Planned interruptions of anti-HIV treatment

Socioeconomic and clinical factors explaining the risk of unstructured antiretroviral therapy interruptions among Kenyan adult patients

A cross-sectional study was conducted to assess the extent of unstructured HIV treatment interruptions (TIs) and investigate the effects of socioeconomic, socio-demographic, HIV treatment-related and clinical factors on the magnitude and rate of the same among adult patients at a Kenyan regional referral center. Four hundred and twenty-one adult patients actively receiving antiretroviral therapy at Nyeri County Referral Hospital since 2003 were randomly selected to complete a health survey questionnaire. Electronic records were used to obtain their HIV treatment utilization history. The marginal effects of selected determinants on prevalence and rate of TI were assessed by fitting multiple Poisson log-linear regression models. In total, 392 patients participated in the study. HIV TI was prevalent with 64.5% having had at least one TI of 3 months or more during treatment. The risk of TI was significantly higher in those longer on treatment (prevalence ratio = 1.2, 95% confidence interval [CI] 1.12-1.28). Greater risk of TI was also associated with lower income (prevalence rate ratio [PRR] = 0.9, 95% CI 0.83-1.00), low medication adherence (PRR = 0.3, 95% CI 0.13-0.72), inconsistent treatment engagement (PRR = 0.4, 95% CI 0.19-0.75) and, contrarily, fewer adverse drug reactions (PRR = 0.9, 95% CI 0.90-0.97). Unstructured HIV TIs appear to be fairly common at the study site. The results suggest that efforts to minimize HIV TI could benefit from treatment-continuity monitoring strategies that target the high-risk sub-samples identified.

Intrapatient Evolutionary Dynamics of Human Immunodeficiency Virus Type 1 in Individuals Undergoing Alternative Treatment Strategies with Reverse Transcriptase Inhibitors

Structured treatment interruption (STI) has been trialed as an alternative to lifelong antiretroviral therapy (ART). We retrospectively performed single genome sequencing of the HIV-1 pol region from three patients representing different scenarios. They were either failing on continuous therapy (CT-F), failing STI (STI-F), or suppressing on STI (STI-S). Over 460 genomes were generated from three to five different time points over a 2-year period. We found multiple-linked-resistant mutations in both treatment failures. However, the CT-F patient showed a stepwise accumulation of diverse, linked mutations whereas the STI-F patient had lineage turnover between treatment periods with recirculation of wild-type and resistant variants from reservoirs. The STI-F patient showed a 7-fold increase in the third codon position substitution rate relative to the first and second positions compared to a 2-fold increase for CT-F and increased purifying selection in the pol gene (62 vs. 22 sites, respectively). An understanding of intrapatient viral dynamics could guide the future direction of treatment interruption strategies.

Antiretroviral treatment interruption leads to progression of liver fibrosis in HIV-hepatitis C virus co-infection

OBJECTIVE

Despite potential negative consequences, HIV/hepatitis C virus (HCV) co-infected patients may discontinue antiretroviral treatment (ART) for several reasons. We examined the impact of ART interruption on liver fibrosis progression in co-infected adults, using the aspartate aminotransferase-to-platelet ratio index (APRI) as a surrogate marker of liver fibrosis.

METHOD

Data were analyzed from a multisite prospective cohort of 541 HIV-HCV co-infected adults. ART interruption was included as a time-updated variable and defined as the cessation of all antiretrovirals for at least 14 days. The primary endpoint was the development of an APRI score at least 1.5. Time-dependent Cox proportional hazards regression and inverse probability-of-treatment weighting (IPTW) in a marginal structural model were used to evaluate the association of baseline and time-varying covariates with developing significant fibrosis.

RESULTS

Patients were followed for a median of 1.02 years; 10% (n = 53) interrupted ART and 10% (n = 53) developed significant fibrosis. After accounting for potential confounders, including CD4 T-cell count, HIV viral load, baseline APRI score, age and gender, the hazard ratio for ART interruption was 2.52 (95% confidence interval 1.20-5.28). Use of IPTW resulted in a similar effect estimate, suggesting that mediation by time-varying confounders was negligible.

CONCLUSION

ART interruption was associated with an increased risk of fibrosis progression in HIV-HCV co-infection that was only partially accounted for by HIV viral load and CD4 T-cell counts. Our findings suggest that liver disease progression observed in ART-treated co-infected patients is partly due to the consequences of treatment interruptions.

The impact of combination antiretroviral therapy and its interruption on anxiety, stress, depression and quality of life in Thai patients

OBJECTIVE

Investigation on anxiety, stress, depression, and quality of life (QoL) within STACCATO, a randomised trial of two treatment strategies: CD4 guided scheduled treatment interruption (STI) compared to continuous treatment (CT).

PARTICIPANTS

Thai patients with HIV-infection enrolled in the STACCATO trial.

METHODS

Anxiety, depression assessed by the questionnaires Hospital Anxiety and Depression Scale (HADS) and DASS, stress assessed by the Depression Anxiety Stress Scale (DASS), and QoL evaluated by the HIV Medical Outcome Study (MOS-HIV) questionnaires. Answers to questionnaires were evaluated at 4 time-points: baseline, 24 weeks, 48 weeks and at the end of STACCATO.

RESULTS

A total of 251 patients answered the HADS/DASS and 241 answered the MOS-HIV of the 379 Thai patients enrolled into STACCATO (66.2 and 63.6% respectively). At baseline 16.3% and 7.2% of patients reported anxiety and depression using HADS scale. Using the DASS scale, 35.1% reported mild to moderate and 9.6% reported severe anxiety; 8.8% reported mild to moderate and 2.0% reported severe depression; 42.6% reported mild to moderate and 4.8% reported severe stress. We showed a significant improvement of the MHS across time (p=0.001), but no difference between arms (p=0.17). The summarized physical health status score (PHS) did not change during the trial (p=0.15) nor between arm (p=0.45). There was no change of MHS or PHS in the STI arm, taking into account the number of STI cycle (p=0.30 and 0.57) but MHS significant increased across time-points (p=0.007).

CONCLUSION

Antiretroviral therapy improved mental health and QOL, irrespective of the treatment strategy.

Using mathematical modeling and control to develop structured treatment interruption strategies for HIV infection

The goal of this article is to suggest that mathematical models describing biological processes taking place within a patient over time can be used to design adaptive treatment strategies. We demonstrate using the key example of treatment strategies for human immunodeficiency virus type-1 (HIV) infection. Although there has been considerable progress in management of HIV infection using highly active antiretroviral therapies, continuous treatment with these agents involves significant cost and burden, toxicities, development of drug resistance, and problems with adherence; these latter complications are of particular concern in substance-abusing individuals. This has inspired interest in structured or supervised treatment interruption (STI) strategies, which involve cycles of treatment withdrawal and re-initiation. We argue that the most promising STI strategies are adaptive treatment strategies. We then describe how biological mechanisms governing the interaction over time between HIV and a patient's immune system may be represented by mathematical models and how control methods applied to these models can be used to design adaptive STI strategies seeking to maintain long-term suppression of the virus. We advocate that, when such mathematical representations of processes underlying a disease or disorder are available, they can be an important tool for suggesting adaptive treatment strategies for clinical study.

Highly active antiretroviral therapy interruption: predictors and virological and immunologic consequences

OBJECTIVE

To characterize the magnitude and the predictors of highly active antiretroviral therapy (HAART) interruption (TI) and to investigate its immunologic and virological consequences.

METHODS

Using Concerted Action on Seroconversion to AIDS and Death in Europe data from 8,300 persons with well-documented seroconversion dates, we identified subjects with stable first HAART (for at least 90 days) not initiated during primary infection. A TI was defined as an interruption of all antiretroviral therapy drugs for at least 14 days.

RESULTS

Of 1,551 subjects starting HAART, 299 (19.3%) interrupted treatment. Median (interquartile range) duration of the TI was 189 (101-382) days. The cumulative probability (95% confidence interval) of TI at 2 years was 15.9% (14.0%-18.1%). Women were more likely to have a TI than men in the same exposure group (35.8% vs 24.2% among drug users, 22.1% vs 13.3% among heterosexuals; P < 0.05). Higher baseline viremia and poor immunologic response to HAART were associated with higher probabilities of TI. Median (interquartile range) individual CD4 cell loss during TI was 94 (1-220) cells/microL. Older age at HAART (>40 yr), lower pre-HAART nadir (<200 cells/microL), and lower CD4 at start of TI (<350 cells/microL) were significantly associated with greater relative CD4 loss during TI.

CONCLUSIONS

We estimate that almost 1 in 6 subjects on HAART interrupts treatment by 2 years. Further research is needed to investigate the reasons why TI is higher in women. We have identified characteristics of subjects with the greatest risk for CD4 loss in whom TI may have greater risks.

HIV/AIDS epidemiology, pathogenesis, prevention, and treatment

The HIV-1 pandemic is a complex mix of diverse epidemics within and between countries and regions of the world, and is undoubtedly the defining public-health crisis of our time. Research has deepened our understanding of how the virus replicates, manipulates, and hides in an infected person. Although our understanding of pathogenesis and transmission dynamics has become more nuanced and prevention options have expanded, a cure or protective vaccine remains elusive. Antiretroviral treatment has transformed AIDS from an inevitably fatal condition to a chronic, manageable disease in some settings. This transformation has yet to be realised in those parts of the world that continue to bear a disproportionate burden of new HIV-1 infections and are most affected by increasing morbidity and mortality. This Seminar provides an update on epidemiology, pathogenesis, treatment, and prevention interventions pertinent to HIV-1.

Structured treatment interruptions (STI) in chronic unsuppressed HIV infection in adults

BACKGROUND

Structured treatment interruptions (STI) of antiretroviral therapy (ART) have been investigated as part of novel treatment strategies, with different aims and objectives depending on the populations involved. These populations include: 1) patients who initiate ART during acute HIV infection; 2) patients with chronic HIV infection, on ART, with successfully suppressed viremia; and 3) patients with chronic HIV infection and treatment failure, with persistent viremia due to multi-drug resistant HIV (Hirschel 2001; Deeks 2002; Miller 2003). In an earlier Cochrane review (Pai 2005), we had summarized the evidence about the effects of STI in chronic suppressed HIV infection. In this review, we summarize the evidence on STI in patients with chronic unsuppressed HIV infection due to drug-resistant HIV. Unsuppressed HIV infection describes those patients who cannot suppress viremia, due to the presence of multi-drug-resistant virus. It is also referred to as treatment failure. Drug resistance is identified by the presence of resistant mutations at baseline.STI as a treatment strategy in HIV-infected patients with chronic unsuppressed viremia involves interrupting ART in controlled clinical settings, for a pre-specified duration of time. These interruptions have various aims, including the following: 1) to allow wild virus to re-emerge and replace the resistant mutant virus, with the hope of improving the efficacy of a subsequent ART regimen; 2) to halt development of drug resistance and to preserve subsequent treatment options; 3) to alleviate treatment fatigue and reduce drug-related adverse effects; and 4) to improve quality of life (Miller 2003; Montaner 2001; Vella 2000;).

OBJECTIVES

The objective of our systematic review was to synthesize the evidence on the effect of structured treatment interruptions in adult patients with chronic unsuppressed HIV infection.

SEARCH STRATEGY

We included all available intervention studies (randomized controlled trials and non-randomized trials) conducted in HIV-infected patients worldwide. We searched nine databases, covering the period from January 1996 to February 2006. We also scanned bibliographies of relevant studies and contacted experts in the field to identify unpublished research, abstracts and ongoing trials. In the first screen, a total of 3186 potentially eligible citations from nine databases and sources were identified, of which 2047 duplicate citations were excluded. The remaining 1139 citations were examined in detail, and we further excluded 951 citations that were modeling studies, animal studies, case reports, and opinion pieces. As shown in Figure 01, 188 citations were identified in the second screen as relevant for full-text screening. Of these, 60 basic science studies, editorials and abstracts were excluded and 128 full-text articles were retrieved. In the third screen, all full-text articles were examined for eligibility in our review. These were subclassified into three categories: 1) chronic suppressed HIV infection; 2) chronic unsuppressed HIV infection; and 3) acute HIV infection. Studies were further excluded if their abstracts did not contain enough information for inclusion in our reviews. A total of 62 studies were finally classified into chronic suppressed, acute, and chronic unsuppressed categories. Of these, 17 trials met the eligibility criteria for this review.

SELECTION CRITERIA

Inclusion criteriaAll available randomized or non-randomized controlled trials investigating planned treatment interruptions among patients with chronic unsuppressed HIV infection. Early pilot non-randomized prospective studies on treatment interruptions of fixed and variable durations were also included. Relevant abstracts on randomized controlled trials were also included if they contained sufficient information. Exclusion criteriaEditorials, reviews, modeling studies, and basic science studies were excluded. Studies on STI among patients with chronic suppressed HIV infection were summarized in a separate review. Studies on STI in primary HIV infection were beyond the scope of this review.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data, evaluated study eligibility and quality. Disagreements were resolved in consultation with a third reviewer.A total of seventeen studies on STI were included in our review. However, due to significant heterogeneity across studies (i.e. in study design, populations, baseline characteristics, and reported outcomes; and in reporting of measures of effect, hazard ratios, and risk ratios), we considered it inappropriate to perform a meta-analysis.

MAIN RESULTS

In early pilot non-randomized trials, a pattern was evident across studies. During treatment interruption, a decline in CD4 cell counts, increase in viral load, and a shift in the level of genotypic drug resistance towards more of a wild-type HIV virus was reported. This suggests that STI may be used to increase drug susceptibility to an optimized salvage regimen upon treatment re-initiation. These studies generated useful data and hypotheses that were later tested in randomized controlled trials. Randomized controlled trials rated high on quality. Of the eight randomized controlled trials reviewed, seven had been completed while one was ongoing and remains blinded. Of the seven completed randomized controlled trials, six have reported consistent virologic and immunologic patterns, and found no significant benefit in virologic response to subsequent ART in the STI arm, compared to the control arm. In addition, the largest completed randomized trial reported greater numbers of clinical disease progression events and evidence of prolonged negative impact on CD4 cell counts in the STI arm (Beatty 2005; Benson 2004; Deeks 2001; Lawrence 2003; Walmsley 2005; Ruiz 2003). The single RCT with divergent findings from the others (GigHAART), reporting a significant virologic and immunologic benefit due to STI, was different in prescribing a shorter STI duration and a salvage ART regimen of 8-9 drugs. There were also differences in the patient population characteristics with this study, targeting those with very advanced HIV disease (Katlama 2004). Although we await the unblinded results of the eighth RCT (OPTIMA), the evidence so far does not support STI in the setting of chronic unsuppressed HIV infection with antiretroviral treatment failure (Brown 2004; Holodniy 2004; Kyriakides 2002; Singer 2006).

AUTHORS' CONCLUSIONS

The current available evidence primarily supports a lack of benefit of STI before switching therapy in patients with unsuppressed HIV viremia despite ART. There is evidence of harm in attempting STI in patients with relatively advanced HIV disease, due to the associated CD4 cell decline and the increased risk of clinical disease progression. At this time, there is no evidence to recommend the use of STI in this clinical category of patients with treatment failure.

Predictive factors of treatment interruption duration in a cohort of HIV-1 infected patients with CD4 count greater than 350 cells per mm3

OBJECTIVE

To determine predictive factors of treatment interruption (TI) duration within a cohort of HIV-1 infected patients having stopped their treatment with CD4 above 350 cells per mm(3).

DESIGN

Data were collected from computerized medical records. Patients were selected if they were HIV-1 positive, 18 years of age or older, and had stopped their treatment between January 1st, 1999 and July 1st, 2003, with CD4 count above 350 cells per mm(3). The study period was censored on October 1st, 2003. Patients were assessed every 3 months from inclusion to censure. A survival analysis using the Cox proportional hazard model was performed.

RESULTS

One hundred eighty-five patients were included. The median duration of TI was 43 weeks. Sixty-three patients remained off-treatment at censure. In the multivariate analysis, TI duration was shorter if CD4 nadir was below 250 cells per mm(3) before TI (relative hazard, 2.10), age superior to 40 (relative hazard, 1.72), viral load higher than 2.3 log.copies per ml (relative hazard, 1.52), and CDC class C (relative hazard, 1.78) at TI. Neither CD4 cell count at TI, numbers of treatments, nor duration of treatment and infection before TI were independent predictive factors of early treatment resumption (TR).

CONCLUSION

Some clinical and biological data may be used as predictive factors of early TR. Our results can have implications on future therapeutic strategies, in which the goal of therapy is to maintain CD4 cell count above a predetermined threshold using cycles of therapy followed by prolonged interruption according to CD4 count.

Interruption thérapeutique chez des patients infectés par le virus de l'immunodéficience humaine : évolution clinique et biologique

OBJECTIVE

The authors had for aim to evaluate the clinical and biological evolution in HIV-infected patients with viraemia lower than 30,000 copies/mL having decided to interrupt their treatment.

PATIENTS AND METHODS

Patients with highly active antiretroviral therapy (HAART) for more than 3 months followed by treatment interruption longer than 1 month were included in a retrospective analysis.

RESULTS

Forty-six patients having stopped treatment between November 1999 and July 2003 were included. The median duration of treatment interruption was 9.5 months. During the study, no clinical event occurred for 21 patients, and at least 1 clinical event occurred for the 25 others. The median CD4(+) cell counts (CD4) before and at the end of treatment interruption were 597/mm(3) and 437/mm(3), respectively (P<0.001). The median values of viral load before and at the end of treatment interruption were <50 and 23749 copies/mL, respectively (P<0.001). Among the 26 patients having started a new HAART, pre-treatment interruption and post-new HAART median CD4 (with a median delay after HAART of 9.7 months) were 548 and 432.5/mm(3) (P=0.02). Pre-treatment interruption and post-new HAART median viral load were 131.5 and 94.5 copies/mL (NS).

CONCLUSIONS

Treatment interruption must be used with caution in spite of the absence of virological impact, because CD4 cell count after new HAART is lower than CD4 preceding treatment interruption. Treatment interruption is contraindicated for patients with AIDS. Physicians must carefully follow other patients who decide on a treatment interruption.

Structured treatment interruptions (STI) in chronic suppressed HIV infection in adults

BACKGROUND

Although antiretroviral treatment (ART) has led to a decline in morbidity and mortality of HIV-infected patients in developed countries, it has also presented challenges. These challenges include increases in pill burden; adherence to treatment; development of resistance and treatment failure; development of drug toxicities; and increase in cost of HIV treatment and care. These issues stimulated interest in investigating the short-term and long-term consequences of discontinuing ART, thus providing support for research in structured treatment interruptions (STI). Structured treatment interruptions of antiretroviral treatment involve taking supervised breaks from ART. STI are defined as one or more planned, timing pre-specified, cyclical interruptions in ART. STI are attempted in monitored clinical settings in eligible participants. STI have generated hopes of reducing drug toxicities, decreasing costs and total time on treatment in HIV-positive patients. The first STI was attempted in the case of a patient in Germany, who later permanently discontinued treatment. This successful anecdotal case report led to several trials on STI worldwide.

OBJECTIVES

The objective of this systematic review was to assess the effects of structured treatment interruptions (STI) of antiretroviral therapy (ART) in the management of chronic suppressed HIV infection, using all available high-quality studies.

SEARCH STRATEGY

Nine databases covering the time period from January 1996 to March 2005 were searched. Bibliographies were scanned and experts contacted in the field to identify unpublished research and ongoing trials. Two reviewers independently extracted data, and evaluated study eligibility and quality. Disagreements were resolved in consultation with a third reviewer. Data from 33 studies were included in the review.

SELECTION CRITERIA

STI is a planned, timing pre-specified experimental intervention. In our review, we decided to include all available intervention trials in HIV-infected patients, with or without control groups. We reviewed evidence from 18 randomized and non-randomized controlled trials, and 15 single arm trials. Single arm trials were included because these pilot studies made significant contribution to the early development and refutation of hypotheses in STI.

DATA COLLECTION AND ANALYSIS

Trials included in this review varied in study participants, methodology and reported inconsistent measures of effect. Due to this heterogeneity, we did not attempt to meta-analyse them. Results were tabulated and a qualitative systematic review was done

MAIN RESULTS

For the purpose of this review, STI strategies were classified either as a timed-cycle STI strategy or a CD4-guided STI strategy. In timed-cycle STI strategy, a predetermined period of fixed duration (e.g. one week, one month) off ART was attempted followed by resumption of ART, while closely monitoring changes in CD4 levels and viral load levels. Predetermined criteria for interruption and resumption were laid out in this strategy. Timed-cycle STI fell out of favor due to reports of development of resistance in many studies. Moreover, there were no significant immunological and virological benefits, and no reduction in toxicities, reported in these studies. In CD4-guided STI strategy, ART was interrupted for variable durations guided by CD4 levels. Participants with high nadir CD4 levels qualified for this approach. A reduction in costs of ART, a reduction in mutation, and a better tolerability of this CD4-guided STI strategy was reported. However, concerns about long-term safety of this strategy on immunological, virological, and clinical outcomes were also raised.

AUTHORS' CONCLUSIONS

Timed-cycle STI have not been proven to be safe in the short term. Although CD4-guided STI strategy has reported favorable outcomes in the short term, the long-term safety, efficacy and tolerability of this strategy has not been fully investigated. Based on the studies we reviewed, the evidence to support the use of timed-cycle STI and CD4-guided STI cycles as a standard of care in the management of chronic suppressed HIV infection is inconclusive.

Evaluation of SIV-lipopeptide immunizations administered by the intradermal route in their ability to induce antigen specific T-cell responses in rhesus macaques

Numerous clinical and experimental observations have shown that cellular immunity, in particular CD8+ T-lymphocytes, plays an important role in the control of HIV infection. We have focused on a lipopeptide vaccination strategy that has been shown to induce polyepitopic T-cell responses in both animals and humans, in order to deliver simian immunodeficiency virus (SIV) antigens to rhesus macaques. Given the relevance of antigen administration route in the development of an effective cellular immune response, this study was designed to assess SIV lipopeptide immunizations administered either by the intradermal (ID) or the intramuscular (IM) routes in their ability to elicit GAG and NEF multispecific T-lymphocytes in the rhesus macaque. Antigen specific T-cell responses were observed between 7 and 11 weeks following vaccination in both groups. Macaques immunized by the IM route yielded antigen-specific IFN-gamma secreting lymphocytes in response to no more than two pools of peptides derived from SIV-NEF. In contrast, among the four ID-immunized macaques, two presented multi-specific T-cell responses to as many as four pools of SIV-NEF and/or GAG peptides. Responses persisted 16 weeks following the vaccination protocol in one of the ID-vaccinated macaques. The induction of such responses is of great clinical relevance in the development of an effective HIV vaccine. Given the crucial role of CD8+ T-lymphocytes in HIV/SIV containment, vaccination through the intradermal route should merit high consideration in the development of an AIDS vaccine.

Development of HIV with Drug Resistance after CD4 Cell Count--Guided Structured Treatment Interruptions in Patients Treated with Highly Active Antiretroviral Therapy after Dual--Nucleoside Analogue Treatment

BACKGROUND

For patients with human immunodeficiency virus (HIV) infection, structured treatment interruption (STI) is an attractive alternative strategy to continuous treatment, particularly in resource-restrained settings, because it reduces both side effects and costs. One major concern, however, is the development of resistance to antiretroviral drugs that can occur during multiple cycles of starting and stopping therapy.

METHODS

HIV genotypic drug resistance was investigated in 20 HIV-infected Thai patients treated with highly active antiretroviral therapy (HAART) and CD4 cell count-guided STI after dual nucleoside reverse-transcriptase inhibitor (NRTI) treatment. Resistance was tested at the time of the switch from dual-NRTI treatment to HAART and when HAART was stopped during the last interruption.

RESULTS

After STI, one major drug-resistance mutation occurred (T215Y), and, in the 4 samples with preexisting major mutations (D67N [n=2], K70R [n=2], T215Y [n=2], and T215I [n=1]), the mutations disappeared. All mutations in the HIV protease gene were minor mutations already present, in most cases, before STI was started, and their frequency was not increased through STI, whereas the frequency of reverse-transcriptase gene mutations significantly decreased after the interruptions. After the 48-week study period, no patients had virological failure. Long-term follow-up (108 weeks) showed 1 case of virological failure in the STI arm and 1 in the continuous arm. No virological failure was seen in patients with major mutations.

CONCLUSIONS

Major HIV drug-resistance mutations were not induced through CD4 cell count-guided treatment interruptions in HIV-infected patients successfully treated with HAART after dual-NRTI therapy.

Diminished proliferation of human immunodeficiency virus-specific CD4+ T cells is associated with diminished interleukin-2 (IL-2) production and is recovered by exogenous IL-2

Virus-specific CD4(+) T-cell function is thought to play a central role in induction and maintenance of effective CD8(+) T-cell responses in experimental animals or humans. However, the reasons that diminished proliferation of human immunodeficiency virus (HIV)-specific CD4(+) T cells is observed in the majority of infected patients and the role of these diminished responses in the loss of control of replication during the chronic phase of HIV infection remain incompletely understood. In a cohort of 15 patients that were selected for particularly strong HIV-specific CD4(+) T-cell responses, the effects of viremia on these responses were explored. Restriction of HIV replication was not observed during one to eight interruptions of antiretroviral therapy in the majority of patients (12 of 15). In each case, proliferative responses to HIV antigens were rapidly inhibited during viremia. The frequencies of cells that produce IFN-gamma in response to Gag, Pol, and Nef peptide pools were maintained during an interruption of therapy. In a subset of patients with elevated frequencies of interleukin-2 (IL-2)-producing cells, IL-2 production in response to HIV antigens was diminished during viremia. Addition of exogenous IL-2 was sufficient to rescue in vitro proliferation of DR0101 class II Gag or Pol tetramer(+) or total-Gag-specific CD4(+) T cells. These observations suggest that, during viremia, diminished in vitro proliferation of HIV-specific CD4(+) T cells is likely related to diminished IL-2 production. These results also suggest that relatively high frequencies of HIV-specific CD4(+) T cells persist in the peripheral blood during viremia, are not replicatively senescent, and proliferate when IL-2 is provided exogenously.

Discontinuing combination antiretroviral therapy during the first trimester of pregnancy: Insights from plasma human immunodeficiency virus-1 RNA viral load and CD4 cell count

OBJECTIVE

Options for human immunodeficiency virus-1-infected women who are already receiving antiretroviral medications when they become pregnant include the continuation or discontinuation of the therapy during the first trimester. These two strategies are compared in terms of plasma human immunodeficiency virus viral load and CD4 cell count.

STUDY DESIGN

Seventy women who attended the II Department of Obstetrics and Gynecology were identified. Four different periods for laboratory evaluations were decided: presuspension, suspension, second trimester, and third trimester.

RESULTS

Thirty-two women (46%) discontinued antiretroviral therapy; 38 women (54%) did not. Whereas plasma HIV virus viral load and CD4 cell count did not significantly vary during pregnancy in patients who did not interrupt the therapy, these two variables were influenced significantly by the discontinuation of treatment (P<.001 for both). Human immunodeficiency virus viral load increased during the suspension period and regressed promptly to basal levels as soon as the therapy was reintroduced. A transitory decrease in CD4 cell count was also documented, but the recovery tended to be slower.

CONCLUSION

The suspension of combination antiretroviral therapy during the first trimester of pregnancy transiently corresponds to an increase in human immunodeficiency virus viral load and a decline of CD4 cell count.

An open-label randomized clinical trial of novel therapeutic strategies for HIV-infected patients in whom antiretroviral therapy has failed: rationale and design of the OPTIMA Trial

OPTIMA (OPTions In Management with Antiretrovirals) is a clinical trial with a factorial randomization to evaluate the hypotheses that mega-antiretroviral therapy (ART) consisting of five or more anti-HIV drugs compared to standard-ART consisting of four or fewer anti-HIV drugs and a 3-month antiretroviral drug-free period (ARDFP) compared to no ARDFP will delay the occurrence of new or recurrent acquired immunodeficiency syndrome events or death, and prove to be more cost-effective in treating human immunodeficiency virus-infected individuals previously exposed to ART drugs from the current three main classes. The aim is to randomize 1,700 participants to four treatment strategy arms: (1) ARDFP+standard-ART; (2) ARDFP+mega-ART; (3) no ARDFP+standard-ART; (4) no ARDFP+mega-ART. The planned study duration is 3.5 years with 2.5 years of intake and a minimum 1 year of follow-up. The OPTIMA Trial was initiated in June 2001 at 30 U.S. Department of Veterans' Affairs hospitals, 22 hospitals in Canada, and 25 hospitals in the United Kingdom. This is the first large-scale, multicenter, randomized controlled trial to compare the relative efficacy of these different therapeutic strategies. We discuss the rationale behind the OPTIMA Trial design as well as the issues arising from the conduct of a trial that involves three national clinical trial agencies.

Effects of quasi-species heterogeneity of HBV on response to IFN-a therapy

AIM: To study effects of quasi-species heterogeneity of hepatitis B virus (HBV) on response to interferon(IFN)-α therapy.

METHODS: Serum quasi-species heterogeneity of HBV in 20 patients (10 responders and 10 non-responders) with chronic hepatitis B before administration of IFN-α was detected with conformation-sensitive gel electrophoresis (CSGE), and the relationship between response to IFN-α and quasi-species heterogeneity of HBV was analyzed.

RESULTS: No significant difference in levels of HBV DNA between responders (7.27×10¹⁰±8.79×10¹⁰) and non-responders (5.16×10¹⁰±5.13×10¹⁰) before IFN-α therapy was found (P > 0.05). But the quasi-species complexity and genetic diversity in non-responders were significantly higher than those in responders (8.30±1.89 vs 18.5±2.68, P < 0.001 and 0.926±0.008 vs 0.869±0.016, P < 0.001).

CONCLUSION: The level of quasi-species heterogeneity of HBV was reversely associated with the probability of response to IFN-α therapy.

Stage of the epidemic and viral phenotype should influence recommendations regarding mother-to-child transmission of HIV-1

This article argues for a new approach to use of nevirapine in the prevention of vertical transmission of HIV-1. Existing antenatal surveillance should be strengthened to plan geographical allocation, and subsequent evaluation, of a "nevirapine plus" programme. As the epidemic evolves the programme should also and, ideally, care should be tailored to individual women. Underpinning this approach is evidence that a more virulent viral phenotype appears in many patients with advanced HIV-1 infection. This phenotype will become more common at the population level as the epidemic progresses. As efficacy of zidovudine correlates with viral phenotype, and use of the drug may alter phenotype, there is an urgent need for a replacement that is safe to use with nevirapine.