Background: Following the favorable results of the double-blinded phase (DBP) of the ANRS Ipergay trial, an open-label extension study (OLE) was implemented where all participants received TDF/FTC for on demand PrEP. We wished to assess whether PrEP and condom trajectory uses changed in the OLE.
Methods: Follow-up in OLE was performed every two months and included online questionnaires collecting sexual behaviour and PrEP adherence during the last anal intercourse. A longitudinal multi-trajectory model was implemented for two outcomes: PrEP use (correct/sub-optimal versus no PrEP), and condom use for anal sex (yes/no) and we compared DBP to OLE.
Results: 333 participants who participated to both study phases were analyzed. Four trajectories of PrEP use and three trajectories of condom use were identified in the DBP (Figure). During OLE, there was no change in PrEP trajectories. However, there was a decrease of condom use in the “high-level users of condom (C-HLU)” trajectory that most participants compensated by using PrEP: among participants in this trajectory 62% used PrEP systematically (PrEP-SU) and 33% used PrEP progressively (24% and 9% respectively for PrEP-HLU and PrEP-LLU). For the two remaining condom use trajectories (C-MLU and C-LLU) there was no change during the OLE, and most of participants continued using PrEP: 54% used PrEP systematically, and 35% used PrEP progressively.
Conclusions: In the OLE of the ANRS-IPERGAY trial, the reported decrease in condom use was compensated by high PrEP use. However, special attention must be paid to the remaining subgroup of MSM with declining use of condom that did not compensate by using PrEP.

Trajectories of PrEP and Condom use
[Trajectories of PrEP and Condom use]

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