1. Preferences regarding emerging HIV prevention technologies among Toronto men who have sex with men
Darrell H.S. Tan1, Jayoti Rana1, Shawn Fowler2, Trevor A. Hart3, James Wilton4, Ahmed M. Bayoumi1
1. St. Michael’s Hospital; 2. Hassle Free Clinic; 3. Ryerson University; 4. Ontario HIV Treatment Network
Abstract WEAC0102. July 26, 2017

2. Disclosure
I have received investigator-initiated research grants from Gilead and Viiv
I am a Site Principal Investigator for industry-sponsored clinical trials by GSK

3. Background
New HIV prevention technologies (NPTs) are currently in development, each with unique attributes that may appeal differently to different users
Long-acting injectable agents (eg. cabotegravir)
Rectal microbicides (eg. tenofovir reduced glycerin 1% gel)
Understanding patient preferences can inform:
How providers discuss, present and frame NPTs with patients
How policy-makers project uptake and population-level impact

4. Background
A Discrete Choice Experiment (DCE) is a health economics method for quantifying such preferences, involving:
1. Identifying attributes of interest (eg. route of administration)
2. Assigning levels to each attribute (eg. pill, injection, etc.)
3. Creating scenarios combining these attributes/levels
4. Having participants choose between scenarios
5. Mixed logistic regression to assess trade-offs between attributes
We used a DCE to characterize preferences for NPTs among Toronto MSM

5. Methods Design: Administered within an anonymous survey
Participants: Adult MSM undergoing anonymous point-of-care HIV testing
Setting: Hassle Free Clinic + 3 satellite sites
Downtown sexual health clinic serving large MSM population
Highest HIV+ rate of all anonymous testing sites in Ontario

6. Discrete Choice Experiment
12 “choice sets”, each presenting 3 options:
Two hypothetical NPT options
“Usual methods to prevent HIV infection” (excluding PrEP)
NPT options differed according to 4 attributes:
Route/frequency: daily pill, on-demand pill, monthly injection, on-demand rectal gel
HIV prevention efficacy: 50%, 65%, 80%, 99% risk reduction
Side effects: none, mild (nausea, injection site reaction, or rectal discomfort)
Risk of resistance: no, low, moderate chance of decreasing future treatment options

7. Example question

8. Analyses Pilot phase (first 62 respondents) to ensure:
Questions understandable
Trade-offs being made
Mixed logistic regression to infer relative preferences for attributes and to estimate heterogeneity
Beta coefficients then linearly transformed so that utility
0 = least preferred combination of NPT attributes
100 = most preferred combination of NPT attributes
Latent class analysis to identify response patterns

9. Results
306 respondents of which 53 excluded from DCE analyses due to invariant responses (n=38), on PrEP (n=12), all missing responses (n=2), transgender (n=1)
Characteristic
Value
Age
31 (25-38)
Race
White
Asian
Latino/Hispanic
South Asian
Middle Eastern
Black
Other
169 (55.2)
56 (18.3)
24 (7.8)
19 (6.2)
14 (4.6)
12 (3.9)
Characteristic
Value
Education
High school
College/Undergrad
Grad/Professional
40 (13.2)
161 (53.0)
103 (33.9)
# partners, past 6 mo.
6 (3, 10)
# times condomless receptive anal sex, past 6 mo.
0 (0, 2)
Aware of PrEP
278 (90.9)

10. Utility scores by attribute & level
Variable
Coefficient
95% Conf. Int.
No PrEP
47.3
(38.6 to 56.0)
Formulation and side effects
Daily pill
9.8
(0.7 to 18.9)
Daily pill with mild nausea
-31.8
( to 47.1)
On-demand pill
16.5
(4.6 to 28.3)
On-demand pill with mild nausea
14.6
(1.6 to 27.7)
Monthly injection
4.9
(-6.7 to 16.6)
Monthly injection, mild site reaction
-3.5
(-16.9 to 10.0)
On-demand rectal gel
-4.5
(-16.4 to 7.3)
On-demand rectal gel, mild discomfort
-11.8
(-26.9 to 3.4)
Efficacy
50% risk reduction
40.2
(35.8 to 44.5)
65% risk reduction
52.4
(46.7 to 58.1)
80% risk reduction
64.7
(57.7 to 71.7)
99% risk reduction
80.2
(71.6 to 88.9)
Risk of resistance
No Risk
3.3
(1.5 to 5.1)
Low Risk
2.9
(1.3 to 4.4)
Moderate Risk
-8.3
(-10.5 to -6.2)

11. Illustrative examples
Variable
Coefficient
No PrEP
47.3
Formulation and side effects
Daily pill
9.8
Daily pill with mild nausea
-31.8
On-demand pill
16.5
On-demand pill with mild nausea
14.6
Monthly injection
4.9
Monthly injection, mild site reaction
-3.5
On-demand rectal gel
-4.5
On-demand rectal gel, mild discomfort
-11.8
Efficacy
50% risk reduction
40.2
65% risk reduction
52.4
80% risk reduction
64.7
99% risk reduction
80.2
Risk of resistance
No Risk
3.3
Low Risk
2.9
Moderate Risk
-8.3
Best combination:
On-demand pill
No side effects
99% efficacy
No risk of resistance
Utility score = 100

12. Illustrative examples
Variable
Coefficient
No PrEP
47.3
Formulation and side effects
Daily pill
9.8
Daily pill with mild nausea
-31.8
On-demand pill
16.5
On-demand pill with mild nausea
14.6
Monthly injection
4.9
Monthly injection, mild site reaction
-3.5
On-demand rectal gel
-4.5
On-demand rectal gel, mild discomfort
-11.8
Efficacy
50% risk reduction
40.2
65% risk reduction
52.4
80% risk reduction
64.7
99% risk reduction
80.2
Risk of resistance
No Risk
3.3
Low Risk
2.9
Moderate Risk
-8.3
Best combination:
On-demand pill
No side effects
99% efficacy
No risk of resistance
Utility score = 100
Worst combination:
Daily pill
Mild side effects
50% efficacy
Moderate risk of resistance
Utility score = 0

13. Illustrative examples
Variable
Coefficient
No PrEP
47.3
Formulation and side effects
Daily pill
9.8
Daily pill with mild nausea
-31.8
On-demand pill
16.5
On-demand pill with mild nausea
14.6
Monthly injection
4.9
Monthly injection, mild site reaction
-3.5
On-demand rectal gel
-4.5
On-demand rectal gel, mild discomfort
-11.8
Efficacy
50% risk reduction
40.2
65% risk reduction
52.4
80% risk reduction
64.7
99% risk reduction
80.2
Risk of resistance
No Risk
3.3
Low Risk
2.9
Moderate Risk
-8.3
Injection
Mild side effects
80% efficacy
Low risk of resistance
Utility score = 64.1

14. Illustrative examples
Variable
Coefficient
No PrEP
47.3
Formulation and side effects
Daily pill
9.8
Daily pill with mild nausea
-31.8
On-demand pill
16.5
On-demand pill with mild nausea
14.6
Monthly injection
4.9
Monthly injection, mild site reaction
-3.5
On-demand rectal gel
-4.5
On-demand rectal gel, mild discomfort
-11.8
Efficacy
50% risk reduction
40.2
65% risk reduction
52.4
80% risk reduction
64.7
99% risk reduction
80.2
Risk of resistance
No Risk
3.3
Low Risk
2.9
Moderate Risk
-8.3
Injection
Mild side effects
80% efficacy
Low risk of resistance
Utility score = 64.1
Rectal gel
Utility score = 55.8

15. Utility scores by attribute & level

16. Trade-offs: What is the minimum efficacy a strategy must have in order to be preferred over no PrEP?
(95% CI)
On-demand pill
50.5
(43.9 to 57.2)
Daily pill
58.7
(50.6 to 66.8)
Monthly injection
64.7
(58.0 to 71.4)
On-demand rectal gel
76.2
(68.2 to 84.2)

17. Heterogeneity in utility scores
Average score=47.3

18. Minimum efficacy required for strategy to be preferred over no PrEP
Latent class analysis identified four subsets of participants
Minimum efficacy required for strategy to be preferred over no PrEP
Class 1
(40.5%) 2
(20.7%) 3
(21.9%) 4
(16.9%)
Daily pill
15.6%
>100%
66.4%
88.0%
Daily pill with mild nausea
<0%
86.5%
94.7%
On-demand pill
64.3%
77.7%
On-demand pill with mild nausea
82.8%
83.3%
Monthly injection
22.6%
69.7%
84.2%
Monthly injection, mild site reactions
14.7%
64.5%
85.8%
On-demand rectal gel
31.1%
91.7%
71.0%
On-demand rectal gel, mild discomfort
3.8%
71.7%
Favours pill
Averse to all
Averse to gel
Ambivalent

19. Limitations Context: Toronto, Summer 2016 Simplifying assumptions
Social acceptability of PrEP modest, rising slowly
Simplifying assumptions
eg. severity of side effects always mild
Only considered 4 attributes
Hypothetical bias

20. Conclusions
Attitudes towards emerging PrEP formulations among MSM are heterogeneous
Most favoured: On-demand pill with no side effects, 99% efficacy, no risk of resistance
Least favoured: Daily pill causing nausea, 50% efficacy, moderate risk of resistance
HIV prevention efficacy was primary driver of utility
Preferences or aversions towards specific routes of administration may affect uptake of and adherence to emerging HIV prevention strategies

21. Acknowledgements All participants in the pilot and final phases
DHST is supported by a New Investigator Award from