Virological treatment failure of protease inhibitor therapy in an unselected cohort of HIV-infected patients

Impact of HIV type 1 protease, reverse transcriptase, cleavage site, and p6 mutations on the virological response to quadruple therapy with saquinavir, ritonavir, and two nucleoside analogs

Genotype alterations of HIV-1 protease, reverse transcriptase, cleavage sites p7/p1 and p1/p6, as well as p6(gag) and transframe protein p6* were studied in an observational cohort of 42 individuals who received antiretroviral therapy consisting of saquinavir, ritonavir, and two nucleoside analogs. In a multivariate logistic regression analysis, the prior protease inhibitor experience (odds ratio, 6.20; 95% CI, 1.22-31.38) and the presence of primary protease mutations (odds ratio, 9.99; 95% CI, 1.05-94.72) were independently associated with virological failure. Moreover, a trend was observed in that individuals with N-terminal amino acid insertions in the proline-rich motif of the p6(gag) protein were less likely to experience virological failure (OR, 0.17; 95% CI, 0.02-1.35; p = 0.09). In contrast, the presence of secondary protease, reverse transcriptase, or cleavage site mutations was not independently associated with treatment failure. However, mutations at cleavage site p7/p1 (p = 0.01) and C-terminal p6* mutations (p = 0.02) were both associated with primary protease mutations. In conclusion, the presence of primary protease mutations was the most important predictor of the subsequent virological response. Moreover, there is some evidence that insertions in the proline-rich area of the p6(gag) protein may affect the virological response. The relationship between mutations of cleavage sites or C-terminal p6* residues and protease mutations suggests that these alterations may serve a compensatory role, increasing viral fitness.

Preclinical psychopharmacology of AIDS-associated dementia: lessons to be learned from the cognitive psychopharmacology of other dementias

Following a brief discussion of the epidemiology, underlying neuropathological mechanisms, neuropsychological symptoms and present treatment strategies of AIDS-associated dementia (AAD), parallels are drawn between the longer standing research on drugs for the treatment of other cognitive disorders, particularly senile dementia, and ongoing efforts to develop psychopharmacological approaches for the treatment of the cognitive impairments in AAD. Important aspects of hypotheses designed to guide such a research are indicated with the help of a speculative, paradigmatic hypothesis concerning the role of cortical cholinergic inputs in AAD. Furthermore, aspects of validity of animal models, and cognition as a crucial intervening variable in the effects of potential treatments, are evaluated.

Virologic outcome and predictors of virologic failure of highly active antiretroviral therapy containing protease inhibitors

In this observational single-center cohort study outside the clinical trial setting, outcome and predictors of virologic failure of highly active antiretroviral therapy (HAART) containing a protease inhibitor were evaluated in human immunodeficiency (HIV)-infected persons. The study population consisted of 807 protease inhibitor-naive HIV-seropositive patients who initiated antiretroviral therapy with reverse transcriptase inhibitors and protease inhibitors (indinavir, nelfinavir, ritonavir) between January 1997 and January 1999. Demographic variable, plasma HIV-1 RNA levels, CD4+ T-cell count, adverse drug reactions, and adherence to HAART were assessed. Virologic treatment response was defined as a decrease in plasma HIV-1 RNA load from baseline to below 500 copies per milliliter after 12 months of therapy. Levels of HIV-1 RNA were undetectable in 43% of patients at 12 months. Factors associated with failure to suppress viral load included age 40 years or younger, baseline CD4+ T cell count less than 200 x 10(6) per liter baseline viral load greater than 4.3 log(10) per milliliter, and non-adherence to HAART. After adjustment by logistic regression, non-adherence was the only statistically significant variable associated with virologic failure (odds ratio 0.38, 95% confidence interval 0.21 to 0.67). Unselected patients in whom protease inhibitor is started in a usual clinical setting achieve viral suppression less frequently than do patients in controlled clinical trials. Failure to adherence to HAART was the strongest predictor of virologic failure.

A randomized, double-blind, placebo-controlled study of itraconazole capsules for the prevention of deep fungal infections in immunodeficient patients with HIV infection

OBJECTIVES

To determine whether systemic or deep fungal infections can be prevented, a double-blind, placebo-controlled, phase III trial of itraconazole prophylaxis was undertaken in HIV-infected patients.

METHODS

HIV-1 infected patients with CD4 counts < 300 cells/microL were treated with itraconazole (200 mg per day) or matching placebo and followed for 2 years. Development of deep fungal infections, episodes of mucocutaneous candidiasis, change in CD4 count, survival and safety data were collected at each study visit.

RESULTS

Three hundred and seventy-four patients received study medication, 187 were given itraconazole and 187 matching placebo. Time to development of deep fungal infection did not differ between groups, in an intention to treat analysis. Low CD4 cell count and prior use of Pneumocystis carinii pneumonia (PCP) prophylaxis were significantly associated with a more rapid development of deep fungal infection (P = 0.044 and 0.017, respectively). Itraconazole treatment significantly reduced the incidence of oral candidosis (25% vs. 48% P < 0.001) and time to development of oral candidosis (508 vs. 413 days, P < 0.001) but not the number of deep fungal infections (11 vs. 13). Survival did not differ significantly between groups (nine vs. 14 deaths). CD4 counts decreased significantly over time in both study arms. Adverse events did not differ between groups; 20% vs. 23% stopped study medication due to an adverse experience.

CONCLUSIONS

Although itraconazole prophylaxis significantly reduced the number and time to development of oral candidosis, too few episodes of deep fungal infection were noted to determine whether itraconazole prophylaxis was effective for this condition. Chronic itraconazole treatment is well tolerated in HIV-infected patients with marked immunodeficiency.

A randomized trial of nelfinavir, ritonavir, or delavirdine in combination with saquinavir-SGC and stavudine in treatment-experienced HIV-1-infected patients

PURPOSE

To evaluate the 24-week impact of saquinavir-enhancing antiretroviral therapy on viral replication in patients previously treated with nucleoside analogues with or without prior saquinavir hard-gel capsules (HGC).

METHOD

Patients were randomized in three groups to receive the following: Group 1-nelfinavir (750 mg tid), saquinavir soft-gel capsule (SGC) (800 mg tid), and stavudine (40 mg bid); Group II-ritonavir (400 mg bid), saquinavir-SGC (400 mg bid), and stavudine (40 mg bid); or Group III-delavirdine (400 mg tid), saquinavir-SGC (800 mg tid), and stavudine (40 mg bid). Viral loads, CD4 count, and safety were assessed over a 24-week period with an additional 6-month follow-up.

RESULTS

73 patients received randomized therapy; 14 of whom were SQV naïve, with a median baseline viral load of 3.6 log(10) and a CD4 count of 370 cells/mm(3). By 6 months, the median decreases in plasma viral loads were 0.26, 0.71, and 0.29 log(10) copies/mL for groups I, II, and III, respectively. The median increases in CD4 counts, for groups I, II, and III, were 52, 40, and 69 cells/mm(3) at 6 months, respectively. Changes in viral load and CD4 counts at 6 months and 1 year were not significantly different between the treatment groups. More patients discontinued therapy in the ritonavir arm (35%) for drug intolerance or toxicity compared to either the nelfinavir or delavirdine arms (15% and 5%, respectively). In a multivariate analysis, baseline viral load, younger age, and baseline saquinavir resistance were significantly associated with detectable viral load at 24 weeks.

CONCLUSION

The use of antiretroviral agents that pharmacokinetically boost saquinavir levels has a modest benefit in saquinavir-experienced patients.

The insufficient suppression of viral load by saquinavir hard gel is reversible: a retrospective cohort study

PURPOSE

To assess the effect of changing antiretroviral therapy in patients initially treated with saquinavir hard gel capsule (hgc).

METHOD

A retrospective cohort study comparing the virological and immunological responses in antiretroviral-naïve patients initially treated with a regimen of saquinavir-hgc, zidovudine, and lamivudine, with patients receiving either ritonavir or indinavir on a background of zidovudine and lamivudine.

RESULTS

Twenty-nine patients starting with saquinavir-hgc as the protease inhibitor (PI) component were compared to 58 patients starting with ritonavir (n = 16) or indinavir (n = 42). Median follow-up time was 30 and 33 months, respectively. Twelve, 18, 24, and 30 months after starting a regimen including saquinavir-hgc, 72%, 50%, 4%, and 0% of patients still received this PI. At these time points, 35%, 24%, 59%, and 74% of the patients in the saquinavir group obtained an HIV-RNA <500 copies/mL compared to 76%, 72%, 66%, and 65% in the indinavir/ritonavir group. No significant difference in CD4 count between the two groups was observed.

CONCLUSION

We found that saquinavir-hgc, in combination with nucleoside reverse transcriptase inhibitors, suppressed viral load insufficiently in HIV patients naïve to antiretroviral therapy. However, the suboptimal effect of saquinavir-hgc seems reversible after optimizing the antiretroviral regimen, at least for the short term.

Identification of novel HLA-A2-restricted human immunodeficiency virus type 1-specific cytotoxic T-lymphocyte epitopes predicted by the HLA-A2 supertype peptide-binding motif

Virus-specific cytotoxic T-lymphocyte (CTL) responses are critical in the control of human immunodeficiency virus type 1 (HIV-1) infection and will play an important part in therapeutic and prophylactic HIV-1 vaccines. The identification of virus-specific epitopes that are efficiently recognized by CTL is the first step in the development of future vaccines. Here we describe the immunological characterization of a number of novel HIV-1-specific, HLA-A2-restricted CTL epitopes that share a high degree of conservation within HIV-1 and a strong binding to different alleles of the HLA-A2 superfamily. These novel epitopes include the first reported CTL epitope in the Vpr protein. Two of the novel epitopes were immunodominant among the HLA-A2-restricted CTL responses of individuals with acute and chronic HIV-1 infection. The novel CTL epitopes identified here should be included in future vaccines designed to induce HIV-1-specific CTL responses restricted by the HLA-A2 superfamily and will be important to assess in immunogenicity studies in infected persons and in uninfected recipients of candidate HIV-1 vaccines.

Hyper-excretion of human immunodeficiency virus type 1 RNA in saliva

Anatomical compartments (e.g., the reproductive tract) are reservoirs of human immunodeficiency virus type-1 (HIV-1) and potential sites of residual infection in patients receiving anti-retroviral therapy (ART). Viral hyper-excretion relative to blood is a hallmark of reservoirs. To determine whether hyper-excretion can occur in the oral cavity, we compared viral loads in blood plasma and saliva of 67 adults. Salivary viral hyperexcretion was defined as a four-fold or higher viral load in saliva than in plasma. HIV-1 RNA was detected in 79% of plasma samples, in 44% of unfiltered saliva samples, in 16% of filtered saliva samples, and in 59% of saliva-derived cell pellets. Compared with non-hyper-excretors (n = 62), hyper-excretors (n = 5) had elevated levels of viral RNA in unfiltered saliva and saliva-derived cells, HIV-associated periodontal disease, gingival inflammation, and no combination ART. Morphological characterization of cell pellets identified lymphocytes as a likely HIV-1 source. These collective findings are consistent with an oral HIV-1 reservoir in selected individuals.

The use of and response to second-line protease inhibitor regimens: results from the EuroSIDA study

OBJECTIVE

To describe the use of second line protease-inhibitor (PI) regimens across Europe and to determine factors associated with virological and immunological response.

DESIGN

Analysis of data from 984 patients with a median follow-up of 21 months enrolled in EuroSIDA. Patients started their second PI-containing regimen at least 16 weeks after starting the first PI-containing regimen and with viral load > 1000 copies/ml.

METHODS

Virological response was defined as a viral load < 500 copies/ml and immunological response as an increase of 50 x 10(6)/l or more in CD4 lymphocyte count.

RESULTS

The median CD4 cell count at starting the second PI was 171 x 10(6) cells/l; viral load was 4.45 log copies/ml. As a second PI regimen, 45% were using a dual PI, while of those on one PI, indinavir (42%) and nelfinavir (34%) were most common. In multivariate Cox models, a higher viral load at starting the second PI [relative hazard (RH), 0.67 per 1 log higher; 95% confidence interval (CI), 0.58-0.77; P < 0.0001) and a lower CD4 cell count (RH, 1.15 per 50% higher; 95% CI, 1.06-1.26; P = 0.0014) were associated with a reduced probability of virological response. Those who had achieved viral suppression on the first PI-regimen were more likely to respond to the second (RH, 1.65; 95% CI, 1.30-2.10; P < 0.0001) as were those who added one or two new nucleosides to their second PI.

CONCLUSIONS

Patients who initiate a second PI regimen at lower viral load, higher CD4 cell count or who added new nucleosides tended to be more likely to achieve a viral load < 500 copies/ml. The roles of cross-resistance and adherence in response to second-line regimens needs further investigation.

Efficacy, tolerance, and pharmacokinetics of the combination of stavudine, nevirapine, nelfinavir, and saquinavir as salvage regimen after ritonavir or indinavir failure

The high rate of protease inhibitor treatment failure in clinical cohorts makes it necessary to define novel salvage therapies. In a prospective study of 31 HIV-infected patients included in a salvage regimen with stavudine, nevirapine, nelfinavir, and saquinavir, viral load decreased a median of 1.65 log(10) and 1.95 log(10) after 6 and 12 months of treatment, respectively, and 35 and 56% of patients had an HIV RNA level below 50 copies/ml at the same time points. At baseline, the mean number of mutations in the protease gene was 10 (2-19), and the V82A and L90M mutations were present in 54 and 21% of patients. The presence of the V82A mutation did not affect significantly the rate of response (36 vs. 38%), whereas the L90M mutation was associated with treatment failure (0 vs. 43%). Plasma trough levels of nelfinavir (NFV) and saquinavir (SQV), in a twice daily dosing regimen, were above the protein-corrected IC(95) in most patients despite the addition of an enzymatic inducer such as nevirapine, and peak levels were 2- and 5-fold increased with respect to standard doses. However, pharmacokinetics of saquinavir-hard gel capsule (SQV-hgc) did not improve significantly in the three times daily dosing regimen. In conclusion, the combination of stavudine, nevirapine, nelfinavir, and saquinavir increased plasma drug levels and produced an adequate virological response in patients who had failed indinavir or ritonavir therapy. This degree of response is not significantly decreased in the presence of genotypic mutations associated with indinavir/ritonavir (IDV/RTV) resistance.

Predictors of Virological Response in HIV-Infected Patients to Salvage Antiretroviral Therapy that Includes Nelfinavir

Different salvage strategies have been used to regain control in patients with HIV who have virological failure on combination antiretroviral therapy. We conducted a cohort study of 63 extensively antiretroviral pretreated patients who initiated nelfinavir as part of salvage therapy, to determine predictors of virological response. The maximum HIV RNA response was >0.5 log10 copies/ml reduction in 43 patients (68%), including 21 patients (33%) who had suppression to <500 copies/ml. Corresponding response rates at 24 weeks were 41 and 19%, respectively. Responders and non-responders could not be distinguished by mean baseline HIV RNA or CD4 cell count, duration of prior protease inhibitor (PI) use, introduction of an initial non-nucleoside reverse transcriptase inhibitor or the number of antiretroviral agents changed when nelfinavir was added, likely reflecting the homogeneity of the population studied. The only parameter predictive of response was virus genotype. Response rates were lower in patients with increasing numbers of primary ( P=0.045) or secondary ( P=0.001) PI mutations. The addition of increasing numbers of reverse transcriptase mutations further impaired response rates ( P=0.004).

Virological and immunological response to HAART therapy in a community-based cohort of HIV-1-positive individuals

PURPOSE

To determine virological and immunological response to highly active antiretroviral therapy (HAART) and to investigate factors influencing response in a community-based setting.

METHOD

Plasma HIV RNA levels and CD4 cell counts were studied in 168 unselected individuals starting HAART including indinavir or ritonavir or hard-gel saquinavir-containing regimens.

RESULTS

Overall, 60% of the patients reduced their HIV RNA to below 500 Eq/mL, but half of them experienced a subsequent virologic rebound. Patients with higher baseline HIV RNA, higher baseline CD4 cell count, and simultaneous initiation of combination therapy and patients on indinavir or ritonavir regimen were more likely to have virologic response within 6 months since HAART initiation. Patients with lower baseline CD4 cell count and with lower rates of viral clearance had a higher probability of a subsequent virologic rebound. Forty percent of the patients had increased their CD4 cell counts by more than 100 cells/microL (immunologic response). The probability of immunologic response was independent of baseline HIV RNA levels and CD4 cell count; however, the more complete the virologic suppression, the higher the probability of immunologic response. Thirty percent of the patients had discordance between virologic and immunologic responses.

CONCLUSION

The rate of virologic failure in this unselected group of patients was higher than that observed in randomized clinical trials, but only a minority (11%) of the patients were treatment naïve. Starting combination therapy simultaneously and initiating antiretroviral therapy before advanced HIV disease has developed predict virologic response, whereas the magnitude of viral suppression predicts mid to long immunological response.

Prospective randomized two-Arm controlled study to determine the efficacy of a specific intervention to improve long-term adherence to highly active antiretroviral therapy

BACKGROUND

Nearly perfect compliance seems to be indispensable to obtain the maximum benefit from highly active antiretroviral therapy (HAART). Interventions to ensure a high level of adherence during a relatively long-term period of therapy are necessary.

METHODS

This is a prospective, randomized, two-arm controlled study including patients starting their first-or second-line HAART who were randomized to receive psychoeducative intervention to implement adherence (experimental group [EG]) or a usual medical follow-up (control group [CG]). We aimed to study the efficacy of a psychoeducative intervention to ensure long-term adherence to HAART, its relation with the virologic efficacy of treatment, and to determine the variables related to long-term adherence. Visits were made at weeks 0, 4, 24, and 48 for data collection. Self-reported adherence was registered at each visit and its veracity was tested by randomized blood analyses performed without previous warning to 40% of patients. Appropriate adherence was defined as the consumption of >/=95% of medication prescribed. Statistical analyses were performed both by the as treated (AT) and the intention to treat missing = failure (ITT) methods.

RESULTS

In all, 116 patients were included. At week 48, 94% of patients in the EG versus 69% controls achieved adherence >/=95% (p =.008); 89% of patients in the EG versus 66% controls had HIV-1 RNA levels <400 copies/ml (p =.026). Overall, 85% of patients with adherence >/=95% but only 45% of those with adherence <95% had viral load (VL) <400 copies/ml (p =. 008). In multivariate analysis, variables significantly related to adherence were having received a psychoeducative intervention (odds ratio [OR], 6.58; p =.04), poor effort to take medication (OR, 5.38; p =.03), and high self-perceived capacity to follow the regimen (OR, 13.76; p =.04). Self-reported adherence and drug plasma levels coincided in 93% of cases. However, differences in adherence did not reach statistical significance in the ITT analysis although a clear tendency toward benefit was observed in EG.

CONCLUSIONS

Specific and maintained psychoeducative interventions based on excellence on clinical practice are useful to keep high levels of adherence as well as high levels of viral suppression. There is a clear relation between high adherence levels and virologic success. Assessment of certain specific variables related to adherence may be helpful to monitor patient's compliance in the clinical setting.

HIV-1 drug resistance genotyping. A review of clinical and economic issues

The development of mutations associated with resistance to antiretroviral therapy (ART) has been shown to be a major cause of treatment failure in patients infected with HIV-1. These resistance mutations can be assessed by a genotyping test that probes for specific mutations within the HIV genome or sequences specific genes, at a cost $US500/test (2000 prices). The stated goal of HIV-1 genotyping is to target HIV therapy effectively. This, as shown in the preliminary research, should result in better clinical outcomes and a lower incidence of virological failure and may be associated with lower costs of treatment. Failure of ART may result in an increase in costs of at least $US250 per patient per month, as assessed in 1 study, with costs rising further as patients experience multiple virological failures. Therefore, there is an economic as well as a therapeutic premium on the prevention of ART failure. The actual economic cost of genotyping has been preliminarily explored in the context of the antiretroVIRal ADAPTation (VIRADAPT) trial, which found no significant difference in the 1-year treatment cost of patients with and without genotyping. There is some evidence of cost neutrality or savings with genotypic testing but it needs to be further explored within the context of carefully framed prospective trials.

Shift in HIV resistance genotype after treatment interruption and short-term antiviral effect following a new salvage regimen

OBJECTIVE

To investigate the changes in genotypic drug-resistance pattern, plasma HIV RNA and CD4 cell count after treatment interruption and assess the short-term antiviral effect of a new salvage regimen.

DESIGN

Prospective study of 38 patients with multiple failing regimens who had completely stopped all medication for 3 months before a three to five-drug regimen was reintroduced according to clinical guidelines.

METHODS

Patients were tested for HIV resistance before and after treatment interruption by population-based sequencing and clonal analysis of selected patients.

RESULTS

Discontinuation of therapy for 3 months was associated with a median increase in HIV RNA of 0.4 log10 and a median decrease in CD4 cell count of 43 x 10(6)/l. Sixty-one per cent of patients had a shift from the drug-resistant genotype to a predominantly wild-type genotype. The patients significantly likely to show genotype reversion were those in Centers for Disease Control groups A or B, who had been exposed to few drugs, had a low plasma HIV RNA, or a high CD4 cell count. The only independent factor predicting genotype reversion was the clinical stage. The median change in plasma HIV RNA at month 3 after treatment reintroduction was -2.3 log10 copies/ml in patients who had genotype reversion compared with -0.6 log10 copies/ml in patients without genotype reversion (P = 0.004).

CONCLUSION

Suspending treatment for 3 months after multiple failures could be a suitable strategy for optimizing salvage therapy provided it is instituted early, before the HIV disease becomes too advanced.

Three-year effectiveness of highly active antiretroviral treatment in the Luxembourg HIV cohort

Clinical trials have shown that highly active antiretroviral treatment (HAART) is able to reduce HIV plasma viral loads to undetectable in 70% to 90% of patients and to increase CD4 cell counts. HAART in community settings (i.e., nonclinical trial situations) is reported to be much less effective.

STUDY DESIGN

Observational study.

PURPOSE

The aim of our study was to evaluate the effectiveness of protease inhibitor (PI)-based HAART in the Luxembourg HIV cohort after 36 months of treatment in previously treated and untreated patients. The secondary aim was to identify surrogate markers associated with long-term virologic and immunologic outcomes.

PATIENTS AND METHOD

Seventy-three PI-naive patients, who started on HAART, combining one PI and two nucleoside reverse transcriptase inhibitors (NRTIs),with a follow-up of 3 years, were evaluated with plasma viral load and CD4 cell counts every 3 months and were analyzed retrospectively. Patients who had been treated previously with NRTI (n = 48) were at a more advanced stage of disease.

RESULTS

Overall, there was a mean decrease in viral load compared to baseline of -1.89 log RNA copies/mL (SD = 1.40) that persisted at month 36. Sixty-two percent (62%) of patients reached an undetectable viral load (i.e., below 500 copies/mL): 82% and 53% of NRTI-naive and NRTI-experienced patients, respectively (p =.013). CD4 cell counts increased progressively in both groups with a sustained effect (mean increase of 146 cells/mL +/- 241) at month 36. NRTI-naive patients had a mean increase of 257 cells/mL (SD = 305), in contrast to experienced patients who had an increase of 108 cells/mL (SD = 206) at 3 years. Proportions of patients with a CD4 count under 200 cells/mL fell after 3 years for NRTI-naive (from 66% to 43%) and for experienced patients (from 32% to 13%). Predictors of short duration of viral load response were in decreasing order of importance: clinical AIDS, the use of saquinavir hard gel formulation as initial PI, and the number of NRTIs previously used. Viral load response was the only significant predictor of CD4 changes.

CONCLUSION

In a community setting, effectiveness of PI-based HAART at 3 years is still achieved for most patients. NRTI-experienced patients have a good long-term response rate even if it is lower than NRTI-naive patients. A poor treatment response is associated with a more advanced stage of disease before HAART is introduced.

Immunological, virological and clinical response to highly active antiretroviral therapy treatment regimens in a complete clinic population. Royal Free Centre for HIV Medicine

BACKGROUND

Highly active antiretroviral therapy (HAART) is now widely used in clinical practice and gives rise to a range of immunological, virological and clinical responses.

OBJECTIVES

To describe the immunological, virological and clinical response to HAART and to examine the frequency of modification of the HAART regimen among patients from a single treatment centre.

METHODS

Kaplan-Meier estimation and incidence rates were used to describe responses to HAART (a protease inhibitor or non-nucleoside drug in addition to at least two nucleoside analogues) among 421 patients from the Royal Free Hospital in London.

RESULTS

The median CD4 cell count at starting HAART was 186 x 10(6) cells/l [interquartile range (IQR) 76-310] and viral load was 5.13 log10 copies/ml (IQR 4.66-5.56). At 6 months after starting HAART, 51.1% of patients were estimated to have experienced a 100 x 10(6) cells/l increase in CD4 cell count; the median time for viral load to fall below 400 copies/ml was 3.7 months (95% confidence interval 3.2-4.4). At 6 months after the first viral load was < 400 copies/ml, 16.4% of patients were estimated to have failed on the basis of a single viral load > 400 copies/ml and 12.4% were estimated to have failed if the more stringent definition of two viral loads above the limit of detection was used. Compared with the pre-HAART era, the incidence of death among patients on HAART was one sixth of that level; new AIDS-defining illnesses was one seventh; and hospital admissions was one fifth. In total, 141 patients (33.5%) stopped at least one of the antiretroviral agents included as part of their HAART regimen; the occurrence of side effects was the most common reason (n = 63; 44.7%).

CONCLUSION

A good response occurred to an initial HAART regimen. There was a high rate of virological relapse, which varied considerably according to the definition of failure used. Even so, the rates of clinical progression and hospital admissions observed to date were low. Further follow-up of these patients is required to determine their long-term immunological, virological and clinical outcome.

Efficacy and safety of twice daily first-line ritonavir/indinavir plus double nucleoside combination therapy in HIV-infected individuals. German Ritonavir/Indinavir Study Group

OBJECTIVE

To evaluate the virological efficacy and safety of quadruple therapy with two nucleoside analogues and ritonavir (400 mg twice daily) plus indinavir (400 mg twice daily) combination in antiretroviral therapy-naive patients.

DESIGN AND METHODS

An open-label, uncontrolled multicentre trial. Antiretroviral therapy-naive patients (n = 90) with high median baseline HIV RNA levels of 220,000 copies/ml (range, 36,000-2,943,000 copies/ml) and median CD4 cell count of 189 x 10(6)/l (range, 4-656 x 10(6)/l) were started on a twice daily regimen of either zidovudine/lamivudine (49%), stavudine/lamivudine (38%) or stavudine/didanosine (13%) plus ritonavir 400 mg twice daily and indinavir 400 mg twice daily combination therapy. CD4 cell counts and HIV RNA were determined at weeks 0, 4, 8, 12, 16, 20, and 24. Statistical analysis was performed on treatment as well as intent-to-treat, where missing values were accounted for as failure.

RESULTS

In the intent-to-treat analysis at week 24, the proportion of patients with HIV RNA of < 500 copies/ml, and < 80 copies/ml was 86.7% and 71.1%, respectively. In the on-treatment analysis at week 24, 80.0% of patients had undetectable viral load in the ultrasensitive assay (< 80 copies/ml; n = 80). The quadruple therapy was well tolerated except for mild diarrhoea, initial nausea and increased triglyceride levels. Treatment was stopped in seven (7.7%) patients because of adverse events and three (3.3%) were lost to follow-up.

CONCLUSIONS

Our preliminary data suggest that the protease inhibitor combination ritonavir/indinavir plus double nucleoside therapy appears to be effective and safe in short-term treatment (up to 24 weeks).

Absence of zidovudine resistance in antiretroviral-naive patients following zidovudine/lamivudine/protease inhibitor combination therapy: virological evaluation of the AVANTI 2 and AVANTI 3 studies

OBJECTIVES

To assess the role of resistance mutations in subjects experiencing virological failure on zidovudine (ZDV) and lamivudine (3TC) combined with a protease inhibitor (PI) to those failing on ZDV/3TC alone.

DESIGN AND METHODS

Samples were obtained from previously antiretroviral therapy-naive subjects enrolled into two studies, AVANTI 2 and AVANTI 3. Subjects were randomized to receive either: ZDV/3TC or ZDV/3TC plus indinavir (IDV) for 52 weeks (AVANTI 2), and ZDV/3TC or ZDV/3TC and nelfinavir (NFV) for 28 weeks (AVANTI 3). Emergence of viral resistance mutations was monitored by population sequencing and phenotypic resistance was determined by the recombinant virus assay.

RESULTS

Genotypic data were obtained for subjects with plasma HIV-1 RNA > 400 copies/ml. In AVANTI 2, ZDV mutations were detected in 27% of ZDV/3TC-treated patients at week 52, but were absent in subjects treated with ZDV/3TC/IDV. No subjects from either arm of AVANTI 3 developed ZDV resistance mutations at week 28. The M184V mutation developed in most ZDV/3TC-treated subjects from both studies. The presence of M184V was, however, associated with significantly lower plasma viral RNA levels when compared with values obtained before initiation of treatment. There was a high frequency (4 of 11) of the protease L10F substitution in ZDV/3TC/IDV-treated patients that was associated with virological failure but did not result in phenotypic resistance to any of the PIs tested.

CONCLUSIONS

ZDV mutations were not detected in ZDV/3TC/PI-treated patients and they developed slowly in those treated with ZDV/3TC. Few protease mutations known to confer phenotypic PI resistance developed in the ZDV/3TC/PI arms of either study. The low prevalence of ZDV and PI mutations is encouraging regarding the future treatment options of these patients.

Patient-reported nonadherence to HAART is related to protease inhibitor levels

OBJECTIVE

To compare self-reported nonadherence with antiretroviral therapy (ART) with predose plasma levels of protease inhibitor (PI).

DESIGN

A cross-sectional study of consecutive patients from a university-based HIV clinic in Rome, Italy, was conducted. One hundred and forty HIV-infected patients were prescribed regimens containing ritonavir or indinavir. A patient questionnaire assessing knowledge of treatment regimen, adherence behavior, reasons for taking and missing therapy, factors influencing adherence, and health behaviors was administered. A predose PI plasma level was measured concurrently.

RESULTS

By patient report, 12% missed at least one dose "yesterday," and 24% missed doses in the last 3 days; 14% had a predose plasma concentration below the assay limit of quantitation (2 ritonavir and 18 indinavir samples). Confusion, poor psychological well-being, long office wait, running out of drugs between visits, having relatives to remind the patient to take medication, children, and alteration of sense of taste were related to unquantifiable predose levels of PI. In multivariable analysis, reported nonadherence (odds ratio [OR], 15.8; 95% confidence interval [CI], 4.0-63.3) and confusion (OR, 9.9; 95% CI, 1.4-69.6) were related to unquantifiable predose levels of PI.

CONCLUSION

Self-report of missing a dose of antiretroviral medication "yesterday" was related to an unmeasurable plasma PI level.

Role of hydroxyurea in treatment of disease due to human immunodeficiency virus infection

The potential role of hydroxyurea in the treatment of human immunodeficiency virus (HIV) infection was first supported by in vitro experiments that demonstrated control of viral production in activated and resting T cells. More recently, controlled clinical trials demonstrated that the addition of hydroxyurea to nucleoside-including regimens (chiefly of didanosine but also of stavudine and lamivudine) enhances their antiviral potency. It is believed that the cytostatic effect of hydroxyurea is at least partially responsible for its antiviral effect, through the down-modulation of cellular proliferation. Such an effect has also been credited for the blunted CD4 T cell responses that are characteristically observed when hydroxyurea is added to nucleoside-including regimens. The adjunctive antiviral effect of hydroxyurea-as well as its favorable dosing schedule, safety profile, and cost-makes it a very attractive addition to our therapeutic armamentarium. Further research is urgently needed to delineate the most appropriate use of this compound in the setting of HIV antiretroviral therapy.

Outcome of a second-line protease inhibitor-containing regimen in patients failing or intolerant of a first highly active antiretroviral therapy

The outcome of second-line protease inhibitor (PI)-containing highly active antiretroviral therapy (HAART) was investigated in 263 patients who were failed by (n = 148) or intolerant of (n = 115) a first HAART regimen. The endpoints were virologic failure (decline in HIV RNA < 1 log10 copies/ml after > or = 2 months) and discontinuation due to intolerance/toxicity. During a median follow-up of 483 days (33-1087 days), 154 patients (59%) discontinued the second regimen, 86 (33%) because of intolerance/toxicity; another 135 patients (51.3%) showed virologic failure. Independent factors associated with virologic failure (Cox's model) were 7 to 12 months of first HAART (hazard ratio [HR] 1.70 versus < or = 6 months: 95% confidence interval [CI], 1.08-2.70) and gender (HR 1.58 males versus females: 95% CI, 1.04-2.30); the negatively associated factors were advanced age (HR 0.61 > 34 years versus < or = 34 years: 95% CI, 0.42-0.88), a saquinavir-containing first HAART (HR 0.57 versus indinavir: 95% CI, 0.34-0.93) and change due to intolerance/toxicity (HR 0.58 versus failure: 95% CI, 0.35-0.98). The independent variables predictive of discontinuation due to intolerance/toxicity were the reason for switching (HR 1.79 intolerance versus failure: 95% CI, 1.02-3.16) and the first protease inhibitor (PI) regimen (HR 0.42 ritonavir versus indinavir: 95% CI, 0.22-0.80). Given that patients who are failed by a first regimen are at high risk of having rescue therapy fail as well, second-line regimens including therapies directed by testing of drug resistance patterns of clinical viral isolates are warranted. Patients experiencing toxicity due to a first PI-containing regimen are at risk of toxicity to other PIs and should be addressed to PI-sparing HAART.

Salvage therapy with abacavir plus a non-nucleoside reverse transcriptase inhibitor and a protease inhibitor in heavily pre-treated HIV-1 infected patients. Swiss HIV Cohort Study

BACKGROUND

Highly active antiretroviral therapy (HAART) may fail, especially in pre-treated patients.

OBJECTIVE

To examine retrospectively whether heavily pre-treated patients not responding to HAART at least once respond to a salvage therapy with abacavir, a nucleoside reverse transcriptase inhibitor (NRTI) plus a non-nucleoside analogue reverse transcriptase inhibitor (NNRTI) and one or two protease inhibitors (PI).

PATIENTS

We retrospectively identified and analysed patients followed in the Swiss HIV Cohort Study with > 1000 HIV RNA copies/ml on HAART, naive to abacavir who were switched to abacavir plus one NNRTI (efavirenz or nevirapine) and one or two PI which had not been used in the previous HAART.

RESULTS

Of 23 identified HIV-infected patients with four (median) therapy changes before salvage, 10 patients (43%) achieved a decrease of plasma HIV RNA > 0.5 log10 at 6 months of therapy. After 6 months only two patients had an HIV-1 RNA < 500 copies/ml, one of them < 50 copies/ml. Seven patients increased their CD4 cell counts by > 30% above baseline. Three patients, all with CD4 cell counts < 100 x 10(6)/l before salvage therapy had a > 30% decline in CD4 cell count. An extended number of resistance-associated mutations was found in almost all patients at baseline. One patient had two new AIDS-defining events. Five patients (22%) discontinued treatment because of side-effects, mainly occurrence of a rash.

CONCLUSION

Salvage therapy in intensively pre-treated patients has a low virological success rate despite usage of abacavir and NNRTI. Nevertheless, this did not correlate with immunological and clinical course. This study emphasizes the difficulty of second-line treatment in HIV-1 infection and stresses the need for new compounds.

A novel phenotypic drug susceptibility assay for human immunodeficiency virus type 1

Although combination antiretroviral therapy has resulted in a considerable improvement in the treatment of human immunodeficiency virus (HIV) type 1 (HIV-1) infection, the emergence of resistant virus is a significant obstacle to the effective management of HIV infection and AIDS. We have developed a novel phenotypic drug susceptibility assay that may be useful in guiding therapy and improving long-term suppression of HIV replication. Susceptibility to protease (PR) and reverse transcriptase (RT) inhibitors is measured by using resistance test vectors (RTVs) that contain a luciferase indicator gene and PR and RT sequences derived from HIV-1 in patient plasma. Cells are transfected with RTV DNA, resulting in the production of virus particles that are used to infect target cells. Since RTVs are replication defective, luciferase activity is measured following a single round of replication. The assay has been automated to increase throughput and is completed in 8 to 10 days. Test results may be useful in facilitating the selection of optimal treatment regimens for patients who have failed prior therapy or drug-naive patients infected with drug-resistant virus. In addition, the assay can be used to evaluate candidate drugs and assist in the development of new drugs that are active against resistant strains of HIV-1.

[Effect of antiretroviral treatment and prophylaxis for opportunistic infections on survival of patients with AIDS]

OBJECTIVE

To analyze the influence of anti-retroviral therapy (ART) and prophylaxis against opportunist disease on survival of patients with AIDS.

PATIENTS AND METHODS

Study of AIDS patients diagnosed from January 1996 to October 1997 in a Madrid hospital. An analysis was made of demographic, clinical, and immunological data, as well as ART and prophylaxis against Pneumocystis carinii pneumonia (PCP) and tuberculosis (TB). Both univariate and multivariate analyses were performed, as well as Kaplan-Meier curves.

RESULTS

A total of 205 patients were included in the study (83% male) with a median age of 34 years. ART, PCP prophylaxis, and TB prophylaxis were received by 147 (72%), 141 (69%) and 22 (11%) patients, respectively. Among individuals on ART, the likelihood of survival at 12 and 22 months since diagnosis of AIDS was made was 79% and 76%, respectively, and among non treated individuals 54% and 54%, respectively (p < 0.05). ART was associated with a 57% decrease in death risk, and regarding PCP prophylaxis, no benefit on survival was found.

CONCLUSIONS

ART was significantly associated with a lower risk of death among AIDS patients. The survival rate was not increased with PCP prophylaxis.

Insights into the reasons for discontinuation of the first highly active antiretroviral therapy (HAART) regimen in a cohort of antiretroviral naïve patients. I.CO.N.A. Study Group. Italian Cohort of Antiretroviral-Naïve Patients

OBJECTIVE

To evaluate the frequency of discontinuation of the first highly active antiretroviral regimen (HAART) and the factors predictive of discontinuing for toxicity and failure in a population-based cohort of HIV-positive individuals in Italy, naïve from antiretrovirals at enrolment.

METHODS

The study population consisted of individuals who initiated HAART and had at least one follow-up visit. The primary end-points were discontinuation of any component of HAART for drug toxicity and discontinuation for failure. Survival analyses were performed to identify predictive factors for reaching the two end-points.

RESULTS

Eight hundred and sixty-two individuals initiated HAART; in 727 of them (84.3%) this consisted of two nucleoside reverse transcriptase inhibitors (NRTI) and one protease inhibitor (PI). Over a median follow-up of 45 weeks, 312 patients (36.2%) discontinued therapy: 182 (21.1%) discontinued due to toxicity, 44 (5.1%) due to failure. The probability of discontinuing HAART at 1 year was 25.5% [95% confidence interval (CI), 21.9-28.9] due to toxicity and 7.6% (95% CI, 4.9-1 0.3) due to failure. Independent factors associated with discontinuation for toxicity were: gender [relative hazard (RH) = 0.51; 95% CI, 0.32-0.80 for men versus women], type of treatment (indinavir-containing regimens, RH = 1.94; 95% CI, 1.10-3.41 and ritonavir-containing regimens, RH = 3.83; 95% CI, 2.09-7.03 versus hard-gell saquinavir) and time spent on treatment (RH = 0.89; 95% CI, 0.80-0.98 for each additional month). Discontinuation due to failure was independently associated with the most recent HIV-RNA (RH = 3.20; 95% CI, 1.74-5.88 for log10 copies/ml higher), and with type of treatment (indinavir-containing regimens, RH = 0.21; 95% CI, 0.06-0.78 and ritonavir-containing regimens, RH = 0.23; 95% CI, 0.04-1.26 versus hard-gell saquinavir).

CONCLUSIONS

If the current HAART regimen caused no toxicity, less than 10% of naïve patients discontinue their first HAART regimen because of failure after 1 year from starting therapy.

Phase III study of granulocyte-macrophage colony-stimulating factor in advanced HIV disease: effect on infections, CD4 cell counts and HIV suppression. Leukine/HIV Study Group

OBJECTIVE

To evaluate the effect of adjuvant granulocyte-macrophage colony-stimulating factor (GM-CSF) (sargramostim, yeast-derived recombinant human GM-CSF) on incidence and time to opportunistic infection or death, plasma HIV-RNA, and CD4 cell count in patients with advanced HIV disease.

METHODS

This Phase III randomized, double-blind, placebo-controlled trial enrolled subjects with CD4 cell counts < or = 50 x 10(6)/l or < or = 100 x 10(6)/l with a prior AIDS-defining illness on stable antiretroviral therapy. Subjects were stratified by baseline HIV-RNA level (> or = or < 30,000 copies/ml) and randomized to receive subcutaneous injections of GM-CSF 250 microg or placebo three times per week for 24 weeks. Subjects were permitted to continue on blinded drug for up to 20 months. Subjects were evaluated for infections, plasma HIV-RNA, lymphocyte counts, changes in antiretroviral therapy, toxicity, and survival.

RESULTS

Three-hundred and nine subjects received at least one dose of study drug, 70% completed 24 weeks of therapy. Groups were well matched at baseline. Significant increases in CD4 cell and neutrophil counts were observed at 1, 3, and 6 months in the GM-CSF group. GM-CSF significantly reduced the incidence of overall infections (78% placebo versus 67% GM-CSF; P = 0.03) and delayed time to first infection (56 days placebo versus 97 days GM-CSF; P = 0.04). No statistical difference in cumulative opportunistic infections was observed between groups; however, among subjects without an opportunistic infection prior to study, the GM-CSF group demonstrated a trend towards fewer subjects with an opportunistic infection on study (26% placebo versus 8% GM-CSF; P = 0.08). Change in HIV-RNA was not significantly different between groups, but significantly fewer GM-CSF subjects with baseline viral load < 30,000 copies/ml had changes in antiretroviral therapy for increased viral load (42% placebo versus 21% GM-CSF; P = 0.01). In patients with HIV-RNA levels below the limit of detection at baseline, more GM-CSF patients maintained an undetectable viral load at 24 weeks (54% placebo versus 83% GM-CSF; P = 0.02). GM-CSF was well tolerated.

CONCLUSIONS

GM-CSF significantly increased CD4 cell count and decreased virological breakthrough and overall infection rate in subjects with advanced HIV disease.

Impact of combination therapies on HIV risk perceptions and sexual risk among HIV-positive and HIV-negative gay and bisexual men

The availability of improved HIV treatments may prompt reduced concern about HIV and sexual risk. Gay and bisexual men (N = 554, 17% HIV-positive) completed measures of treatment attitudes, sexual risk, and assumptions regarding the infectiousness of sexual partners. A substantial minority reported reduced HIV concern related to treatment advances. Reduced HIV concern was an independent predictor of sexual risk, particularly among HIV-positive men. In response to hypothetical scenarios describing sex with an HIV-positive partner, participants rated the risk of unprotected sex to be lower if the partner was taking combination treatments and had an undetectable viral load, relative to scenarios with a seropositive partner not taking combination treatments. Prevention efforts must address attitudinal shifts prompted by recent treatment successes, stressing the continued importance of safer sex, and that an undetectable viral load does not eliminate infection risks.

Dual nucleoside regimens in nonadvanced HIV infection: prospective follow-up of 130 patients, Aquitaine Cohort, 1996 to 1998. Groupe d'Epidémiologie Clinique du SIDA en Aquitaine (GECSA)

OBJECTIVE

To describe the response to combinations of two nucleoside reverse transcriptase inhibitors (NRTIs) initiated early in the course of HIV infection under routine circumstances and to research prognostic factors indicating good virologic response.

SETTING

Patients of the Aquitaine Cohort, a hospital-based open cohort that had been recruiting since 1987 in five public hospitals of the Aquitaine region in southwestern France.

METHODS

Prospective cohort study of antiretroviral-naive patients with CD4+ cell counts >0.350 x 10(9)/L who started dual NRTI therapy between January 1996 and June 1997. Intent-to-treat analysis and multivariate logistic regression were used with data collected up to March 31, 1998.

RESULTS

In this study, 130 patients were enrolled with a median follow-up of 14 months. At the time of first prescription, 79% were in U. S. Centers for Disease Control and Prevention (CDC) group A, 16% in group B, and 5% in group C; median CD4+ cell count was 0.466 x 10(9)/L and median HIV RNA level was 4.52 log10 copies/ml. The two main combinations used were zidovudine (AZT) plus zalcitabine (ddC; 38%) and AZT plus didanosine (ddI; 37%). At week 52, median CD4+ and HIV RNA responses were, respectively, +80 cells and -1.6 log; the proportions of patients with HIV RNA level <5000 and <500 copies/ml were 70% and 45%, respectively, and 96% of the patients had a CD4+ cell count >0.350 x 10(9)/L at that time. At their last follow-up, 3 patients had reached been diagnosed with full-blown AIDS and the AIDS-free survival probability at 1 year was 98.2% (95% confidence interval [CI], 93.1-99.6); 1 death had occurred. The only significant variable associated with an undetectable HIV RNA level at 1 year was a lower HIV RNA level at the first prescription of dual therapy.

CONCLUSION

Our data indicate that dual nucleoside combinations could be a therapeutic option for patients diagnosed and observed during follow-up in the early course of HIV infection.

A randomized trial of interferon alpha therapy for HIV type 1 infection

The immunologic and virologic efficacy and safety of interferon a (IFN-alpha) administered in combination with zidovudine (ZDV) and zalcitabine (ddC) was evaluated in HIV-infected subjects with CD4+ cell counts between 300 and 500 cells/ml and no more than 14 weeks of prior antiretroviral therapy. A total of 256 subjects enrolled in an open-label, randomized controlled trial. Subjects were randomized equally into treatment groups. All subjects received ZDV and ddC, while half also receive IFN-alpha (3 MU subcutaneously every 24 hr). At 48 weeks the median average area under the curve minus baseline (AAUCMB) for plasma HIV-1 RNA for the two-drug group was -0.68 versus -0.75 log10 copies/ml for the IFN-alpha group (p = 0.046). Mean HIV-1 RNA changes from baseline to 48 weeks for these groups were -0.65 and -1.12 log10 copies/ml, respectively (p = 0.010). The median AAUCMB for CD4+ cell count for the two-drug group was 28 versus -1 cells/mm3 for the IFN-alpha group (p = 0.011). Neutropenia, anemia, and drug intolerance were more common in the IFN-alpha group. This study demonstrates that IFN-alpha inhibits HIV-1 replication but attenuates the CD4+ cell response to dual therapy with ZDV and ddC.

Factors associated with clinical and virological failure in patients receiving a triple therapy including a protease inhibitor

OBJECTIVE

To determine the predictors of virological and clinical failure in patients receiving a protease inhibitor as part of triple therapy.

METHODS

From the French Hospital Database on HIV, 1402 protease inhibitor-naive patients starting a highly active antiretroviral therapy regimen with ritonavir, saquinavir-hard gel capsule (hgc) or indinavir between July 1996 and March 1997, and with measured HIV RNA at baseline and at 12 months, were studied for progression to a new AIDS-defining event (ADE) or death. Virological failure was defined as plasma HIV RNA > 1000 copies/ml at 12 months. Multivariate analyses were performed using Cox models for clinical outcomes and logistic regression for virological outcomes.

RESULTS

During a median follow-up of 14.1 months, 94 (6.7%) patients experienced an ADE or died. At 12 months, 700 patients (49.9%) had virological failure. In the multivariate analysis, baseline CD4 cell count and viral load were found to be independent predictors of both virological and clinical failure. Neither the type of the first protease inhibitor taken nor previous antiretroviral therapy experience was associated with risk of clinical progression. For virological failure, the use of saquinavir-hgc was associated with a significant 1.96-fold increase in risk compared with indinavir; pre-treated patients were at higher risk than antiretroviral therapy-naive patients.

CONCLUSION

In this study with large samples of patients, the use of saquinavir-hgc was associated with higher risk of virological failure at 12 months than were ritonavir and indinavir; no differences between protease inhibitors were found for clinical progression. As biases cannot be excluded, a longer duration of follow-up will be necessary to answer the question of whether the results are really discrepant or simply reflect the delay between virological failure and clinical manifestations.

High-level resistance to 3'-azido-3'-deoxythimidine due to a deletion in the reverse transcriptase gene of human immunodeficiency virus type 1

A variant of human immunodeficiency virus type 1 (HIV-1) possessing a deletion in the reverse transcriptase (RT) gene at codon 67 was identified in a patient who had failed combination antiretroviral therapy. This deletion initially emerged under the selective pressure of combination therapy with 3'-azido-3'-deoxythymidine (AZT) plus 2',3'-dideoxyinosine. It has persisted for more than 3 years in association with the accumulation of a variety of other well-described drug resistance mutations and an uncharacterized mutation at RT codon 69 (T69G). Phenotypic studies demonstrated that the codon 67 deletion by itself had little effect on AZT sensitivity. However, in the context of the T69G mutation and three other mutations known to be associated with AZT resistance (K70R, T215F, and K219Q), this deletion led to a increase in AZT resistance from 8. 5-fold to 445-fold. A further increase in resistance (up to 1, 813-fold) was observed when two mutations associated with nonnucleoside RT inhibitor resistance (K103N and L74I) were added to the deletion T69G K70R T215F K219Q construct. Hence, these results establish that a deletion at RT codon 67 may be selected for in the presence of antiretroviral therapy and may lead to high-level resistance to AZT.

Persisting Long-Term Benefit of Genotype-Guided Treatment for HIV-Infected Patients Failing Haart. The Viradapt Study: Week 48 Follow-Up

Objective

We report the 12 months follow-up of the patients who participated in the Viradapt study.

Methods

A total of 108 HIV-infected patients failing antiretroviral (ARV) therapy (HIV RNA >10000 copies/ml, therapy >6 months with nucleoside reverse transcriptase inhibitors, >3 months with protease inhibitors (PIs) were randomized into two arms: standard of care in the control arm, and treatment according to the resistance mutations in the protease and reverse transcriptase genes in the study arm. After the first 6 months of the randomized study, open-label, genotype-guided treatment was offered in both arms. A multivariate analysis was performed to assess the predictive factors of treatment success (HIV RNA <200 copies/ml).

Results

The two arms were comparable in terms of risk factors, age, sex, previous treatments, CD4 cell count and log10 HIV-1 RNA at baseline. At week 24, an interim combined analysis showed a statistically significant difference in the drop in viral load at months 3 and 6 ( P=0.015, repeated measures analysis of variance) in favour of the genotype group. Patients in both arms were then offered open-label genotyping. Genotype analysis was performed every 3 months, and treatment changes could accordingly be made. As some of the patients in the control arm had already progressed to months 9 or 12, only 69% (30/43) of these patients received genotype-guided treatment changes. In the genotype arm, the mean drop in HIV RNA of 1.15 log10 copies/ml, obtained at month 6, persisted at months 9 and 12 (1.15 log10 copies/ml ±0.17). In the control arm, an additional drop in HIV RNA to 0.98 log10 ±0.22 copies/ml was observed by month 12. In control patients receiving open-label genotype, the percentage of patients with HIV-1 RNA levels below detection limit (200 copies/ml) rose from 14% at month 6 to 30.5% at month 12. This percentage in the study arm remained stable at 31.3% and 30% at months 9 and 12, respectively. Genotype-guided therapy, primary protease mutations and PI plasma concentrations were significantly correlated with virological success.

Conclusions

In this heavily pretreated patient population, genotype-guided therapy resulted in a sustained reduction in HIV RNA of greater than one log10 throughout a 1 year follow-up period. Performance of genotype-guided therapy may have contributed to the additional viral load reduction seen in patients in the control group who received open-label genotyping after the 6 month point. Multivariate analysis showed that the presence of primary protease mutations, performance of genotype-guided treatment changes and PI plasma concentrations independently affected virological response.

Immunologic and virologic responses to HAART in severely immunocompromised HIV-1-infected children

OBJECTIVE

To determine the long-term immunologic and virologic effects of highly active antiretroviral therapy (HAART) in children with AIDS.

DESIGN

A prospective observational study.

SETTING

Two pediatric HIV clinics.

PARTICIPANTS

Twenty-five protease-inhibitor naive HIV-infected children (aged 2-18 years) with advanced disease (CD4 < or =6%).

INTERVENTION

HAART (one protease inhibitor and one or more nucleoside analogs). Diphtheria and tetanus immunization in six patients after 18 months of therapy.

MAIN OUTCOME MEASURES

Changes in percentage of CD4 cells and plasma HIV-1 RNA levels; post-treatment assays of lymphoproliferative responses to recall antigens; CD4 cell memory phenotype.

RESULTS

Median duration of follow-up was 18.8 months (range, 7.5-28 months). At baseline the CD4 cell percentage was 2% (range, 0-6%), this increased significantly to 16% (range, 3-48%) above baseline at 12 months (P = 0.002). The mean maximum CD4 cell increase was 20.7% (range 4-48%) which corresponds to 657x10(6) cells/l (range, 30-2240x10(6) cells/l) above baseline. By contrast, the median viral load was not significantly lower at 12 months than at baseline (P = 0.34), and only 25% of the patients had sustained undetectable viral load. Of the reconstituted CD4 cells 70% were naive, and none of the subjects had lymphoproliferative responses to tetanus and diphtheria although 40% did develop responses to Candida, an environmental antigen. A single immunization with diphtheria and tetanus toxoid produced lymphoproliferative responses to tetanus in three out of six patients.

CONCLUSIONS

HAART was associated with sustained increases in CD4 cell counts, despite a high incidence of 'virologic failure'. CD4 counts and the proportion of naive cells were higher than have been reported in adults, which may be a reflection of greater thymic activity in children. Memory cell clones for antigens encountered in the past which are not prevalent before therapy could not be expanded without additional antigenic exposure.

Efavirenz, nelfinavir, and stavudine rescue combination therapy in HIV-1-positive patients heavily pretreated with nucleoside analogues and protease inhibitors

Tolerability, activity, and pharmacokinetic parameters of a combination therapy with efavirenz (EFV), nelfinavir (NFV), and stavudine (d4T) were evaluated in this study. Forty-seven HIV-1-infected study subjects, naive to NFV and nonnucleoside reverse transcriptase inhibitors (NNRTIs), who had experienced virologic failure while being treated with combination antiretroviral therapies including protease inhibitors (PIs), were enrolled. At baseline, HIV-1 viral load in plasma was 4.8 log10, CD4+ count was 204 cells/microl (both mean values); patients had received a mean of 3.1 different treatments (range, 2-5 treatments). Study medications were generally well tolerated; 7 of 47 patients (14.8%) were dropped from the study because of related drug toxicity. At week 24, mean plasma viral load (pVL) was reduced by 1.9 log10, with mean CD4+ count increased to 324 cells/microl (+/-59% from baseline); pVL was below the limit of detection (500 copies/ml) in 46.1% of patients. An extended follow-up study was performed at 12 months. Results showed a reduction of 1.7 log10 in pVL from basal values that was consistent with values observed at months 3 and 6. A history of previous use of PIs represented a negative prognostic marker. Sequencing analysis, performed in a subset of patients, showed the presence of multiple point mutations associated with PI resistance. Pharmacokinetic analysis demonstrated a marked interindividual variability in NFV plasma concentrations, producing in 4 of 18 patients (22%) trough concentrations lower than minimum effective concentration. In pretreated patients, further studies are needed to characterize the pharmacokinetic factors that affect response to therapy and the association of these results with the 95% inhibitory concentration (IC95) determined by phenotyping.

Incidence and predictors of virologic failure of antiretroviral triple-drug therapy in a community-based cohort

Highly active antiretroviral therapy fails to reach its recommended goal of sustained suppression of viral replication in a substantial proportion of patients. We analyzed incidence and predictors of virologic failure of the first regimen of a triple-drug combination therapy, including a protease inhibitor and two nucleoside analog reverse transcriptase inhibitors (NRTIs), in 274 HIV-infected patients. Long-term virologic response to combination therapy including salvage regimens was assessed 2.5 years after treatment initiation. During an initial observation period of up to 1.8 years (median, 0.8 years) 152 patients (55%) experienced sustained suppression of HIV-1 RNA to <500 copies/ml. Failure to reduce viral load to <500 copies/ml within 6 months (initial failure) was observed in 51 patients (19%). Independent risk factors for initial failure included higher baseline viral load; addition of a protease inhibitor to an unchanged NRTI regimen; use of saquinavir hard-gel capsules; and longer duration of prior NRTI treatment. Within a median of 7 months viral load rebound above 500 copies/ml occurred in 71 of 223 patients (32%) whose viral load had initially decreased below this threshold. In proportional hazard analysis none of the potential risk factors was significantly associated with viral load rebound. However, in 40 patients (56%) with viral load rebound, incomplete adherence to therapy or treatment interruptions preceded the rebound. Virologic outcome after 2.5 years correlated with initial response to the first regimen: viral load was <500 copies/ml in 88, 55, and 21% of patients with sustained suppression, viral load rebound, and initial failure, respectively.

HIV-1 genotypic resistance patterns predict response to saquinavir-ritonavir therapy in patients in whom previous protease inhibitor therapy had failed

BACKGROUND

Tests for resistance to HIV drugs are available for clinical use; however, their predictive value has not been fully assessed.

OBJECTIVES

To determine HIV-1 genotypic predictors of a virologic response to saquinavir-ritonavir therapy in patients in whom at least one previous protease inhibitor-containing regimen had failed and to compare the predictive value of baseline genotype with that of standard clinical evaluation.

DESIGN

Retrospective clinical cohort study.

SETTING

University-based HIV clinic.

PATIENTS

54 HIV-1-infected adults treated with saquinavir-ritonavir who had experienced virologic failure while receiving a protease inhibitor-containing regimen for at least 3 months.

MEASUREMENTS

HIV-1 reverse transcriptase and protease gene sequences, CD4 cell counts, clinical characteristics, detailed antiretroviral treatment history, and plasma HIV-1 RNA levels at baseline and at three follow-up time points (median, 4, 12, and 26 weeks). Virologic failure was defined as a plasma HIV RNA level greater than 1000 copies/mL.

RESULTS

In 22 patients (41%), a plasma HIV-1 RNA level less than 500 copies/mL was achieved by week 12; in 15 patients (28%), this response was maintained through week 26. Clinical characteristics predicting a poorer response included a diagnosis of AIDS, lower CD4 cell count, and higher plasma HIV RNA level (P<0.03). Number of previous nucleoside reverse transcriptase inhibitors, previous protease inhibitor therapy, and duration of previous protease inhibitor therapy were predictors of poorer response (P<0.01). Multivariate regression models revealed that protease mutations present at the initiation of saquinavir-ritonavir therapy were the strongest predictors of virologic response. A model of clinical features explained up to 45% of the variation in virologic outcomes by week 12, whereas the explained variance was 71% when genotypic predictors were included.

CONCLUSIONS

In patients in whom protease inhibitor-containing antiretroviral therapy fails, HIV-1 genotype is predictive of virologic response to subsequent therapy. This predictive capacity adds to that of standard clinical evaluation.