AVANTI 3: a randomized, double-blind trial to compare the efficacy and safety of lamivudine plus zidovudine versus lamivudine plus zidovudine plus nelfinavir in HIV-1-infected antiretroviral-naive patients

The objective of our randomized, multicentre, double-blind, placebo-controlled study was to investigate the safety, tolerability, and antiretroviral and immunological effect of double and triple combination therapy regimens. A total of 105 antiretroviral therapy-naive patients were randomized to receive either zidovudine (300 mg twice per day) plus lamivudine (150 mg twice per day) plus nelfinavir placebo (three times per day) (n=52), or zidovudine/lamivudine (dose as before) plus nelfinavir (750 mg three times per day) (n=53) for 28 weeks. After this time, patients were allowed to switch to open-label zidovudine/lamivudine/nelfinavir. The overall log10 reduction from baseline in plasma HIV-1 RNA was significantly greater in the zidovudine/lamivudine/nelfinavir group than the zidovudine/lamivudine group (P=0.001; median treatment difference, -1.01 log10 copies/ml; 95% confidence interval -1.23 to -0.79), as measured by the average area under the curve minus baseline over 28 weeks. Increases from baseline in CD4 cell counts were statistically significantly greater in the zidovudine/ lamivudine/nelfinavir group (101.5 cells/ml) than the zidovudine/lamivudine group (47.0 cells/ml; P=0.027) at week 28. Of note, the addition of nelfinavir from weeks 28-52 led to an increase in the proportion of subjects with plasma HIV-1 RNA <400 copies/ml from 17% (9/52 patients on zidovudine/lamivudine) to 50% (13/26 patients who switched to zidovudine/lamivudine/nelfinavir). Incidence of drug-related adverse events was similar in the two groups, except for nausea (more common in zidovudine/lamivudine group; 40 versus 17%) and diarrhoea (more common in zidovudine/lamivudine/nelfinavir group; 45 versus 14%). In conclusion, our study confirms the efficacy of triple combination therapy with two nucleoside analogues and a protease inhibitor compared with double-nucleoside therapy. Interestingly, the addition of nelfinavir to zidovudine/lamivudine, even after 6 months of double nucleoside therapy, led to a substantial virological benefit that was sustained over 24weeks in a subset of patients.     

Results of the ALBI trial: a randomized comparison of stavudine/didanosine, zidovudine/lamivudine and alternating treatment in antiretroviral-naive patients

In the ALBI trial, 151 antiretroviral-naive patients with plasma human immunodeficiency virus type 1 (HIV-1) RNA levels of 10,000 to 100,000 copies/ml and CD4 cell counts > or = 200 cells/mm3 received 24 weeks of treatment with stavudine/didanosine (n=51), zidovudine/lamivudine (n=51) or stavudine/didanosine for 12 weeks followed by zidovudine/lamivudine (n=49). Baseline plasma HIV-1 RNA and CD4 cell counts were comparable in the treatment groups. The mean decrease in plasma HIV-1 RNA at 24 weeks in the stavudine/didanosine group (2.26 log10) was significantly greater than that in either the zidovudine/lamivudine group (1.26 log10) or the alternating treatment group (1.58 log10) (P<0.0001 for both). Proportions of patients with plasma HIV-1 RNA level <500 copies/ml (91% vs 42% and 60%) and <50 copies/ml (47% versus 4% and 9%) were significantly greater in the stavudine/didanosine group (P<0.001 for pairwise comparisons). Stavudine/didanosine was associated with a mean increase in CD4 cell count (124 cells/mm3) significantly greater than that in the zidovudine/lamivudine group (62 cells/mm3, P<0.01) and comparable to that in the alternating group (118 cells/mm3). All study regimens were well tolerated. These findings, indicating superiority of stavudine/didanosine over zidovudine/lamivudine in virological and immunological response over 24 weeks, suggest that the combination should be considered as a basis for highly active antiretroviral therapy.     

Highly active antiretroviral therapy versus zidovudine/nevirapine effects on early breast milk HIV type-1 Rna: a phase II randomized clinical trial

BACKGROUND: Defining the effect of antiretroviral regimens on breast milk HIV type-1 (HIV-1) levels is useful to inform the rational design of strategies to decrease perinatal HIV-1 transmission. METHODS: Pregnant HIV-1 seropositive women (CD4+ T-cell count >250 and <500 cells/mm3) electing to breastfeed in Nairobi, Kenya were randomized to highly active antiretroviral therapy (HAART; zidovudine [ZDV], lamivudine and nevirapine [NVP]) during pregnancy and 6 months post-partum or to short-course ZDV plus single-dose NVP (ZDV/NVP). Breast milk samples were collected two to three times per week in the first month post-partum. RESULTS: Between November 2003 and April 2006, 444 breast milk samples were collected from 58 randomized women during the first month after delivery. Between 3 and 14 days post-partum, women in the HAART and ZDV/NVP arms had a similar prevalence of undetectable breast milk HIV-1 RNA. From 15 to 28 days post-partum, women in the HAART arm had significantly lower levels of breast milk HIV-1 RNA than women randomized to ZDV/NVP (1.7 log10 copies/ml [limit of detection] versus >2.10 log10 copies/ml, P<0.001). In contrast to breast milk HIV-1 RNA, suppression of plasma HIV-1 RNA during the neonatal period was consistently several log10 greater in the HAART arm compared with the ZDV/NVP arm. CONCLUSIONS: HAART resulted in lower breast milk HIV-1 RNA than ZDV/NVP; however, ZDV/NVP yielded comparable breast milk HIV-1 RNA levels in the first 2 weeks post-partum. Breast milk HIV-1 RNA remained suppressed in the ZDV/NVP arm despite increased plasma HIV-1 levels, which might reflect local drug effects or compartmentalization.     

Immunological and virological activity of zalcitabine and zidovudine in combination in HIV-positive people with CD4 cell counts of between 200-500 cells/mm3

We evaluated the effect of combination therapy with zidovudine (AZT) plus zalcitabine (ddC) in human immunodeficiency virus type 1 (HIV-1)-infected patients who had not previously received antiretroviral treatment ('naive' patients). The immunological and virological parameters evaluated were CD4 cell count, syncytium-inducing (SI) viral phenotype and plasma HIV-1 RNA copies/ml (HIV viral load). A total of 75 patients entered the study, with CD4 cell counts between 200 and 500 cells/mm3. All received zidovudine (200 mg) plus zalcitabine (0.75 mg) three times daily for 24 weeks. Treatment was well tolerated. However, four patients presented with anaemia (haemoglobin < 10.0 g/dl) and one patient had both anaemia and neutropenia (0.8 x 10(9) neutrophils/l). Combination therapy with zidovudine plus zalcitabine resulted in a pronounced improvement of virological and immunological markers. Approximately 25% of patients achieved undetectable plasma HIV RNA levels (< 200 copies/ml) at week 24. At the end of the study (24 weeks) a significant reduction (> 0.5 log) of plasma HIV RNA was observed in approximately 70% of patients and in 50% an even greater decrease (> 1 log) was achieved. The most significant decrease in mean plasma HIV RNA levels was observed at week 4, whereas the highest increase in CD4 cell count was found at week 24. Approximately 80% of patients who showed baseline plasma HIV RNA levels below 20000 copies/ml had less than 5000 copies/ml at week 24. The plasma HIV RNA reduction observed at week 4 was significantly maintained at week 24. Therefore, we can rapidly select those who will not respond to therapy and adjust the treatment after a short interval. Our study supports the idea of early therapy because all patients who reached undetectable levels of plasma HIV RNA at week 24 had at baseline a median plasma HIV RNA load of 2560 copies/ml. In conclusion, zidovudine in combination with zalcitabine was well tolerated in the majority of patients and led to a significant reduction in plasma HIV RNA copies in most of the patients with initial viraemia lower than 20000 copies/ml.     

Virological and pharmacological parameters predicting the response to lopinavir-ritonavir in heavily protease inhibitor-experienced patients

The genotypic inhibitory quotient (GIQ) has been proposed as a way to integrate drug exposure and genotypic resistance to protease inhibitors and can be useful to enhance the predictivity of virologic response for boosted protease inhibitors. The aim of this study was to evaluate the predictivity of the GIQ in 116 protease inhibitor-experienced patients treated with lopinavir-ritonavir. The overall decrease in human immunodeficiency virus type 1 (HIV-1) RNA from baseline to month 6 was a median of -1.50 log(10) copies/ml and 40% of patients had plasma HIV-1 RNA below 400 copies/ml at month 6. The overall median lopinavir study-state C(min) concentration was 5,856 ng/ml. Using univariate linear regression analyses, both lopinavir GIQ and the number of baseline lopinavir mutations were highly associated with virologic response through 6 months. In the multivariate analysis, only lopinavir GIQ, baseline HIV RNA, and the number of prior protease inhibitors were significantly associated with response. When the analysis was limited to patients with more highly mutant viruses (three or more lopinavir mutations), only lopinavir GIQ remained significantly associated with virologic response. This study suggests that GIQ could be a better predictor of the virologic response than virological (genotype) or pharmacological (minimal plasma concentration) approaches used separately, especially among patients with at least three protease inhibitor resistance mutations. Therapeutic drug monitoring for patients treated by lopinavir-ritonavir would likely be most useful in patients with substantially resistant viruses.     

ACTG 260: a Randomized, Phase I-II, Dose-Ranging Trial of the Anti-Human Immunodeficiency Virus Activity of Delavirdine Monotherapy

ACTG 260 was an open-label, four-arm trial designed to study the safety and anti-human immunodeficiency virus (anti-HIV) activity of delavirdine monotherapy at three ranges of concentrations in plasma compared to those of control therapy with zidovudine or didanosine. Delavirdine doses were adjusted weekly until subjects were within their target trough concentration range (3 to 10, 11 to 30, or 31 to 50 microM). A total of 113 subjects were analyzed. At week 2, the mean HIV type 1 (HIV-1) RNA level declines among the subjects in the three delavirdine arms were similar (0.87, 1.08, and 1.02 log10 for the low, middle, and high target arms, respectively), but by week 8, the subjects in the pooled delavirdine arms showed only a 0.10 log10 reduction. In the subjects in the nucleoside arm, mean HIV-1 RNA level reductions at weeks 2 and 8 were 0.67 and 0.55 log10, respectively. Because viral suppression by delavirdine was not maintained, the trial was stopped early. Rash, which was usually self-limited, developed in 36% of subjects who received delavirdine. Delavirdine monotherapy has potent anti-HIV activity at 2 weeks, but its activity is time limited due to the rapid emergence of drug resistance.     

AVANTI 1: randomized, double-blind trial to evaluate the efficacy and safety of zidovudine plus lamivudine versus zidovudine plus lamivudine plus loviride in HIV-infected antiretroviral-naive patients. AVANTI Study Group

The objective of this randomized double-blind, placebo-controlled trial was to investigate the effect of combination antiretroviral therapy on plasma HIV-1 RNA as measured by HIV RNA PCR and to assess the safety and tolerability of such regimens. The trial was carried out in seven European countries, Australia and Canada and involved antiretroviral-naive patients (n = 106) with CD4 counts between 150-300 cells/mm3 (CDC group A) and 150-500 cells/mm3 (CDC group B/C). Patients were randomly assigned to zidovudine (200 mg three times daily) plus lamivudine (300 mg twice daily) or to zidovudine plus lamivudine plus loviride (100 mg three times daily) for 52 weeks. The main outcome measures were degree and duration of reduction of plasma HIV-1 RNA as measured by RNA PCR and the development of drug-related toxicities sufficiently severe to warrant dose modification, interruption or permanent discontinuation. A mild, though statistically significant difference in favour of zidovudine plus lamivudine plus loviride for log10 plasma HIV-1 RNA (P = 0.022), as compared to zidovudine plus lamivudine, was observed using area-under-the-curve minus baseline (AUCMB). An increase in CD4 cell count in the zidovudine plus lamivudine plus loviride group was observed with a median improvement of 124 cells/mm3 at week 52 compared with 70 cells/mm3 in the zidovudine plus lamivudine group (P = 0.06). Both treatment regimens were well tolerated.     

Anti-human immunodeficiency virus type 1 activity of an anti-CD4 immunoconjugate containing pokeweed antiviral protein.

The ability of an alpha CD4-pokeweed antiviral protein (PAP) immunoconjugate to inhibit replication of human immunodeficiency virus type 1 (HIV-1) was evaluated in vitro with 22 clinical HIV-1 strains obtained from four seropositive asymptomatic individuals, three patients with AIDS-related complex, and four patients with AIDS. Fifteen isolates were from zidovudine-untreated individuals, whereas seven isolates were obtained after 24 to 104 weeks of therapy with zidovudine, alone or alternating with zalcitabine. Mean zidovudine 50% inhibitory concentrations (IC50s) were 126 nM (range, 1 to 607 nM) for isolates from zidovudine-untreated individuals and 2,498 nM (range, 14 to 6,497 nM) for strains from patients treated with antiretroviral agents. Mean alpha CD4-PAP IC50s were 48 x 10(-3) nM (range, 0.02 x 10(-3) to 212 x 10(-3) nM) for isolates from zidovudine-untreated individuals, and 16 x 10(-3) nM (range, 2 x 10(-3) to 28 x 10(-3) nM) for isolates from treated patients. Overall, higher concentrations of alpha CD4-PAP were necessary to inhibit HIV-1 strains from untreated individuals at more advanced stages of disease. Seventeen isolates were susceptible to zidovudine (mean IC50, 117 nM), and five were resistant to zidovudine (mean IC50, 3,724 nM). Mean alpha CD4-PAP IC50s were 43 x 10(-3) nM for zidovudine-susceptible isolates and 19 x 10(-3) nM for isolates resistant to zidovudine. All HIV-1 strains had IC50s greater than 0.5 nM for unconjugated PAP, the alpha CD19-PAP immunoconjugate, and monoclonal antibody alpha CD4. At concentrations as high as 5,000 nM, alphaCD4-PAP did not inhibit colony formation by normal bone marrow progenitor cells(BFU-E, CFU-GM , and CFU-GEMM) or myeloid cell lines (KG-1 and HL-60) and did not decrease cell viabilities of T-cell (Jurkat) or B-cell (FL-112 and Raji) precursor lines. Overall, alphaCD4-PAP demonstrated more potent anti-HIV-1 activity than zidovudine and inhibited replication of zidovudine-susceptible and zidovudine-resistant viruses at concentrations that were not toxic to lymphohematopoietic cell populations.     

Prediction of HIV-1 RNA suppression and its durability during treatment with zidovudine/lamivudine

To predict the probability of long-term viral suppression during treatment with zidovudine and lamivudine, human immunodeficiency virus type 1 (HIV-1) RNA values were retrospectively pooled for 1083 patients from six randomized, double-blind clinical trials. All analyses of HIV-1 RNA were obtained using the Roche Amplicor assay or its earlier prototype. Time to loss of response was evaluated by Kaplan-Meier analysis; Cox proportional hazards models were used to assess the influence of baseline variables. Among 523 patients with < or = 6 months of prior zidovudine treatment, the probability of HIV-1 RNA suppression below 400 copies/ml at 48 weeks was 71% in those with baseline HIV-1 RNA < 5000 copies/ml, but only 14% in those with HIV-1 RNA between 50,000 and 200,000 copies/ml. Among 560 patients with > 6 months of prior zidovudine treatment, the rates of sustained viral suppression were lower, but also significantly associated with the baseline HIV-1 RNA. Multivariate analyses showed no independent effect of CD4 cell count, age, sex, race, or CDC disease stage on the probability of sustained HIV-1 RNA suppression. When patients with < or = 6 months of prior therapy were stratified based on the magnitude of HIV-1 RNA nadir achieved during treatment, those who reached a nadir of < 400 copies/ml retained this response for significantly longer time periods than the ones who only achieved partial viral suppression. In conclusion, baseline HIV-1 RNA levels and the duration of prior zidovudine therapy strongly predict the antiretroviral efficacy of zidovudine/lamivudine. The baseline parameters should influence the choice of the antiretroviral regimen.     

Safety, pharmacokinetics, and efficacy of (+/-)-beta-2',3'-dideoxy-5-fluoro-3'-thiacytidine with efavirenz and stavudine in antiretroviral-naïve human immunodeficiency virus-infected patients

Racivir [RCV; (+/-)-beta-2',3'-dideoxy-5-fluoro-3'-thiacytidine], a 50:50 racemic mixture of the two beta nucleoside enantiomers, is currently in development for the treatment of human immunodeficiency virus type 1 (HIV-1) infections. RCV was administered once a day orally for 14 days at doses of 200, 400, or 600 mg in combination with stavudine and efavirenz to HIV-1-infected treatment-na?ve male volunteers in a phase Ib/IIa study. Six volunteers at each dose were monitored for a total of 35 days for tolerance, pharmacokinetics, and plasma HIV RNA levels. RCV in combination with stavudine and efavirenz was well tolerated at all doses tested. Pharmacokinetic parameters were dose proportional, and the maximum concentration of drug in serum at all doses exceeded the 90% effective concentration for wild-type HIV-1. Viral loads dropped as expected in all dosage groups, with mean reductions from 1.13 to 1.42 log10 by day 4 and 2.02 to 2.43 log10 by day 14. HIV RNA levels remained suppressed for more than 2 weeks in the absence of any additional therapy, with mean viral loads ranging from 2.1 to 2.6 log10 below baseline through day 28. By day 35, HIV RNA levels began to increase but still remained >1 log10 below baseline levels.