Pharmacokinetics of maraviroc, raltegravir, darunavir, and etravirine in the semen of HIV-infected men

HIV-RNA decay in paired blood and semen samples of subjects receiving their first dolutegravir-based ART regimen

BACKGROUND AND OBJECTIVES

We aimed to investigate to what extent a first-line DTG-based ART regimen reduces HIV-RNA in semen compared to plasma.

STUDY DESIGN

In this prospective, observational study, ART-naïve, HIV-infected males starting their first ART regimen with DTG plus TDF/FTC or ABC/3TC were enrolled. Paired blood (BP) and seminal plasma (SP) samples were collected at baseline (T0) and at week-2/4/12/24 after ART initiation. Sexually transmitted infections (STI) were ruled out before enrolment.

RESULTS

Median baseline HIV-RNA levels were lower in SP compared to BP (657 versus 38.200 copies/ml, p < 0.001), three subjects had undetectable semen HIV-RNA. After 12 weeks of treatment, HIV-RNA was below the quantification limit in both BP and SP of 11 pts (61.1%). Discordant results were obtained in 6 subjects (33.3%), showing quantifiable HIV-RNA in blood only (2 cases) and in semen only (4 cases). Finally, one subject had a positive HIV-RNA in SP/BP. At W24, only in 2/16 subjects (12.5%) HIV-RNA was detectable in semen, while in the others it was negative on SP/BP. No concurrent STI was found in subjects with detectable VL in semen.

CONCLUSIONS

DTG demonstrated effectiveness in reducing VL with different kinetics in blood and semen, despite seminal viral suppression after 6 months of ART was not obtained in the totality of subjects.

Effect of Monotherapy with Darunavir/Ritonavir on Viral Load in Seminal Fluid, and Quality Parameters of Semen in HIV-1-Positive Patients

Patients with human immunodeficiency virus type 1 (HIV-1) who receive antiretroviral therapy (ART) often achieve increased survival and improved quality of life. In this respect, monotherapy with darunavir/ritonavir (mDRV/r) can be a useful treatment strategy. This prospective study analyses the effect of mDRV/r on sperm quality and viral load in a group of 28 patients who had previously been given conventional ART and who had recorded a viral load <20 copies/mL for at least six months. These patients were given mDRV/r at a dose of 800/100 mg for 48 weeks. At baseline (V0), CD4, CD8, FSH, LH and testosterone levels were measured, together with HIV-1 viral load in plasma and semen. In addition, seminal fluid quality was studied before mDRV/r treatment was prescribed. At week 48 (V1), HIV-1 viral load in plasma and semen and the quality of the seminal fluid were again measured. The results obtained indicate that at V0, 10% of the patients with ART had a positive viral load in seminal fluid (>20 copies/ml), and that at V1, after mDRV/r treatment, this figure had fallen to 3%. The quality of seminal fluid was close to normal in 57% of patients at V0 and in 62% at V1. We conclude that, similar to ART, mDRV/r maintains HIV-1 viral load in most patients, and that there is no worsening in seminal fluid quality.

A long-acting formulation of the integrase inhibitor raltegravir protects humanized BLT mice from repeated high-dose vaginal HIV challenges

OBJECTIVES

Pre-exposure prophylaxis (PrEP) using antiretroviral drugs (ARVs) has been shown to reduce HIV transmission in people at high risk of HIV infection. Adherence to PrEP strongly correlates with the level of HIV protection. Long-acting injectable ARVs provide sustained systemic drug exposures over many weeks and can improve adherence due to infrequent parenteral administration. Here, we evaluated a new long-acting formulation of raltegravir for prevention of vaginal HIV transmission.

METHODS

Long-acting raltegravir was administered subcutaneously to BALB/c, NSG (NOD-scid-gamma) and humanized BLT (bone marrow-liver-thymus) mice and rhesus macaques. Raltegravir concentration in peripheral blood and tissue was analysed. Suppression of HIV replication was assessed in infected BLT mice. Two high-dose HIV vaginal challenges were used to evaluate protection from HIV transmission in BLT mice.

RESULTS

Two weeks after a single subcutaneous injection of long-acting raltegravir in BLT mice (7.5 mg) and rhesus macaques (160 mg), the plasma concentration of raltegravir was comparable to 400 mg orally, twice daily in humans. Serum collected from mice 3 weeks post-administration of long-acting raltegravir efficiently blocked HIV infection of TZM-bl indicator cells in vitro. Administration of long-acting raltegravir suppressed viral RNA in plasma and cervico-vaginal fluids of infected BLT mice, demonstrating penetration of active raltegravir into the female reproductive tract. Using transmitted/founder HIV we observed that BLT mice administered a single subcutaneous dose of long-acting raltegravir were protected from two high-dose HIV vaginal challenges 1 week and 4 weeks after drug administration.

CONCLUSIONS

These preclinical results demonstrated the efficacy of long-acting raltegravir in preventing vaginal HIV transmission.

Understanding HIV compartments and reservoirs

The spectrum of HIV-1 cellular reservoirs is highly diversified, and their role varies according to the milieu of the anatomical sites in which the virus replicates. In this light, mechanisms underlying HIV-1 persistence in anatomical compartments may be profoundly different from what is observed in peripheral blood. This scenario is further complicated by sub-optimal drug penetration in tissues allowing persistent and cryptic HIV-1 replication in body districts despite undetectable viremia. On this basis, this review aims at providing recent insights regarding the critical role of HIV-1 cellular reservoirs in different anatomical compartments, and their relationship with the pathogenesis of HIV-1 infection. A comprehensive definition of the complex interplay between the virus and its reservoir is critical in order to set up prophylactic and therapeutic strategies aimed at achieving the maximal virological suppression and hopefully in the near future the cure of HIV-1 infection (either functional or biological).

Pharmacokinetics of antiretrovirals in genital secretions and anatomic sites of HIV transmission: implications for HIV prevention

The incidence of HIV remains alarmingly high in many parts of the world. Prophylactic use of antiretrovirals, capable of concentrating in the anatomical sites of transmission, may reduce the risk of infection after an unprotected sexual exposure. To date, orally and topically administered antiretrovirals have exhibited variable success in preventing HIV transmission in large-scale clinical trials. Antiretroviral mucosal pharmacokinetics may help explain the outcomes of these investigations. Penetration and accumulation of antiretrovirals into sites of transmission can influence dosing strategies and pre-exposure prophylaxis clinical trial design. Antiretroviral tissue distribution varies widely within and between drug classes, attributed in part to their physicochemical properties and tissue-specific drug transporter expression. Nucleoside(-tide) reverse transcriptase inhibitors, the CCR5 antagonist maraviroc, and the integrase inhibitor raltegravir demonstrate the highest penetration into the male and female reproductive tracts and colorectal tissue relative to blood. This review describes antiretroviral exposure in anatomic sites of transmission, and places these findings in context with the prevention of HIV and the efficacy of pre-exposure prophylactic strategies.

Clinical pharmacokinetic, pharmacodynamic and drug-interaction profile of the integrase inhibitor dolutegravir

Dolutegravir is a second-generation integrase strand transfer inhibitor (INSTI) currently under review by the US Food and Drug Administration for marketing approval. The in vitro, protein-adjusted 90 % inhibitory concentration (IC90) of dolutegravir for wild-type virus is 0.064 μg/ml, and it retains in vitro anti-HIV 1 activity across a broad range of viral phenotypes that are known to confer resistance to the currently marketed INSTIs, raltegravir and elvitegravir. Dolutegravir has a terminal elimination half-life of 13-14 h and maintains concentrations over the in vitro, protein-adjusted IC90 for more than 30 h following a single dose. Additionally, dolutegravir has low inter-subject variability compared with raltegravir and elvitegravir. A plasma exposure-response relationship has been well described, with antiviral activity strongly correlating with trough concentrations. Phase III trials have assessed the antiviral activity of dolutegravir compared with efavirenz and raltegravir in antiretroviral (ARV)-naive patients and found that dolutegravir achieved more rapid and sustained virologic suppression in both instances. Additionally, studies of dolutegravir activity in patients with known INSTI-resistant mutations have been favourable, indicating that dolutegravir retains activity in a variety of INSTI-resistant phenotypes. Much like currently marketed INSTIs, dolutegravir is very well tolerated. Because dolutegravir inhibits the renal transporter organic cation transporter 2, reduced tubular secretion of creatinine leads to non-progressive increases in serum creatinine. These serum creatinine increases have not been associated with a decreased glomerular filtration rate or progressive renal impairment. Dolutegravir's major and minor metabolic pathways are uridine diphosphate glucuronosyltransferase 1A1 and cytochrome P450 (CYP)-3A4, respectively, and it neither induces nor inhibits CYP isoenzymes. Thus dolutegravir has a modest drug interaction profile. However, antacids significantly decrease dolutegravir plasma exposure and should be separated by 2 h before, or 6 h after, a dolutegravir dose. In summary, dolutegravir is the first of the second-generation INSTIs and exhibits a predictable pharmacokinetic profile and a well-defined exposure-response relationship. Dolutegravir retains activity despite the presence of some class-resistant mutations and achieves rapid and sustained virologic suppression in ARV-naive and ARV-experienced patients. Clinically, dolutegravir is poised to become a commonly used component of antiretroviral regimens.