Baseline Resistance and Virological Outcome in Patients with Virological Failure who Start a Regimen Containing Abacavir: Eurosida Study

Objectives

To investigate the ability of several HIV-1 drug-resistance interpretation systems, as well as the number of pre-specified combinations of abacavir-related mutations, to predict virological response to abacavir-containing regimens in antiretroviral therapy-experienced, abacavir-naive patients starting an abacavir-containing regimen in the EuroSIDA cohort.

Patients and methods

A total of 100 HIV-infected patients with viral load (VL) >500 copies/ml who had a plasma sample available at the time of starting abacavir (baseline) were included. Resistance to abacavir was interpreted by using eight different commonly used systems that consisted of rules-based algorithms or tables of mutations. Correlation between baseline abacavir-resistance mutations and month 6 virological response was performed on this population using a multivariable linear regression model accounting for censored data.

Results

The baseline VL was 4.36 log10 RNA copies/ml [interquartile range (IQR): 3.65–4.99 log10 RNA copies/ml] and the median CD4 cell count was 210 cells/μl (IQR: 67–305 cells/μl). Our patients were pre-exposed to a median of seven antiretrovirals (2–12) before starting abacavir therapy. The median (range) number of abacavir mutations (according to the International AIDS Society-USA) detected at baseline was 3.5 (0–8). Overall, the Kaplan–Meier estimate of the median month 6 VL decline was 0.86 log10 RNA copies/ml [95% confidence intervals (95% CI): 0.45–1.24]. The VL in those patients ( n=31) who intensified treatment by adding only abacavir decreased by a median 0.20 log10 RNA copies/ml (95% CI: -0.18; +0.94). The proportion of patients who harboured viruses fully resistant to abacavir among the eight genotypic resistance interpretation algorithms ranged from 12% [Agence Nationale de Recherches sur le SIDA (ANRS)] to 79% [Stanford HIV RT and PR Sequence Database (HIVdb)]. Some interpretation systems showed statistically significant associations between the predicted resistance status and the virological response while others showed no consistent association. The number of active drugs in the regimen was associated with greater virological suppression (additional month 6 VL reduction per additional sensitive drug=0.51, 95% CI: 0.15–0.88, P=0.006); baseline VL was also weakly associated (additional month 6 VL reduction per log10 higher=0.30, 95% CI: -0.02; +0.62, P=0.06). In contrast, the number of drugs previously received was associated with diminished viral reduction (additional month 6 VL reduction per additional drug=-0.14, 95% CI: -0.28; 0.00, P=0.05).

Conclusions

Our results revealed a high degree of variability among several genotypic resistance interpretation algorithms currently in use for abacavir. Therefore, the interpretation of genotypic resistance for predicting response to regimens containing abacavir remains a major challenge.

Response to Antiretroviral Therapy among Patients Exposed to Three Classes of Antiretrovirals: Results from the Eurosida Study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2–5.2], CD4 lymphocyte count 150/mm3 (IQR 60–274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load <500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P=0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P=0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P=0.02), number of new drugs in the regimen (RH 1.20 per drug; P=0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P=0.035) and time spent on HAART with viral load >1000 copies/ml (RH 0.96 per extra month; P=0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

Neutropenia in patients with HIV infection: a case control study in a cohort of 1403 patients between 1982 and 1993

The relationship between neutropenia and increased risks of severe infections in patients with HIV infection and the factors associated with neutropenia-induced infections was studied by a retrospective comparative study using matched case-control analysis. A database (1982-1993) of 1870 patients with HIV infection was searched, and from 484 patients with neutropenia, 177 patients were paired with 177 nonneutropenic control subjects. Descriptive analysis and development of logistic models were used to determine factors associated with the risk of developing bacterial infections and major fungal infections. The occurrence of severe bacterial and fungal infections was significantly higher in neutropenic patients (p < or = 0.001). Bacteremia was more common in neutropenic patients than in nonneutropenic patients (p < or = 0.02) in the matched case-control analysis. Risk of severe infections was strongly associated with the neutrophil count (p < or = 0.05), clinical stage, and hemoglobin level (p < 0.005) when paired patients were compared. More neutropenic episodes occurred between 1991 to 1993, possibly due to prolonged survival and the increasing use of concomitant myelosuppressive therapies. Neutropenic HIV-infected patients are significantly at risk of developing severe infections at the end-stage of HIV disease, and this may have a major impact on hospitalization and death. Preventing neutropenia could dramatically improve the quality of life of these patients.

Discontinuation of maintenance therapy for CMV retinitis in AIDS patients on highly active antiretroviral therapy

The use of highly active antiretroviral therapy (HAART) has dramatically modified the natural history of cytomegalovirus retinitis (CMVR) in AIDS patients. In this context, we discontinued maintenance therapy in eight AIDS patients with previous CMVR and a good and persistent immune and virological response to HAART (CD(4) >/= 75/mm(3) in all patients, viral load </=30,000 copies of RNA/ml in seven patients and negative CMV viremia in six patients whose viremia was evaluated). The median recurrence-free interval before maintenance discontinuation was 613 days (326-787). No recurrence was observed after a median follow-up of 248 days (183-368) without maintenance therapy. In conclusion, discontinuation of maintenance therapy for CMVR in AIDS patients with good immune response to HAART can be considered and appears to be safe with a careful follow-up.

Use of hydroxyurea in heavily pretreated patients with HIV infection

This study was designed to assess the potential benefit of hydroxyurea (HU) on virological and immunological markers in heavily pretreated human immunodeficiency virus (HIV)-infected patients. A total of 118 patients received hydroxyurea as treatment added to their current antiviral therapy ('add' group), or as treatment added together with a switched nucleoside reverse transcriptase inhibitor or protease inhibitor or with the introduction of an additional antiviral agent ('add and switch' group). Efficacy of HU was also compared among patients receiving didanosine- and non-didanosine-containing regimens. Results showed that HU was not associated with a significant decline in plasma HIV-1 RNA, and no significant difference in plasma HIV-1 RNA changes was noted between patients who did and did not receive didanosine. The absolute number of CD4 cells, but not the CD4 percentage, declined significantly from baseline. Significantly more grade 3-4 neutropenia occurred among patients receiving HU combined with zidovudine, although the discontinuation rate for haematological toxicity was similar in zidovudine- and non-zidovudine-treated patients.

A controlled trial of dapsone versus pyrimethamine-sulfadoxine for primary prophylaxis of Pneumocystis carinii pneumonia and toxoplasmosis in patients with AIDS

Pneumocystis carinii pneumonia (PCP) is the most common opportunistic human immunodeficiency virus (HIV)-related infection, occurring in 85% of HIV infected patients without prophylaxis. Preventive treatment is required when CD4 cell count falls below 200 cells per cubic millimeter. Cotrimoxazole has been shown to be highly effective but alternative drug regimens are often necessary because of the frequent drug hypersensitivity exhibited by HIV infected patients. The aim of this prospective, open, randomized, one-site study, involving HIV-infected patients with a CD4 cell count below 200/mm3, or a percentage under 20%, randomly assigned to receive either dapsone 50 mg daily or Fansidar one tablet weekly, was to compare the efficacy and safety of these drugs in the primary prophylaxis of PCP. Both dapsone and Fansidar appear to be safe and effective alternative agents for the prevention of PCP. Their role in Toxoplasma gondii prophylaxis requires further evaluation.

[Impact of anti-retroviral treatment with protease inhibitors on the evolution of cytomegalovirus retinitis in the patient carrying acquired immunodeficiency syndrome]

Up to now cytomegalovirus retinitis (CMVR) recurrence in AIDS patients was considered to be very high, even on maintenance therapy. Protease inhibitors (PI) are antiretroviral molecules which, with more efficacity than reverse transcriptase inhibitors, decrease viral charge and increase CD4's count aswell as survival. We analysed the impact of PI on CMVR evolution in a retrospective review of 18 patients with CMVR on maintenance therapy and PI treatment. In a first group, 13 patients started PI some time after CMVR diagnosis (median CD4 = 9/mm3). A second group of 5 patients developed CMVR (median CD4 = 63/mm3) after initiation of PI. In the first group, incidence of CMVR recurrences/1000 patients days was 6,45 (2323 patients days of follow-up (PDFU) before starting PI and 3,44 (4066 PDFU) after starting PI. In this group, during the follow-up's period of CD4's count inferior to 75/mm3, incidence of CMVR is 6,84/1000 patients days and becomes 0,86/1000 patients days during the follow-up's period of CD4's count superior to 75/mm3. In the second group, incidence of CMVR was 0/1000 patients days (1972 PDFU). In summary, incidence of CMVR decreases with PI's treatment. Interruption of CMVR maintenance therapy could be considered in patients with CD4's count higher than 75/mm3.

Survival of European patients with Kaposi's sarcoma as AIDS-defining condition during the first decade of AIDS. AIDS in Europe Study Group

OBJECTIVES

To determine whether the survival of patients with Kaposi's sarcoma as first manifestation of AIDS has changed between 1979 and 1989; and to define whether prognosis factors could be identified.

PATIENTS AND METHODS

This is a multicentric retrospective cohort study from 52 centers in 17 European countries involving adults AIDS patients diagnosed between 1979 and 1989. Variables such as age, sex, geographical regions, transmission groups, date of Kaposi's sarcoma diagnosis, zidovudine use, CD4+ cell count and concomitant opportunistic infections or AIDS-related malignancies were evaluated by using uni- and multivariable proportional hazard models. Log-rank tests were used to determine which variables were associated with survival.

RESULTS

From the 6,546 AIDS patients recruited in the database of the AIDS in Europe Study Group, 1,394 were diagnosed with Kaposi's sarcoma at the time of AIDS diagnosis, from 1979 and 1989. A total of 1,047 Kaposi's sarcoma patients died during the follow-up period. By Kaplan-Meier analyses, the median and mean survival for these Kaposi's sarcoma patients were 17 and 25 months, respectively, with no change over time. However, age, sex (female), geographic region, low CD4+ cell count (< 150 x 10(6)/l) and some opportunistic infections and non-Hodgkin's lymphoma were associated with a poorer prognosis. Zidovudine use, year of diagnosis and risk factor for HIV-1 infection brought no additional information as predictor of mortality.

CONCLUSIONS

This study suggests that the survival of patients with Kaposi's sarcoma as first manifestation of AIDS has remained poor during the last decade in contrast with the overall AIDS survival which had significantly improved from a median of 13-18 months during the same period of observation. There is a need for further prospective information to explain the worse prognosis in women and the geographical variations.

Epidemiology of AIDS-related Kaposi's sarcoma in Europe over 10 years. AIDS in Europe Study Group

OBJECTIVES

To determine the incidence and risk factors associated with Kaposi's sarcoma (KS) occurrence as an AIDS-defining condition or after the diagnosis of AIDS.

DESIGN

Multicentre retrospective cohort study of AIDS in Europe database from 52 clinical centres in 17 European countries.

METHODS

Patients' charts (n = 6546) were reviewed and collected in the database of the AIDS in Europe Study Group from 1979 to 1989. At the time of AIDS diagnosis 1394 patients had KS, whereas an additional 525 others developed KS after AIDS diagnosis. Univariate analysis and development of multivariate models determined factors associated with KS occurrence.

RESULTS

Frequency of KS as an AIDS-defining condition significantly declined over time (P < 0.0001). In our cohort of patients, homo-/bisexual men from central Europe with CD4 cell counts > 150 x 10(6)/l were statistically more likely to develop KS at the time of AIDS diagnosis (P < 0.0001). For patients with an AIDS diagnosis other than KS, the probability of developing KS during the follow-up was 10 and 24% after 12 and 36 months, respectively. Variables significantly associated with a further KS development were transmission group, central European residence, previous herpes simplex infection other than ulcers, and low CD4 cells (< 150 x 10(6)/l). Previous zidovudine therapy had no influence on KS appearance. For patients who developed KS subsequent to AIDS diagnosis, there was no significant decline of the incidence over the 10-year time period.

CONCLUSIONS

This large cohort study clearly shows that demographic data such as sex, transmission group and region of Europe have a major influence on KS development. It also suggests that KS as an AIDS-defining disease occurs earlier in the course of the chronic HIV infection than other opportunistic diseases. Reasons for geographical variations and its declining frequency as an initial AIDS diagnosis remain undetermined.

Pharmacokinetics of R 82913 in AIDS patients: a phase I dose-finding study of oral administration compared with intravenous infusion

The pharmacokinetics of oral administration of R 82913, or tetrahydroimidazol [4,5,1-jk]-benzodiazepin-2(1H)-one or -thione (TIBO), was compared with those of intravenous administration in five AIDS patients. TIBO was administered as a single daily 1-h infusion of 100 mg for 29 days and orally as a single daily dose for 14 days with three consecutive regimens of 100, 200, and 100 mg with probenecid (1 g) daily. Each cycle was followed by a wash-out period. Oral bioavailability of TIBO appears to be low and is not improved by the adjunction of probenecid. Trough levels obtained with oral administration systematically remained far below the 90% inhibitory concentration of TIBO against human immunodeficiency virus type 1 (HIV-1). Tolerance of TIBO was excellent. No clinical efficacy could be demonstrated. p24 antigenemia decreased significantly in one patient under intravenous therapy. TIBO derivatives are promising anti-HIV-1 agents in vitro, but improvement of oral bioavailability is needed before implementation of long-term efficacy and tolerability studies. Moreover, rapid emergence of resistance, which has been recently documented, constitutes a major problem with most nonnucleoside reverse transcriptase inhibitors.