Clinical progression and virological failure on highly active antiretroviral therapy in HIV-1 patients: a prospective cohort study. Swiss HIV Cohort Study

HIV epidemiology and treatment - 1999

Potent antiretroviral treatment has led to a dramatic decrease in HIV-associated morbidity and mortality. This paper reviews (1) current recommendations for the initiation of antiretroviral therapy, (2) the natural history of HIV infection after initiation of treatment, and (3) toxicity and resistance issues.

A comparison of exposure groups in the EuroSIDA study: starting highly active antiretroviral therapy (HAART), response to HAART, and survival

BACKGROUND

Concerns have been raised that intravenous drug users may be less likely to start highly active antiretroviral therapy (HAART) and that adherence to therapy may be poor among this group of patients. Given the decreased mortality and incidence of AIDS-defining illnesses among patients with HIV who start HAART, this may lead to a poorer prognosis among intravenous drug users.

PURPOSE

To compare homosexual men, intravenous drug users, and heterosexuals in EuroSIDA, a prospective European cohort of 7331 patients with HIV in terms of starting a HAART treatment regimen, immunologic and virologic response to therapy, and survival.

METHODS

6645 patients were included in this analysis. Logistic regression and Cox proportional hazards models were used to investigate the factors associated with use of HAART regimens and survival following recruitment to the EuroSIDA study.

RESULTS

In a multivariate logistic regression model, intravenous drug users were significantly less likely to be receiving HAART at recruitment to EuroSIDA (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.37-0.62; p<.0001) when compared with homosexual men. Similarly, during follow-up, intravenous drug users were at a 27% reduced risk of starting HAART, after adjustment for other factors related to starting HAART (relative hazard [RH], 0.73; 95% CI, 0.64-0.82; p<.0001). There were no differences between heterosexual and homosexual patients, and similar results were found within regions of Europe (South, Central and Northern). Among those patients who started HAART, there were no significant differences between exposure groups in CD4 lymphocyte count response to HAART or virologic response to HAART. After adjustment for factors related to survival, intravenous drug users were at a small, but nonsignificant increased risk of death compared with homosexuals (RH 1.16; 95% CI, 0.99-1.38; p = .074).

CONCLUSIONS

Intravenous drug users were significantly less likely to start HAART, but among those who did, response to therapy was similar to that of other exposure groups. There were no differences in risk of death. If intravenous drug users continue to use HAART less commonly than other exposure groups, it may result in a poorer prognosis, a different spectrum of AIDS-defining illnesses, and differential long-term clinical needs.

Analysis of the discontinuation of protease inhibitor therapy in routine clinical practice

We evaluated the frequency of and reasons for discontinuation of protease inhibitor therapy in a cohort of HIV-infected patients in a prospective observational study. We included 230 HIV-infected patients who had started protease inhibitor therapy between November 1996 and July 1997. Mean baseline CD4 count was 138 cells/microl and HIV-RNA 4.5 log10. Forty-five percent of patients had prior AIDS and 77% had been treated with nucleoside analogues. Saquinavir-treated patients were at a less advanced stage of HIV disease. Overall, 41.3% of patients discontinued therapy, and their last HIV-RNA measured higher than that of patients who continued therapy: 4.07 vs. 2.70 log10 (p < 0.0001). Reasons for discontinuation of therapy were poor adherence (including abandonment) (18.6%), drug intolerance (12.1%), virological failure (7%) and physician decision (3.5%). In a multivariate model, factors associated with drug discontinuation were not taking indinavir (OR 0.26, 95% CI 0.12-0.59) and being pretreated with nucleoside analogues (OR 3.42, 95% CI 1.58-7.42). We concluded that in routine clinical practice a high proportion of patients discontinued protease inhibitors during the first 6 months of therapy, the main reason being the patient's own decision (abandonment or poor adherence). Psychological support and counselling are warranted in patients when initiating protease inhibitor therapy.

Saquinavir hard gel suppresses viral load insufficiently in HIV-infected patients naive to anti-retroviral therapy: a retrospective cohort study

Protease inhibitors are important components in anti-retroviral regimens. In this retrospective study 29 HIV-infected patients treated with a regimen of zidovudine, lamivudine and saquinavir hard gel in 1 centre in Denmark were compared with 58 patients treated with zidovudine, lamivudine and ritonavir or indinavir followed at 5 other centres in Scandinavia. All patients were naive to anti-retroviral therapy prior to institution of the actual anti-retroviral regimen and were followed for a median of 1.3 and 1.4 y respectively. The 2 groups did not differ significantly with respect to age, gender, route of infection, ethnic background, viral load, CD4 count, AIDS at baseline or frequency of clinical controls. Six and 12 months after initiating anti-retroviral therapy, 31% and 34% of the patients on the saquinavir regimen obtained HIV-RNA < or = 500 compared with 76% and 73% in the control group (p < 0.001). In contrast to viral load, the increase in CD4 count did not differ significantly between the 2 groups. In conclusion, we found that with respect to suppression of viral load a regimen of saquinavir, zidovudine and lamivudine seemed to be inferior to a regimen of zidovudine, lamivudine and ritonavir or indinavir.

HIV-Protease inhibitors reduce cell adherence of Candida albicans strains by inhibition of yeast secreted aspartic proteases

Since the introduction of new anti-retroviral agents such as human immunodeficiency virus (HIV) protease inhibitors, oropharyngeal candidiasis is less often observed in acquired immune deficiency syndrome patients. Secretory aspartic proteases of Candida albicans, which have similarities to the HIV aspartic proteases, are pathogenicity factors that have been intensively investigated in recent years. The inhibitory effect of four different HIV aspartic protease inhibitors (ritonavir, saquinavir, indinavir, and nelfinavir), on the activity of different Candida albicans secretory aspartic proteases was demonstrated. These anti-retroviral agents were able to inhibit Candida albicans secretory aspartic proteases 1, 2, and 3 which are involved in Candida adherence. As a consequence of these results we used selected HIV protease inhibitors in an adherence assay of Candida cells to epithelial cells. Ritonavir and saquinavir inhibited adherence of Candida albicans under the chosen experimental conditions similarly to the in vitro results, whereas indinavir had no effect. This inhibition was shown to be concentration dependent. The specificity of these effects with respect to the secretory aspartic proteases was demonstrated by competitive binding experiments using purified recombinant secretory aspartic proteases. On the basis of these studies we conclude that lower rates of oropharyngeal candidiasis in individuals receiving potent anti-retroviral therapy could reflect not only an improvement in the immune system but also direct inhibition of Candida secretory aspartic proteases by HIV protease inhibitors.

Natural history of HIV infection in the era of combination antiretroviral therapy

BACKGROUND

The use of protease inhibitor-containing (PI) combination antiretroviral therapy has led to a reduction in the incidence of opportunistic illness and mortality (events) in HIV infection. We wished to quantify the changing incidence of these events in our clinical practice and delineate the relationship between CD4, HIV-1 RNA, and development of events in patients receiving PI combination therapy.

METHODS

We assessed HIV-infected patients with CD4 counts < or =500 cells x10(6)/l. We calculated the incidence of events from 1994 through 1998 and analyzed the association of temporal changes in event incidence and use of antiretroviral therapy. In patients on PI combination therapy, we determined the probability of achieving and maintaining an undetectable HIV-1 RNA response and determined the association of CD4, HIV-1 RNA, and developing an event.

RESULTS

The incidence of opportunistic illness declined from 23.7 events/100 person-years in 1994 to 14.0 events/100 person-years in 1998 (P<0.001). Mortality declined from 20.2 deaths/100 person-years in 1994 to 8.4 deaths/ 100 person-years in 1998 (P<0.001). Use of PI combination therapy was associated with a relative rate of opportunistic illness or death of 0.66 [95% confidence interval (CI), 0.51-0.85; P<0.001]. The relative incidence of each of 16 opportunistic illnesses was approximately the same in 1998 as in 1994 except for lymphoma, cervical cancer and wasting syndrome which do not appeared to have declined in incidence. Approximately 60% of patients who received PI therapy achieved an undetectable HIV-1 RNA, and 65% of these patients maintained durable suppression of HIV-1 RNA. Achieving an undetectable HIV-1 RNA was associated with a decreased risk of an event, and was the variable most strongly associated with an increase in CD4 level. By multivariate analysis, the concurrent CD4 level was most strongly associated with developing an event.

CONCLUSIONS

We observed a significant decline in the incidence of opportunistic illness and death from 1994 through 1998 associated with combination antiretroviral therapy. Patients who develop events while being treated with PI combination therapy were not likely to have achieved an undetectable HIV-1 RNA and are likely to have a low concurrent CD4 level.

Plasma HIV viral load in patients with hemophilia and late-stage HIV disease: a measure of current immune suppression. Multicenter Hemophilia Cohort Study

BACKGROUND

For patients infected with HIV, plasma HIV viral load in early disease predicts long-term prognosis. However, the implications of viral load measurements late in HIV disease are uncertain.

OBJECTIVE

To evaluate the relation between plasma HIV viral load and subsequent risk for disease progression in patients with late-stage HIV disease.

DESIGN

Retrospective cohort study.

SETTING

16 treatment centers for patients with hemophilia.

PATIENTS

389 patients with hemophilia and late-stage HIV disease (CD4 count < 200 cells/mm3).

MEASUREMENTS

Plasma HIV viral load was measured at baseline. Patients were followed for AIDS-related illnesses (primary outcome) and, specifically, Pneumocystis carinii pneumonia (secondary outcome).

RESULTS

HIV viral load strongly predicted AIDS-related illness. For patients with viral loads less than 4.00 log10 copies/mL, the 1-year actuarial risk was 0% and the 5-year risk was 25%. For patients with viral loads of at least 6.00 log10 copies/mL, the 1-year actuarial risk was 42% and the 5-year risk was 78%. A linear relation existed between viral load and risk for AIDS-related illness (hazard ratio, 2.37 per 1og10 copies/mL; P < 0.001). In addition, viral load most strongly predicted risk for illness immediately after viral load testing; this predictive relation attenuated over time (P = 0.002). These findings changed little after adjustment for CD4 cell counts that were updated during follow-up. In the first year after viral load was measured, it predicted occurrence of P. carinii pneumonia (hazard ratio, 4.69 per 1og10 copies/mL; P < 0.001).

CONCLUSIONS

In patients with hemophilia and late-stage HIV disease, viral load predicts disease progression independently of CD4 cell counts. Because viral load most strongly predicts progression immediately after load is measured, it seems to reflect the current level of immunosuppression.

Effect of indinavir and higher CD4+ T-cell count on viral load response after 6 months of highly active antiretroviral therapy

This retrospective, unmasked chart review was undertaken to determine which HIV-infected patients receiving protease inhibitors (PIs) for the first time were most likely to experience a decrease in plasma viral load (PVL) and which factors were associated with a PVL < 500 copies/mL below the detectable limits after 6 months. A total of 308 patients aged > 15 years with a PVL > 500 copies/mL received therapy that included a PI in addition to other antiretroviral therapies (128 patients, saquinavir hard-gel capsule 600 mg TID; 107 patients, indinavir 800 mg TID; and 73 patients, ritonavir 600 mg BID). The choice of drug was at individual clinicians' discretion. Patients were followed for a median of 10 (range, 6 to 21) months. Of the 128 patients who received saquinavir, 45% were switched to another PI (33%, indinavir; 12%, ritonavir). Seventy percent of the 73 patients initially given ritonavir were switched (45%, indinavir; 25%, saquinavir), as were 23% of the 107 patients initially given indinavir (15%, saquinavir; 8%, ritonavir). A total of 34.1% (n = 105) of patients achieved a PVL < 500 copies/mL; in 51.6%, PVL decreased > 0.5 log copies/mL. In this subgroup, both treatment-naive patients and those who were receiving a new combination of antiretroviral therapy when they started PI treatment had a more pronounced decline in PVL (P < 0.001). After adjustment by logistic regression analysis for age, sex, mode of transmission, and duration of highly active antiretroviral therapy (HAART), CD4+ cell count and initial type of PI received were independently associated with PVL < 500 copies/mL. In the present study, the treatment success rate was low (34.1%) compared with rates observed in randomized, controlled trials. A higher CD4+ cell count and use of indinavir at the initiation of HAART are associated with a better viral load response.

Salvage treatment against human immunodeficiency virus

Despite dramatic declines in human immunodeficiency virus (HIV)-associated morbidity and mortality as a result of highly active antiretroviral combination therapies, including protease inhibitors, treatment failure occurs at such high rates as 20-50%. As drug regimens are very demanding, even short decreases of drug concentrations may trigger resistance. Viral loads can be decreased to very low concentrations, and there is no strict cut-off regarding the definition of treatment failure. Nevertheless, continuous detection of HIV of more than 50 copies per mL blood plasma is a predictor of increasing viral loads and of a suboptimal response to therapy. From a theoretical point of view, treatment changes should be made at low HIV RNA levels, but fewer options often dictate a more conservative approach. Drug susceptibility testing will be of increasing value, especially in patients experiencing drug failure for the first time. Success of salvage therapies is closely connected with the use of new compounds including new drug classes. As drugs susceptible to a multi-drug-resistant HIV are not yet available, regimens with more than three or even with five to nine drugs are used in clinical trials. Salvage therapies often fail in virological terms, ie in 50-80% of patients, depending primarily on the treatment history, but immunological and clinical stability can often be achieved.

Effectiveness and Pitfalls of Initial Highly Active Antiretroviral Therapy in HIV-Infected Patients in Routine Clinical Practice

Objective

To assess the long-term effectiveness of and factors associated with response to protease inhibitors (PIs) in a cohort of treatment-naive HIV-infected patients.

Design and setting

Prospective study in a tertiary care centre.

Subjects

A total of 207 treatment-naive patients starting PIs from March 1996 to May 1998. Main outcome measures: Clinical, virological and immunological outcomes, and adherence to therapy after 12 months.

Results

Baseline median CD4 cell count and viral load were 160 cells/mm3 and 5 log10 copies/ml, respectively. After 48 weeks, 168 patients (81%) reached plasma HIV-RNA levels below 400 copies/ml, and the mean increase in CD4 cell count was 196 cells/mm3. Clinical events were observed in 29 patients (14%) after a median time of 100 days on therapy, yet mortality was extremely low (0.9%). By multivariate analysis, adherence over 90% [relative risk (RR), 16.66; 95% confidence interval (CI), 5.26–50; P=0.00001] and AIDS diagnosis at baseline (RR 0.35; 95% CI, 0.14–0.90; P=0.02) were the strongest predictors for virological suppression. An immunological recovery over 100 cells/mm3 was significantly associated with an initial virological response (RR 2.94; 95% CI, 1.31–6.66; P=0.009) and adherence over 90% (RR 3.44; 95% CI, 1.61–7.69; P=0.005). There were high rates of change with the first PI (40%), mostly due to adverse events (51%), but it did not compromise long-term effectiveness. Conclusions: Initial PI treatment in the clinical setting is able to reach equally good outcomes as those found in controlled trials. Changes in therapy due to toxicity do not compromise a successful outcome, which clearly depends on an adequate adherence to therapy.