Simon Dobson

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Two dose Q-HPV Vaccine Study

• Simon Dobson
• BC Childrens Hospital
• Vaccine Evaluation Centre
• Child Family Research Institute
• Vancouver
• University of British Columbia, Canada

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Disclosures

• I have carried out vaccine clinical trials for
• Merck
• GlaxoSmithkline
• Novartis
• Sanofi Pasteur
• Dynavax
• I have been on Advisory Boards for
  GlaxoSmithkline and Merck
• I have been on the National Advisory Committee on
  Immunization (Canada)

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Why do this study?

• Cervical cancer is second most common cancer in
  women worldwide (500,000 per year)
• HPV vaccines offer the opportunity of primary
  prevention
• Barriers are vaccine cost and accessibility

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Why do this study?

• Pre-licensure studies showed that 9-13 year olds
  responded better to the vaccine than 16-26 year
  olds
• Would it be possible to use this better response
  as an opportunity to use two instead of three
  doses?

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Study Funded byBritish Columbia Ministry of
HealthThe Provincial Governments of Quebec and
Nova Scotia
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Trial design 2 dose versus 3 dose HPV vaccine
study a phase III post licensure randomized
controlled trial
Sample Size N825
Study group 1 9-13 year olds females N260
Study group 3 16-26 year olds females N305
Study group 2 9-13 year old females N260
Study arm, Gardasil 0 and 6 months
Control arms, Gardasil 0, 2 and 6 months
Primary outcome Anti-HPV 16 and 18 GMT, t 7
months
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Primary Endpoints

• Differences in Geometric Mean Titres (GMT) of
  antibodies to HPV 16 and HPV 18 at Month 7
• Non-inferiority will be declared if lower bounds
  of the adjusted 95 CI of GMT ratios for HPV 16
  and HPV 18 are greater than 0.5

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Geometric Mean Titres in the Intention To Treat
Population
Dobson S et al. JAMA 2013
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GMT Ratios in the Intention To Treat Population
Dobson s et al. JAMA 2013
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Conclusions

• Following a 2 dose regimen in 9-13 year old
  girls, antibody responses to HPV-16,-18,-6,-11
  were non-inferior through 36 months, as compared
  to a 3-dose regimen in young adult women

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GMT Ratios in the Intention To Treat Population
Dobson s et al. JAMA 2013
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Why is this important?

• Better use of resources
• Protects more girls
• Worldwide, saves lives

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But.. Still need answers to two questions

• What is the duration of protection?
• This is known for neither 3 doses nor 2 dosesyet
• Does 2 doses work as well as 3 doses?
• A Canadian study has started
• Extended 2 1 schedules are also possible