MOPEB134

Title

Incentives conditioned on tenofovir levels to increase adherence among young women on PrEP in Cape Town

Presenter

Linda-Gail Bekker

Authors

C. Celum¹, K. Gill², J. Morton¹, G. Stein¹, K. Thomas¹, M. McConnell³, A. van der Straten⁴, J. Baeten¹, M. Duyver², E. Mendel², K. Naidoo², L. Myers², J. Dallimore², L. Weisner², L.-G. Bekker²

Institutions

¹University of Washington, Seattle, United States, ²Desmond Tutu HIV Centre, University of Cape Town, Cape Town, South Africa, ³Harvard School of Public Health, Boston, United States, ⁴RTI International, Research Triangle Park, United States

Background: In placebo-controlled PrEP trials, African adolescent girls and young women (AGYW) had low adherence; < 30% with detectable plasma tenofovir. The 3P demonstration project evaluated PrEP adherence and the effect of incentives conditioned on high tenofovir levels among South African AGYW.
Methods: 200 sexually active, HIV-negative AGYW ages 16-25 in Masimpumulele township near Cape Town were enrolled March 2017-18. Adherence was assessed by tenofovir diphosphate (TFV-DP) concentrations in red cells in dried blood spots (DBS), a measure of cumulative use in the prior month. TFV-DP>700 fmol/punch was chosen as the threshold for high adherence (correlates with >4 doses/week and associated with high efficacy in MSM). At enrollment, 101 AGYW were randomized to the incentive arm (counseling at months 2 and 3 about the prior month''s drug level with a 200 Rand, $13, incentive conditioned on TFV-DP>700), and 99 to the standard arm (counseling at months 2 and 3 about the prior month''s drug level without an incentive). Visits were at 0,1, 2, 3, 6, 9 and 12 months. Month 3 levels were compared by study arm by intention to treat (ITT) analysis, assuming women without a visit and missing a test were not highly adherent.
Results: Women had a median age of 19; 30% had chlamydia, gonorrhea or trichomonas at enrollment. Retention was 89% at month 3. In the first 3 months, all but one sample had detectable TFV-DP; median TFV-DP at months 1, 2, and 3 were 622, 707, and 694 fmol/punch, respectively. We observed a somewhat higher proportion of AGYW with TFV-DP >700 fmol/punch at month 3 in the conditional incentive arm (45/81, 56%) than the standard arm (35/83, 42%), RR=1.32 (95% CI 0.96, 1.81, p=0.09), and in ITT analysis, 45/97 (46%) vs. 35/97 (36%), RR=1.29 (0.92, 1.81; p=0.15).
Conclusions: PrEP adherence was very good among high-risk African AGYW in Cape Town, with almost half having tenofovir levels that have been associated with protection among MSM at 3 months, demonstrating these AGYW were motivated and able to use PrEP. Incentives conditioned on high drug levels in the prior month had a modest but nonsignificant association with the likelihood of high adherence.

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