Ben Bavinton, (The Kirby Institute) discusses how the Opposites Attract' stdy will address the unanswered questions about wther treatment as prevention will work for gay men. This presentation was given at the AFAO/NAPWA Gay Men's HIV Health Promotion Conference in May 2012.

1. The Opposites Attract Study:
Building the evidence for
“treatment as prevention” in gay male
serodiscordant relationships
Ben Bavinton
The Kirby Institute for infection and immunity in society
University of New South Wales, Sydney
May 2012

2. BACKGROUND
• Studies in heterosexual serodiscordant couples have
provided critical evidence for the role of HIV
treatment in preventing HIV transmission.
• Observational studies conducted in Africa showed a
relationship between HIV treatment/undetectable viral
load and transmission.
• In 2011, HTPN 052 found a 96% reduction in HIV
transmission in serodiscordant couples where the
HIV-positive partner had undetectable viral load.

3. HPTN052: A 96% reduction in HIV transmission risk
Cohen, MS et al, 2011

4. BACKGROUND: Unanswered questions
• There is a lack of evidence on ‘Treatment As
Prevention’ in homosexual men.
• The effectiveness of ‘Treatment As Prevention’ may
be different because:
– HIV transmission risk is higher for anal sex compared to
vaginal sex.
– HIV transmission has increased in gay men despite more
HIV-positive gay men receiving ART.
– Semen viral load does not perfectly correlate with blood viral
load: specific ARTs, STIs and adherence to ART can all
impact on this correlation.

5. BACKGROUND: Unanswered questions
• The durability of ‘Treatment As Prevention’
– HTPN052 participants will be followed for at least one year
• Detailed sociobehavioural information
– How do people in serodiscordant couples communicate
about viral load?
– How do they negotiate protected and unprotected sex in this
context?
– Do relationship agreements involve viral load?
– Knowledge, beliefs and attitudes about HIV, viral load, and
risk.

6. CURRENT RESEARCH
• The PARTNER Study
– 73 active sites recruiting across Europe in 14 countries.
– Over 650 couples recruited (50% of the target).
– Gay couples make up one-third of the sample to-date.

7. CURRENT RESEARCH
• The PARTNER Study
– 73 active sites recruiting across Europe in 14 countries.
– Over 650 couples recruited (50% of the target).
– Gay couples make up one-third of the sample to-date.
• The Opposites Attract Study

8. OPPOSITES ATTRACT STUDY PARTNERS
• Coordinated by the Kirby Institute at UNSW.
• 14 sexual health and general practice clinics in
Sydney, Melbourne, Brisbane and Adelaide.
• Potential to expand to further clinical sites in Cairns,
Canberra, and possibly Bangkok.
• Involvement of community partners.

9. OPPOSITES ATTRACT STUDY AIMS
1. Does HIV treatment/undetectable viral load reduce
HIV transmission in anal sex?
2. How do gay men use viral load to negotiate UAI
within serodiscordant relationships?
3. Do STIs modify the relationship between viral load
and HIV transmission?
4. Is semen viral load related to transmission?
– What is the correlation between viral load in blood and
semen?

10. OPPOSITES ATTRACT STUDY AIMS
• Data collected will also enable:
– Documenting behavioural risk compensation and its effect
on transmission
– Per contact probabilities of transmission
– Additional effect of PrEP/PEP (when used)

11. OPPOSITES ATTRACT STUDY DESIGN
• Prospective longitudinal cohort study.
• Open enrolment for up to four years.
• Unit of recruitment is a pair (couple) comprising two
men in an ongoing sexual relationship where one is
HIV positive and the other HIV negative at baseline.
• Pairs to be replaced if they “break up” or withdraw
(>30% per year).

12. OPPOSITES ATTRACT STUDY DESIGN
• A total of approximately 520 serodiscordant male
homosexual pairs in an ongoing sexual relationship
(involving anal sex).
• 240 pairs under follow-up at any given time after the
first year.
• Over 680 couple-years of follow-up.

13. OPPOSITES ATTRACT STUDY DESIGN
• Defining the term “couple” or “pair”:
– Relationship must be sexual in nature and ongoing
– Must involve anal intercourse at least monthly (on average)
– Does not need to be a “romantic, committed” relationship
(e.g. “boyfriends”)
– The nature of the relationship can change, providing that it
remains ongoing and sexual in nature
– No required length of relationship: “Do you think you will still
be having sex with each other in 3-6 months?”
• Study does not preclude men with multiple regular
partners, however participants can enroll with only
one partner at a time

14. OPPOSITES ATTRACT STUDY DESIGN
• The study revolves around the routine clinical
management schedule of the HIV-positive partner
– At least two clinic visits per year where viral load is taken
– Partners attend clinic visits within 2 weeks of each other
• Standard of care testing for viral load, CD4, HIV
antibodies and STIs (STIGMA & ASHM guidelines)
• Types of clinic visits:
– Enrolment visit
– Baseline visit
– Follow-up visits
– Seroconversion visit (if seroconversion occurs)

15. OPPOSITES ATTRACT STUDY DESIGN
• Phylogenetic testing of viruses if seroconversion
occurs to determine if transmission was within the
pair.
– Results of phylogenetic testing will not be provided to
participants or clinics.
• After each clinic visit (within 48 hours), both partners
complete an online questionnaire.

16. QUESTIONNAIRES
HIV-Positive Partner HIV-Negative Partner
• Demographics • Demographics
• HIV and treatment • HIV testing
• Adherence • STI testing and symptoms
• STI testing and symptoms • Relationships
• Relationships and communication • Agreements and communication
• Self-efficacy • Partner viral load
• Attitudes • Sexual behaviour with study partner
• Study involvement • Sexual behaviour with others
• Group sex
• PEP and PrEP
• Self-efficacy
• Attitudes
• Study involvement

17. SEMEN SUB-STUDY
• Semen collection to occur in Sydney.
• Aiming for 30% or more of the HIV-positive men
• Voluntary participation (separate consent form)
• Semen collection at the time of every clinic visit
• Semen collection on the same day or within 2 days of
the clinic visit
• Semen viral load and phylogenetic analysis (in cases
of partner’s seroconversion) at end of study

18. RECRUITMENT
• Mixture of clinic- and community-based recruitment.
• Aim to have 240 pairs enrolled by the end of 2012.
• Overall goal: for every HIV-positive gay man in each
clinic and each city more broadly to be aware of the
study.

19. CHALLENGES
• There are substantial challenges to conducting longitudinal
‘Treatment As Prevention’ studies among gay men.
CHALLENGE 1:
• High break-up rate (break-up rate of non-committed
relationships likely to be even higher than 30%).
• The study will need ongoing recruitment until the last six
months of the study to replace pairs that break up.

20. CHALLENGES
CHALLENGE 2:
• High levels of non-monogamy in gay male relationships
and UAI with casual partners is not uncommon.
• Phylogenetic analysis to determine transmission within
study partnerships is essential.
– Blood sample requirements

21. CHALLENGES
CHALLENGE 3:
• Infection most likely in the early stages of
relationships rather than in long-term, established
relationships.
• Recruitment will attempt to target men in new relationships
and men in non-committed yet ongoing sexual
relationships.
– Challenging, as the study burden falls primarily on the HIV-
negative partner.

22. CHALLENGES
CHALLENGE 4:
• Legal implications for HIV-positive participants.
• Legal advice sought and protections put in place.
1. Documented that both partners have good knowledge of HIV
transmission risks (quiz and education)
2. HIV-negative partner signs a statement that he is aware his
partner is HIV-positive.
3. Details about unprotected anal sex collected only from the
HIV-negative partner.
4. Phylogenetic test results not provided back to participants or
clinics.

23. COMMUNITY SUPPORT
• Support from community-based organisations is vital
to the success of the Opposites Attract Study.
• Central involvement of community organisations
through every stage of study development and
implementation.
• Especially important for recruitment.

24. RECRUITING NOW!
• Sydney • Melbourne
– East Sydney Doctors – Centre Clinic
– Holdsworth House – Northside Clinic
– Taylor Square Private Clinic – Prahran Market Clinic
– Dr Doong’s Surgery – Alfred Hospital
– RPA Sexual Health – Melbourne Sexual Health
– IBAC – St Vincent’s Centre
– Sydney Sexual Health Centre
• Brisbane • Adelaide
– Gladstone Road Medical – O’Brien Street General
Centre Practice

25. STUDY CONTACTS
• www.OppositesAttract.net.au
• OppositesAttract@unsw.edu.au
• Opposites Attract Research Assistant:
1800 129 073