Comparison of the QUANTIPLEX HIV-1 RNA 2.0 assay with the AMPLICOR HIV-1 MONITOR 1.0 assay for quantitation of levels of human immunodeficiency virus type 1 RNA in plasma of patients receiving stavudine-didanosine combination therapy

We compared the QUANTIPLEX HIV-1 RNA 2.0 assay with the AMPLICOR HIV-1 MONITOR 1.0 assay for quantitation of human immunodeficiency virus type 1 (HIV-1) RNA in plasma in the Stadi trail, which evaluated a stavudine plus didanosine combination therapy in 52 patients. HIV-1 RNA baseline values measured with AMPLICOR HIV-1 MONITOR 1.0 were significantly higher than those measured with QUANTIPLEX HIV-1 RNA 2.0, and decreases in HIV-1 RNA levels from baseline were also found to be significantly higher when measured with the AMPLICOR HIV-1 MONITOR 1.0 assay. The frequency of HIV-1 RNA levels below the lower limit of quantitation was significantly higher with QUANTIPLEX HIV-1 RNA 2.0 than with AMPLICOR HIV-1 MONITOR 1.0. Reanalysis of these results by an ultrasensitive procedure of AMPLICOR HIV-1 MONITOR 1.0 or by a modified version of the test that included additional primers adapted for non-B HIV-1 clades yielded greater differences between the QUANTIPLEX HIV-1 RNA 2.0 assay and the AMPLICOR HIV-1 MONITOR 1.0 assay. Our results indicate that a valid comparison of the virological efficacies obtained with different antiretroviral drug regimens requires the use of the same viral load quantitation procedure; further standardization between the different HIV-1 RNA quantitation kits is therefore needed.

Efficacy and safety of stavudine and didanosine combination therapy in antiretroviral-experienced patients

OBJECTIVES

To assess the efficacy, tolerance, and safety of combination antiretroviral therapy with didanosine and stavudine in HIV-infected patients with CD4+ cell counts > 100 x 10(6)/l and HIV plasma RNA > 10(4) copies/ml previously treated with other antiretroviral agents for at least 3 months.

DESIGN

In this open, multicentre, non-randomized, Phase II pilot study, adult patients were administered didanosine (200 mg twice daily) plus stavudine (40 mg twice daily) for 6 months. Patients for whom the first regimen had led to undetectable HIV RNA levels were offered a second 6-month course of treatment; those who had achieved insufficient immunological and virological gains in the first 6 months were given a new combination.

METHODS

Primary evaluation of efficacy was based on viral load measured by branched DNA second-generation testing (lower limit of detection, 500 copies/ml) and CD4+ cell counts; secondary evaluations included AIDS-defining events and clinical side-effects.

RESULTS

Sixty-five patients with median prior antiretroviral therapy of 24 months (65 with zidovudine, 29 with zalcitabine) were included in the study. At baseline, median CD4+ cell count was 198 x 10(6)/l and median plasma HIV RNA was 80000 copies/ml (4.9 log10 copies/ml). In this heavily pretreated population, an increase in the mean CD4+ cell count was observed (+70 x 10(6)/l at 24 weeks). In addition, rapid and prolonged antiviral activity was seen, with a mean maximal decrease of 1.1 log10 copies/ml at week 4, a mean decrease of 0.89 log10 copies/ml at week 24, and a plasma RNA viraemia < 500 copies/ml achieved in 14% of patients at week 24.

CONCLUSIONS

Combination therapy with stavudine and didanosine is safe and leads to a sustained antiviral effect, even in patients with prolonged prior antiretroviral exposure and low CD4+ cell counts.

Resolution of severe Kaposi's sarcoma after initiation of antiretroviral triple therapy

OBJECTIVES

To study the relationship between effective antiretroviral therapy, monitored by CD4 counts, and it s influence on the clinical course of AIDS associated Kaposi's sarcoma.

METHODS

Four representative cases with AIDS and advanced Kaposi's sarcoma (KS) showed improvement of histologically proven KS s in various sites, including pulmonary disease, treated with liposomal doxorubicin. CD4 counts increased significantly during administration of triple antiretroviral therapy. In three cases chemotherapy cycles were extended and subsequently discontinued for 4, 14 and 4 months, respectively, without any relapse. In one other case interferonalpha therapy has been started overlapping with doxorubicin prior to permanent discontinuation of doxorubicin.

CONCLUSIONS

Data of those patients suggest that in patients with increasing CD4 counts KS's chemotherapy intervals should be extended or even discontinued. In some patients change of therapy to interferon alpha can be considered. A potent combined antiretroviral therapy may enhance efficiency of KS treatment even in patients with high CD4 counts.

An open randomized controlled trial of zidovudine plus lamivudine versus stavudine plus lamivudine

OBJECTIVE

To compare the antiretroviral effect and safety of zidovudine (ZDV)-lamivudine (3TC) with that of stavudine (d4T)-3TC.

METHODS

In an open randomized controlled trial antiretroviral therapy-naive patients who had CD4+ counts > or = 200 x 10(6)/l and plasma HIV RNA load > or = 10000 copies/ml were randomized to receive ZDV-3TC (200 mg three times daily and 150 mg twice daily, respectively) or d4T-3TC (40 mg and 150 mg, both twice daily). If the plasma HIV RNA level at week 8 or thereafter was > 500 copes/ml, indinavir was added at the next scheduled visit. Genotypic resistance analysis of the reverse transcriptase gene was performed at week 0 and 12. Results over 24 weeks were reported.

RESULTS

Forty-seven patients were treated (24 took ZDV-3TC; 23 took d4T-3TC). Plasma HIV RNA levels decreased from median 4.80 to 3.15 log10 copies/ml (ZDV-3TC, P < 0.0001) and from 4.98 to 3.03 log10 copies/ml (d4T-3TC, P < 0.0001) after 12 weeks of treatment. Indinavir was added at week 12 in 11 out of 21 patients with ZDV-3TC and in 10 out of 22 patients with d4T-3TC. Median virus load at week 24 was 2.41 log10 and 2.29 log10 copies/ml (P=0.14), respectively. Seventy-five per cent (15 out of 20; ZDV-3TC) and 95% (18 out of 19; d4T-3TC) of patients had a virus load of < 500 copies/ml. Genomic evidence for 3TC resistance was found in all patients tested (11/11 ZDV-3TC and 12/12 d4T-3TC). At week 12, CD4 cell counts had increased with a median of 110 x 10(6)/l in the ZDV-3TC group (baseline, 315 x 10(6)/l) and a median of 115 x 10(6)/l in the d4T-3TC group (baseline 290 x 10(6)/l). At week 24, the median increases were 90 and 120 x 10(6)/l, respectively. Overall the increase of CD4+ cells was higher in the d4T-3TC group (P=0.02).

CONCLUSION

d4T-3TC is at least as effective as ZDV-3TC, but 3TC resistance emerged in all patients investigated. The virological response of the dual nucleoside combination is of short duration. However, after addition of indinavir the virus load could be reduced to < 500 copies/ml in the majority of patients. The increase in CD4+ cell count was significantly greater in the d4T-3TC group. To prevent 3TC resistance, the drug should not be used in regimens containing only two nucleosides, irrespective the virus load at baseline.

Risk of HIV dementia and opportunistic brain disease in AIDS and zidovudine therapy

OBJECTIVE

To determine the incidence of HIV dementia and opportunistic brain disease in AIDS relative to the use of licensed antiretoviral medication (zidovudine, zalcitabine, didanosine, and stavudine).

METHOD

Medical records were evaluated retrospectively in a longitudinal cohort of 1109 patients with AIDS during the period 1991-4. Treatment groups were defined by start and duration of zidovudine treatment, the drugs used most often during this period were: (a) no zidovudine, (b) zidovudine before AIDS, (c) zidovudine before and after AIDS, and (d) zidovudine used in AIDS. Main outcome measures were cumulative incidence and survival from AIDS to onset of HIV dementia, progressive multifocal leukoencephalopathy (PML), cerebral toxoplasmosis, and primary CNS lymphoma.

RESULTS

Risk of brain disease including HIV dementia and opportunistic brain disease was reduced in patients who started zidovudine before AIDS and continued in AIDS (relative risk (RR) 0.55, 95% confidence interval (95% CI) 0.36-0.84) as well as zidovudine initiated in AIDS (RR 0.27, 95% CI 0.17-0.45) compared with untreated subjects. Treatment effects were not constant over time, decreasing by 14%-32% for each six months of follow up. This was supported by unadjusted incidences across groups stratified by duration of zidovudine use, indicating reduced risk with treatment for up to 18 months but not with longer duration of use of zidovudine. Other antiretroviral drugs had no significant effect, although these were used by only 14% of patients in this cohort.

CONCLUSION

The time limited but effective neuroprotection offered by zidovudine monotherapy for <18 months suggests that non-specific mechanisms of cerebral immunological defence may benefit from antiretroviral treatment. Due to the limitations of a retrospective study these findings require confirmation and further investigation in the context of current combination drug treatments.

A placebo-controlled trial of didanosine plus stavudine, with and without hydroxyurea, for HIV infection. The Swiss HIV Cohort Study

OBJECTIVE

To explore the short-term effects on surrogate markers for HIV progression of didanosine (ddl) plus stavudine (d4T), with or without hydroxyurea.

DESIGN

Randomized, double-blinded, prospective study.

SETTING

Swiss HIV Cohort Study.

PATIENTS

A total of 144 patients (75% antiretroviral-naive) were studied (mean baseline HIV-1 RNA, 4.53 log10 copies/ml; mean CD4 cell count, 370 x 10(6)/l).

INTERVENTION

Patients received ddl (200 mg twice daily) plus d4T (40 mg twice daily), with additional hydroxyurea (500 mg twice daily) or placebo.

MAIN OUTCOME MEASURES

The primary endpoint was a reduction of viraemia below 200 copies/ml after 12 weeks. At that time, patients who did not reach the primary endpoint were withdrawn in the hydroxyurea arm, whereas patients in the placebo group had the option of adding hydroxyurea to ddl and d4T. All patients were followed until week 24.

RESULTS

After 12 weeks, 54% of the patients randomized to hydroxyurea had viraemia below 200 copies/ml, compared with 28% on placebo (P < 0.001). Using an ultrasensitive assay with a limit of detection of 20 copies/ml, 19% of patients receiving hydroxyurea had viraemia levels below 20 copies/ml, compared with 8% on placebo (P = 0.05). Mean decrease in HIV-1 RNA was 2.3 and 1.7 log10 copies/ml for hydroxyurea and placebo groups, respectively (P = 0.001). Hydroxyurea was found to induce lymphopenia (-124 x 10(6)/l). Increase in CD4 cell counts was +28 x 10(6)/l during hydroxyurea treatment compared with +107 x 10(6)/l on placebo (P = 0.001).

CONCLUSIONS

Hydroxyurea improved the antiviral activity of d4T and ddl over a 12-week period, but was associated with a smaller increase in CD4 cell counts due to hydroxyurea-induced lymphopenia.

Cerebrospinal-fluid HIV-1 RNA and drug concentrations after treatment with lamivudine plus zidovudine or stavudine

BACKGROUND

Treatment and prevention of HIV-1-related central-nervous-system disease may be dependent on penetration of antiretroviral drugs into the central nervous system. Few data are available about cerebrospinal-fluid penetration and concomitant changes of HIV-1-RNA concentrations during treatment with antiretroviral agents. We investigated these effects in HIV-1-infected people.

METHODS

28 antiretroviral-naive individuals with CD4 cell counts of 200/microL or more and plasma HIV-1-RNA concentrations of 10,000 or more copies/mL who were free of neurological symptoms were randomly assigned lamivudine plus either stavudine (n = 17) or zidovudine (n = 11). We did lumbar punctures on 28 individuals before and 22 individuals after 12 weeks of treatment to assess HIV-1-RNA and drug concentrations in cerebrospinal fluid.

FINDINGS

All 28 individuals had detectable HIV-1-RNA concentrations in the cerebrospinal fluid (median 4.64 log10 copies/mL and 4.20 log10 copies/mL in the lamivudine plus zidovudine and lamivudine plus stavudine groups, respectively). There was no correlation between plasma and cerebrospinal-fluid HIV-1-RNA concentrations (r = 0.18, p = 0.35). After 12 weeks of treatment none of the individuals had detectable HIV-1-RNA concentrations in the cerebrospinal fluid. The highest drug concentration in the cerebrospinal fluid was for lamivudine followed by stavudine and zidovudine. Concentrations were consistent over time, unlike plasma concentrations. Therefore, we found time-dependent cerebrospinal-fluid to plasma drug-penetration ratios, which were highest for zidovudine followed by stavudine and lamivudine.

INTERPRETATION

The two drug combinations were equally effective in the decrease of cerebrospinal fluid HIV-1-RNA concentrations. All drugs penetrated the cerebrospinal fluid. Antiretroviral drugs other than zidovudine might be useful in the prevention of AIDS dementia complex.

Direct transport of 2',3'-didehydro-3'-deoxythymidine (D4T) and its ester derivatives to the cerebrospinal fluid via the nasal mucous membrane in rats

We investigated the absorption and transport of 2',3'-didehydro-3'-deoxythymidine (D4T) and its ester prodrugs from the nasal cavity in rats. The absorption of D4T and its acetate (C2-D4T) was rapid and almost complete, although the hemi-succinate (Suc-D4T) was absorbed rather slowly; the plasma concentrations of the prodrug, Suc-D4T, and regenerated D4T remained unchanged throughout the experimental period (180 min). Concentrations in the cerebrospinal fluid (CSF) following intravenous (i.v.) and intranasal (i.n.) administration were also measured. After i.n. administration, drug concentrations were higher in the fraction derived from the subarachnoid space located close to the nasal mucosa than those in the fractions located far from the nasal cavity. This difference was not found following the i.v. administration of the drugs. Following nasal administration, the intact Suc-D4T was found in the CSF at a concentration higher than that of D4T, although transport of the intact prodrug to the CSF was not observed following i.v. administration. These results suggest that direct transport of the drugs from the nasal cavity to the CSF significantly contributes to the higher concentrations in CSF of D4T and/or its ester prodrugs, and indicate the possible value of nasal administration for the treatment of patients with AIDS dementia.

A single-dose study to assess the penetration of stavudine into human cerebrospinal fluid in adults

Penetration of stavudine into the cerebrospinal fluid (CSF) was studied in healthy humans. In this open, randomized study, a single oral dose of 40 mg of stavudine was given to 12 fasting volunteers > or = 18 years of age. Subjects were divided into three groups based on the time of CSF sampling (i.e., 0.75-1.25, 2-3, or 4-5 hours after dosing). Blood samples were collected over an 8-hour period after dosing and included a sample simultaneous with CSF collection to permit an estimate of CSF : plasma ratios. Stavudine concentrations in plasma and CSF were determined by a validated high-performance liquid chromatography method. Repeated measurements of vital signs, physical examination, and clinical laboratory tests indicated that the stavudine dose was well tolerated. CSF levels were not detected 0.75 to 1.25 hours after dosing. Thereafter, levels were detected in the CSF of five subjects; the mean concentration was 61 ng/ml. The mean CSF: plasma ratio increased with time, from 0.16 at 2 to 3 hours postdose in one subject to 0.40 at 4 to 5 hours postdose in four subjects. In conclusion, the mean stavudine concentration of 61 ng/ml achieved in the CSF of five subjects exceeds the ED50 of clinical isolates of HIV (230 nM, 52 ng/ml).

A pilot study of combination therapy with indinavir, stavudine (d4T), and didanosine (ddI) in children infected with the human immunodeficiency virus

Twelve children infected with the human immunodeficiency virus were treated orally with indinavir, stavudine, plus didanosine for 12 to 48 weeks. Therapy was limited in some cases by nonadherence, intolerance, toxicity, and virologic failure. Marked increases in CD4+ lymphocyte counts and decreases in plasma human immunodeficiency virus RNA concentrations suggest that the regimen has potent antiviral activity.

Antiviral effect of double and triple drug combinations amongst HIV-infected adults: lessons from the implementation of viral load-driven antiretroviral therapy

OBJECTIVE

To study the antiviral effect and predictors of response to two- and three-drug regimens amongst antiretroviral-naive individuals using an intent-to-treat analysis.

MAIN OUTCOME MEASURE

Suppression of plasma viral load to < 500 copies/ml.

PATIENTS

A total of 420 (264 double drug, 156 triple drug) individuals in a province-wide treatment programme were studied.

RESULTS

A decrease in plasma viral load to < 500 copies/ml was documented in 197 (47%) subjects. This was independently associated with a lower baseline plasma viral load (odds ratio, 3.67; 95% confidence interval, 2.13-6.30) and initiation onto a three-drug regimen (odds ratio, 3.86; 95% confidence interval, 2.24-6.66). Median plasma viral load failed to reach < 500 copies/ml and in fact rebounded in the two-drug group. In contrast, 91 (58%) subjects receiving three drugs reached < 500 copies/ml during the study period.

CONCLUSION

These results support the use of powerful triple drug regimens as initial therapy in HIV-infected individuals.