A tale of two countries: all-cause mortality among people living with HIV and receiving combination antiretroviral therapy in the UK and Canada

OBJECTIVES

We sought to compare all-cause mortality of people living with HIV and accessing care in Canada and the UK.

METHODS

Individuals from the Canadian Observational Cohort (CANOC) collaboration and UK Collaborative HIV Cohort (UK CHIC) study who were aged ≥ 18 years, had initiated antiretroviral therapy (ART) for the first time between 2000 and 2012 and who had acquired HIV through sexual transmission were included in the analysis. Cox regression was used to investigate the difference in mortality risk between the two cohort collaborations, accounting for loss to follow-up as a competing risk.

RESULTS

A total of 19 960 participants were included in the analysis (CANOC, 4137; UK CHIC, 15 823). CANOC participants were more likely to be older [median age 39 years (interquartile range (IQR): 33, 46 years) vs. 36 years (IQR: 31, 43 years) for UK CHIC participants], to be male (86 vs. 73%, respectively), and to report men who have sex with men (MSM) sexual transmission risk (72 vs. 56%, respectively) (all P < 0.001). Overall, 762 deaths occurred during 98 798 person-years (PY) of follow-up, giving a crude mortality rate of 7.7 per 1000 PY [95% confidence interval (CI): 7.1, 8.3 per 1000 PY]. The crude mortality rates were 8.6 (95% CI: 7.4, 10.0) and 7.5 (95% CI: 6.9, 8.1) per 1000 PY among CANOC and UK CHIC study participants, respectively. No statistically significant difference in mortality risk was observed between the cohort collaborations in Cox regression accounting for loss to follow-up as a competing risk (adjusted hazard ratio 0.86; 95% CI: 0.72-1.03).

CONCLUSIONS

Despite differences in national HIV care provision and treatment guidelines, mortality risk did not differ between CANOC and UK CHIC study participants who acquired HIV through sexual transmission.

Clinical Utility of Current NNRTIs and Perspectives of New Agents in This Class under Development

Highly active antiretroviral therapy (HAART) has significantly reduced the number of deaths caused by AIDS. However, the antiviral efficacy of HAART comprising protease inhibitors (PIs) and nucleoside reverse transcriptase inhibitors (NRTIs) is frequently accompanied by a decrease in patients' quality of life. PI-based therapies often fail due to poor adherence caused by heavy pill burden, complex dosing schedules and undesirable side effects. The current trend is to switch from PI-based to PI-sparing regimens consisting of non-nucleoside reverse transcriptase inhibitors (NNRTIs) and NRTIs. Despite some encouraging results from NNRTI-containing therapies, two major concerns in using the currently available NNRTIs remain: 1) low genetic barrier to the emergence of resistance and 2) cross-resistance due to single mutations that often render the whole class of NNRTIs ineffective. Clearly, new and improved NNRTIs are needed to address these concerns.

Evolution of HIV treatment guidelines in high- and low-income countries: converging recommendations

Over the past 15 years, antiretroviral treatment guidelines for HIV infection have evolved significantly, reflecting the major advances in this therapeutic area. Evidenced-based recommendations have largely replaced expert opinion, while diagnostic monitoring and therapeutic interventions have become more sophisticated and effective. Just 10 years ago, there was a marked difference in access to antiretroviral therapy for patients in wealthy and impoverished countries. The increasing availability of therapy across the globe, however, has made it possible for international guidelines to resemble more closely those in high-income countries. This article compares the evolution of antiretroviral therapy treatment guidelines from the United States Department of Health and Human Services and the World Health Organization, focusing on when to initiate ART in asymptomatic patients and in those with an opportunistic infection; initial regimens in the general population and in special populations; when to change and what to change; and laboratory monitoring.

Cohort profile: Antiretroviral Therapy Cohort Collaboration (ART-CC)

The advent of effective combination antiretroviral therapy (ART) in 1996 resulted in fewer patients experiencing clinical events, so that some prognostic analyses of individual cohort studies of human immunodeficiency virus-infected individuals had low statistical power. Because of this, the Antiretroviral Therapy Cohort Collaboration (ART-CC) of HIV cohort studies in Europe and North America was established in 2000, with the aim of studying the prognosis for clinical events in acquired immune deficiency syndrome (AIDS) and the mortality of adult patients treated for HIV-1 infection. In 2002, the ART-CC collected data on more than 12,000 patients in 13 cohorts who had begun combination ART between 1995 and 2001. Subsequent updates took place in 2004, 2006, 2008, and 2010. The ART-CC data base now includes data on more than 70,000 patients participating in 19 cohorts who began treatment before the end of 2009. Data are collected on patient demographics (e.g. sex, age, assumed transmission group, race/ethnicity, geographical origin), HIV biomarkers (e.g. CD4 cell count, plasma viral load of HIV-1), ART regimen, dates and types of AIDS events, and dates and causes of death. In recent years, additional data on co-infections such as hepatitis C; risk factors such as smoking, alcohol and drug use; non-HIV biomarkers such as haemoglobin and liver enzymes; and adherence to ART have been collected whenever available. The data remain the property of the contributing cohorts, whose representatives manage the ART-CC via the steering committee of the Collaboration. External collaboration is welcomed. Details of contacts are given on the ART-CC website (www.art-cohort-collaboration.org).

Non-uptake of highly active antiretroviral therapy among patients with a CD4 count < 350 cells/μL in the UK

OBJECTIVES

Current British HIV Association (BHIVA) guidelines recommend that all patients with a CD4 count <350 cells/μL are offered highly active antiretroviral therapy (HAART). We identified risk factors for delayed initiation of HAART following a CD4 count <350 cells/μL.

METHODS

All adults under follow-up in 2008 who had a first confirmed CD4 count <350 cells/μL from 2004 to 2008, who had not initiated treatment and who had >6 months of follow-up were included in the study. Characteristics at the time of the low CD4 cell count and over follow-up were compared to identify factors associated with delayed HAART uptake. Analyses used proportional hazards regression with fixed (sex/risk group, age, ethnicity, AIDS, baseline CD4 cell count and calendar year) and time-updated (frequency of CD4 cell count measurement, proportion of CD4 counts <350 cells/μL, latest CD4 cell count, CD4 percentage and viral load) covariates.

RESULTS

Of 4871 patients with a confirmed low CD4 cell count, 436 (8.9%) remained untreated. In multivariable analyses, those starting HAART were older [adjusted relative hazard (aRH)/10  years 1.15], were more likely to be female heterosexual (aRH 1.13), were more likely to have had AIDS (aRH 1.14), had a greater number of CD4 measurements < 350 cells/μL (aRH/additional count 1.18), had a lower CD4 count over follow-up (aRH/50 cells/μL higher 0.57), had a lower CD4 percentage (aRH/5% higher 0.90) and had a higher viral load (aRH/log(10) HIV-1 RNA copies/ml higher 1.06). Injecting drug users (aRH 0.53), women infected with HIV via nonsexual or injecting drug use routes (aRH 0.75) and those of unknown ethnicity (aRH 0.69) were less likely to commence HAART.

CONCLUSION

A substantial minority of patients with a CD4 count < 350 cells/μL remain untreated despite its indication.

Transmission network parameters estimated from HIV sequences for a nationwide epidemic

BACKGROUND

Many studies of sexual behavior have shown that individuals vary greatly in their number of sexual partners over time, but it has proved difficult to obtain parameter estimates relating to the dynamics of human immunodeficiency virus (HIV) transmission except in small-scale contact tracing studies. Recent developments in molecular phylodynamics have provided new routes to obtain these parameter estimates, and current clinical practice provides suitable data for entire infected populations.

METHODS

A phylodynamic analysis was performed on partial pol gene sequences obtained for routine clinical care from 14,560 individuals, representing approximately 60% of the HIV-positive men who have sex with men (MSM) under care in the United Kingdom.

RESULTS

Among individuals linked to others in the data set, 29% are linked to only 1 individual, 41% are linked to 2-10 individuals, and 29% are linked to ≥10 individuals. The right-skewed degree distribution can be approximated by a power law, but the data are best fitted by a Waring distribution for all time depths. For time depths of 5-7 years, the distribution parameter ρ lies within the range that indicates infinite variance.

CONCLUSIONS

The transmission network among UK MSM is characterized by preferential association such that a randomly distributed intervention would not be expected to stop the epidemic.

Ongoing changes in HIV RNA levels during untreated HIV infection: implications for CD4 cell count depletion

BACKGROUND

Understanding of the interplay between plasma HIV RNA level and CD4 cell count depletion in untreated infection remains incomplete.

METHODS

We studied 1169 people with HIV seen for care at a major London clinic while naive to antiretroviral therapy. We considered pairs (n = 5940) of consecutive simultaneously measured CD4 cell count and plasma HIV RNA values from patients who had never started therapy. Baseline was the first date when both measures were known.

RESULTS

HIV RNA levels increased variably and often substantially from baseline (60% experience an increase of over 50 000 copies/ml by 5 years of follow-up). The current HIV RNA level (i.e. first value of the pair) was strongly associated with the time-standardized change in CD4 cell count, with a mean 106 cells/microl per year greater rate of CD4 cell count decline per log-copy/ml higher current HIV RNA level (P < 0.0001). After adjustment for the current level, higher baseline HIV RNA was not associated with CD4 cell count decline. There was no average CD4 cell count decline with current HIV RNA level below 3.0 log-copies/ml, compared with a 159 cells/microl per year decline for those with HIV RNA at least 5.5 log-copies/ml (P < 0.0001). Further, the current CD4 cell count predicted subsequent changes in HIV RNA level (0.04 log-copies/year greater increases per 100 cells/microl lower CD4 cell count; P < 0.0001).

CONCLUSION

The often substantial increases in HIV RNA level observed in untreated HIV infection appear fundamentally linked to CD4 cell count depletion. Research into mechanisms by which HIV RNA levels rise over time should yield insights into the causes of CD4 cell count depletion, as the two processes are intimately linked.

History of viral suppression on combination antiretroviral therapy as a predictor of virological failure after a treatment change

OBJECTIVES

HIV-infected persons experience different patterns of viral suppression after initiating combination antiretroviral therapy (cART). The relationship between such differences and risk of virological failure after starting a new antiretroviral could help with patient monitoring strategies.

METHODS

A total of 1827 patients on cART starting at least one new antiretroviral from 1 January 2000 while maintaining a suppressed viral load were included in the analysis. Poisson regression analysis identified factors predictive of virological failure after baseline in addition to traditional demographic variables. Baseline was defined as the date of starting new antiretrovirals.

RESULTS

Four hundred and fifty-one patients (24.7%) experienced virological failure, with an incidence rate (IR) of 7.3 per 100 person-years of follow-up (PYFU) [95% confidence interval (CI) 6.7-8.0]. After adjustment, patients who had rebounded in the year prior to baseline had a 2.4-times higher rate of virological failure after baseline (95% CI 1.77-3.26; P<.0001), while there was no increased incidence in patients whose last viral rebound was >3 years prior to baseline [Incidence rate ratio (IRR) 1.06; 95% CI 0.75-1.50; P=0.73] compared with patients who had never virally rebounded. Patients had an 86% (95% CI 1.36-2.55; P<.0001), 53% (95% CI 1.06-2.04; P=0.02) and 5% (95% CI 0.80-1.38; P=0.72) higher virological failure rate after baseline if they were virally suppressed <50%, 50-70% and 70-90% of the time they were on cART prior to baseline, respectively, compared with those virally suppressed >90% of the time.

DISCUSSION

Intensive monitoring after a treatment switch is required in patients who have rebounded recently or have a low percentage of time suppressed while on cART. Consideration should be given to increasing the provision of adherence counselling.

A national review of assessment and monitoring of HIV-infected patients

OBJECTIVES

The British HIV Association (BHIVA) audit subcommittee aimed to survey UK clinic policy and practice regarding baseline assessment and immunization of newly diagnosed HIV-positive patients, and frequency of follow-up and testing in established patients in the UK.

METHODS

UK centres providing HIV care were requested to complete an online survey between October 2006 and March 2007.

RESULTS

111 centres participated in the survey. 89.2% of centres routinely performed baseline HIV resistance testing. 99% of centres had a policy of routine screening for hepatitis B. Only 91% of centres were routinely offering a sexual health screen at diagnosis. Frequency of routine follow-up for patients not requiring antiretroviral therapy (ART) and stable on ART varied between three and six months.

DISCUSSION

This review showed variations in practice regarding the post diagnosis assessment and routine monitoring of HIV patients. It is of concern that not all centres perform baseline HIV resistance testing. It has also been noted that hepatitis B vaccination is not being offered to non-immune patients at diagnosis. Less frequent follw-up of stable patients (both on and off ART) should allow resources to be focussed on those with specific clinical needs.

Restoration of anti-tetanus toxoid responses in patients initiating highly active antiretroviral therapy with or without a boost immunization: an INITIO substudy

INITIO is an open-labelled randomized trial evaluating first-line therapeutic strategies for human immunodeficiency virus-1 (HIV-1) infection. In an immunology substudy a tetanus toxoid booster (TTB) immunization was planned for 24 weeks after initiation of highly active antiretroviral therapy (HAART). All patients had received tetanus toxoid immunization in childhood. Generation of proliferative responses to tetanus toxoid was compared in two groups of patients, those receiving a protease inhibitor (PI)-sparing regimen (n = 21) and those receiving a PI-containing (n = 54) regimen. Fifty-two participants received a TTB immunization [PI-sparing (n = 15), PI-containing (n = 37)] and 23 participants did not [PI-sparing (n = 6) or PI-containing (n = 17)]. Cellular responses to tetanus antigen were monitored by lymphoproliferation at time of immunization and every 24 weeks to week 156. Proportions with a positive response (defined as stimulation index > or = 3 and Delta counts per minute > or = 3000) were compared at weeks 96 and 156. All analyses were intent-to-treat. Fifty-two participants had a TTB immunization at median 25 weeks; 23 patients did not. At weeks 96 and 156 there was no evidence of a difference in tetanus-specific responses, between those with or without TTB immunization (P = 0.2, P = 0.4). There was no difference in the proportion with response between those with PI-sparing or PI-containing regimens at both time-points (P = 0.8, P = 0.7). The proliferative response to tetanus toxoid was unaffected by initial HAART regimen. Anti-tetanus responses appear to reconstitute eventually in most patients over 156 weeks when treated successfully with HAART, irrespective of whether or not a TTB immunization has been administered.

Usage of stavudine (D4T) - a retrospective analysis in a South London hospital

British HIV Association (BHIVA) guidelines are updated on a regular basis with emergence of new clinical evidence. In June 2003, the BHIVA guidelines recommended that stavudine (D4T)-containing regimens are less preferred if other viable options are available. A retrospective analysis was conducted to establish whether local prescribing practice reflects national guidance offered by BHIVA. This study identifies 28 patients on D4T combinations, which represents 2% of the total treated group in our clinic population. In all, 89% (25/28) of patients had a viral load of <50 copies/mL and CD4 counts ranged from 122 to 1016 cells/mm(3). In this study, 12/28 patients had documented lipodystrophy. Seventeen out of 28 patients had no clear documented reasons for remaining on D4T, eight patients preferred to continue and three patients continued because of genotypic findings. This study shows that a small proportion of patients are still on D4T-containing regimen for the following reason - patient's choice, side-effects, toxicities and interaction. The majority of patients remaining on D4T had documented lipodystrophy changes. Therefore, clinicians continuing to prescribe D4T should document the precise reason for its continued use. If patients prefer to continue D4T, this should be well documented to circumvent any medicolegal consequences, should toxicity develop later.

Patients' Perceptions of Highly Active Antiretroviral Therapy in Relation to Treatment Uptake and Adherence

OBJECTIVE

To test the utility of the necessity-concerns framework in predicting highly active antiretroviral therapy (HAART) uptake and adherence.

METHODS

This was a prospective follow-up study. Consecutive patients who were not currently receiving HAART were referred by their HIV physician. Immediately after a recommendation of HAART, patients completed the Beliefs about Medicines Questionnaire assessing their perceptions of personal necessity for HAART and concerns about potential adverse effects. The influence of these beliefs on the decision to accept or decline HAART and adherence 12 months later were assessed.

RESULTS

One hundred fifty-three participants were given a recommendation of HAART, and 136 (88.9%) returned completed questionnaires. Thirty-eight participants (28%) initially rejected the treatment offer. Uptake of HAART was associated with perceptions of personal necessity for treatment (odds ratio [OR]=7.41, 95% confidence interval [CI]: 2.84 to 19.37) and concerns about potential adverse effects (OR=0.19, 95% CI: 0.07 to 0.48). There was a significant decline in adherence over time. Perceived necessity (OR=2.19, 95% CI: 1.02 to 4.71) and concerns about adverse effects (OR=0.45, 95% CI: 0.22 to 0.96), elicited before initiating HAART, predicted subsequent adherence. These associations were independent of clinical variables and depression.

CONCLUSIONS

The necessity-concerns framework is a useful theoretic model for understanding patient perspectives of HAART and predicting uptake and adherence, with implications for the design of evidence-based interventions.

Highly Active Antiretroviral Therapy and Human Immunodeficiency Virus–Associated Primary Cerebral Lymphoma

From a cohort of 9621 human immunodeficiency virus type 1-infected individuals, we identified 61 patients with primary central nervous system lymphoma (PCL) who had a median survival of 1.3 months. We compared clinicopathologic variables of patients who were treated in the pre-highly active antiretroviral therapy (HAART) and HAART eras and investigated whether exposure to antiretroviral agents with differing cerebrospinal fluid penetrations was associated with risk for PCL. All statistical tests were two-sided. Incidence of PCL was lower in the HAART era (1.2 cases per 1000 patient-years, 95% confidence interval [CI] = 0.8 to 1.9) than in the pre-HAART era (three cases per 1000 years, 95% CI = 2.1 to 4.0; P<.001), and overall survival was longer (median survival = 32 days, range = 5-315 days, versus 48 days, range = 15-1136 days; log rank P = .03). In the HAART era, fewer patients had prior acquired immunodeficiency syndrome-defining illnesses than in the pre-HAART era (64% versus 90%; P = .013), and patients were more likely to have the diagnosis of PCL confirmed histologically or by polymerase chain reaction (77% versus 26%; P<.001). Exposure to specific antiretroviral agents was not associated with risk for PCL.

Stavudine, lamivudine and nevirapine combination therapy for treatment of HIV infection and AIDS in adults

BACKGROUND

A favourable regimen for people infected with HIV/AIDS is one that provides optimal efficacy, durability of antiretroviral activity, tolerability, and has low adverse effects and drug-drug interactions. The combination of the non-nucleoside reverse transcriptase inhibitor nevirapine (NVP), and two nucleoside reverse transcriptase inhibitors, stavudine (d4T) and lamivudine (3TC), is widely used as first-line therapy, especially in low-resource countries. Analysis of the efficacy, durability and tolerability of the regimen is thus important to clinicians, consumers and policy-makers living in both rich and poor countries.

OBJECTIVES

To examine the efficacy of the stavudine, lamivudine and nevirapine regimen for the treatment of HIV infection and AIDS in adults.

SEARCH STRATEGY

We used the comprehensive search strategy developed specifically by the Cochrane HIV/AIDS Review Group to identify HIV/AIDS randomised controlled trials, and searched the following electronic databases: MEDLINE (searched July 2004); Embase (searched October 2004); and CENTRAL (July 2004). This search was supplemented with a search of AIDSearch (April 2005) to identify relevant conference abstracts, as well as searching reference lists of all eligible articles. The search was not limited by language or publication status.

SELECTION CRITERIA

Randomised controlled trials of the stavudine, lamivudine and nevirapine regimen, compared with any other regimens for treating HIV/AIDS, in antiretroviral treatment-naive or antiretroviral treatment-experienced adults.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the methodological quality of the trials and extracted data.

MAIN RESULTS

Our search resulted in 1,148 records, of which two studies described trials that met our inclusion criteria. One trial was a small single-centre Australian trial of 70 antiretroviral-naive participants, while the other trial was a large, multicentre trial, conducted in 14 countries, of 1,216 antiretroviral-naive participants. In both trials over 60% of participants were male. As the therapeutic combinations compared in both trials were not identical, it was not possible to conduct a meta-analysis to increase the power of the results. The main findings, therefore, are from the much larger trial, which was of a high quality. This trial found that there was no statistically significant difference in the efficacy (measured by treatment failure) between nevirapine and efavirenz (EFZ), when used in combination with 3TC and d4T (RR = 1.16; 95%CI: 0.95, 1.41). There was no statistically significant difference between once daily or twice-daily dosing of NVP, when used in combination with 3TC and d4T (RR = 1.00; 95%CI: 0.83; 1.21). It also showed that, compared with NVP plus EFZ, 3TC and d4T, a once-daily dosing of NVP, in combination with 3TC and d4T, performs better in averting treatment failure (RR = 0.82; 95%CI: 0.67, 1.00) than does twice-daily dosing of NVP with 3TC and d4T (RR = 0.82; 95%CI: 0.69; 0.97). Frequency of toxicity was higher in participants receiving NVP, compared with EFZ.

AUTHORS' CONCLUSIONS

The combination of nevirapine, 3TC and d4T is as efficacious as a combination of efavirenz, 3TC and d4T. Once-daily NVP with twice-daily 3TC and d4T is as efficacious as twice-daily NVP, 3TC and d4T. However, toxicity may be increased in the once-daily NVP regime. Additional trials of sufficient duration are required to provide better evidence for the use of this combination as a first line therapy. Ideally, trials should use standardised assessment measures especially with respect to measuring viral load, so that results can be compared and combined in meta-analyses.

Durable efficacy of enfuvirtide over 48 weeks in heavily treatment-experienced HIV-1-infected patients in the T-20 versus optimized background regimen only 1 and 2 clinical trials

BACKGROUND

The T-20 Versus Optimized Background Regimen Only (TORO) 1 and TORO 2 clinical trials are open-label, controlled, parallel-group, phase 3 studies comparing enfuvirtide plus an optimized background (OB) of antiretrovirals (n = 661) with OB alone (n = 334) in treatment-experienced HIV-1-infected patients.

METHODS

The primary objective at week 48 was to investigate durability of efficacy, as measured by the percentage of patients maintaining their week 24 response or improving. Efficacy analyses used the intent-to-treat population.

RESULTS

A total of 73.7% of patients randomized to the enfuvirtide group remained on treatment through week 48 versus 21.3% originally randomized to the control group. At week 48, a higher proportion of week 24 responders maintained their response or were new responders in the enfuvirtide group than in the control group in each responder category: HIV-1 RNA level > or =1.0 log(10) change from baseline, <400 copies/mL and <50 copies/mL (37.4%, 30.4%, and 18.3% in the enfuvirtide group vs. 17.1%, 12.0%, and 7.8% in the control group, respectively; P < 0.0001 for all comparisons). CD4 cell count increases from baseline were twice as great in the enfuvirtide group as in the control group.

CONCLUSION

These data demonstrate durable efficacy of enfuvirtide plus OB over 48 weeks.

Saquinavir 500 mg Film-Coated Tablets Demonstrate Bioequivalence to Saquinavir 200 mg Hard Capsules When Boosted with Twice-Daily Ritonavir in Healthy Volunteers

Objective

To establish the bioequivalence of a 500 mg film-coated tablet of saquinavir mesylate (FCT SQV) to the 200 mg hard-capsule saquinavir mesylate (HC SQV), both boosted with ritonavir and administered under fed conditions.

Methods

We carried out a multi-centre, open-label, randomized, two-sequence, four-period, two-treatment, replicated crossover study in 93 healthy men and 7 healthy women. Individuals were randomly assigned to receive sequential single doses of saquinavir in one of two treatment sequences: ABAB or BABA. Individuals received 100mg ritonavir twice daily for 24 days. On days 14, 17, 20 and 23, study participants took 1000mg of HC SQV (five 200 mg capsules, treatment A) or FCT SQV (two 500 mg tablets, treatment B) with a high-fat, high-calorie breakfast, and pharmacokinetic analyses were carried out over the next 24 hours. Area under the saquinavir concentration–time curve (AUC0–∞), maximum saquinavir plasma concentration (Cmax), time to Cmax and terminal half-life were calculated. The relative bioavailability of FCT SQV versus HC SQV was calculated as the ratio of the respective estimated mean saquinavir AUC0-∞ and Cmax. The calculation was based on an ANOVA including the factors site, sex, sequence, period, treatment and study participant to the log-transformed parameters log(AUC0-∞) and log(Cmax); the relative bioavailability and the 90% confidence intervals (CIs) were estimated using the treatment contrasts of the ANOVA. Bioequivalence was concluded as for both parameters, AUC0-∞ and Cmax, the 90% CIs for the relative bioavailability were entirely included in the reference region [0.80–1.25].

Results

Saquinavir plasma concentration–time profiles for the two formulations were similar. Geometric mean AUC0-∞ and Cmax values were clearly increased for FCT SQV (26 826 versus 24 430 h*ng/ml; and 3644 versus 3064 ng/ml, respectively); ratios of mean exposures were estimated to be 1.10 for AUC0-∞ and 1.19 for Cmax of saquinavir. However, the corresponding two-sided 90% CIs (1.04–1.16 and 1.14–1.25, respectively) all fell within the limits set for equivalence (0.80, 1.25). The adverse event profile for FCT SQV was similar to that for HC SQV.

Conclusion

The new 500 mg FCT SQV formulation is bioequivalent to the 200 mg HC SQV formulation, at the dose of 1000 mg, in combination with 100 mg ritonavir under fed conditions. The 500 mg FCT SQV formulation reduces pill count for boosted saquinavir (SQV/r) from six capsules to three tablets twice daily. This may increase patient acceptability of SQV/r, particularly in less treatment-experienced patients.

Multicenter evaluation of the NucliSens EasyQ HIV-1 v1.1 assay for the quantitative detection of HIV-1 RNA in plasma

The Nuclisens EasyQ HIV-1 v1.1 assay (Biomerieux) is a real-time detection method combined with NASBA technology designed to measure plasma HIV-RNA. Its performance was assessed in 1008 clinical specimens collected from individuals infected with clade B (774) and non-B (234) HIV-1 variants at four European laboratories. The results were compared with those obtained using three other commercial viral load assays: Cobas Amplicor Monitor HIV-1 v1.5 (Roche), Versant HIV-1 RNA assay (Bayer) and Nuclisens HIV-1 QT (Biomerieux). Overall, the linearity, specificity and reproducibility of the EasyQ assay was comparable with that from the other tests. The correlation coefficient (R) between methodologies was 0.85 for Amplicor; 0.87 for Versant; and 0.91 for Nuclisens. The specificity of the assay was 99.4%. Of note, Versant missed 17% of specimens with non-B subtypes which could be detected by EasyQ, while Amplicor provided similar results than EasyQ. HIV-1 group O specimens were only detected by the EasyQ assay. In conclusion, the performance of the EasyQ assay seems to be similar to that of other HIV-1 viral load tests currently on the market, but it is more sensitive than Versant for HIV-1 non-B subtypes and shows a wider dynamic range than Amplicor. Moreover, as it incorporates the advantage of real-time detection procedures, it facilitates high throughput and short turnaround time.

The management of HIV-1 protease inhibitor pharmacokinetic interactions

The HIV-1 protease inhibitors (PIs) are widely used in combination antiretroviral therapy for the management of HIV-1 infection. Certain characteristics of the PIs, in particular their metabolism being mainly via the cytochrome P450 isoenzyme group and their gastric absorption being pH dependent, make them prone to clinically significant drug interactions with other antiretrovirals, concomitant medication and complementary treatments. Owing to the nature of the disease, individuals with HIV are frequently prescribed complex treatment regimens (both for the management of intolerance, toxicity and viral resistance to antiretroviral therapy, and in the management of co-morbid states) that may interact with PI therapy. For many of these potential interactions, few data are available. This review will focus on the current use of PIs, highlighting some important management issues encountered with common pharmacokinetic interactions seen in clinical practice.

The effect of baseline CD4 cell count and HIV-1 viral load on the efficacy and safety of nevirapine or efavirenz-based first-line HAART

BACKGROUND

A substantial number of patients start their first-line antiretroviral therapy at an advanced stage of an HIV-1 infection. Potential differences between specific drug regimens in antiviral efficacy and safety in these patients are of major importance.

METHODS

A post-hoc analysis within the randomized controlled 2NN trial comparing efficacy between regimes containing nevirapine (NVP), efavirenz (EFV), or both, in addition to stavudine and lamivudine.

PRIMARY OUTCOME

risk of virologic failure in different strata of baseline CD4 T-lymphocyte counts and plasma HIV-1 RNA concentrations (pVL). Virologic failure: never reaching a pVL < 400 copies/ml, or a rebound to two consecutive values > 400 copies/ml.

RESULTS

The risk of virologic failure was increased at very low CD4 counts (< 25 x 10(6) cells/l) compared to CD4 counts > 200 x 10(6) cells/l [hazard ratio (HR), 1.28; 95% confidence interval (CI), 0.93-1.77]. The same was seen for a pVL > or = 100,000 copies/ml compared to a lower pVL (HR, 1.20; CI, 0.96-1.50). There were no statistically significant differences between NVP and EFV in risk of virologic failure within any of the CD4 or pVL strata, although EFV performed slightly better in the low CD4 stratum. The incidence of rash in the NVP group was significantly higher in female patients with higher CD4 cell counts, while adverse events in the EFV group were not associated with CD4 cell count.

CONCLUSIONS

Initial antiretroviral therapy including NVP or EFV is effective in patients with an advanced HIV-1 infection. A high baseline CD4 cell count is associated with the occurrence of rash in female patients using NVP.

The case for earlier treatment of HIV infection

Current US guidelines advise that antiretroviral therapy for asymptomatic HIV patients should definitely be started for those who have CD4(+) cell counts of >200 cells/ microL, but antiretroviral therapy is often not started at CD4(+) cell counts much above that level. Guidelines advocating later therapy for HIV infection have been based mainly on sparse and limited cross-sectional data and have been predicated on avoiding drug-related toxicity and viral drug resistance. However, emerging data about factors that contribute to survival and the availability of newer, less toxic drugs are eroding this position. Earlier initiation of antiretroviral therapy--namely, for patients with CD4(+) cell counts of >350 cells/ microL--may, in fact, be associated with lower mortality, better immune improvement, and less drug-related toxicity. These findings coincide with the introduction of antiretroviral drugs that have become more effective and less difficult to take. Earlier initiation of therapy may also reduce HIV transmission, an important public health consideration, and may be beneficial in terms of overall therapeutic cost-effectiveness. Given these accumulating data, we believe reconsideration of the "when-to-start" question is timely and justified.

Findings from the British HIV Association's national clinical audit of first-line antiretroviral therapy and survey of treatment practice and maternity care, 2002

OBJECTIVES

To assess the impact of and adherence to the British HIV Association (BHIVA) guidelines in routine clinical practice in the UK and Ireland.

METHODS

A self-completed postal survey of practice with regard to HIV management and maternity care of HIV-positive women was carried out. A case-note review of all patients starting their first antiretroviral (ART) therapy (up to a maximum of 25 patients) between April and September 2002 was also performed.

RESULTS

A total of 113 treatment centres participated. Ninety-nine units (88%) use the BHIVA ART guidelines as part of their treatment policy. Problems revealed by the survey include limited access to some ARTs in a small number of units and a wait longer than 4 weeks before the first assessment of patients started on ART in some units. Thirty-one centres (33%) felt that their maternity services had reached the government target of >90% antenatal HIV testing by October 2002. A total of 942 case-notes audited showed shortfalls in reported pretreatment testing of blood glucose, lipids and hepatitis C virus. Three patients had not strictly met the BHIVA guidelines for starting ART, but all had a high viral load (>100 000 HIV-1 RNA copies/mL). The majority (844 patients; 90%) had started on recommended therapies, most commonly two nucleoside reverse transcriptase inhibitors and a nonnucleoside reverse transcriptase inhibitor. The other 98 patients (10%) were given a variety of nonstandard triple or quadruple ART.

CONCLUSIONS

This audit again shows a high rate of consistency and quality of care of patients with HIV across the UK and Ireland. Problems with pretreatment assessment and early follow up of patients starting ART have been found.

Protease inhibitors potentiate chemotherapy-induced neutropenia

Pharmacokinetic interactions between chemotherapy and highly active antiretroviral therapy (HAART) are described, but there are few data on their clinical relevance. Patients with systemic AIDS-related non-Hodgkin lymphoma (ARL) were treated with concomitant HAART and infusional cyclophosphamide-doxorubicin-etoposide (CDE) chemotherapy. We compared neutropenia according to whether patients received protease inhibitor (PI)-based HAART or non-PI regimens. Differences in survival, response rates, immunologic parameters, and virologic parameters were also investigated. The day-10 (Mann-Whitney U test; P = .012) and day-14 (P = .025) neutrophil counts were significantly lower in patients receiving PIs, though there were no differences in the number of days of granulocyte colony-stimulating factor (G-CSF) administered between groups (P = .16). Grade 3 or 4 infections requiring hospitalization were recorded for a total of 58 (31%) of 190 cycles of CDE: 23 (48%) of 48 when prescribed PIs and 35 (25%) of 142 with concomitant PI-sparing HAART (chi(2) test; P = .0025). There were no statistically significant differences in the response rates, relapse-free survival, or disease-free survival between patients receiving PIs and those not receiving PIs. PI-based HAART appears to significantly potentiate the myelotoxicity of CDE chemotherapy. This potentiation may be a consequence of microsomal enzyme inhibition reducing the metabolism of cytotoxics in this regimen.

The relationship between nevirapine plasma concentrations and abnormal liver function tests

Abnormal liver function tests are frequently observed in HIV-infected individuals receiving nevirapine (NVP). Here we investigate the relationship between total and unbound plasma concentrations of NVP and the liver enzymes alanine aminotransferase (ALT) and gamma-glutamyl transferase (gammaGT). HIV-infected individuals [n = 85, 22 female, 34 hepatitis C or B virus (HCV or HBV(+))] receiving NVP (200 mg bd; median duration 66 weeks, range 3-189) and two nucleoside reverse transcriptase inhibitors (NRTIs) were enrolled into this study. Blood samples were taken at C(trough) (12 hr postdose) for measurement of NVP and liver function tests (ALT and gammaGT). Plasma protein bound and unbound drug was separated using ultrafiltration and NVP concentrations quantified using HPLC-MS/MS. A linear relationship was observed between total and unbound NVP C(trough) (r(2) = 0.77, p < 0.0001). Patients with elevated ALT (>37 IU/liter; n = 31) had higher NVP unbound C(trough) than those with ALT within the normal range (median 2268 vs. 1694 ng/ml, p = 0.04) but there was no difference in total C(trough). Logistic regression revealed no association between higher NVP C(trough) and ALT elevations. Significantly higher NVP total and unbound C(trough) were observed in patients with increased gammaGT (>40 IU/liter; n = 63; total 6747 vs. 4530 ng/ml, p = 0.001; unbound 2113 vs. 1557 ng/ml, p = 0.03). Significantly higher unbound NVP C(trough) was observed in HCV/HBV(+) (median 2275 vs. 1726 ng/ml, p = 0.02) and on bivariate analysis, higher NVP C(trough) was associated with HCV/HBV coinfection (chi(2) = 4.228; p = 0.04). Overall we found no strong association between NVP concentrations and hepatotoxicity. Although in this study NVP was well tolerated in HCV/HBV coinfected patients, higher plasma concentrations were observed.

Comparison of sequential three-drug regimens as initial therapy for HIV-1 infection

BACKGROUND

The optimal sequencing of antiretroviral regimens for the treatment of infection with human immunodeficiency virus type 1 (HIV-1) is unknown. We compared several different antiretroviral treatment strategies.

METHODS

This multicenter, randomized, partially double-blind trial used a factorial design to compare pairs of sequential three-drug regimens, starting with a regimen including zidovudine and lamivudine or a regimen including didanosine and stavudine in combination with either nelfinavir or efavirenz. The primary end point was the length of time to the failure of the second three-drug regimen.

RESULTS

A total of 620 subjects who had not previously received antiretroviral therapy were followed for a median of 2.3 years. Starting with a three-drug regimen containing efavirenz combined with zidovudine and lamivudine (but not efavirenz combined with didanosine and stavudine) appeared to delay the failure of the second regimen, as compared with starting with a regimen containing nelfinavir (hazard ratio for failure of the second regimen, 0.71; 95 percent confidence interval, 0.48 to 1.06), as well as to delay the second virologic failure (hazard ratio, 0.56; 95 percent confidence interval, 0.29 to 1.09), and significantly delayed the failure of the first regimen (hazard ratio, 0.39) and the first virologic failure (hazard ratio, 0.34). Starting with zidovudine and lamivudine combined with efavirenz (but not zidovudine and lamivudine combined with nelfinavir) appeared to delay the failure of the second regimen, as compared with starting with didanosine and stavudine (hazard ratio, 0.68), and significantly delayed both the first and the second virologic failures (hazard ratio for the first virologic failure, 0.39; hazard ratio for the second virologic failure, 0.47), as well as the failure of the first regimen (hazard ratio, 0.35). The initial use of zidovudine, lamivudine, and efavirenz resulted in a shorter time to viral suppression.

CONCLUSIONS

The efficacy of antiretroviral drugs depends on how they are combined. The combination of zidovudine, lamivudine, and efavirenz is superior to the other antiretroviral regimens used as initial therapy in this study.