CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

Results: Of 191 women enrolled in the DOT phase, 179 were randomized to the self-administered phase. Median age was 26 years (range 18-52), 80%were unmarried and 83% unemployed. PrEP coverage differed by arm as shown in the table (P<0.001). Fewer pills were required in T and E compared with D (p < 0.001). Side effects were uncommon in D, and less frequent in T and E. Adherence to the assigned regimen was greater in D compared with T and E (P<0.001); adherence to post-intercourse dosing in the nondaily arms was low. When sex was reported in the prior week, both plasma TFV (consistent with >1 pill in prior week) and PBMC TFV diphosphate (consistent with >2 pills in prior week) were detected in more women in D at weeks 10 and 30, compared with T and E (p < 0.05). HIV seroconversions were not significantly different by arm.

Conclusions: The majority of women took oral PrEP when made available in an open label study. Daily dosing resulted in better coverage of sex acts and adherence, and higher drug levels. Daily dosing may foster better habit formation and provide the most forgiveness for missed doses at observed adherence levels. These findings support current recommendations for daily use of oral FTC/TDF PrEP in women. 979 Correlates of Early Adherence in VOICE PrEP Trial Differ Between Oral and Vaginal Products Ariane van der Straten 1 ; Elizabeth R. Brown 2 ; James Dai 2 ; Craig Hendrix 3 ; Karen Liu 2 ; Cynthia Grossman 4 ; Z M. Chirenje 5 ; Jeanne Marrazzo 6 1 RTI, San Francisco, CA, US; 2 Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA, US; 3 Johns Hopkins University School of Medicine, Baltimore, MD, US; 4 National Institute of Mental Health (NIMH), Bethesda, MD, US; 5 University of Zimbabwe–University of California San Francisco Research Collaboration, Harare, Zimbabwe; 6 University of Washington, Seattle, WA, US Background: VOICE was a phase IIB trial of daily oral tenofovir disoproxil fumarate (TDF), oral TDF-emtricitabine (FTC), and 1% vaginal tenofovir (TFV) gel for HIV chemoprevention, in Uganda, Zimbabwe and South Africa (RSA). Plasma TFV levels objectively measure product use and correlate with efficacy. We measured plasma TFV levels ( ≥ 0.3 ng/mL) in a subset of VOICE participants on active products at their first quarterly visit, and assessed factors associated with early product use. Methods: Of 5029 enrollees, we analyzed available TFV levels in plasma samples taken at 3 months post-randomization fromwomen assigned to active product and not on product hold. We examined a pre-determined set of demographic, socio-behavioral and clinical factors assessed at baseline or 3 months and their association (at p<0.05 significance level) with TFV detection in the oral and gel groups. All analyses were weighted to adjust for the sampling design. Weighted generalized linear models with a log-link and robust standard errors were fitted to estimate prevalence ratio (PR) of detectable TFV in plasma, adjusting for country. Results: Of 1146 participants assessed at 3-month follow-up, 33% had TFV detectable in the oral group (N=637) and 27% in the gel group (N=509), respectively. TFV detection by group and country is summarized in the table below. Controlling for country, factors associated with TFV detection in the oral group were: receiving material support from partner (PR=0.64; p=0.02) and frequent alcohol use (PR=1.93; p<0.01). In the gel group, factors associated with TFV detection were: age ≥ 25 (PR=1.6; p=0.03), partner disapproval of product use (PR=0.34, p=0.02) and social harm (PR=0.23 p=0.04). In both groups, moderate perceived HIV risk was associated with detecting TFV.

Poster Abstracts

Conclusions: In these VOICE participants, use of oral tablets and gel at initial PK assessment varied by country. Further, different factors correlated with product use in the oral and gel groups, suggesting geographical, demographic and relationship difference in end-users characteristics for different routes of administration. This study adds to the growing body of evidence that choice of biomedical prevention options will be critical to address the varying prevention needs of women at risk of HIV.

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CROI 2015