Short-term CD4 cell response after highly active antiretroviral therapy initiated at different times from seroconversion in 1,500 seroconverters

Effect of the timing of antiretroviral treatment initiation on CD4 count in children and youths living with HIV in North India

BACKGROUND

Immediate start of antiretroviral treatment (ART) among non-hospitalized outpatient children living with HIV may improve or worsen clinical outcomes due to immune reconstitution.

OBJECTIVE

Role of immediate versus post-stabilization start of antiretroviral treatment in children and youths living with HIV on CD4 count and viral load suppression.

METHODS

This was a single blinded, randomized controlled trial conducted on outpatients attending a tertiary care hospital associated HIV clinic in North India. We enrolled ART-naive children and youths living with HIV aged 18 months to 21 years in a 1:1 ratio. Block randomization was done using computerized software. Children and youths living with HIV were either started with ART on diagnosis immediately within 24 h (Group A) or post stabilization at 2 weeks (Group B) as per National AIDS Control Organization (NACO) India guidelines. Both groups were comparable for baseline characteristics.

RESULTS

There was no significant difference seen in CD4 counts between two groups at 6 months follow up. CD4 count increased significantly in immediate group but not in post-stabilization group at 6 months. No significant changes/differences was seen in WHO clinical staging or anthropometry; one patient developed tuberculosis in both groups. Viral load at 6 months in both the groups did not differ significantly.

CONCLUSION

Immediate ART in children and youths living with HIV results in significant increase in CD4 count at 6 months follow up exemplifying immunological response to ART.

Model-based prediction of CD4 cells counts in HIV-infected adults on antiretroviral therapy in Northwest Ethiopia: A flexible mixed effects approach

Background

CD4 cell counts is widely used as a biomarker for treatment progression when studying the efficacy of drugs to treat HIV-infected patients. In the past, it had been also used in determining eligibility to initiate antiretroviral therapy. The main aim of this was to model the evolution of CD4 counts over time and use this model for an early prediction of subject-specific time to cross a pre-specified CD4 threshold.

Methods

Hospital based retrospective cohort study of HIV-infected patients was conducted from January 2009 to December 2014 at University of Gondar hospital, Northwest Ethiopia. Fractional polynomial random effect model is used to model the evolution of CD4 counts over time in response to treatment and to estimate the individual probability to be above a pre-selected CD4 threshold. Human subject research approval for this study was received from University of Gondar Research Ethics Committee and the medical director of the hospital.

Results

A total of 1347 patients were included in the analysis presented in this paper. The cohort contributed a total of 236.58 per 100 person-years of follow-up. Later the data were divided into two periods: the first is the estimation period in which the parameters of the model are estimated and the second is the prediction period. Based on the parameters from the estimation period, model based prediction for the time to cross a threshold was estimated. The correlations between observed and predicted values of CD4 levels in the estimation period were 0.977 and 0.982 for Neverapine and Efavirenz containing regimens, respectively; while the correlation between the observed and predicted CD4 counts in the prediction period are 0.742 and 0.805 for NVP and EFV, respectively.

Conclusions

The model enables us to estimate a subject-specific expected time to cross a CD4 threshold and to estimate a subject-specific probability to have CD4 count above a pre-specified threshold at each time point. By predicting long-term outcomes of CD4 count of the patients one can advise patient about the potential ART benefits that accrue in the long-term.

The benefit of immediate compared with deferred antiretroviral therapy on CD4+ cell count recovery in early HIV infection

OBJECTIVE

To assess the impact of immediate vs. deferred antiretroviral therapy (ART) on CD4 recovery among individuals early in HIV infection.

DESIGN

Using serologic markers of early infection together with self-reported dates of infection and HIV diagnosis, ART-naive participants who were randomized to immediate vs. deferred ART in the Strategic Timing of Antiretroviral Treatment trial were classified into subgroups of duration of HIV infection at baseline. CD4 cell count recovery over follow-up according to duration of HIV infection was investigated.

METHODS

Three subgroups were defined: first, infected 6 months or less (n = 373); second, infected 6-24 months (n = 2634); and third, infected 24 months or longer (n = 1605). Follow-up CD4, CD8, and CD4 : CD8 ratio for the immediate and deferred ART groups were compared by subgroup using linear models. For the deferred ART group, decline to CD4 less than 350 cells/μl or AIDS according to infection duration was compared using time-to-event methods.

RESULTS

Follow-up CD4 cell count differences (immediate minus deferred) were greater for those recently infected (+231 cells/μl) compared with the two other subgroups (202 and 171 cells/μl; P < 0.001). CD4 : CD8 ratio treatment differences varied significantly (P < 0.001) according to duration of infection. In the deferred ART group, decline to CD4 less than 350 cells/μl or AIDS was greater among those recently infected (16.1 vs. 13.2 and 10.5 per 100 person years for those infected 6-24 and ≥24 months; P = 0.002).

CONCLUSION

In this randomized comparison of immediate vs. deferred ART, the CD4 cell count difference was greatest for those recently infected with HIV, emphasizing the importance of immediate ART initiation.

Timing of antiretroviral therapy initiation after diagnosis of recent human immunodeficiency virus infection and CD4(+) T-cell recovery

We retrospectively examined the timing of antiretroviral therapy (ART) initiation and CD4(+) T-cell recovery over 36 months among recent human immunodeficiency virus (HIV) infections using BED (HIV-1 subtypes B, E and D) immunoglobulin G capture enzyme immunoassay (BED-CEIA). Regardless of baseline CD4(+) counts, individuals (n = 393) who initiated ART >2 months after diagnosis had significantly decreased probability and rate of achieving CD4(+) counts ≥900 cells/μL or ≥600 cells/μL than those individuals (n = 135) who started ART earlier (≤2 months). But the mean CD4(+) counts in two groups converged after 30 months of treatment. Early ART initiation leads to accelerated CD4(+) recovery, but does not offer a long-term advantage in CD4(+) counts.

Impact of pre-therapy viral load on virological response to modern first-line HAART

BACKGROUND

We tested whether pre-HAART viraemia affects the achievement and maintenance of virological success in HIV-1-infected patients starting modern first-line therapies.

METHODS

A total of 1,430 patients starting their first HAART (genotype-tailored) in 2008 (median; IQR: 2006-2009) were grouped according to levels of pre-HAART viraemia (≤ 30,000, 30,001-100,000, 100,001-300,000, 300,001-500,000 and > 500,000 copies/ml). The impact of pre-therapy viraemia on the time to virological success (viraemia ≤ 50 copies/ml) and on the time to virological rebound (first of two consecutive viraemia values > 50 copies/ml after virological success) were evaluated by Kaplan-Meier curves and Cox regression analyses.

RESULTS

Median pre-HAART viraemia was 5.1 log10 copies/ml (IQR 4.5-5.5), and 53% of patients had viraemia > 100,000 copies/ml. By week 48, the prevalence of patients reaching virological success was > 90% in all pre-HAART viraemia ranges, with the only exception of range > 500,000 copies/ml (virological success = 83%; P < 0.001). Higher pre-HAART viraemia was tightly correlated with longer median time to achieve virological success. Cox multivariable estimates confirmed this result: patients with pre-HAART viraemia > 500,000 copies/ml showed the lowest hazard of virological undetectability after adjusting for age, gender, pre-HAART CD4+ T-cell count, transmitted drug resistance, calendar year and third drug administered (adjusted hazard ratio [95% CI]: 0.27 [0.21, 0.35]; P < 0.001). Pre-HAART viraemia > 500,000 copies/ml was also associated with higher probability of virological rebound compared with patients belonging to lower viraemia strata at weeks 4, 12 and 24 (P = 0.050).

CONCLUSIONS

At the time of modern HAART, and even though an average > 90% of virological success, high pre-HAART viraemia remains an independent factor associated with delayed and decreased virological success. Patients starting HAART with > 500,000 copies/ml represent a significant population that may deserve special attention.

Heterogeneity in outcomes of treated HIV-positive patients in Europe and North America: relation with patient and cohort characteristics

BACKGROUND

HIV cohort collaborations, which pool data from diverse patient cohorts, have provided key insights into outcomes of antiretroviral therapy (ART). However, the extent of, and reasons for, between-cohort heterogeneity in rates of AIDS and mortality are unclear.

METHODS

We obtained data on adult HIV-positive patients who started ART from 1998 without a previous AIDS diagnosis from 17 cohorts in North America and Europe. Patients were followed up from 1 month to 2 years after starting ART. We examined between-cohort heterogeneity in crude and adjusted (age, sex, HIV transmission risk, year, CD4 count and HIV-1 RNA at start of ART) rates of AIDS and mortality using random-effects meta-analysis and meta-regression.

RESULTS

During 61 520 person-years, 754/38 706 (1.9%) patients died and 1890 (4.9%) progressed to AIDS. Between-cohort variance in mortality rates was reduced from 0.84 to 0.24 (0.73 to 0.28 for AIDS rates) after adjustment for patient characteristics. Adjusted mortality rates were inversely associated with cohorts' estimated completeness of death ascertainment [excellent: 96-100%, good: 90-95%, average: 75-89%; mortality rate ratio 0.66 (95% confidence interval 0.46-0.94) per category]. Mortality rate ratios comparing Europe with North America were 0.42 (0.31-0.57) before and 0.47 (0.30-0.73) after adjusting for completeness of ascertainment.

CONCLUSIONS

Heterogeneity between settings in outcomes of HIV treatment has implications for collaborative analyses, policy and clinical care. Estimated mortality rates may require adjustment for completeness of ascertainment. Higher mortality rate in North American, compared with European, cohorts was not fully explained by completeness of ascertainment and may be because of the inclusion of more socially marginalized patients with higher mortality risk.

Early antiretroviral therapy: the role of cohorts

PURPOSE OF REVIEW

To review the data that contribute to the debate on the optimal time to initiate highly active antiretroviral therapy in HIV-infected individuals, with a focus on the information that is available from cohort studies.

RECENT FINDINGS

The findings from cohort studies generally support initiation of highly active antiretroviral therapy at CD4 cell counts more than 350 cells/microl. In particular, the findings that death rates among treated HIV-infected individuals are higher than those in the general population, and that the risks of AIDS and serious non-AIDS events are higher in those with lower CD4 cell counts (even when the count remains >350 cells/microl), suggest that earlier initiation of highly active antiretroviral therapy may prevent some excess morbidity and mortality. However, given the lack of adjustment for lead-time bias in many analyses, the potential for residual confounding and the possible incomplete ascertainment of relevant outcomes in cohorts, it cannot be concluded that the benefits of highly active antiretroviral therapy when started at higher CD4 cell counts will outweigh the possible detrimental effects.

SUMMARY

Whereas the data from cohort studies currently support initiation of highly active antiretroviral therapy at CD4 cell counts more than 350 cells/microl, there is an urgent need for data from randomized trials to inform this decision.

Should HIV therapy be started at a CD4 cell count above 350 cells/microl in asymptomatic HIV-1-infected patients?

PURPOSE OF REVIEW

The aim is to review the available data that contribute to the debate on the optimal time to initiate highly active antiretroviral therapy (HAART) in HIV-infected individuals with a CD4 cell count more than 350 cells/microl.

RECENT FINDINGS

Although few randomized data exist that can contribute to this debate, a number of findings from observational studies generally support earlier initiation of HAART. In particular, the findings that death rates remain higher in HIV-infected individuals than in uninfected individuals, even when successfully treated, and that both AIDS and several serious non-AIDS events are more common in those with a lower CD4 cell count (even when this count is above 350 cells/microl), suggest that earlier initiation of HAART may prevent much of the excess morbidity and mortality that remains in this patient group.

SUMMARY

Currently, the data would generally support initiation of HAART in patients with CD4 cell counts more than 350 cells/microl. However, given the strong potential for confounding in observational studies and the lack of adjustment for lead-time bias in many analyses, it is not possible to rule out possible long-term detrimental effects of earlier use of HAART until the results from fully powered randomized trials that directly address this issue become available.

Diagnosis and management of acute HIV infection

HIV infection starts as an acute, systemic infection, followed by a chronic period of clinical latency, usually lasting 3 to 10 years, which precedes the eventual collapse of the immune system. It is increasingly recognized that events occurring during acute HIV infection may determine the natural course of the disease. The very dynamic events of acute HIV infection provide multiple opportunities for biologic interventions, such as anti-retroviral or immune-based therapies. Similarly, the implementation of public health measures during acute HIV infection could help control epidemics or outbreaks. Many of the dramatic possibilities for intervention in acute HIV infection remain unproved, not the least because of traditional difficulty of diagnosing patients during this early period. This article reviews the natural history, pathogenesis and clinical presentation of acute HIV infection, and suggests a diagnostic and therapeutic approach to guide clinicians dealing with patients with suspected or confirmed acute HIV infection.

Acute HIV infection: the impact of anti-retroviral treatment on cellular immune responses

The overall value of initiating anti-retroviral therapy during the acute phase of human immunodeficiency virus type 1 (HIV-1) infection remains unclear. From a clinical perspective, the lack of data from controlled randomized clinical trials limits understanding of long-term effects of treatment on the clinical course of HIV infection. Based on available data, the impact of anti-retroviral therapy during acute infection on the immune response against HIV-1 is not particularly encouraging. Recent observations on the very early depletion of lymphocyte reservoirs in the gastrointestinal tract may partially explain the limited benefit of anti-retroviral therapy initiated during the acute phase of HIV-1 infection. This may also help to explain the dichotomy between early observations demonstrating apparent immunological benefit with early anti-retroviral treatment that were associated none the less with inability to control viral replication following treatment interruption.

Improved virological response to highly active antiretroviral therapy in HIV-1-infected patients carrying the CCR5 ?32 deletion

BACKGROUND

Patients heterozygous for the C-C chemokine receptor 5 (CCR5) Delta32 deletion spontaneously progress less rapidly to AIDS and death than do wild-type patients. We investigated whether the CCR5 Delta32 deletion has an impact on immunological, virological and clinical responses to highly active antiretroviral therapy (HAART) in HIV-1-infected patients.

PATIENTS AND METHODS

We included in the study 565 HIV-1-infected patients from the French HIV-1 infected cohort with documented date of seroconversion (SEROCO)/haemophiliacs HIV-1 infected (HEMOCO) cohorts, who started HAART after 1996. We investigated virological responses to HAART at 6 months (defined as a plasma HIV-1 RNA measurement below the threshold of detection or a 2 log HIV-1 RNA decrease) and at 12 months (defined as a plasma HIV-1 RNA measurement below the threshold of detection) and clinical response to HAART by Kaplan-Meier survival curves, with AIDS and death as outcomes.

RESULTS

The Delta32 heterozygous patients (n=83; 15%) had a better virological response to HAART than wild-type patients (73 vs 53% at 6 months, P=0.01; and 60 vs 44% at 12 months, P=0.01). This better virological response was still observed after adjustment for antiretroviral status (whether or not patients were naïve to antiretroviral therapy), year of HAART initiation, number of new antiretroviral drugs and baseline viral load. There was no statistical difference between heterozygous patients and wild-type patients in terms of survival and AIDS-free survival.

CONCLUSIONS

CCR5 Delta32 heterozygous patients were more likely to have a virological response to HAART than wild-type patients at 6 and 12 months. However, this virological response did not produce better immunological and clinical responses. The long-term impact of the Delta32 deletion on survival in HIV-1-infected treated patients should be investigated in a meta-analysis.

Response to highly active antiretroviral therapy among severely immuno-compromised HIV-infected patients in Cambodia

BACKGROUND

HAART efficacy was evaluated in a real-life setting in Phnom Penh (Médecins Sans Frontières programme) among severely immuno-compromised patients.

METHODS

Factors associated with mortality and immune reconstitution were identified using Cox proportional hazards and logistic regression models, respectively.

RESULTS

From July 2001 to April 2005, 1735 patients initiated HAART, with median CD4 cell count of 20 (inter-quartile range, 6-78) cells/microl. Mortality at 2 years increased as the CD4 cell count at HAART initiation decreased, (4.4, 4.5, 7.5 and 24.7% in patients with CD4 cell count > 100, 51-100, 21-50 and < or = 20 cells/microl, respectively; P < 10). Cotrimoxazole and fluconazole prophylaxis were protective against mortality as long as CD4 cell counts remained < or = 200 and < or = 100 cells/microl, respectively. The proportion of patients with successful immune reconstitution (CD4 cell gain > 100 cells/microl at 6 months) was 46.3%; it was lower in patients with previous ART exposure [odds ratio (OR), 0.16; 95% confidence interval (CI), 0.05-0.45] and patients developing a new opportunistic infection/immune reconstitution infection syndromes (OR, 0.71; 95% CI, 0.52-0.98). Similar efficacy was found between the stavudine-lamivudine-nevirapine fixed dose combination and the combination stavudine-lamivudine-efavirenz in terms of mortality and successful immune reconstitution. No surrogate markers for CD4 cell change could be identified among total lymphocyte count, haemoglobin, weight and body mass index.

CONCLUSION

Although CD4 cell count-stratified mortality rates were similar to those observed in industrialized countries for patients with CD4 cell count > 50 cells/microl, patients with CD4 cell count < or = 20 cells/microl posed a real challenge to clinicians. Widespread voluntary HIV testing and counselling should be encouraged to allow HAART initiation before the development of severe immuno-suppression.

Comparative potency of three antiretroviral therapy regimes in primary HIV infection

BACKGROUND

Virally mediated destruction of HIV-specific CD4+ T-cells in primary HIV infection (PHI) may be abrogated by potent antiretroviral therapy (ART) started in acute infection. To best achieve the most rapid reduction in primary viraemia we compared three different ART regimens in PHI.

STUDY DESIGN AND METHODS

A sequential, unblinded, non-randomized prospective cohort study. The primary endpoint was time to achieve plasma viral load (pVL) < 50 copies HIV RNA/ml. One hundred and five patients identified with PHI according to the definition: HIV antibody negative with positive HIV DNA (n = 22), HIV antibody positive with a documented negative test within the previous 6 months (n = 53), low-level incident 'detuned' assay (n = 10) or an evolving HIV-antibody test (n = 20) were recruited. Ninety of 105 individuals chose to take a short course of ART at PHI whereas 15 of 105 declined therapy. Seventy-nine of 90 were included for analysis and were allocated sequentially to either three (29 of 79) or four-drug (33 of 79) or protease inhibitor-containing ART (17 of 79).

RESULTS

A mathematical model-based analysis of viral decay indicated significantly faster viral load decline in patients receiving the four-drug regimen (P = 0.01). This conclusion was supported by a non-significant on-treatment analysis of the time taken to reach pVL <50 copies HIV RNA/ml (P = 0.07) but not by the corresponding intend-to-treat analysis. This discordance was caused by greater toxicities associated with the four-drug regimen, although the differences were not significant.

CONCLUSION

Of the three treatment regimens compared, the four-drug arm enhanced the rate of decline of primary viraemia but at the cost of toxicity.

Do HIV Disease Progression and HAART Response Vary among Injecting Drug Users in Europe?

Prior to HAART availability, there was no evidence of a geographical variation in HIV disease progression among injecting drug users (IDU) from different European regions. Nowadays, factors of importance regarding HIV disease progression in the face of HAART availability, such as HAART access, adherence, and the organization of care for IDU may differ across Europe. Therefore we studied HIV disease progression in a European study of IDU with known dates of HIV-seroconversion. Results show that with ongoing HAART availability, the risk of HIV disease progression has continued to decrease. When accounting for pre-AIDS death (in AIDS analyses) and non-natural deaths (suicide, overdose, accidents and homicide, in analyses of death) which are common among IDU, the risk of AIDS and death has decreased by as much as 65% and 75%, respectively, in 2000/2001. Results show little geographic variation in progression to AIDS. All-cause mortality was higher in IDU from Glasgow than elsewhere, while in the Valencian region (Spain) IDU were at a significantly lower risk of non-natural deaths. The timing of HAART initiation by treatment-naïve IDU likewise differed across Europe: IDU in Amsterdam, Innsbruck, and Edinburgh started at significantly lower CD4 counts than IDU in Paris, Geneva, Glasgow, and the Valencian region, but the subsequent short-term immune response was similar. In conclusion, the risk in progression to AIDS or natural death is similar across western Europe although IDU across Europe differ in other factors, such as the risk of non-natural death and the timing of HAART initiation.

Response to highly active antiretroviral therapy varies with age: the UK and Ireland Collaborative HIV Paediatric Study

OBJECTIVE

To evaluate the effect of age, CD4 percentage (CD4%) and plasma HIV-1 RNA on response to highly active antiretroviral therapy (HAART) in previously untreated children.

DESIGN

Cohort study.

METHODS

We examined the association between age at HAART initiation, and CD4 and HIV-1 RNA response using logistic and Cox regression, adjusting for sex, route of infection and pre-HAART values.

RESULTS

CD4% increases of > 10% at 6 months were more likely in younger children [odds ratio (OR), 0.84 per year, P < 0.001] and those with lower pre-HAART CD4% (OR, 0.67 per 5% higher, P < 0.001), but were not related to pre-HAART HIV-1 RNA (P = 0.6). In contrast, HIV-1 RNA suppression < 400 copies/ml at 6 months was more likely in older children (OR, 1.09 per year, P = 0.03), and was unrelated to pre-HAART HIV-1 RNA or CD4% (P > 0.3). CD4% was still increasing during the second year following HAART initiation (60% followed > 24 months). Longer-term increases in CD4% occurred faster, and decreases in HIV-1 RNA occurred more slowly in younger children. The median time to CD4% >/= 30% after initiating HAART with CD4% </= 25% was under 12 months for children under 2 years irrespective of pre-HAART CD4%, and increased progressively in older children and as CD4% decreased.

CONCLUSIONS

Children respond immunologically to HAART irrespective of pre-HAART HIV-1 RNA or clinical status. However, immunological response is better in younger children and those with lowest CD4%, whereas younger children have poorer virological response, increasing the risk of resistance. Differences in response to HAART according to age and underlying risk of disease progression should be considered when initiating HAART in children.