CD4-guided scheduled treatment interruptions compared with continuous therapy for patients infected with HIV-1: results of the Staccato randomised trial.

BACKGROUND: Stopping antiretroviral therapy in patients with HIV-1 infection can reduce costs and side-effects, but carries the risk of increased immune suppression and emergence of resistance. METHODS: 430 patients with CD4-positive T-lymphocyte (CD4) counts greater than 350 cells per muL, and viral load less than 50 copies per mL were randomised to continued therapy (n=146) or scheduled treatment interruptions (n=284). Median time on randomised treatment was 21.9 months (range 16.4-25.3). Primary endpoints were proportion of patients with viral load less than 50 copies per mL at the end of the trial, and amount of drugs used. Analysis was intention-to-treat. This study is registered at ClinicalTrials.gov with the identifier NCT00113126. FINDINGS: Drug savings in the scheduled treatment interruption group, compared with continuous treatment, amounted to 61.5%. 257 of 284 (90.5%) patients in the scheduled treatment interruption group reached a viral load less than 50 copies per mL, compared with 134 of 146 (91.8%) in the continued treatment group (difference 1.3%, 95% CI-4.3 to 6.9, p=0.90). No AIDS-defining events occurred. Diarrhoea and neuropathy were more frequent with continuous treatment; candidiasis was more frequent with scheduled treatment interruption. Ten patients (2.3%) had resistance mutations, with no significant differences between groups. INTERPRETATION: Drug savings with scheduled treatment interruption were substantial, and no evidence of increased treatment resistance emerged. Treatment-related adverse events were more frequent with continuous treatment, but low CD4 counts and minor manifestations of HIV infection were more frequent with scheduled treatment interruption.

Biphasic decline of CD4 cell count during scheduled treatment interruptions.

In 115 patients whose scheduled treatment interruptions (STI) lasted 24 weeks, the CD4 cell count declined by a median of 30 cells/ml/week during the first 4 weeks, compared with 3 cells/ml/week during the next 20 weeks. In multivariate regression, a pronounced early fall in CD4 cells correlated with a higher CD4 cell count at the start of STI, with more gain in CD4 cells during antiretroviral treatment preceding STI, and with a higher viral load at week 4.

A prospective trial of structured treatment interruptions in human immunodeficiency virus infection.

BACKGROUND: According to the "autovaccination hypothesis," reexposure to human immunodeficiency virus (HIV) during treatment interruptions may stimulate the HIV-specific immune response and lead to low viremia after withdrawal of highly active antiretroviral treatment (HAART). Many patients who started HAART earlier in their disease course than is currently recommended would like to discontinue, but it is unknown whether it is safe to do so. OBJECTIVES: To determine whether repeated treatment interruptions of HAART (1) stimulated the cytotoxic HIV-specific immune response and whether such stimulation correlated with low viremia off treatment, and (2) were safe with respect to clinical complications, development of viral resistance, and decline in CD4 cell counts. DESIGN: Interventional study with before-after comparison. SETTING: Outpatient clinics of university hospitals in Switzerland and Spain. PATIENTS: A total of 133 patients receiving HAART, with a median CD4 cell count of 740/ microL, and whose viral load had been undetectable for a median of 21 months. INTERVENTIONS: HAART was interrupted for 2 weeks, restarted, and continued for 8 weeks. After 4 such cycles, treatment was indefinitely suspended 40 weeks after study entry. MAIN OUTCOME MEASURES: HIV-specific cytotoxic T-cell responses were evaluated by interferon gamma enzyme-linked immunospot analysis. The proportion of "responders" (viral load <5000 copies/mL) was measured at weeks 52 and 96. HIV-related diseases and CD4 cell counts were recorded. RESULTS: Seventeen percent of patients (95% confidence interval, 11%-25%) were responders at week 52, and 8% at week 96. Low pre-HAART viral load and lack of rebound during weeks 0 to 40 predicted response. HIV-specific CD8+ T cells increased between week 0 (median, 343 spot-forming cells per million peripheral blood lymphocytes [SFC/106 PBL]) and week 52 (median, 1930 SFC/106 PBL), but there was an inverse correlation between response and the number of spot-forming cells. Eighty-five (64%) of 133 patients stopped therapy for at least 12 weeks, and 55 (41%) for at least 56 weeks. The median CD4 cell count decreased from 792/ microL to 615/ microL during the first 12 weeks without treatment, but stabilized thereafter. One patient (0.75%) developed drug resistance necessitating salvage treatment. There were no AIDS-related clinical complications. CONCLUSIONS: Results of this study do not favor the autovaccination hypothesis. Treatment interruptions did not provoke clinical complications, and there was little drug resistance. Comparative trials will have to show what benefit, if any, is associated with intermittent, as opposed to continuous treatment.

A controlled trial of granulocyte macrophage-colony stimulating factor during interruption of HAART.

OBJECTIVES: To explore the effect of granulocyte macrophage colony stimulating factor (GM-CSF) on viral load and CD4 cell count during interruption of highly active antiretroviral therapy (HAART). METHODS: Patients on effective HAART (CD4 cell count > 400 x 10(6)/l; viral load < 50 HIV RNA copies/ml) were randomized to one of two groups: 12 weeks' treatment interruption plus, during the first 4 weeks, 300 microg GM-CSF (Leucomax-Novartis) by subcutaneous injection three times weekly (GM-CSF group); 12 weeks' scheduled treatment interruption (STI-only group). Viral load, CD4 cell count, clinical events and side effects of treatment were monitored. RESULTS: Thirty-three patients, 15 in the GM-CSF group and 18 in the STI-only group, were evaluated according to the intention-to-treat principle. The two groups were well matched with regard to pre-HAART viral loads and CD4 cell counts. During STI, viraemia was approximately two to three times lower in the group receiving GM-CSF (max 4.97 versus 5.45 in STI-only group; P = 0.03). Fifteen out of 17 patients in the STI-only group showed a decrease in their CD4 cell count between weeks 0 and 4 (median decrease 231 x 10(6) cells/l; P < 0.001); there was no such tendency in the GM-CSF group (P = non-significant when comparing CD4 cell counts at weeks 0 and 4). The median CD4 cell AUC (area under the curve) from week 0 to week 12 was higher in the GM-CSF group (9166 cells.week) than in patients without GM-CSF (7257), P = 0.02. GM-CSF produced local reactions in 88% of patients, and generalized symptoms such as fever, back pain or headache in 82% of patients. Seventy-six percent of patients completed the planned course of 12 injections. CONCLUSIONS: The administration of GM-CSF blunted the viral rebound following interruption of HAART, and largely prevented a decrease of CD4 cell counts during a 12-weeks-treatment interruption. A better understanding of the underlying mechanism(s) may help to identify synergistic treatment targets and improved administration protocols to enhance control of chronic HIV infection.

Failures of 1 week on, 1 week off antiretroviral therapies in a randomized trial.

BACKGROUND: Scheduled treatment interruptions are being evaluated in an effort to decrease costs and side effects of highly active antiretroviral therapy (HAART). A schedule of 1 week on and 1 week off therapy offers the promise of 50% less drug exposure with continuously undetectable HIV RNA concentration. METHODS: In the Staccato study 600 patients on successful HAART were to be randomized to either continued therapy, CD4-guided therapy, or one week on, one week off therapy. A scheduled preliminary analysis evaluated effectiveness in the 1-week-on-1-week-off arm. RESULTS: Of 36 evaluable patients, 19 (53%) had two successive HIV RNA concentrations > 500 copies/ml at the end of the week off therapy, and were classified as virological failure. Most of those who failed took didanosine, stavudine, saquinavir, and ritonavir (11 patients). In these patients, there was no evidence of mutations suggestive of drug resistance, and plasma saquinavir levels were within the expected range. Two of three patients failing on triple nucleotides had drug resistance mutations, but nonetheless responded to reintroduction of triple nucleotide therapy. One of two patients taking nevirapine, and one of eight taking efavirenz, also failed. Both had resistance mutations at the time of failure, but not at baseline. CONCLUSIONS: The 1-week-on-1-week-off schedule, as tested in the Staccato study, showed an unacceptably high failure rate and was therefore terminated.

No change in calculated creatinine clearance after tenofovir initiation among Thai patients.

OBJECTIVES: Thai patients have a lower average body weight than patients from western Europe or the USA. Tenofovir is largely prescribed at the standard dosage of 300 mg once daily: therefore, the per kilogram dose is higher in Thailand than in the USA. We asked the question whether this higher per kilogram dose was associated with more nephrotoxicity. METHODS: Thai patients from the Staccato trial were treated with tenofovir/lamivudine combined with ritonavir-boosted saquinavir. Creatinine values were measured before the start of tenofovir and then every 12 weeks. Renal function was assessed using the Cockcroft-Gault formula and the MDRD formula. To compare CL(CR) before and after tenofovir, the t-paired or Wilcoxon signed rank tests were used. One-way analysis of variance and Spearman's correlation coefficient were used to study CL(CR) longitudinally. RESULTS: CL(CR) remained stable after a median of 21 weeks on tenofovir (difference of +1.06 mL/min; 95% CI -2.7-4.8, P=0.58), even among patients with underlying diseases. The mean CL(CR) remained stable across time (P=0.17). CONCLUSIONS: We did not find renal dysfunction on tenofovir among Thai patients included in the Staccato trial. Tenofovir could be safely prescribed at a standard dosage of 300 mg once daily in the Thai population.