No Virological Failure in Semen During Properly Suppressive Antiretroviral Therapy Despite Subtherapeutic Local Drug Concentrations

High discordance in blood and genital tract HIV-1 drug resistance in Indian women failing first-line therapy

Objectives

Examine HIV-1 plasma viral load (PVL) and genital tract (GT) viral load (GVL) and drug resistance in India.

Methods

At the YRG Centre for AIDS Research and Education, Chennai, we tested: PVL in women on first-line ART for ≥6 months; GVL when PVL >2000 copies/mL; and plasma, genital and proviral reverse transcriptase drug resistance when GVL >2000 copies/mL. Wilcoxon rank-sum and Fisher's exact tests were used to identify failure and resistance associations. Pearson correlations were calculated to evaluate PVL-GVL associations. Inter-compartmental resistance discordance was evaluated using generalized estimating equations.

Results

Of 200 women, 37% had detectable (>400 copies/mL) PVL and 31% had PVL >1000 copies/mL. Of women with detectable PVL, 74% had PVL >2000 copies/mL, of which 74% had detectable GVL. Higher PVL was associated with higher GVL. Paired plasma and genital sequences were available for 21 women; mean age of 34 years, median ART duration of 33 months, median CD4 count of 217 cells/mm3, median PVL of 5.4 log10 copies/mL and median GVL of 4.6 log10 copies/mL. Drug resistance was detected in 81%-91% of samples and 67%-76% of samples had dual-class resistance. Complete three-compartment concordance was seen in only 10% of women. GT-proviral discordance was significantly larger than plasma-proviral discordance. GT or proviral mutations discordant from plasma led to clinically relevant resistance in 24% and 30%, respectively.

Conclusions

We identified high resistance and high inter-compartmental resistance discordance in Indian women, which might lead to unrecognized resistance transmission and re-emergence compromising treatment outcomes, particularly relevant to countries like India, where sexual HIV transmission is predominant.

Antiretroviral bioanalysis methods of tissues and body biofluids

Research in the many areas of HIV treatment, eradication and prevention has necessitated measurement of antiretroviral (ARV) concentrations in nontraditional specimen types. To determine the knowledgebase of critical details for accurate bioanalysis, a review of the literature was performed and summarized. Bioanalytical assays for 31 ARVs, including metabolites, were identified in 205 publications measuring various tissues and biofluids. 18 and 30% of tissue or biofluid methods, respectively, analyzed more than one specimen type; 35-37% of the tissue or biofluid methods quantitated more than one ARV. 20 and 76% of tissue or biofluid methods, respectively, were used for the analysis of human specimens. HPLC methods with UV detection predominated, but chronologically MS detection began to surpass. 40% of the assays provided complete intra- and inter-assay validation data, but only 9% of publications provided any stability data with even less for the prevalent ARV in treatments.

HIV-1 RNA may decline more slowly in semen than in blood following initiation of efavirenz-based antiretroviral therapy

Objectives

Antiretroviral therapy (ART) decreases HIV-1 RNA levels in semen and reduces sexual transmission from HIV-1-infected men. Our objective was to study the time course and magnitude of seminal HIV-1 RNA decay after initiation of efavirenz-based ART among 13 antiretroviral-naïve Kenyan men.

Methods

HIV-1 RNA was quantified (lower limit of detection, 120 copies/mL) in blood and semen at baseline and over the first month of ART. Median log₁₀ HIV-1 RNA was compared at each time-point using Wilcoxon Signed Rank tests. Perelson’s two-phase viral decay model and nonlinear random effects were used to compare decay rates in blood and semen.

Results

Median baseline HIV-1 RNA was 4.40 log₁₀ copies/mL in blood (range, 3.20–5.08 log₁₀ copies/mL) and 3.69 log₁₀ copies/mL in semen (range, <2.08–4.90 log₁₀ copies/mL). The median reduction in HIV-1 RNA by day 28 was 1.90 log₁₀ copies/mL in blood (range, 0.56–2.68 log₁₀ copies/mL) and 1.36 log₁₀ copies/mL in semen (range, 0–2.66 log₁₀ copies/mL). ART led to a decrease from baseline by day 7 in blood and day 14 in semen (p = 0.005 and p = 0.006, respectively). The initial modeled decay rate was slower in semen than in blood (p = 0.06). There was no difference in second-phase decay rates between blood and semen.

Conclusions

Efavirenz-based ART reduced HIV-1 RNA levels more slowly in semen than in blood. Although this difference was of borderline significance in this small study, our observations suggest that there is suboptimal suppression of seminal HIV-1 RNA for some men in the early weeks of treatment.

Pharmacokinetics of antiretroviral drugs in anatomical sanctuary sites: the male and female genital tract

HIV resides within anatomical 'sanctuary sites', where local drug exposure and viral dynamics may differ significantly from the systemic compartment. Suboptimal antiretroviral concentrations in the genital tract may result in compartmentalized viral replication, selection of resistant mutations and possible re-entry of wild-type/resistant virus into the systemic circulation. Therefore, achieving adequate antiretroviral exposure in the genital tract has implications for the prevention of sexual and vertical transmission of HIV. Penetration of antiretrovirals in the genital tract is expressed by accumulation ratios derived from the measurement of drug concentrations in time-matched seminal plasma/cervicovaginal fluid and plasma samples. Penetration varies by gender and may be drug (as opposed to class) specific with high interindividual variability. Concentrations in seminal plasma are highest for nucleoside analogues and lowest for protease inhibitors and efavirenz. Seminal accumulation of newer agents, raltegravir and maraviroc, is moderate (rank order of accumulation is nucleoside/nucleotide reverse transcriptase inhibitors [lamivudine/zidovudine/tenofovir/didanosine > stavudine/abacavir] > raltegravir > indinavir/maraviroc/nevirapine >> efavirenz/protease inhibitors [amprenavir/atazanavir/darunavir > lopinavir/ritonavir > saquinavir] > enfuvirtide). In the female genital tract, the nucleoside analogues exhibit high accumulation ratios, whereas protease inhibitors have limited penetration; however, substantial variability exists between individuals and study centres. Second generation non-nucleoside reverse transcriptase inhibitor etravirine, and maraviroc and raltegravir, demonstrate effective accumulation in cervicovaginal secretions (rank order of accumulation is nucleoside/nucleotide reverse transcriptase inhibitor [zidovudine/lamivudine/didanosine > emtricitabine/tenofovir] > indinavir > maraviroc/raltegravir/darunavir/etravirine > nevirapine/abacavir > protease inhibitors [amprenavir/atazanavir/ritonavir] > lopinavir/stavudine/efavirenz > saquinavir).

HIV Protease Inhibitors: Effect on the Opportunistic Protozoan Parasites

The impact of highly active antiretroviral therapy (HAART) in the natural history of AIDS disease has been allowed to prolong the survival of people with HIV infection, particularly whose with increased HIV viral load. Additionally, the antiretroviral therapy could exert a certain degree of protection against parasitic diseases. A number of studies have been evidenced a decrease in the incidence of opportunistic parasitic infections in the era of HAART. Although these changes have been attributed to the restoration of cell-mediated immunity, induced by either non-nucleoside reverse transcriptase inhibitors or HIV protease inhibitors, in combination with at least two nucleoside reverse transcriptase inhibitors included in HAART, there are evidence that the control of these parasitic infections in HIV-positive persons under HAART, is also induced by the inhibition of the proteases of the parasites. This review focuses on the principal available data related with therapeutic HIV-protease inhibitors and their in vitro and in vivo effects on the opportunistic protozoan parasites.

Antiretroviral drug concentrations in the male and female genital tract: implications for the sexual transmission of HIV

PURPOSE OF REVIEW

To summarize the recent literature (2008-2010) on antiretroviral (ARV) drug disposition into the male and female genital tract.

RECENT FINDINGS

Recent studies have confirmed that penetration of antiretroviral agents into the male and female genital tracts are both drug and sex specific. Concentrations achieved vary considerably depending on the class of drug studied, the sampling techniques used and the times samples are obtained.

SUMMARY

There appear to be several patterns of drug penetration into the male and female genital tract. In addition there appear to be different patterns of genital shedding under the influence of antiretroviral therapy. What effect these factors will have on the sexual transmission of HIV or the evolution and transmission of resistant HIV remains to be seen.

Current and Novel Inhibitors of HIV Protease

The design, development and clinical success of HIV protease inhibitors represent one of the most remarkable achievements of molecular medicine. This review describes all nine currently available FDA-approved protease inhibitors, discusses their pharmacokinetic properties, off-target activities, side-effects, and resistance profiles. The compounds in the various stages of clinical development are also introduced, as well as alternative approaches, aiming at other functional domains of HIV PR. The potential of these novel compounds to open new way to the rational drug design of human viruses is critically assessed.

HIV protease inhibitors: recent clinical trials and recommendations on use

BACKGROUND

HIV protease inhibitors (PIs) are potent antiretroviral drugs that represent a pivotal component of highly active antiretroviral therapy (HAART). PIs have evolved over the years to gain in potency, convenience, tolerability and genetic barrier to resistance.

OBJECTIVE

Updated summary of evidence-based information about the efficacy and safety of PIs on initial, simplification and rescue interventions in HIV patients.

METHODS

Review of available data reported in peer-reviewed journals, medical conferences and treatment guidelines.

RESULTS

Due to their characteristics, PIs are, and will remain, a cornerstone component in most lines of antiretroviral therapy. The antiviral activity, tolerability and convenience of PIs have improved significantly in recent years. Differences between compounds within this class may favour their use in specific situations, such as the friendly metabolic profile of atazanavir in patients with cardiovascular disease or the high genetic barrier of darunavir or tipranavir in heavily pretreated individuals with HIV.

Determining seminal plasma human immunodeficiency virus type 1 load in the context of efficient highly active antiretroviral therapy

The semen plasma virus load is measured to ensure the safety of sperm processing during medically assisted procreation (MAP) for couples with a human immunodeficiency virus type 1 (HIV-1)-infected man. A practical, automated protocol using the COBAS Ampliprep CAP/CTM kit in the COBAS TaqMan96 system was developed to measure the HIV-1 load in semen plasma samples. HIV-1 was detected in 13.4% of the semen samples processed at our MAP center. Of the eight patients having a detectable semen HIV-1 load, five had no detectable virus in their blood plasma. This highlights the residual risk of HIV-1 transmission during unprotected intercourse and raises the question of the possible consequences of ineffective highly active antiretroviral therapy in the genital tract.

Potential impact of early antiretroviral therapy on transmission

PURPOSE OF REVIEW

In this review, we will discuss the potential of early highly active antiretroviral therapy (HAART) to reduce the sexual transmission of HIV on an individual and population level. We will focus on the biological plausibility and behavioural factors associated with HAART use and interventions that might influence such a strategy.

RECENT FINDINGS

Empiric and phylogenetic studies support the view that recent HIV infection is a highly infectious disease stage. Evidence increasingly demonstrates that individuals on fully suppressive HAART are significantly less likely to transmit HIV to sexual partners and some even suggest that such individuals cannot transmit HIV. Changes in risk behaviour are associated with the availability of HAART but behavioural studies offer contradictory observations regarding the direction and magnitude of these changes. This in turn makes the intricate assumptions and therefore outcomes of many complex mathematical modelling studies less secure. Furthermore, there is evidence that it is those individuals with undiagnosed HIV infection who contribute significantly to onward sexual transmission.

SUMMARY

At an individual level, HAART will reduce viral load and, therefore, infectiousness, although whether to zero or not remains controversial. At a population level, if recent infection and undiagnosed infections continue to drive onward transmission, earlier treatment will only alter the pandemic if accompanied by an improvement in diagnosing the undiagnosed and recognizing recent infection.

Discordance in HIV-1 viral loads and antiretroviral drug concentrations comparing semen and blood plasma

OBJECTIVES

For individuals not on antiretroviral therapy, the risk of heterosexual transmission of HIV appears negligible when blood plasma (BP) viral loads are <1500 HIV-1 RNA copies/mL. It is not clear whether this observation can be extrapolated to individuals on highly active antiretroviral therapy (HAART). Because of differential tissue penetration, antiretroviral drug concentrations may be sufficient to maintain an undetectable viral load in the BP yet not achieve adequate levels to suppress HIV in the genital tract. Therefore, we wanted to correlate HIV viral loads and drug concentrations in semen plasma (SP) and BP.

METHODS

Thirty-three men were included. All were on combination antiretroviral therapy with an undetectable BP viral load for at least 1 year. Blood and semen samples were collected within 2 h of each other and tested for HIV RNA by the NucliSens QT (bioMerieux, St Laurent, QC, Canada) method; drug concentrations were determined by liquid chromatography tandem mass spectrometry.

RESULTS

Two of the 33 patients (6.1%) with BP viral loads below detection had time-matched HIV viral loads in SP > or =700 copies/mL. Both patients were on efavirenz, the SP concentrations of which were < or =10% of the levels in BP and well below the minimal therapeutic drug monitoring target concentration required to suppress HIV.

CONCLUSIONS

Because, at least in part, of poor drug penetration into the genital tract, an undetectable HIV viral load in the BP does not guarantee an undetectable viral load in semen. In view of this, caution should be taken in concluding that patients on HAART with suppressed viraemia are sexually non-infectious.

Antiretroviral drug concentrations and HIV RNA in the genital tract of HIV-infected women receiving long-term highly active antiretroviral therapy

OBJECTIVE

Our objective was to determine antiretroviral drug concentrations and human immunodeficiency virus (HIV) RNA rebound in cervicovaginal fluid (CVF) in relation to blood plasma (BP) in women receiving suppressive highly active antiretroviral therapy (HAART).

METHODS

Thirty-four HIV-infected women who had plasma HIV RNA levels < or =80 copies/mL for at least 6 months were enrolled. Sixty-eight paired CVF and BP drug concentrations and HIV RNA levels were determined before and 3-4 h after drug administration. For each woman and antiretroviral drug, the CVF:BP drug concentration ratios before and after drug administration were calculated. The nonparametric Wilcoxon rank sum test was used to determine if these ratios were different from 1.0.

RESULTS

Lamivudine (administered to 20 patients) and tenofovir (administered to 16) had significantly higher concentrations in CVF than in BP before drug administration, with mean CVF:BP concentration ratios of 3.19 (95% confidence interval, 1.2-8.5) and 5.2 (95% confidence interval, 1.2-22.6), respectively. Efavirenz (administered to 13 patients) and lopinavir (administered to 6) had significantly lower concentrations in CVF, with mean CVF:BP concentration ratios of 0.01 (95% confidence interval, 0.00-0.03) and 0.03 (0.01-0.11), respectively. During the study visit (median time after enrollment, 6 months), BP and CVF detectable HIV RNA levels were observed 7 patients (20.6%) and 1 patient (2.9%), respectively.

CONCLUSION

Despite lower CVF concentrations of key HAART components, such as efavirenz and lopinavir, virologic rebound was rare. The high concentrations of tenofovir and lamivudine in CVF may have implications for the prevention of sexual transmission during HAART and for pre-exposure or postexposure prophylaxis.