M) did not induce high titers of neutralizing antibodies and/or were difficult to manufacture F Fusion Matrix RNP complex 31 G Attachment Lipid membrane RSV F subunit vaccines: potential target populations Elderly Older high-risk children (not RSV naïve) Pregnant women 32 Recent advances in understanding RSV F structure have guided vaccine development RSV F exists in a prefusion and postfusion state Prefusion F is not naturally stable Historically, not believed that neutralizing epitopes were exposed in postfusion F Recent data from Novartis, Novavax, and NIAID,NIH indicate that postfusion RSV F contains neutralizing epitopes 33 Swanson KA. Proc Natl Acad Sci USA. 2011; 108(23): McLellan J S et al., J. Virol.2011;85:

Novartis postfusion RSV F vaccine protective in preclinical trials Cotton rats immunized with postfusion RSV F trimer developed high titers of RSV neutralizing antibody and were protected

2011; 108(23): 9619-24 RSV F nanoparticle vaccine is currently being evaluated in clinical trials Developed by Novavax Engineered RSV F expressed in baculovirus spontaneously forms

0 Day 0 Day 30 Day 60 Phase II studies in women of childbearing age anticipated to begin later this year 35 http://www.novavax.com/download/file/presentations/rsv-f-phase-1-poster-2011_gs.

12 Novartis postfusion RSV F vaccine protective in preclinical trials Cotton rats immunized with postfusion RSV F trimer developed high titers of RSV neutralizing antibody and were protected against viral challenge Similar RSV F subunit vaccine is being developed for clinical trials 34 Swanson KA. Proc Natl Acad Sci USA. 2011; 108(23): RSV F nanoparticle vaccine is currently being evaluated in clinical trials Developed by Novavax Engineered RSV F expressed in baculovirus spontaneously forms nanoparticles Preclinical studies showed protection against RSV challenge Phase I studies in healthy adults completed Day 0 Day 30 Day 60 Phase II studies in women of childbearing age anticipated to begin later this year 35 Additional approaches to RSV subunit vaccine development NanoBio and Merck Joint venture using NanoBio oil-in-water nanometer emulsion droplets (NanoStat) and Merck proprietary RSV antigen Goal is to produce a nonreplicating thermostable intranasal vaccine that will induce systemic as well as local immunity 36 12

13 Summary: RSV F subunit vaccines New RSV F subunit vaccines are in clinical trials or about to be tested in clinical trials Clinical trials will determine: Magnitude of antibody response Duration of antibody response Ability of RSV F subunit vaccines to induce neutralizing as well as non-neutralizing RSV F antibodies 37 Live RSV vaccines 38 Live RSV vaccines: potential advantages and limitations Durable immunity Not associated with disease enhancement in RSV-naïve populations Ease of administration (nose drop or nasal spray); Infection not inhibited by maternal antibody Suitable only for RSV-naïve populations Delicate balance between attenuation and immunogenicity 39 13

14 Live RSV vaccines Live attenuated recombinant RSV vaccines Live vectored RSV vaccines 40 Live attenuated (native) RSV vaccines cpts 248/404/1030/ SH Vaccine in clinical trials (MEDI-559) Codon-stabilized version (cps-2) RSV MEDI M Attenuating mutations in ra2cp248/404/1030/ SH Cold passage (cp), temperature sensitive (ts), and gene deletions 3' 5' NS1 NS2 N P M SH G F M2 L cp cp 404 cp cp cp cp mutations Val-299-Ile (N) Glu-225-Asp (F) Thr-539-Ile (F) C-(319)-Tyr (L) His-1690-Tyr (L) 42 cp ts mutations* 248 Gln-831-Leu (L) 1030 Tyr-1321-Asn (L) 404 T-C (Gene-start M2) * Likely reduce viral RNA synthesis 14

15 Initial clinical experience with ra2cp248/404/1030/ SH Well tolerated in RSV seropositive, seronegative children & young infants Highly restricted in replication compared to less attenuated candidates RSV neutralizing antibody responses detected in older children RSV neutralizing antibody responses difficult to detect in infants, but replication of 2 nd vaccine dose restricted, indicating that protective immunity was induced Some genetic reversion of point mutations detected, but at least 4 of 5 attenuating elements detected in all recovered vaccine virus 43. Karron R. J Infect Dis.2005; 191(7): Current status of ra2cp248/404/1030/ SH MEDI-559: NCT Phase I/II study in RSV-naïve infants and children <23 months completed in 2012; Analysis underway (MedImmune) Codon-stabilized version (cps-2) expected to be available for clinical trials in the near future (MedImmune; NIAID/NIH) 44 Luongo C et al., J Virol. 2012; 86(19): RSV MEDI M2-2: a novel rrsv deletion mutant 3' 5' NS1 NS2 N P M SH G F M2 L M2-2 is an RNA regulatory factor Deletion of M2-2 results in: Decreased RNA replication Increased transcription and antigen expression RSV MEDI M2-2 is currently being evaluated in RSV-naïve infants and children (NCT ) 45 15

16 Summary: live-attenuated rrsv vaccines Two types of rrsv vaccines currently in development: ra2cp248/404/1030/ SH and genetically stabilized derivatives MEDI M2-2 Results of clinical trials needed to determine whether these candidate vaccines will achieve the right balance of attenuation and immunogenicity 46 Vectored RSV vaccines Replication-competent Bovine/human parainfluenza virus type 3 Sendai virus Replication-defective Alphavirus Adenovirus 47 Potential advantages of vectored RSV vaccines Enhanced growth & stability compared to native RSV vaccines May protect against two pathogens (PIV3, Sendai/HPIV1) May overcome maternal immunity (alphavirus) Potential disadvantages: Single RSV antigen (F) represented Immune response to RSV may be decreased relative to vector 48 16

MEDI-534: a chimeric rb/hpiv3/rsv F vaccine RSV F b/h PIV3 3 N P/C M hpiv3 F hpiv3 HN L 5 Immunogenic and protected African green monkeys against RSV challenge after a single combined

17 MEDI-534: a chimeric rb/hpiv3/rsv F vaccine RSV F b/h PIV3 3 N P/C M hpiv3 F hpiv3 HN L 5 Immunogenic and protected African green monkeys against RSV challenge after a single combined intranasal/intratracheal dose Well-tolerated in RSV seropositive children Dose-ranging (10 4,10 5, 10 6 ) in 6-24 m.o. RSV seronegative children completed; Analysis underway 49 Gomez M et al., Pediatr Infect Dis J. 2009; 28(7): MEDI-534: antibody responses in RSV seronegative children 50 Bernstein DI et al., Pediatr Infect Dis J. 2012; 31(2): Sendai-vectored RSV vaccine (rsv-rsv-f) Sendai virus is a mouse pathogen, closely related to HPIV1 Whether Sendai infects humans is unknown In cotton rats, rsv-rsv-f induces neut. Ab & protects against RSV challenge No advantage of rsv-rsv-f + rsv-rsv-g Native Sendai currently being evaluated in children (NCT ; St. Jude s Children s Research Hospital) 51 Zhan X et al., Vaccine 2007; 25(52):

Replication-defective vectors: alphavirus and adenovirus Venezuelan equine encephalitis (VEE) has been used to produce RSV F alphavirus replicon particles (VRPs) that protect mice and cotton

Other vectors ( MVA, Salmonella, rhinovirus) ISCOMs F subunit coupled to novel adjuvants 53 RSV vaccines: what will the next decade bring?

18 Replication-defective vectors: alphavirus and adenovirus Venezuelan equine encephalitis (VEE) has been used to produce RSV F alphavirus replicon particles (VRPs) that protect mice and cotton rats against RSV RSV F has also been expressed in monkey or chimpanzee adenovirus vectors (GenVec; Okairos) and these are expected to enter clinical trials shortly 52 Other novel technologies Other vectors ( MVA, Salmonella, rhinovirus) ISCOMs F subunit coupled to novel adjuvants 53 RSV vaccines: what will the next decade bring? Novel technologies have led to the development of new replicating and non-replicating RSV vaccine candidates Type of RSV vaccine to be used will depend upon the population to be immunized Wider array of possibilities now than ever before 54 18

19 Our goal: to protect infants and children world wide against RSV

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00약제부봄호c03逞풚 경희대학교 동서신의학병원 약품 정보지 2 0 0 7. S P R I N G. V O L. 0 1 신약 소개 02 Journal Review 03 Special Subject 04 복약 지도 06 의약품 안전성 정보 07 약제부 알림 07 약제부 업무 소개 08 E A S T - W E S T N E O M E D I C A L C E N T E R 본 약품