Background: Intermittent HIV-1 RNA detection in seminal plasma may occur in patients with undetectable plasma viral load (pVL) on standard triple-drug therapy. Few data are available regarding HIV-1 RNA detection in seminal plasma samples from virologically-suppressed patients receiving a maintenance dual therapy, and DTG+3TC in particular.
Methods: In this ANRS167 LAMIDOL sub-study, a non-comparative open-label, single arm, multicenter trial, semen samples were collected at D0 and W24 of DTG+3TC. HIV-1 RNA was quantified in seminal plasma using COBASĀ® TaqManĀ® HIV-1 Test, v2.0 (limit of quantification [LOQ]=100 c/mL). Ultra-sensitive pVL (USpVL) was performed with centrifugation of the maximum volume of available plasma to reach a LOQ of 3 c/mL. The limit of detection (LOD) was defined as an undetected PCR signal. Plasma and seminal plasma drug concentrations (Cmin) were measured using UPLC-MS/MS.
Results: Among the 104 enrolled patients, seminal plasma samples were collected from 18 participants, including 16 paired samples at D0 and W24 of DTG+3TC. Median (IQR 25-75%) total DTG blood plasma Cmin and DTG seminal plasma Cmin were 1880 ng/mL (1377-2337; n=29) and 198 ng/mL (94-239; n=34), respectively. While the unbound/total DTG blood plasma Cmin ratio was 0.21% (0.17-0.25%; n=29), the seminal plasma/blood plasma total DTG Cmin ratio was 12% (8-15%; n=29), suggesting a DTG accumulation in the male genital tract. HIV-1 RNA was detected in seminal plasma of 3 patients: 1 at D0 (5.9%, 95%CI: 0.1-28.6) and 2 other at W24 (11.8%, 95%CI: 1.5-36.4). All, except one, presented a DTG Cmin in seminal plasma above the in vitro protein-binding adjusted IC90 values (64 ng/mL). All these 3 patients had a concomitant undetectable USpVL, they did not experienced virological failure or plasma viral blip along the study and had no concomitant sexually transmitted infection.
Conclusions: No differences were observed regarding seminal plasma HIV-1 RNA detection in patients under triple therapy and at W24 of a maintenance DTG+3TC dual-drug therapy.

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