High levels of adherence to a rectal microbicide gel and to oral Pre-Exposure Prophylaxis

• Published in: PloS one 2017-07, Vol.12 (7), p.e0181607
• Main Authors: Carballo-Diéguez, Alex, Balán, Ivan C, Brown, William, Giguere, Rebecca, Dolezal, Curtis, Leu, Cheng-Shiun, Marzinke, Mark A, Hendrix, Craig W, Piper, Jeanna M, Richardson, Barbra A, Grossman, Cynthia, Johnson, Sherri, Gomez, Kailazarid, Horn, Stephanie, Kunjara Na Ayudhya, Ratiya Pamela, Patterson, Karen, Jacobson, Cindy, Bekker, Linda-Gail, Chariyalertsak, Suwat, Chitwarakorn, Anupong, Gonzales, Pedro, Holtz, Timothy H, Liu, Albert, Mayer, Kenneth H, Zorrilla, Carmen, Lama, Javier, McGowan, Ian, Cranston, Ross D
• Format: Article
• Language: English
• Subjects: Analysis; Anti-infective agents; Dosage and administration; Health aspects; MSM (Men who have sex with men); Patient compliance; Transgender people
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0181607

Trials to assess microbicide safety require strict adherence to prescribed regimens. If adherence is suboptimal, safety cannot be adequately assessed. MTN-017 was a phase 2, randomized sequence, open-label, expanded safety and acceptability crossover study comparing 1) daily oral emtricitabine/tenofovir disoproxil fumarate (FTC/TDF), 2) daily use of reduced-glycerin 1% tenofovir (RG-TFV) gel applied rectally, and 3) RG-TFV gel applied before and after receptive anal intercourse (RAI)-if participants had no RAI in a week, they were asked to use two doses of gel within 24 hours. Product use was assessed by mixed methods including unused product return count, text messaging reports, and qualitative plasma TFV pharmacokinetic (PK) results. Convergence interviews engaged participants in determining the most accurate number of doses used based on product count and text messaging reports. Client-centered adherence counseling was also used. Participants (N = 187) were men who have sex with men and transgender women enrolled in the United States (42%), Thailand (29%), Peru (19%) and South Africa (10%). Mean age was 31.4 years (range 18-64 years). Based on convergence interviews, over an 8-week period, 94% of participants had [greater than or equal to]80% adherence to daily tablet, 41% having perfect adherence; 83% had [greater than or equal to]80% adherence to daily gel, 29% having perfect adherence; and 93% had [greater than or equal to]80% adherence to twice-weekly use during the RAI-associated gel regimen, 75% having perfect adherence and 77% having [greater than or equal to]80% adherence to gel use before and after RAI. Only 4.4% of all daily product PK results were undetectable and unexpected (TFV concentrations