Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Are Specific Antiretrovirals associated with an Increased Risk of Discontinuation due to Toxicities or Patient/Physician Choice in patients with Hepatitis C Virus Coinfection?

Background

Liver damage associated with hepatitis C (HCV) may influence the likelihood of experiencing discontinuation due to toxicities or patient/physician choice (TOXPC) in patients taking combination antiretroviral therapy (cART). Little information to address this concern is available from clinical trials as patients with HCV are often excluded.

Aims

To compare incidence rates of discontinuation due to TOXPC associated with specific antiretrovial drugs in patients with or without HCV.

Patients/methods

A total of 4929 patients from EuroSIDA under follow-up from January 1999 on a specific nucleoside pair (zidovudine/lamivudine, didanosine/stavudine, stavudine/lamivudine, or other) with a third drug (abacavir, nelfinavir, indinavir, nevirapine, efavirenz, lopinavir/ ritonavir or other boosted-protease inhibitor (PI)-containing regimen) and with known HCV serostatus were studied for the incidence of discontinuation of any nucleoside pair or third drug due to TOXPC. Incidence rate ratios were derived from Poisson regression models.

Results

In total 1358 patients had HCV (27.5%). During 12 799 person-years of follow-up there were 2141 discontinuations due to TOXPC for nucleoside pairs and 2501 for third drugs. The incidence of discontinuation due to TOXPC was consistently higher in patients with HCV after stratification by nucleoside pair or third drug. After adjustment for CD4+ count, gender, exposure group, time on HAART, region and treatment regimen, there were few differences in the rate of discontinuation due to TOXPC in those with HCV compared with those without for any nucleoside pairs or third drugs. Similar results were seen when concentrating on discontinuation due to toxicities alone.

Conclusions

Although patients with HCV generally had higher rates of discontinuation due to TOXPC compared with patients without HCV, there was little evidence to suggest that this was associated with any specific nucleoside pair or third drug used as part of cART. Our results do not suggest that any specific component of cART is more poorly tolerated in patients with HCV or that the presence of HCV should influence the choice between antiretrovirals used as part of a cART regimen.

Thymidine Analogue Mutation Profiles: Factors Associated with Acquiring Specific Profiles and their Impact on the Virological Response to Therapy

Background

Studies have suggested that HIV-1 may develop thymidine analogue mutations (TAMs) by one of two distinct pathways – the TAM1 pathway (including mutations 41L, 210W and 215Y) or the TAM2 pathway (including mutations 67N, 70R and 219E/Q) – under the pressure of a not fully suppressive thymidine-analogue-containing regimen.

Methods

Frozen plasma samples stored in the EuroSIDA repository were selected and sent to two central laboratories for genotypic analysis. We considered 733 patients with at least one genotypic test showing ≥1 TAMs (the first of these tests in chronological order was used). TAM1 and TAM2 genotypic profiles were defined in accordance with previous literature. Statistical modelling involved logistic regression and linear regression analysis for censored data.

Results

The observed frequencies of patterns classifiable as TAM1 or TAM2 profiles were markedly higher than the probabilities of falling into these classifications by chance alone. The chance of detecting a TAM2 profile increased by 25% per additional year of exposure to zidovudine. We found that mutations 67N and 184V were not associated with a particular TAM profile. In the presence of TAM2 profiles, the adjusted mean difference in the 6-month viral reduction was 0.96 log10 copies/ml (95% confidence interval: 0.20; 1.73) higher in patients who started stavudine-containing regimens instead of zidovudine-containing regimens.

Conclusions

This study provides evidence that the suggested TAM clustering is a real phenomenon and that it may be driven by which thymidine analogue the patients has used. In patients with TAM2-resistant viruses, stavudine appears to retain greater viral activity than zidovudine.

An algorithm-based genotypic resistance score is associated with clinical outcome in HIV-1-infected adults on antiretroviral therapy

OBJECTIVES

The aim of this study was to evaluate the association between genotypic drug resistance and the occurrence of HIV-related diseases and death in HIV-1-infected adults on antiretroviral therapy.

METHODS

We performed an observational study on patients from an out-patient clinic in a university hospital. Genotypic drug resistance analysis after virological treatment failure was performed in 141 patients receiving two or more antiretroviral drugs. All patients had follow up of at least 6 months after the resistance test. An algorithm was developed to estimate the level of genotypic drug resistance and to assign an actual resistance score (ARS) for the drugs prescribed to each patient. The patient population was divided into quartiles according to patients' ARS values. Our endpoint was the risk of developing an HIV-related disease [Centers for Disease Control and Prevention (CDC) category B or C] during the period starting 6 months prior to and ending 6 months after the genotypic resistance test, or death during the 6 months following the resistance test.

RESULTS

There was a significant association between the level of resistance to the drugs prescribed (ARS) and our clinical endpoint: the odds ratio for an endpoint (with 95% confidence interval) was 3.20 (1.28-7.99), adjusted for CD4 cell count and HIV RNA, in patients in the highest ARS quartile compared with patients in the other three quartiles.

CONCLUSIONS

Our study indicates that patients with high-level genotypic drug resistance are at increased risk of developing an HIV-related disease. This association could not be explained by differences in CD4 cell count or HIV RNA levels.

Baseline Resistance and Virological Outcome in Patients with Virological Failure who Start a Regimen Containing Abacavir: Eurosida Study

Objectives

To investigate the ability of several HIV-1 drug-resistance interpretation systems, as well as the number of pre-specified combinations of abacavir-related mutations, to predict virological response to abacavir-containing regimens in antiretroviral therapy-experienced, abacavir-naive patients starting an abacavir-containing regimen in the EuroSIDA cohort.

Patients and methods

A total of 100 HIV-infected patients with viral load (VL) >500 copies/ml who had a plasma sample available at the time of starting abacavir (baseline) were included. Resistance to abacavir was interpreted by using eight different commonly used systems that consisted of rules-based algorithms or tables of mutations. Correlation between baseline abacavir-resistance mutations and month 6 virological response was performed on this population using a multivariable linear regression model accounting for censored data.

Results

The baseline VL was 4.36 log10 RNA copies/ml [interquartile range (IQR): 3.65–4.99 log10 RNA copies/ml] and the median CD4 cell count was 210 cells/μl (IQR: 67–305 cells/μl). Our patients were pre-exposed to a median of seven antiretrovirals (2–12) before starting abacavir therapy. The median (range) number of abacavir mutations (according to the International AIDS Society-USA) detected at baseline was 3.5 (0–8). Overall, the Kaplan–Meier estimate of the median month 6 VL decline was 0.86 log10 RNA copies/ml [95% confidence intervals (95% CI): 0.45–1.24]. The VL in those patients ( n=31) who intensified treatment by adding only abacavir decreased by a median 0.20 log10 RNA copies/ml (95% CI: -0.18; +0.94). The proportion of patients who harboured viruses fully resistant to abacavir among the eight genotypic resistance interpretation algorithms ranged from 12% [Agence Nationale de Recherches sur le SIDA (ANRS)] to 79% [Stanford HIV RT and PR Sequence Database (HIVdb)]. Some interpretation systems showed statistically significant associations between the predicted resistance status and the virological response while others showed no consistent association. The number of active drugs in the regimen was associated with greater virological suppression (additional month 6 VL reduction per additional sensitive drug=0.51, 95% CI: 0.15–0.88, P=0.006); baseline VL was also weakly associated (additional month 6 VL reduction per log10 higher=0.30, 95% CI: -0.02; +0.62, P=0.06). In contrast, the number of drugs previously received was associated with diminished viral reduction (additional month 6 VL reduction per additional drug=-0.14, 95% CI: -0.28; 0.00, P=0.05).

Conclusions

Our results revealed a high degree of variability among several genotypic resistance interpretation algorithms currently in use for abacavir. Therefore, the interpretation of genotypic resistance for predicting response to regimens containing abacavir remains a major challenge.

Immunoglobulin levels amongst persons with and without human immunodeficiency virus type 1 infection in Uganda and Norway

CD4+-cell count and viral load monitoring are expensive and unavailable to most human immunodeficiency virus (HIV)-infected people in Africa. In an attempt to evaluate alternative methods for monitoring antiretroviral (ARV) therapy, we measured concentrations of immunoglobulin (Ig)A, IgM, IgG and IgG1 amongst adults with and without HIV in Uganda and Norway. We adjusted for disease severity by stratifying HIV-positive subjects on CD4+-cell counts above and below 200 cells/ micro l. Median serum levels of IgG, IgG1 and IgA were significantly higher in HIV-positive persons compared with HIV-negative persons in both countries (P < 0.001 and P = 0.018 for IgA in Ugandan patients). Levels of IgA in Ugandan HIV-negative subjects were significantly lower than those in HIV-positive subjects with low CD4+ compared with those with high CD4+-cell counts (P < 0.001 and P = 0.069, respectively). IgM levels were different between the HIV-negative and the two HIV-positive groups in Norway (P < 0.001). The mean levels of IgM, IgG and IgG1 in HIV-negative and -positive African subjects were generally higher than those in comparable groups of Western subjects. Our results verify that levels of IgA, IgG and IgG1 vary between HIV-negative and -positive individuals in both study populations. Their determination may be useful in monitoring both disease progression and response to ARV therapy.

Response to Antiretroviral Therapy among Patients Exposed to Three Classes of Antiretrovirals: Results from the Eurosida Study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2–5.2], CD4 lymphocyte count 150/mm3 (IQR 60–274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load <500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P=0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P=0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P=0.02), number of new drugs in the regimen (RH 1.20 per drug; P=0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P=0.035) and time spent on HAART with viral load >1000 copies/ml (RH 0.96 per extra month; P=0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

[Antiviral therapy of HIV infection in adults]

BACKGROUND

Great progress has been made in antiviral treatment of HIV disease over the last few years.

MATERIAL AND METHODS

The paper is based on relevant literature and our own experience in the largest HIV clinic in Norway.

RESULTS AND INTERPRETATION

Generally speaking, therapy with at least three active drugs is necessary in order to obtain maximum viral suppression. It is not established what constitutes the best starting-point for therapy, or what combination of drugs is the most efficacious. Treatment should be initiated before clinical immunodeficiency develops. All patients with CD4 counts < or = 0.2 x 10(9)/l should be offered treatment. The initial regimen should be either two nucleoside-analogues and one or two protease inhibitors, or two nucleoside-analogues and efavirenz. In order to avoid resistance and treatment failure, the patient should be thoroughly informed before and during treatment about the importance of good compliance.

[Tuberculosis among HIV-infected persons in Norway]

BACKGROUND

HIV-infected persons have a considerably higher risk of developing active tuberculosis than immunocompetent individuals. Tuberculosis is the only opportunistic infection among HIV-infected persons that presents a potential health risk to the general population.

MATERIAL AND METHODS

We present a review on this topic based on relevant literature and clinical experience.

RESULTS

Treatment options are limited because of interactions between rifamycins and protease inhibitors and non-nucleoside analogues. When concomitant therapy against HIV infection and tuberculosis is indicated, we suggest a first-line regimen of rifabutin combined with either indinavir or nelfinavir. For patients without severe immunodeficiency, anti-retroviral therapy can be postponed until the end of the initial phase of the anti-tuberculosis treatment.

INTERPRETATION

Treatment of concurrent HIV infection and tuberculosis is complex and may involve multiple drug regimens. Treating the latent infection could in many cases prevent active tuberculosis. All HIV-infected persons should be evaluated with respect to active tuberculosis and latent infection.

[Two cases of pneumococcal pericarditis]

BACKGROUND

Bacterial pericarditis is often overlooked, partly because symptoms and signs associated with pericarditis are frequently missing, but also because of the rarity of the disease.

MATERIAL AND METHODS

Two cases of pneumococcal pericarditis treated at Ullevaal University Hospital are presented.

RESULTS

Pneumococcal pericarditis is a rare, but serious complication to infections like pneumonia, pleural empyema, and septicaemia. Patients with an infectious disease who develop signs of elevated central venous pressure, enlarged cardiac silhouette on chest x-ray, or severe hypotension should have an echocardiography performed. If pericardial fluid is present, a diagnostic pericardiocentesis should be considered.

INTERPRETATION

Treatment consists of drainage and antibiotics. Pericardiocentesis and subxiphoid catheter drains may be inadequate because of fibrin precipitation resulting in organization of the fluid. In these cases surgical intervention has traditionally been recommended, but intrapericardial fibrinolysis could be an alternative.

[Tick-borne encephalitis in Norway]

BACKGROUND

Tick-borne encephalitis is caused by a virus that is transmitted to man by tick-bite. The virus is found in central and eastern parts of Europe and also in Sweden.

MATERIAL AND METHODS

We report the first two cases of tick-borne encephalitis resulting from transmission of virus in Norway.

RESULTS

Both patients had been to the island of Tromøy on the south coast of Norway. The course of the disease was very different in the two patients. One patient had significant neurological dysfunction. The other patient had intense headache, but no motor dysfunction. Both patients had reduced general health and fever, and leukocytosis and increased protein was found in the spinal fluid. The incubation period is most often 1 to 2 weeks. The disease may have a bi-phasic course with initial fever, headache and muscle pain. One week later symptoms of encephalitis follow. Subclinical infection is common, especially in children. One third of patients get permanent sequelae after encephalitis. Diagnosis is made by demonstration of antibodies in serum. Treatment is symptomatic.

INTERPRETATION

These two patients indicate that there may be a reservoir of TBE virus in Norway.

[Practical approach to otitis media with methicillin-resistant yellow Staphylococci]

Methicillin-resistant Staphylococcus aureus (MRSA) are multiresistant bacteria, known to cause nosocomial infections. We present a report on a two and a half year-old, recently adopted, child, who suffered from otitis media with discharge. The child was treated with penicillin in Norway without success. Culture revealed methicillin-resistant S aureus. Methicillin-resistant S aureus were also found in the noses of the adoptive parents. After a second unsuccessful course of antibiotics the child was admitted to the Ear, nose, and throat department and was subsequently treated with intravenous vancomycin, mastoidectomy and eradication of the nasal methicillin-resistant S aureus carriage. The admittance to the Ear, nose, and throat department was carefully planned. All departments concerned were thoroughly briefed. The patient was given vancomycin intravenously for 18 days, partly as an out-patient. Subsequent control cultures from the patient and the adoptive parents have all been negative. No one dealing with the patient has been infected. The case illustrates the importance of thorough planning and co-operation between different departments.