Human Papillomaviruses (HPV): The Background, Current Status and Future of Vaccines to Prevent HPV Infection,

Abnormal Genital Lesions and Cervical Cancer

Cosette M. Wheeler, PhD

Departments of Molecular Genetics & MicrobiologyAnd Obstetrics & Gynecology

University of New Mexico Health Sciences CenterAlbuquerque, New Mexico

Learning Objectives

Identify risk factors for acquiring HPV infection

Discuss the causal relationship between HPv and cervical cancer and HPV and genital warts

Identify recent clinical findings on HPV vaccines in development

Papillomaviruses are small DNA viruses that coevolved with ALL animals

HPV Life Cycle

HPV Protein Expression

Late genes L1&L2

Early Genes E6 & E7 Early Genes E4 & E5 Early Genes E1 & E2

Stratum Corneum

Stratum Granulosum

Stratum Spinosum

Stratum Basale

Basement Membrane

Natural history of CC: factors & co-factors

• HPV genotypes• HPV variants• Multiple types• Viral load• Viral integration

• Early AFSI

• High NOSP

• High-risk malepartners

• C. trachomatis

• HSV-2

•Sexual behavior

•Hygiene

•Condom use

•Circumcision• Immunosuppresion

• Cervical inflammation

HPV INFECTION LSIL HSIL INVASIVE

CANCER

NORMAL • Immune

surveillance & response

•Genetic susceptibility

•Viral factors

•Smoking

•Parity

•OC use

•HIV

•Other STIs

Incidence of Cervical HPV Detection in Women From the Time of Onset of Their

First Sexual Relationship

Collins et al. Brit J Obstet Gynecol 2002;109: 96 to 98

Time since first intercourse (months)

0%

10%

20%

30%

40%

50%

60%

70%

0 6 12 18 24 30 36 42 48

Cervical HPV Detection

10 20 30 40 50 Age in Years

HPV 16 or 18 cervical infectionHPV 16 or 18 cervical infectionCINCIN

Sexual debutSexual debut

Invasive Cervix CancerInvasive Cervix Cancer

MenarcheMenarche

CISCIS

Micro-invasive Cervix CancerMicro-invasive Cervix Cancer

Natural History of HPV 16/18-Related Natural History of HPV 16/18-Related Cervical Neoplasia: Cervical Neoplasia:

Estimated Median Age of EventsEstimated Median Age of Events

ASC-US (atypical squamous cells of undetermined significance)

Lifetime Risk of HPV Related Disease

Genital HPV Infection is the Most Common Viral STI Worldwide– Lifetime risk of HPV infection for sexually active males and females ≥ 50%

(80%) Estimated lifetime risk of developing genital warts ~ 10% 1, 2

Women participating in routine screening – abnormal Pap smear: 35%– CIN ~ 25% – invasive cervical cancer: <1%

Women without routine screening

– invasive cervical cancer: 3 to 4%

1) 1 Franco, E. L., et al. in : New Developments in Cervical Screening and Prevention, Oxford, Blackwell Science, 1997: 14-22.

2) 2 Tortolero-Luna, G. Hematology and Oncology Clinics of North America, 13 (1), 1999: 245-257.

Prevalence of HPV DNA in over 1,000 cervical cancer biopsies from 22 countries : 99.7%

J. Pathol. 189: 12-19, 1999

HPV is a necessary cause of invasive cervical cancer worldwide

Colombia

The Philippines

Brazil

SpainMorocco

MaliThailand

Paraguay

USA

BoliviaChile

Argentina

Panama

Canada GermanyPoland

Guinea Benin

TanzaniaUganda

Indonesia

Cuba Algeria

IARC International prevalence survey of HPV types in cervical cancer

Prevalence of HPV types in cervical cancer

Any HPV 99.7 %

HPV 16 57.4 %

HPV 18 16.6 % 81 %

HPV 45 6.8 % 89 %

HPV 31 4.3 % 96%

HPV 33 3.7 %

HPV 52 2.5 %

HPV 58 2.3 %

HPV 35 2.2 %

Geographical distribution of HPV types in cervical cancer

0% 20% 40% 60% 80% 100%

Northern Africa

Subsah. Africa

C.S/ America

S.E.Asia

N.Amer./Europe

HPV type 16 18 45 3133 OTH

A vaccine that prevents HPV16- and 18-related intraepithelial lesions and

neoplasms will be a major advance in anogenital cancer control

HPV Viral-Like Particle (VLP) Vaccines

Schematic of HPV VLP

Electron micrographof VLP

HPV Neutralizing Epitopes Are Conformational and Reside in Pentameric (5 x L1) Capsomere

Subunits Connected by Invading C-termini

Modis Y et al (2002) Atomic Model of the Papillomavirus Capsid. EMBO;21:4754-4762

HPV Vaccine Programs Conducted in 3 Phases Phase I in 300 subjects

– Immunogenicity and tolerability of a range of doses of monovalent HPV L1 VLP vaccines

Phase II in 3,500 subjects– Immunogenicity/tolerability of a range of HPV L1 VLP vaccine

dose formulations – Preliminary proof of efficacy

Koutsky LA, Ault KA, Wheeler CM, Jansen KU, Barr E, Alvarez FB, Chiacchierini LM. Results from a phase II human papillomavirus virus-like particle vaccine efficacy trial. New England Journal of Medicine.2002; 347:1646-1651.

Diane M Harper, Eduardo L Franco, Cosette Wheeler, Daron G Ferris, David Jenkins et al. Efficacy of a bivalent L1 virus-like particle vaccine in prevention of infection with human papillomavirus types 16 and 18 in young women: a randomized controlled trial. Lancet. 2004;364:1757-65.

Villa LL, Costa RLR, Petta CA, Andrade RP, Ault KA, Giuliano AR, Wheeler CM, Koutsky LA et al. A Double-blind, Placebo-controlled Efficacy Trial of a Prophylactic Quadrivalent Human Papillomavirus (Types 6, 11, 16, 18) L1 Virus-Like Particle (VLP) Vaccine in Young Women. Lancet Oncology. 2005;6:271-278.

HPV Vaccine Programs Conducted in 3 Phases (cont.)

Phase III in >20,000 subjects– Efficacy of HPV L1 VLP vaccine vs. vaccine type-related

• CIN 1 • Genital warts • CIN 2/3+

HPV L1 VLP Phase III Vaccines

Quadrivalent HPV Types 6, 11, 16, 18 L1 VLP vaccine (Gardasil®, Merck Research Laboratories, West Point, PA.) – Phase II and III Reported

Di-valent HPV Types 16 and 18 (Cervarix™, GlaxoSmithKline) – Phase II Reported

Vaccine Efficacy

Cohort HPV Type Vaccine(N=366)

Placebo (N=355) % 95%CI

16 0 13 100.0 71.5-100 18 0 4 100.0 7.2-100

ATP

16 and/or 18 0 16 100.0 76.8-100

Vaccine Efficacy Cohort HPV Type

Vaccine(N=560)

Placebo (N=553) % 95%CI

16 4 25 84.5 55.2-94.6 18 1 11 91.1 31.0-98.9

ITT

16 and/or 18 4 31 87.5 64.6-95.6

GSK Vaccine Efficacy: Persistent Infection (all samples)

Harper DM et al, The Lancet, 2004

Summary of HPV-001 Efficacy Data: HPV 16 and/or 18 Cervical Protection

0102030405060708090

100

Vacc

ine

Effica

cy

91% 93%100%

Incide

nt Inf

ection

Persis

tent In

fectio

n

Cytolog

y

Harper et al, The Lancet, 2004

*Analysis of incident/persistent infection and cytology performed in ATP cohort (cervical samples). Analysis of CIN performed in ITT cohort (DNA detected in tissue)

100%

CIN

GSK efficacy study – Global: North America, Latin America, Asia Pacific, Europe– N = 18,000 (15-25 year old women)

National Cancer Institute (NCI) efficacy study– Population-based trial in Guanacaste, Costa Rica– Clinical trial management – Allan Hildesheim (NCI PI),

Rolando Herrero (Costa Rican PI)– N ~12,000 (18-25 year old women)

Both trials assessing CIN 2+ endpoints

GSK Phase III Efficacy Studies

Definitive evaluation of the impact of prophylactic HPV vaccination on cervical

intraepithelial neoplasia grade 2 and 3 (CIN2/3), squamous cell carcinoma in situ (CIS), adenocarcinoma in situ (AIS) and

cervical cancer has been recently reported for Merck quadrivalent HPV 6, 11, 16, and 18

VLP vaccine

Merck Quadrivalent HPV (Types 6, 11, 16, 18) L1 VLP Vaccine Dose-Ranging and Phase II Efficacy

StudyDouble-blind, placebo-controlled study

– In 1106 women aged 16 to 23 (U.S., Brazil, E.U.)– Followed for 3 years, 6 month intervals– 3 formulations of HPV vaccine or Placebo given at

enrollment, Month 2, and Month 6

GroupHPV 6 VLP

(g)HPV 11 VLP (g)

HPV 16 VLP (g)

HPV 18 VLP (g)

Total VLP (g)

Pbo 0 0 0 0 0

*Low 20 40 40 20 120

Med 40 40 40 40 160

High 80 80 40 80 200

*GARDASIL® formulation

Quadrivalent HPV Vaccine Study: Results of Dose-Ranging Phase

10

100

1000

HPV 11 HPV 16 HPV 18HPV 6

Geo

met

ric M

ean

Tite

r (m

MU

/mL)

Placebo

40/40/40/40 g 80/80/40/80 g

20/40/40/20 g

Levels after Natural Infection

Quadrivalent HPV Vaccine Study:Anti-HPV 18 Immunogenicity Over 3.0

Years

Ser

um c

LIA

GM

T, m

MU

/mL

0 2 3 6 7 12 18 24 30 36Time (Months)

10

100

1000

10000

Per-Protocol Subjects (Phase III formulation)

Baseline Seropositive & PCR Negative Subjects (Placebo Group)

Quadrivalent HPV Vaccine Study:Anti-HPV 16 Immunogenicity Over 3.0 Years

Ser

um c

LIA

GM

T, m

MU

/mL

0 2 3 6 7 12 18 24 30 36Time (Months)

10

100

1000

10000 Per-Protocol Subjects (Phase III formulation)Baseline Seropositive & PCR Negative Subjects (Placebo Group)

Quadrivalent HPV Vaccine Study: Efficacy Evaluation by HPV Type

VaccineCases

4

0

0

3

1

VaccineEfficacy

90%

100%

100%

86%

89%

71-97%

95%Confidence

IntervalP-

Value

<10–336

13

3

21

9

PlaceboCases Endpoint

HPV 6/11/16/18 Infxn, CIN, or GW

HPV 6-related

HPV 11-related

HPV 16-related

HPV 18-related Vaccine cases:

– HPV 16: 3 cases single positive at the last visit on record– HPV 18: 1 case persistent HPV 18 infection

Per-Protocol Efficacy Cohort

Villa et al, Lancet Oncology 2005; 6: 271-78.

Antibody levels among non-cases vs. single case of persistent HPV 18 infection (vaccine recipients)

0 2 3 6 7 12 18 24 30 36

Time (Months)

10

100

1000

10000

Ser

um c

LIA

GM

T, m

MU

/mL

Non-Cases for HPV 18 combinedSubject A

____

…..

Detection of HPV 18 DNA

No evidence that HPV vaccine titers are any different in cases compared to non-cases – No minimum protective antibody level known

Phase III Trial of Prophylactic Quadrivalent HPV 6, 11, 16, 18 L1 Virus-Like Particle (VLP)

Vaccine - Merck:

Prevention of Cervical Intraepithelial Neoplasia (CIN) and External Genital Lesions (EGL) – FUTURE I

Prevention of Cervical Intraepithelial Neoplasia (CIN) 2/3 including Adeno- and Squamous-cell Carcinoma in situ (CIS)

-FUTURE II

General Trial Population Impact

FUTURE II Clinical Protocol

Randomized, double-blind, placebo-controlled study in 12,167 women aged 16 to 26 enrolled in 13 countries

1:1 randomization to Gardasil™ or placebo

ThinPrep™ Pap tests, swabs for HPV DNA taken at Day 1 and Months 7, 12, 24, 36, 48, and sera tested at Day 1 in all subjects

Mandatory colposcopy and definitive therapy algorithm based on standard of care

All Pap tests and biopsies processed and read at a central laboratory

Expert Pathology panel read all slides for endpoint determination

FUTURE I and II Trial Primary Disease Endpoints:HPV 6/11-Rleated Extragenital Lesions

HPV 16/18-Related CIN 2, CIN 3 (includes CIS), AIS, or Cervical Cancer

Prepare Consecutive

Sections

CervicalBiopsy

Fixation, Processing & Paraffin Embedding

H&E Staining and Histology

1 2 12 13

Extraction of DNA for HPV Multiplex PCR

3 75

12

54

3

67

12

98

1311

10

No Case

Wart/CIN - FUTURE I +CIN 2/3, AIS, Cancer – FUTURE II

HPV 6/11/16/18PCR Positive

Case

Vaccine TypePCR Negative

Statistical Plan

Primary Efficacy Evaluation in Per-Protocol (PP) Population– received 3 vaccinations within 1 year– no major protocol violations– HPV 16/18 sero(-) at Day 1 and HPV 16/18 DNA(-) Day 1 to Month 7– Cases counted starting after Month 7

Supportive analysis in Modified intention to treat (MITT) population – received ≥1 vaccination– HPV 16/18 sero(-) and HPV 16/18 DNA(-) at Day 1– Cases were counted starting 30 days after Day 1

Timing of efficacy analyses– Interim analyses when 19 endpoint cases seen in PP population– PP population efficacy tested at =0.0204– For the HPV 16/18-related CIN 2, CIN 3 (includes CIS), AIS, or cervical

cancer endpoint in the PP population, 97.96% CI reported. All other CIs are 95%.

Subject Characteristics FUTURE IIVaccine

(N = 6087)Placebo

(N = 6080)Mean age (yrs) 20.0 19.9

Age range (yrs) 15 to 26 15 to 26

Region

North America 460 (8%) 456 (7%)

Latin America 1599 (26%) 1594 (26%)

Asia-Pacific 92 (2%) 89 (2%)

Europe 3936 (64%) 3941 (65%)

Mean Age 1st intercourse among non-virgins (~93.4%)

16.6 16.6

Median Lifetime # of sex partners 2 2

Using hormonal contraception 3613 (59.4%) 3614 (59.5%)

Subject Accounting FUTURE II

Vaccine Placebo Population to which

category applies

(N = 6,087) (N = 6,080) PP MITT

Received ≥ 1 Injection 6,082 6,075

Included in PP 5,301 5,258 Included in MITT 5,736 5,766Reason for exclusion

General protocol violations 275 315 X Sero (+) and/or DNA (+) to HPV 16

at Day 1 954 964 X X at or before Month 7 1,012 1,162 X Sero (+) and/or DNA (+) to HPV 18

at Day 1 397 405 X X at or before Month 7 443 548 X No post-Month 7 follow-up (16/18) 25/35 25/36 X

Clinical Serious Adverse Experience (AE) Summary(Days 1 to 15 Following Any Vaccination Visit)

Vaccine (N=6075)

Placebo (N=6076)

n (%) n (%)Subjects with follow-up 6019 6031

Number (%) of subjects with:

serious AE 17 (0.3) 16 (0.3) serious vaccine-related AE 3 (<0.1) 2 (<0.1)

discontinuation due to a serious AE 2 (<0.1) 1 (<0.1)discontinuation due to a serious vaccine-related AE

0 (<0.1) 1 (<0.1)

discontinuation due to death* 2 (<0.1) 0 (0)

*Deaths: one drug overdose and one traffic accident

Efficacy Results in PP Efficacy – FUTURE IIAverage 17 Months After Completion of the Vaccination Regimen

PP = received 3 vaccinations within 1 year; no major protocol violations; HPV 16/18 sero(-) at Day 1 and HPV 16/18 DNA(-) Day 1 to Month 7; Cases counted starting after Month 7

CIN 3 includes squamous-cell carcinoma in situ (CIS); AIS = adenocarcinoma in situ (AIS)

  Vaccine(N=6,082)

Placebo(N=6,075)  

Efficacy (%)

 CI

  p-

Value  Endpoint n Cases n Cases

CIN 2/3 or AIS              

HPV 16/18-related 5,301 0 5,258 21 100 (76– 100)

< 0.001

HPV 16-related 4,552 0 4,405 16 100 (75– 100)  

HPV 18-related 5,051 0 4,968 8 100

(42– 100)  

By lesion type (worst diagnosis)- All in the Placebo group

CIN 2 5 CIN 3   15 AIS   1

Efficacy Results in MITT Population FUTURE IIAverage 24 Months After the First Vaccination

MITT = received ≥1 vaccination; HPV 16/18 sero(-) and HPV 16/18 DNA(-) at Day 1Cases were counted starting 30 days after first vaccination

  Vaccine(N=6,082)

Placebo(N=6,075)  

Efficacy (%)

 CI

  p-

Value  Endpoint n Cases n Cases

CIN 2/3 or AIS              

HPV 16/18-related 5,736 1 5,766 36 97 (83– 100)

< 0.001

HPV 16-related 4,944 1 4,957 28 96 (78– 100)  

HPV 18-related 5,477 0 5508 11 100

(60– 100)  

By lesion type (worst diagnosis)

CIN 2 10 CIN 3   23 AIS   4

Single case of HPV 16-related CIN 2 (Month 24) in vaccine group. HPV 16 DNA detected at Month 7.

Efficacy Results in MITT Population FUTURE IAverage 26 Months After Completion of the Vaccination Regimen

MITT = received ≥1 vaccination; HPV 16/18 sero(-) and HPV 16/18 DNA(-) at Day 1Cases were counted starting 30 days after first vaccination

CIN 3 includes squamous-cell carcinoma in situ (CIS); AIS = adenocarcinoma in situ (AIS)

  Vaccine(N=2,240)

Placebo(N=2,258)  

Efficacy (%)

 CI

  p-

Value  Endpoint Cases Cases

HPV6/11/16/18-CIN 2 57 97 87%,100% P<0.001

HPV 6-related CIN 1 12 92 43%,100%

HPV 11-related CIN 0 6 100 15%,100%

HPV 16-related CIN 0 32 100 88%,100%

HPV 18-related CIN 1 13 92 49%,100%

Efficacy Results in MITT Population FUTURE I Average 26 Months After Completion of the Vaccination Regimen

  Vaccine(N=2,240)

Placebo(N=2,258)  

Efficacy (%)

 CI

  p-Value

 Endpoint Cases Cases

HPV 6/11/16/18-EGL 3 59 95 84%,99% P<0.001

HPV 6-related EGL 2 34 94 77%,99%

HPV 11-related EGL 1 14 93 53%,100%

HPV 16-related EGL 0 10 100 70%,100%

HPV 18-related EGL 0 7 100 30%, 100%

General Clinical Trial Population Impact of GardasilAverage 24 Months After the First Vaccination

General Population = received ≥1 vaccination; HPV 16/18 sero(+/-) and HPV16/18 DNA(+/-) at Day 1 - Cases were counted starting 30 days after first

vaccination – Gardasil® Trial Population had no more than 4 lifetime sex partners AND an average of only 2

  Vaccine PlaceboReduction

(%) 95%

CI   Endpoint n Cases n Cases

HPV 16/18              

CIN 2/3 or AIS 9831 122 9896 201 39 (23– 52)

VIN 2/3 and VaIN 2/3 8954 8 8962 26 69 (30– 88)  

HPV 6,11,16,18-related CIN, CIN 2/3, AISHPV 6,11,16,18-related genital warts

8814

8954

170

58

8846

8962

317

184

46

69

(35–56)

(58-77) 

SummaryA 3-dose regimen of Gardasil ® was 100% effective in preventing

HPV 16/18-related CIN 2/3 and AIS in women who were HPV 16/18-naïve at enrollment and HPV 16/18 DNA(-) through the vaccination regimen

Efficacy remained high (97%) in MITT population (received ≥ 1 vaccination; includes protocol violators but which excluded women previously exposed to HPV vaccine types)

General trial population impact of Gardasil® was significantly reduced compared to PP or MITT when women who had already been exposed to HPV vaccine types in the past (sero+) or who were currently infected with vaccine types (HPV DNA PCR+) were included

There is no clear evidence that Gardasil® or any other HPV vaccine provides benefit to women who are currently infected or have been infected in the past with HPV vaccine types

Administration of Gardasil® was generally safe and well-tolerated

Other Important Take Home Messages I It is critical that vaccinated and un-vaccinated women

continue being screened under current early detection guidelines

– Current first generation HPV vaccines do not protect against over 12 HPV types that cause ~30% of invasive cervical cancer

– Duration of HPV vaccine immunity is unknown and how and when booster immunizations will be recommended is unknown

Public health and policy efforts are needed to ensure access and encourage high HPV vaccine coverage for all racial, ethnic, and socioeconomic groups, and particularly for girls/women of color, immigrants, those living in rural areas, low-income and uninsured women, and others who have limited access to health care services

Other Important Take Home Messages II

Clinical trials for Gardasil were not conducted in a general population of women (limited inclusion for lifetime sex # of partners and abnormal Pap history) although universal vaccination of women aged 13-26 was recommended

It is likely that the reduction in disease in a random general population will be less than that observed in the general Gardasil trial populations – US population average number of sex partners is ~ ≥ 4 for women ages 21-26

HPV 16/18CIN 2/3 or AIS 39% (23– 52) VIN 2/3 and VaIN 2/3 69% (30– 88)

HPV 6,11,16,18-related CIN, CIN 2/3, AIS 46% (35–56)HPV 6,11,16,18-related genital warts 69% (58-77)

Other Important Take Home Messages III

In many cases women may be paying for HPV vaccines themselves - The potential benefit diminishes with increasing number of lifetime sexual partners

Vaccination of women over age 26 and of males is not currently recommended

HPV testing is not recommended prior to vaccination – current tests are not type-specific and even if and when type-specific HPV tests become available, single tests do not accurately measure current infections and CANNOT assess past exposure

Some Remaining Questions

Given competing health care demands and limited resources, is it rational to vaccinate the general population of women ages 19-26 many who have already been exposed (currently infected ) or whom are presumed immune and who should be attending screening programs ?

Will HPV vaccination give a false sense of protection and result in modification of screening behaviors or practices that will undermine the anticipated benefits of HPV vaccines?

There are no data to provide evidence for changes in screening of vaccinated women - however will financial constraints or alternate interests drive lengthening of Pap smear screening intervals to allow HPV vaccine expenditures ?

As changes in practices continue, will providers implement somewhat costly active screening reminders and pursue missed screens in support of the changing environment and potential problems as we move forward ?

Other Key Issues

If HPV vaccines are shown effective in men, will they be recommended given cost benefit and benefit to overall disease outcomes appear to be minimal based on modeling if penetration in women is high

Will women at greatest risk for this disease be provided to access to HPV vaccines – developing world, impoverished

Required Go-Forward Surveillance and Research

Ongoing research and surveillance should be conducted in diverse populations, including research on

– duration of protective immunity, – population- and lesion-based changes in type-specific

prevalence for the full spectrum of carcinogenic and non-carcinogenic genital HPV types,

– changes in Pap test performance characteristics, – changes in screening practices and behaviors,– comprehensive surveillance for reproductive toxicities,– increasing vaccine coverage and acceptability, and impact

on safe sexual behavior.