Structured treatment interruptions in antiretroviral management of HIV-1

The consequences of treatment interruptions have been investigated in various patient populations. For patients with controlled viraemia, treatment interruption allowing viral rebound may boost HIV-1-specific immunity. The hypothesis that this will be sufficient to control HIV replication in the absence of treatment has received support in studies of patients initiating treatment during primary infections. In patients with chronic infection, treatment interruption has been shown to boost HIV-1-specific immunity in some cases. In patients with virological failure, despite drug-resistant virus, treatment appears to provide benefit, in that interruption results in a decrease in the CD4 cell count and increases in plasma HIV-1-RNA levels. The removal of drug pressure allows the rapid shift to wild-type virus. Whether this will be of benefit to the patient is not clear. Treatment interruption may help reduce the accumulation of long-term toxicities.     

Structured treatment interruptions to control HIV-1 infection

Structured treatment interruptions progressively lowered the rate of viral rebound in some HIV-1 infected patients. This approach should be explored as an alternative to continuous antiretroviral therapies.     

Long-term immunological response in HIV-1-infected subjects receiving potent antiretroviral therapy

OBJECTIVE: To determine the long-term T-lymphocyte response to highly active antiretroviral therapy (HAART) and to define predictors of the immunological response. DESIGN: Cohort study, including 135 HIV-1-infected subjects at a city general practice who commenced HAART between 1996 and 1998. METHODS: Collection of plasma HIV-1 RNA, CD4+ and CD8+ T-lymphocyte data at 3-6 monthly time intervals over 2 years. RESULTS: Seventy-three subjects (54%) achieved suppression of plasma HIV-1 RNA to levels below 400 copies/ml during the observation period, 31 individuals (23%) had detectable plasma HIV-1 RNA below 10,000 copies/ml and 31 subjects (23%) had virological failures with viral loads above 10,000 copies/mL. Median CD4+ T lymphocytes increased from 246 to 463 x 10(6) cells/l, showing a median rise of 20 x 10(6) cells/l per month in the first 3 months and 7 x 10(6) cells/l per month thereafter. The proportion of individuals who reached CD4+ cell counts above 500 x 10(6) cells/l increased from 8% at baseline to 54% at 2 years. Treatment-na?ve individuals, subjects with a large reduction of HIV-1 RNA or a large early CD8+ increase had better early CD4+ responses. Long-term CD4+ T-cell increases were inversely correlated with mean plasma HIV-1 RNA levels. Baseline CD4+ T-cell count was the most important determinant of reaching CD4+ cell counts above 500 x 10(6) cells/l. Nineteen per cent of subjects had no further CD4+ T-cell increases in the second year of therapy despite undetectable viral load. CONCLUSIONS: Immune reconstitution is a slow process, showing a large individual variability. The virological response to HAART was the most important determinant of the immunological short- and long-term response.     

Influence of prior structured treatment interruptions on the length of time without antiretroviral treatment in chronically HIV-infected subjects

The influence of previous structured treatment interruptions (STIs) on the length of time off therapy when highly active antiretroviral treatment (HAART) is discontinued in chronically HIV-infected subjects was assessed. A comparative, retrospective clinical cohort study included patients with plasma viral load (VL) <50 copies/ml and CD4 cell count >500 cells/mm(3) who interrupted HAART. Fifteen patients interrupted HAART after six 2-weeks-off-/4-weeks-on therapy cycles (STI group) and 30 subjects discontinued HAART without previous STIs (NSTI group). The criteria for treatment resumption were development of AIDS-defining clinical events, VL >100,000 copies/ml or CD4 <350 cells/mm(3). Median (IQR) time off therapy was 48 (29-56) weeks in the STI group and 31 (8-77) weeks in the NSTI group (p < 0.15). After 48 weeks, 46% of the patients in the STI group and 40% in the NSTI group remained off HAART (p < 0.74). No patient developed AIDS-defining events and all but one achieved virological control after treatment resumption. The CD4 nadir was 341 (298-464) cells/mm(3) among patients who reinitiated HAART and 560 (364-682) cells/mm(3) in those who remained off therapy by week 48 (p <0.01). Likewise, CD4 count prior to treatment interruption was 902 (806-1040) cells/mm(3) and 1123 (924-1234) cells/mm(3) in subjects resuming and remaining off HAART, respectively (p = 0.03). No relationship between treatment resumption and pre-ART VL or with the time with undetectable VL before enrollment was found. CD4 nadir was a significant predictor for treatment reinitiation in a multivariate analysis. Previous STIs do not influence time off therapy when HAART is definitively discontinued in chronically HIV-infected subjects. CD4 nadir is an important factor in the treatment discontinuation decision.     

The impact on health-related quality of life of treatment interruptions in HIV-1-infected patients

To examine health-related quality of life (HRQOL) before, during and after treatment interruptions (TI) in antiretroviral therapy, we analysed results from Medical Outcomes Study HIV health surveys on 50 HIV-1-infected patients. HRQOL scores decreased during a TI but increased after re-initiating treatment, although scores remained lower than those preceding the TI. The reasons for a TI differentially affected HRQOL. The findings suggest that TI should be based on medical decisions and not used to increase HRQOL.     

Complications after caesarean section in HIV-1-infected women not taking antiretroviral treatment

HIV-1-infected women have a considerably increased risk of postoperative morbidity after caesarean sections. We showed that this risk was independent of current antiretroviral therapy.     

Structured treatment interruption in chronically HIV-1 infected patients after long-term viral suppression

OBJECTIVE: To investigate the virological and immunological impact of a structured treatment interruption (STI) in a cohort of HIV-1 chronically infected patients with a further long-lasting effective virus suppression. METHODS: Twelve HIV-1 chronically infected adults who had maintained viral suppression (< 20 copies/ml) for more than 2 years, as well as a CD4:CD8 ratio > 1 for a median time of 22 months, were included in the study. Participants interrupted their antiretroviral treatment during a maximum period of 30 days or until a viral load rebound > 3000 copies/ml was detected. The same prior antiretroviral regimen was resumed after STI. Kinetics of plasma viral rebound was evaluated every 2 days during the treatment interruption period. Flow cytometry and cell proliferation assays were performed before and after STI. Genotypic resistance was assessed at the time of treatment resumption. RESULTS: No adverse events occurred during the interruption period. In two patients no viral rebound was detected after 30 days of treatment interruption. In the remaining 10 patients, viral load became detectable (> 20 copies/ml) at a median time of 14 days after treatment interruption. Afterwards, viral load increased exponentially with a mean t1/2 of 1.6 days. Treatment was successfully resumed in all patients. No resistance-conferring mutations associated with the pre-interruption antiretroviral regimen were detected. The percentage of CD4 and CD8 lymphocytes did not vary during the STI period; however, the level of expression of T-cell activation antigen CD38 on CD8 T cells increased significantly in response to viral rebound. Four patients gained T-helper cell responses to recall antigens (tuberculin and tetanus toxoid), two of who developed an HIV-specific response to p24. CONCLUSIONS: STI in chronically HIV-1-infected patients is not associated with reductions in CD4 T lymphocytes or to clinical complications in this group of patients after 2 years of effective plasma viral suppression. Viral load rebounds in most but not all patients, without evidence of selection of resistance-conferring mutations. Thereafter, viraemia can be effectively controlled by antiretroviral agent reintroduction. HIV-specific T-helper cell responses may be achieved after one cycle of treatment interruption suggesting some degree of immune-stimulation. These data do not discard consecutive cycles of STI as a therapeutic strategy to boost HIV-specific immunity in order to maintain viral replication under effective control.     

The effect of atorvastatin treatment on HIV-1-infected patients interrupting antiretroviral therapy

We conducted a pilot study to assess the effect of atorvastatin on HIV replication. Patients with stable HAART-controlled infection interrupted therapy and were randomly assigned to a control group or to start atorvastatin 40 or 80 mg/day. Statin groups showed lower serum cholesterol but similar viral loads and CD4 T-cell counts to the control group at weeks 4 and 12. Paradoxically, baseline serum cholesterol, but not atorvastatin, influenced viral rebound at week 4.     

Etravirine-based highly active antiretroviral therapy in HIV-1-infected paediatric patients

Background

We evaluated the efficacy, safety and tolerability of etravirine in paediatric patients vertically infected with HIV‐1.

Methods

A multicentre retrospective study of 23 multidrug‐resistant paediatric patients (five children and 18 adolescents) enrolled in the study from 1 September 2007 to 28 February 2010 was carried out. We performed a longitudinal analysis of immunological, virological and clinical data.

Results

The median age of the patients was 14.2 years [interquartile range (IQR) 12.5–15.8 years]. At baseline, the median HIV‐1 RNA was 29 000 (4.5 log₁₀) HIV‐1 RNA copies/mL (range 4300‐83 000 copies/mL), the median CD4 T‐cell count was 445 cells/μL (range 221–655 cells/μL) and the median CD4 percentage was 19.6% (IQR 13.0‐31.0). Remarkably, 16 of 23 patients (70%) harboured one or more etravirine‐associated resistance mutations. The backbone regimen included at least two fully active drugs in 91% of patients. After etravirine‐based therapy, 20 patients (87%) achieved HIV‐1 RNA<400 copies/mL and 18 of 23 (78%) achieved HIV‐1 RNA<50 copies/mL: three (13%) within the first month, seven (30%) within the first 4 months, and six (26%) between the 5th and 8th months. CD4 T‐cell recovery was observed in 19 patients (83%). The median follow‐up time was 48.4 weeks (IQR 35.7–63.4 weeks); four patients (17%) were exposed to etravirine for >120 weeks. Three mild/short‐term and two moderate skin rashes were observed in the adolescents. Laboratory abnormalities included hypercholesterolaemia (11 of 23 patients), hypertriglyceridaemia (eight of 23 patients), and reduced high‐density lipoprotein cholesterol (10 of 23 patients). Adherence was complete in seven patients (30%). No patients showed complete resistance to etravirine after follow‐up. However, three of 21 patients (14%) who initially showed intermediate resistance interrupted etravirine treatment because of virological failure.

Conclusions

We observed a sustained antiviral response and improved immunological parameters in multidrug‐resistant paediatric patients, most of whom had received etravirine as part of salvage regimens with at least two fully active drugs.     

Hepatotoxicity in HIV-1-infected patients receiving nevirapine-containing antiretroviral therapy.

OBJECTIVES: To assess the incidence and risk factors for hepatotoxicity associated with nevirapine. DESIGN: A prospective cohort study in a teaching and referral hospital involving all consecutive patients who were prescribed a nevirapine-containing antiretroviral regimen between September 1997 and May 2000. METHOD: Cutaneous and hepatic adverse reactions and clinical hepatitis were assessed. Blood analysis including plasma HIV-1 RNA CD4 cell counts, liver chemistry tests, and serology for hepatitis B and C viruses. Hepatotoxicity was defined as an increase of at least threefold in serum alanine aminotransferase or aspartate aminotransferase levels compared with baseline values. RESULTS: Of a total of 610 patients, 82 (13.4%) were antiretroviral naive when commencing nevirapine, and 46.2 and 8.9% were coinfected with hepatitis C and B viruses, respectively. Median duration of exposure to nevirapine was 8.7 months (interquartile range 3.4--14.3). Hepatotoxicity developed in 76 (12.5%), an incidence of 13.1/100 person-years. Kaplan--Meier estimated incidence of hepatotoxicity at 3, 6 and 12 months was 3.7, 9.7 and 20.1%, respectively. In seven (1.1%) patients, hepatotoxicity was associated with clinical hepatitis, which was reversible upon discontinuation of therapy. Multivariate analysis identified the duration of prior exposure to antiretroviral drugs, hepatitis C virus, and higher baseline levels of alanine aminotransferase as independent risk factors for hepatotoxicity. CONCLUSIONS: Hepatotoxicity but not clinical hepatitis was common in HIV-1-infected patients receiving nevirapine-containing regimens and the incidence steadily increased over time. Prolonged exposure to any antiretroviral therapy, coinfection with hepatitis C virus and abnormal baseline levels of alanine aminotransferase identified patients at a higher risk.     

Low CD4+ T cell nadir is an independent predictor of lower HIV-specific immune responses in chronically HIV-1-infected subjects receiving highly active antiretroviral therapy

The influence of CD4(+) T cell nadirs on human immunodeficiency virus (HIV)-specific immune responses in subjects with apparently normal CD4(+) T cell counts is not known. We evaluated the frequency of HIV-1-specific immune responses in a cohort of patients with complete viral suppression (HIV-1 RNA load, <50 copies/mL) who were receiving highly active antiretroviral therapy and had a wide range of CD4(+) T cell nadirs. We found positive associations between CD4(+) T cell nadirs and the magnitude of HIV-specific CD8(+) T cell responses (P=.02) and of T cell helper responses (P=.04). These data show the CD4(+) T cell nadir to be an independent predictor of HIV-specific CD4(+) and CD8(+) T cell responses in HIV-1-infected subjects with optimal suppression of viremia.     

Risks and benefits of structured antiretroviral drug therapy interruptions in HIV-1 infection

BACKGROUND: Structured interruptions of antiretroviral therapy of HIV-1 infected individuals are currently being tested in clinical trials to study the effect interruptions have on the immune responses and control of virus replication. OBJECTIVE: To investigate the potential risks and benefits of interrupted therapy using standard population dynamical models of HIV replication kinetics. METHODS: Standard population dynamical models were used to study the effect of structured therapy interruptions on the immune effector cells, the latent cell compartment and the emergence of drug resistance. CONCLUSIONS: The models suggest that structured therapy interruption only leads to transient or sustained virus control if the immune effector cells increase during therapy. This increase must more than counterbalance the increase in susceptible target cells induced by therapy. The risk of inducing drug resistance by therapy interruptions or the risk of repopulating the pool of latent cells during drug-free periods may be small if the virus population remains at levels considerably below baseline. However, if the virus load increases during drug-free periods to levels similar to or higher than baseline before therapy, both these risks increase dramatically.     

Reactive arthritis responding to antiretroviral therapy in an HIV-1-infected individual

Reactive arthritis (ReA) is an autoimmune seronegative spondyloarthropathy that occurs in response to a urogenital or enteric infection. Several studies have reported a link between ReA and HIV infection. We report a case of an HIV-1-infected patient diagnosed with a disabling ReA who failed to respond to conventional therapy but whose symptoms resolved rapidly after starting antiretroviral therapy (ART). Clinicians may not be cognizant to this phenomenon and so this case report serves to remind clinicians that initiation of antiretroviral therapy should be considered in HIV-infected patients with ReA who are refractory to standard therapy.