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Objective: Accurate estimation of kidney function is critical among persons with HIV (PWH) to avoid under-dosing of antiretroviral therapies and ensure timely referral for kidney transplantation. Existing estimation equations for kidney function include race, the appropriateness of which has been debated. Given advancements in understanding of race and the necessity of accuracy in kidney function estimation, this study aimed to examine whether race, or genetic factors, improved prediction of serum creatinine among PWH., Design: This cross-sectional study utilized data from the Center for AIDS Research Network of Integrated Clinical Systems cohort (2008-2018). The outcome was baseline serum creatinine., Methods: Ordinary least squares regression was used to examine whether inclusion of race or genetic factors [ apolipoprotein-L1 ( APOL1 ) variants and genetic African ancestry] improved serum creatinine prediction. A reduction in root mean squared error (RMSE) greater than 2% was a clinically relevant improvement in predictive ability., Results: There were 4183 PWH included. Among PWH whose serum creatinine was less than 1.7 mg/dl, race was significantly associated with serum creatinine ( β  = 0.06, SE = 0.01, P  < 0.001) but did not improve predictive ability. African ancestry and APOL1 variants similarly failed to improve predictive ability. Whereas, when serum creatinine was at least 1.7 mg/dl, inclusion of race reduced the RMSE by 2.1%, indicating improvement in predictive ability. APOL1 variants further improved predictive ability by reducing the RMSE by 2.9%., Conclusion: These data suggest that, among PWH, inclusion of race or genetic factors may only be warranted at higher serum creatinine levels. Work eliminating existing healthcare disparities while preserving the utility of estimating equations is needed., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: To define the incidence of clinically detected coronavirus disease 2019 (COVID-19) in people with HIV (PWH) in the United States and evaluate how racial and ethnic disparities, comorbidities, and HIV-related factors contribute to risk of COVID-19., Design: Observational study within the CFAR Network of Integrated Clinical Systems cohort in seven cities during 2020., Methods: We calculated cumulative incidence rates of COVID-19 diagnosis among PWH in routine care by key characteristics including race/ethnicity, current and lowest CD4+ cell count, and geographic area. We evaluated risk factors for COVID-19 among PWH using relative risk regression models adjusted with disease risk scores., Results: Among 16 056 PWH in care, of whom 44.5% were black, 12.5% were Hispanic, with a median age of 52 years (IQR 40-59), 18% had a current CD4+ cell count less than 350 cells/μl, including 7% less than 200; 95.5% were on antiretroviral therapy (ART), and 85.6% were virologically suppressed. Overall in 2020, 649 PWH were diagnosed with COVID-19 for a rate of 4.94 cases per 100 person-years. The cumulative incidence of COVID-19 was 2.4-fold and 1.7-fold higher in Hispanic and black PWH respectively, than non-Hispanic white PWH. In adjusted analyses, factors associated with COVID-19 included female sex, Hispanic or black identity, lowest historical CD4+ cell count less than 350 cells/μl (proxy for CD4+ nadir), current low CD4+ : CD8+ ratio, diabetes, and obesity., Conclusion: Our results suggest that the presence of structural racial inequities above and beyond medical comorbidities increased the risk of COVID-19 among PWH. PWH with immune exhaustion as evidenced by lowest historical CD4+ cell count or current low CD4+ : CD8+ ratio had greater risk of COVID-19., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: There are few methodologic examples of how multiple causes of death may be summarized in cause-specific mortality analyses to address limitations of attributing death to a single underlying cause. We propose a cause-of-death weighting approach to estimate the set of risk functions of specific causes of mortality using both underlying and contributing cause-of-death information., Methods: We constructed weights according to a user-specified function. Using data from four southern US human immunodeficiency virus (HIV) clinics, we constructed a cause of death-weighted Aalen-Johansen estimator of the cumulative incidence function to estimate risks of five specific causes of mortality in the full sample and by injection drug use history., Results: Among 7740 HIV-positive patients initiating antiretroviral therapy between 1999 and 2014, the 8-year risk of all-cause mortality was 17.5% [95% confidence interval (CI) = 16.5, 18.4]. The cause of death-weighted risk of HIV-related mortality was 6.7% (95% CI = 6.0, 7.3) and accounted for 39% (95% CI = 35, 42) of total mortality risk. This compared with 10.2% (95% CI = 9.2, 11.2) using only the underlying cause, in which case HIV-related deaths accounted for nearly 60% of total mortality risk. The proportion attributable to cardiovascular disease among those whose HIV risk factor was injection drug use was twice as high using cause-of-death weights compared with only the underlying cause (8%; 95% CI = 5, 11 vs 4%; 95% CI = 1, 6)., Conclusion: Using cause of death-weighted estimators to incorporate multiple causes of death may yield different conclusions regarding the importance of certain causes of mortality. See video abstract: http://links.lww.com/EDE/B706.

Objective: Model trajectories of CD4+ and CD8+ cell counts after starting combination antiretroviral therapy (ART) and use the model to predict trends in these counts and the CD4+ : CD8+ ratio., Design: Cohort study of antiretroviral-naïve HIV-positive adults who started ART after 1997 (ART Cohort Collaboration) with more than 6 months of follow-up data., Methods: We jointly estimated CD4+ and CD8+ cell count trends and their correlation using a bivariate random effects model, with linear splines describing their population trends, and predicted the CD4+ : CD8+ ratio trend from this model. We assessed whether CD4+ and CD8+ cell count trends and the CD4+ : CD8+ ratio trend varied according to CD4+ cell count at start of ART (baseline), and, whether these trends differed in patients with and without virological failure more than 6 months after starting ART., Results: A total of 39 979 patients were included (median follow-up was 53 months). Among patients with baseline CD4+ cell count at least 50 cells/μl, predicted mean CD8+ cell counts continued to decrease between 3 and 15 years post-ART, partly driving increases in the predicted mean CD4+ : CD8+ ratio. During 15 years of follow-up, normalization of the predicted mean CD4+ : CD8+ ratio (to >1) was only observed among patients with baseline CD4+ cell count at least 200 cells/μl. A higher baseline CD4+ cell count predicted a shorter time to normalization., Conclusion: Declines in CD8+ cell count and increases in CD4+ : CD8+ ratio occurred up to 15 years after starting ART. The likelihood of normalization of the CD4+ : CD8+ ratio is strongly related to baseline CD4+ cell count.

Background: US national guidelines call for cost-conscious practices including the selection of antiretroviral therapy., Objective: The objective is to analyze the relative cost-effectiveness of contemporary antiretroviral therapy in real-world clinical settings., Design: Observational cohort study., Methods: Retrospective follow-up study of treatment-naïve persons living with HIV initiating antiretroviral therapy (ART) between January 2007 and December 2012 at an academically affiliated HIV clinic was conducted. Analysis was restricted to patients with the five most commonly prescribed regimens (N = 491). Patients were followed until December 14 to determine the durability of the initial regimen prescribed; median durations were calculated using Kaplan-Meier survival analyses. The average 340b price of the ART regimen 30-day supply was used for cost. Sensitivity analyses were performed adjusting for missing data and pricing indices and using mean durability (±1 SD)., Results: Initial regimens contained emtricitabine and tenofovir, along with a third drug. Median durability was shortest for ritonavir-boosted atazanavir (31.9 months) and longest for ritonavir-boosted darunavir and raltegravir (both 47.8 months). All regimens were dominated, meaning less durable and more costly, relative to efavirenz ($710.64/month) and raltegravir-based regimens ($1075.03/month). These findings were reproduced in sensitivity analysis, although rilpivirine became a valuable option in some scenarios. Relative to the efavirenz-based regimen, raltegravir had an incremental cost of $47/month of additional therapy., Conclusion: In this sample, raltegravir and efavirenz-based regimens are the most cost-effective options for treatment-naive patients. Sensitivity analyses suggest rilpivirine is a reasonable choice in limited scenarios. These findings are relevant given changes in recommended regimens for treatment-naive persons, which include raltegravir and darunavir but exclude efavirenz and rilpivirine-based regimens., Summary: Of five commonly prescribed regimens for treatment-naïve HIV patients in one clinic (2007-2012), emtricitabine and tenofovir with efavirenz and raltegravir were the only consistently cost-effective options; the rilpivirine-based regimen was valuable in limited scenarios. Further data on the comparative effectiveness of efavirenz and rilpivirine are needed before they are abandoned.

Objective: To compare the efficacy, safety, and anti-inflammatory effects of cenicriviroc (CVC), an oral, once-daily C-C chemokine receptor types 5 and 2 antagonist, with those of efavirenz (EFV) in treatment-naive, HIV-1-infected adults., Design: A 48-week, randomized, double-blind, double-dummy phase 2b trial at 43 institutions (USA and Puerto Rico)., Methods: Study participants (HIV-1 RNA ≥1000 copies/ml, CD4 cell count ≥200 cells/μl, C-C chemokine receptor type 5-tropic virus) were randomized 2 : 2 : 1 to CVC 100 mg (CVC100), CVC 200 mg (CVC200), or EFV 600 mg, each administered with emtricitabine/tenofovir disoproxil fumarate. Key end points were virologic success (HIV-1 RNA <50 copies/ml) at week 24 (primary) and week 48 (secondary), safety/tolerability at weeks 24 and 48. Study sites and patients remained blinded until week 48., Results: A total of 143 patients were randomized (CVC100, n = 59; CVC200, n = 56; EFV, n = 28). Virologic success was obtained at week 24 in 76, 73, and 71% of study participants for CVC100, CVC200, and EFV, respectively (all P > 0.05 versus EFV), and at week 48 in 68, 64, and 50%, respectively (all P > 0.05 versus EFV). Resistance mutations emerged in five and zero CVC and EFV-treated study participants, respectively. Virologic nonresponse and nucleoside reverse transcriptase inhibitor resistance decreased when CVC minimum plasma concentration was at least 47.8 ng/ml. Treatment-related adverse events of at least grade 2 and discontinuations because of adverse events were less frequent in CVC-treated study participants. Total and low-density lipoprotein cholesterol decreased with CVC, but increased with EFV. C-C chemokine ligand type 2 (CCL2) (aka monocyte chemotactic protein-1) increased in a dose-dependent manner, whereas soluble CD14 levels decreased with CVC., Conclusion: CVC showed efficacy and favorable safety in treatment-naive HIV-1-infected study participants, supporting selection of CVC200 for phase 3 studies., Trial Registration: NCT01338883.

Objective: To estimate the association between immunologic response to antiretroviral therapy (ART) and non-AIDS defining cancer (NADC) incidence in HIV-infected patients., Design: A prospective cohort including patients with at least 1 cell/μl CD4 cell count and HIV-1 RNA measure after ART initiation between 1996 and 2011 in the Centers for AIDS Research Network of Integrated Clinical Systems, a collaboration of eight HIV clinics at major academic medical centres in the United States., Methods: Measures of immunologic response were 6-month CD4 post-ART, latest CD4 and CD4 count-years, a cumulative measure of CD4 lymphopenia. Cox regression with inverse probability-of-exposure weights was used to calculate adjusted hazard ratios of virus-related and virus-unrelated NADC incidence., Results: Among 9389 patients at ART initiation, median CD4 cell count was 200 cells/μl [interquartile range (IQR) 60-332)], and median HIV-1 RNA was 4.8 log10 copies/ml (IQR 4.3-5.4). Median follow-up was 3.3 years (IQR 1.5-6.5). After 6 months of ART, median CD4 cell count was 304 cells/μl (IQR 163-469). One hundred and sixty-four NADCs were diagnosed during study follow-up, 65 (40%) considered virus-related. Virus-related NADCs were inversely associated with 6-month CD4 cell count (hazard ratio per 100 cells/μl increase=0.71), latest CD4 cell count (hazard ratio per 100 cells/μl increase=0.70) and CD4 cell count-years (hazard ratio per 200 cell-years/μl increase=0.91) independent of CD4 cell count at ART initiation, age and HIV-1 RNA response. No associations were found with virus-unrelated NADCs., Conclusion: Poor CD4 cell count response was strongly associated with virus-related NADC incidence, suggesting an important role for T-cell mediated immunity in pathogenesis. Lower CD4 cell count proximal to cancer diagnosis may be a result of subclinical cancer. Intensified cancer screening should be considered for patients on ART with low CD4 cell counts.

Objective: Maraviroc, a chemokine co-receptor type 5 (CCR5) antagonist, has demonstrated comparable efficacy and safety to efavirenz, each in combination with zidovudine/lamivudine, over 96 weeks in the Maraviroc vs. Efavirenz Regimens as Initial Therapy (MERIT) study. Here we report 5-year findings., Design: A randomized, double-blind, multicenter phase IIb/III study with an open-label extension phase., Methods: Treatment-naive patients with CCR5-tropic HIV-1 infection (Trofile) received maraviroc 300 mg twice daily or efavirenz 600 mg once daily, and zidovudine/lamivudine 300 mg/150 mg twice daily. After the last patient's week 96 visit, the study was unblinded and patients could enter a nominal 3-year open-label phase. Endpoints at the 5-year nominal visit (week 240) included proportion of patients (CCR5 tropism re-confirmed by enhanced sensitivity Trofile) with viral load (plasma HIV-1 RNA) below 50 and 400 copies/ml, and change from baseline in CD4(+) cell count, as well as safety., Results: The proportion of patients maintaining viral load below 50 copies/ml was similar between treatment arms throughout the study and at week 240 (maraviroc 50.8% vs. efavirenz 45.9%). Maraviroc-treated patients had a greater increase from baseline in mean CD4(+) cell count than efavirenz-treated patients at week 240 (293 vs. 271 cells/μl, respectively). Fewer patients on maraviroc vs. efavirenz experienced treatment-related adverse events (68.9 vs. 81.7%) and discontinued as a result of any adverse event (10.6 vs. 21.3%)., Conclusion: Maraviroc maintained similar long-term antiviral efficacy to efavirenz over 5 years in treatment-naive patients with CCR5-tropic HIV-1. Maraviroc was generally well tolerated with no unexpected safety findings or evidence of long-term safety concerns.

Purpose of Review: A number of investigational antiretroviral drugs in clinical development could alter the future treatment landscape for resource-limited settings and contribute to optimized therapy for HIV infection., Recent Findings: Several nucleoside reverse transcriptase inhibitors (NRTIs) are in development, including festinavir (BMS-986001), a thymidine analogue similar to stavudine but with reduced potential for toxicity, CMX-157, a hexadecyloxypropyl conjugate of tenofovir and tenofovir alafenamide (GS-7340), a prodrug of tenofovir achieving much higher intracellular triphosphate concentrations with a lower dose than tenofovir disoproxil fumarate. MK-1439 is a well tolerated once-daily non-NRTI (NNRTI) with activity against most NNRTI-associated resistance mutations. Albuvirtide is a long-acting parenteral fusion inhibitor related to enfuvirtide, and BMS-663068 is an oral HIV attachment/entry inhibitor. Ibalizumab (formerly TNX-355) is an mAb that binds to CD4 and lowers HIV plasma viral RNA in infected patients. Cenicriviroc is a CCR5-antagonist that also has activity against the inflammatory chemokine CCR2. The integrase strand transfer inhibitor (InSTI) dolutegravir was recently approved in the U.S. and is an attractive component of future regimens because of efficacy, tolerability, apparent safety and once-daily dosing; it also maintains some activity against raltegravir and elvitegravir-resistant mutants. The dolutegravir analogue GSK-1265744 appears to be equipotent and is being developed as a long-lasting injectable parenteral agent. The selective cytochrome P450 3A4 inhibitor cobicistat is a better tolerated alternative to ritonavir for pharmacokinetic 'boosting', but may also result in clinically undesirable drug interactions., Summary: There are several investigational antiretroviral drugs with significant promise for inclusion in future primary and secondary combination regimens.

Objective: Peripheral fat loss and visceral fat gain have been reported in HIV infection. There are limited data on long-term change in adipose tissue in HIV-infected patients vs. controls. Therefore, we determined change in regional adipose tissue from baseline examination to 5 years later among participants in the study of Fat Redistribution and Metabolic Change in HIV Infection., Methods: Regional adipose tissue volume was measured using MRI at both examinations in 477 HIV-infected and 214 control men and women. Lipoatrophy was defined as leg subcutaneous adipose tissue (SAT) below the cutoff point marking the lowest decile (10%) of controls at each examination., Results: HIV-infected and control participants showed similar adipose tissue gains. In men, all SAT depots and visceral adipose tissue started lower and remained lower on average in HIV-infected vs. controls. In women, leg and arm SAT also started lower and remained lower in HIV-infected vs. controls. Mean leg SAT of HIV-infected men was 67% of control men at baseline and 65% at follow-up; for women 83% and 77%. At baseline, 48% of HIV-infected participants had lipoatrophy; on average those with baseline lipoatrophy gained 0.96L of leg SAT compared with 1.23L gain for controls in the lowest decile (P = 0.16). At follow-up, 53% of HIV-infected participants had lipoatrophy. In multivariable models, discontinuation of stavudine appeared to produce little gain in leg SAT ( approximately 1.1%/year)., Conclusion: HIV-infected participants did not substantially recover SAT compared with controls, although both showed average gains. HIV-associated lipoatrophy persisted after 5 years of follow-up.

Objectives: CD4 cell count and plasma viral load are well known predictors of AIDS and mortality in HIV-1-infected patients treated with combination antiretroviral therapy (cART). This study investigated, in patients treated for at least 3 years, the respective prognostic importance of values measured at cART initiation, and 6 and 36 months later, for AIDS and death., Methods: Patients from 15 HIV cohorts included in the ART Cohort Collaboration, aged at least 16 years, antiretroviral-naive when they started cART and followed for at least 36 months after start of cART were eligible., Results: Among 14 208 patients, the median CD4 cell counts at 0, 6 and 36 months were 210, 320 and 450 cells/microl, respectively, and 78% of patients achieved viral load less than 500 copies/ml at 6 months. In models adjusted for characteristics at cART initiation and for values at all time points, values at 36 months were the strongest predictors of subsequent rates of AIDS and death. Although CD4 cell count and viral load at cART initiation were no longer prognostic of AIDS or of death after 36 months, viral load at 6 months and change in CD4 cell count from 6 to 36 months were prognostic for rates of AIDS from 36 months., Conclusions: Although current values of CD4 cell count and HIV-1 RNA are the most important prognostic factors for subsequent AIDS and death rates in HIV-1-infected patients treated with cART, changes in CD4 cell count from 6 to 36 months and the value of 6-month HIV-1 RNA are also prognostic for AIDS.

Background: Agents for the treatment of HIV-1-infected patients with resistance to current antiretroviral (ART) drugs are needed., Methods: TMC114-C202 was a randomized, partially blinded, dose-finding study in treatment-experienced HIV-1-infected patients with one or more primary protease inhibitor (PI) mutations and HIV-1 RNA > 1000 copies/ml. Patients were randomized to receive one of four TMC114 doses given with ritonavir (TMC114/r) or investigator-selected control PI drug(s) (CPI); all received an optimized background regimen. The primary intent-to-treat analysis compared the proportion of patients achieving a >or= 1 log10 copies/ml HIV-1 RNA reduction at week 24 between the treatment arms using the time-to-loss of virological response algorithm., Results: For 278 patients at baseline, mean HIV-1 RNA was 4.7 log10 copies/ml, median CD4 cell count was 106 cells/mul; HIV-1 isolates had a median of three primary PI mutations and a median fold change in lopinavir susceptibility of 80. Discontinuation rates were 23% for TMC114/r versus 64% for CPI. More patients in each TMC114/r dose group achieved >or= 1.0 log10 copies/ml reduction in HIV-1 RNA than in the CPI group (45-62% versus 14%; P

Objective: To evaluate the safety and antiretroviral activity of nelfinavir mesylate at two doses as part of a combination regimen in HIV-infected, antiretroviral-naive patients., Design: Phase III, multicenter, double-blind, placebo-controlled trial., Patients and Methods: Two-hundred and ninety-seven patients were randomized to one of three treatment groups: nelfinavir 750 mg three times daily (tid), nelfinavir 500 mg tid, or matching placebo, each in combination with open-label zidovudine (ZDV) 200 mg tid and lamivudine (3TC) 150 mg twice daily (bid). Data were analyzed on an intent-to-treat basis., Results: Sixty-seven percent of patients receiving nelfinavir 750 mg tid, and 50% receiving nelfinavir 500 mg tid in combination with ZDV/3TC achieved HIV RNA < 400 copies/ml compared to 7% receiving ZDV/3TC plus placebo (P < 0.001); 55% and 30% of patients in the nelfinavir-containing arms achieved HIV RNA < 50 copies/ml at week 24. This compared with 4% in the placebo-containing arm. For patients continuing nelfinavir treatment (750 mg or 500 mg tid as treated) for a further 6 months, the proportions achieving < 400 copies/ml at week 48 were 75% and 54% (P = 0.001) and < 50 copies/ml 61% and 37%, respectively (P = 0.004). The mean increases from baseline in CD4 cell counts were also durable in patients receiving the triple combination nelfinavir therapy. The range and incidence of adverse events was similar for the two nelfinavir-containing arms, with diarrhea being the most common adverse event., Conclusions: Nelfinavir plus ZDV/3TC was superior to ZDV/3TC/placebo. In addition, the 750 mg tid nelfinavir dose was better than the 500 mg tid dose. Virologic responses were sustained over 12 months.

Highly active antiretroviral therapy (HAART) can suppress HIV type 1 plasma viremia to undetectable levels for up to 3 years or more. When the therapy is discontinued, viral rebound occurs in a majority of patients, indicating that HAART is unable to completely eradicate the virus. Initial calculations of the half-lives of the infected cells (estimated to be 14-21 days) suggested that only 3 years continuous HAART therapy would be necessary to achieve complete eradication; however, several studies have determined that the half-lives of chronically infected cells are in the order of 6-44 months. New estimates indicate that it may take as long as 60 years to eradicate the virus. Thus, there has been movement toward combining HAART with various means of augmenting and/or reconstituting the host's immune system, especially HIV-1-specific immune responses. The long-term goal is to discontinue HAART and permit the reconstituted immune system to contain whatever small amounts of the virus remain.

Background: Current potent antiretroviral therapy (using a protease inhibitor and two nucleoside reverse transcriptase inhibitors) produces a durable suppression of HIV replication in less than 75% of treated patients. Identification of predictors of successful therapy might allow the development of improved strategies to increase response rates., Methods: We analyzed retrospectively the results from a multicenter, randomized, double-blind Phase III study of combination anti-HIV therapy with nelfinavir, zidovudine, and lamivudine to evaluate the relationship between virological response over 48 weeks of treatment to variables which could potentially serve as early predictors of long-term response. The goal was to produce long-term suppression of viral load to sensitive (<400 copies HIV RNA/ml) and ultrasensitive (<50 copies HIV RNA/ml) limits of quantification with the Amplicor PCR assay., Findings: Baseline viral load, the change in viral load over the first 4 weeks of treatment, the 2 h post-dose nelfinavir levels and the time to respond to HIV RNA levels of <400 copies/ml and <50 copies/ml have the best predictive value in determining response and response duration. Patients who achieved very low viral nadirs (<50 copies HIV RNA/ml) had significantly longer responses than those who achieved nadirs of 50-400 copies HIV RNA/ml., Interpretation: Parameters that can be measured easily at baseline or early after therapy is started can identify patients at high risk of failure with standard treatment. Such patients may be candidates for more aggressive therapy or for alternative strategies designed to improve outcome. In addition, these results support the use of ultra-sensitive HIV RNA assays to predict long-term outcome of anti-HIV therapy.

Objectives: To evaluate, over 12 weeks, the antiretroviral activity and safety of abacavir, used alone and in combination with zidovudine (ZDV), as treatment for HIV-1-infected subjects who had limited or no antiretroviral treatment., Design: Seventy-nine HIV-1-infected subjects, with CD4 cell counts 200-500 x 10(6)/l and <12 weeks of previous treatment with ZDV were enrolled in a multicenter study. Subjects were randomly assigned to one of four cohorts receiving abacavir monotherapy for the first 4 weeks (200, 400, or 600 mg every 8 h daily, or 300 mg every 12 h daily) and, thereafter, combination therapy of abacavir with 600 mg ZDV or ZDV placebo, administered in a double-blind manner for an additional 8 weeks., Methods: Antiretroviral activity was assessed by measuring changes in plasma HIV-1 RNA levels and CD4+ cell counts. Safety was assessed by monitoring clinical adverse events and laboratory abnormalities during the 12-week period and for 4 weeks post-treatment., Results: Treatment with abacavir, alone or in combination with ZDV, produced marked decreases in plasma HIV-1 RNA loads and increases in CD4+ cell counts in all groups. At week 4, median plasma HIV-1 RNA loads decreased by 1.11-1.77 log10 copies/ml and median CD4+ cell counts increased by 63-111 x 10(6)/l in all groups. At week 12, median HIV-1 RNA loads decreased by 1.02-2.24 log10 copies/ml (abacavir monotherapy) and by 1.81-2.01 log10 copies/ml (abacavir-ZDV); median CD4+ cell counts increased by 79-195 x 10(6)/l (abacavir monotherapy) and by 93-142 x 10(6)/l (abacavir-ZDV). At week 12, the percentage of subjects who had plasma HIV-1 RNA levels below 400 and 40 copies/ml were 28 and 11%, respectively (abacavir monotherapy) and 69 and 22%, respectively (abacavir-ZDV). Eight subjects (10%) discontinued the study prematurely because of adverse events; nausea (n = 4) and hypersensitivity (n = 3) were the most common reasons for withdrawal. There were no deaths among the study subjects., Conclusions: In HIV-infected subjects who have received little or no prior antiretroviral therapy, treatment with abacavir alone or in combination with ZDV is well tolerated and resulted in sustained improvements in key immunologic and virologic efficacy parameters through 12 weeks.

We conducted a three-arm, randomized, phase II study to evaluate the combination of zidovudine (600 mg/day) and zalcitabine (2.25 mg/day) alone or with one of two interferon-alpha2a doses (1 mIU or 6 mIU daily). Primary study endpoints included toxicity and changes from baseline for plasma HIV-1 RNA, CD4 cells, and quantitative microculture at weeks 8 and 24. Sixty-three patients with HIV infection and <400 CD4 cells/mm3 were enrolled; four patients discontinued therapy within 2 weeks. Adverse event rates were 37%, 32%, and 60%, respectively, for the nucleoside, 1-mIU interferon, and 6-mIU interferon combination groups. Increasing doses of interferon resulted in significantly greater hematologic toxicity (p = 0.03) and peripheral neuropathy (p = 0.02). Plasma HIV-1 RNA reductions were noted across all treatment groups at week 8 (p < 0.001) but only for the nucleoside and 1-mIU interferon combination groups at week 24 (p < 0.001). Mean reductions in HIV-1 RNA at week 8 were 0.94, 1.29, and 1.40 log10, respectively, for the nucleoside, 1-mIU interferon, and 6-mIU interferon combination groups (p = 0.05); no differences were noted at week 24. No differences in CD4 cell counts were seen. The addition of interferon-alpha2a to zidovudine and zalcitabine resulted in transient enhanced decreases in viral load and increased toxicity.

A number of virologic and immunologic markers, including serum human immunodeficiency virus (HIV)-1 p24 antigen levels, quantitative HIV-1 microculture of plasma or peripheral blood mononuclear cells, and CD4 cell counts, have been used over the past decade to monitor progression of HIV infection. Although these markers are useful, they have not provided a reliable means of assessing prognosis at all stages of the disease or response to antiretroviral treatment. New molecular techniques are now available that measure viral load in HIV-infected patients by detecting and quantifying virion-associated RNA circulating in plasma. These plasma HIV-1 RNA levels appear to correlate with the clinical disease stage and reflect the response to antiretroviral treatment. Because recent studies have demonstrated that baseline plasma HIV-1 RNA levels and changes in these levels are predictive of clinical outcome, it is strongly recommended that these markers be measured routinely and used as a guide in the management of all patients with HIV disease.

To assess the utility of quantitative competitive-polymerase chain reaction (QC-PCR) measurements of plasma human immunodeficiency virus type 1 (HIV-1) RNA and other viral load markers for assessment of antiretroviral therapy, we used archived cryopreserved specimens from a randomized controlled clinical trial of 135 patients (CD4+ T cell count < or = 500/mm3), comparing zidovudine (500 mg/day) versus the nonnucleoside reverse transcriptase inhibitor L-697, 661 (50, 300, or 1,000 mg daily). We evaluated treatment-associated changes in plasma viral load by standard and immune complex-dissociated (ICD) HIV-1 p24 antigen assays, and, in a representative subset of patients (n = 46), by QC-PCR determination of virion-associated HIV-1 RNA. At baseline, HIV-1 RNA was quantifiable by QC-PCR in all patients tested (100%), whereas standard and ICD HIV-1 p24 antigen tests were positive (> or = 30 pg/ml) in 42% and 56%, respectively. All viral load parameters showed significant decreases from baseline within 1 week of initiation of zidovudine, as measured by standard p24 antigen assay, ICD p24 assay, and QC-PCR. At 1 week, patients treated with either 300 or 1,000 mg/day of L-697,661 showed significant decreases from baseline in plasma standard and ICD p24 antigen and QC-PCR-determined HIV-1 RNA levels. Whereas viral load decreases seen with zidovudine were sustained for the duration of treatment, plasma viral markers often returned to pretreatment levels despite ongoing L-697,661 treatment, with evidence of the emergence of drug-resistant virus. Whereas standard p24, ICD p24, and viral RNA levels changed similarly in response to treatment, the superior sensitivity and available dynamic range of plasma viral RNA assays like QC-PCR analysis provide an advantage for clinical monitoring of plasma viral load, allowing tracking of treatment-related changes even in patients with earlier stage disease and lower levels of viral load.

Objectives: To better characterize viral load profiles through the course of HIV-1 disease and in response to treatment, and to further evaluate quantitative competitive polymerase chain reaction for measurement of viral load, we extended our comparative evaluation of this and other viral load measurements to a total of 118 patients, representing all stages of HIV-1 disease., Design: For cross-sectional analysis across the spectrum of HIV-1 disease, plasma viral load was evaluated in 112 HIV-1-infected patients by quantitative competitive polymerase chain reaction analysis, plasma p24 antigen assay, plasma immune complex-dissociated p24 antigen assay and an endpoint dilution viral culture. Longitudinal specimens from six additional patients were analyzed, extending from the time of presentation with symptomatic acute HIV-1 infection through up to more than 2 years of follow-up. Longitudinal specimens were also studied for three patients over the period of initiation of zidovudine treatment, for 6 weeks of treatment and following temporary withdrawal of the treatment., Methods: All measurement techniques were assessed in replicate aliquots of plasma., Results: Quantitative competitive polymerase chain reaction was the most sensitive measure of viral load, and was best correlated with CD4+ T-cell counts. In longitudinally studied patients, this technique also allowed measurement of plasma virus levels throughout the period of follow-up, even when culture and p24 assays became negative following resolution of acute HIV-1 infection. The quantitative competitive polymerase chain reaction was also able to detect rapid and substantial changes in viral load associated with initiation and temporary withdrawal of antiviral treatment., Conclusions: The quantitative competitive polymerase chain reaction is promising as a sensitive and accurate method for measuring plasma viral load in HIV-1-infected patients, and is useful for following changes in viral load over the natural history of infection and following treatment intervention. The technique is particularly useful for patients with > 200 x 10(6) CD4+ T cells/l, in whom other viral markers are typically negative.