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

Sociodemographic factors predict early discontinuation of HIV non-nucleoside reverse transcriptase inhibitors and protease inhibitors

BACKGROUND/OBJECTIVE

HIV infection has a devastating impact on individual and public health, and affects populations disproportionately. Treatment with antiretroviral therapy (ART) saves lives, but long-term adherence to ART is critical to its success. We performed an observational cohort study to determine the influence of race, sex and other sociodemographic factors on early ART discontinuations among HIV-infected persons.

METHODS

TennCare-enrolled adults of black or white non-Hispanic race beginning ART with either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (PI) between 1996-2003 (N=3654) were assessed for early discontinuation. A subgroup of discontinuations was validated using the primary medical record.

RESULTS

Blacks were more likely than whites to discontinue NNRTIs (37 vs. 28%; P=0.003) and PIs (36 vs. 25%; P < or = 0.001). In multivariable models adjusting for race, sex, age, early HIV-related medical encounter, urban residence and TennCare enrollment category, black race, female sex and younger age were independent predictors of discontinuation among those starting PIs. Among persons starting NNRTIs, black race, younger age and a disability-based enrollment category predicted early drug discontinuation, but female sex did not.

CONCLUSIONS

Our results suggest that sociodemographic factors were associated with early NNRTI and PI discontinuation in this population, and some factors were ART class specific.

Clinical, immunological and virological evolution in patients with CD4 T-cell count above 500/mm3: is there a benefit to treat with highly active antiretroviral therapy (HAART)?

To assess the clinical, immunological and virological evolution in HIV-1 infected patients with CD4 T-cell count above 500/mm3, a historical cohort of 202 untreated and 96 patients treated with HAART was longitudinally studied (median follow-up 36 months). Fourteen untreated and 2 treated patients experienced clinical progression (p = 0.09). The difference between baseline CD4 T-cell count and after 3 years, was -240/mm3 in the untreated group +19/mm3 in the HAART group (p < 10(-3)). A better immunological outcome was significantly associated with a HIV sexual contamination (p = 0.01), HAART (p = 0.01), high baseline CD4 T-cell count (p < 10(-3)) and low baseline HIV viral load (p = 0.01). In the HAART group, the incidence rate of antiretroviral modification due to tolerance difficulties was 0.23+/-0.36/patient year. A sustained undetectable HIV viral load was correlated with a low baseline HIV viral load (p = 0.003) and to be antiretroviral naive (p < 10(-3)). Thus, HAART provide a better immunological outcome in patients with high CD4 T-cell count. However, the CD4 decay slope after 3 years, the risk of therapeutic side-effects and the low risk of clinical progression do not support systematic treatment of those patients.

Determinants of long-term highly active antiretroviral treatment efficacy

OBJECTIVES

Predictors of the efficacy of highly active antiretroviral therapy (HAART) have been investigated in several studies. To increase current knowledge, the study aimed to acquire comprehensive data over an extended observation time, to obtain information on possible performance differences among individual drugs, and to identify factors with influence on the initial response to a HAART regimen and the sustainability of the response.

METHODS

The data were obtained from a prospective, single University Medical School HIV cohort. Clinical, laboratory, and treatment parameters for 475 patients were collected over 4.5 years. HAART efficacy was determined by analysis of variance and multivariate survival analysis.

RESULTS

The overall initial complete response (CR) (<500 HIV-1 RNA copies/mL) was 76.3%. Use of indinavir [odds ratio (OR)=2.747, P=0.0009] and the number of new nucleoside reverse transcriptase inhibitors (NRTIs) (OR=1.862, P=0.0017) were positively associated with CR, while initial peripheral blood HIV RNA concentration (OR=0.383, P<0.0001), use of saquinavir hard gel capsules (OR=0.531, P=0.0302), the number of successive HAART regimens (OR=0.631, P<0.0001), and the number of previously used NRTIs (OR=0.728, P=0.0081) were negatively associated with CR. Sustainability of CR was positively correlated with use of indinavir [hazard ratio of relapse (HR)=0.255, P<0.0001] and haemoglobin levels (HR=0.873, P=0.0124), but negatively correlated with initial HIV RNA concentration (HR=1.273, P=0.0003) and the number of previously used NRTIs (HR=1.587, P<0.0001). A higher number of consecutive HAART regimens was associated with a markedly reduced CR, but with only a slightly higher risk of relapse.

CONCLUSIONS

The initial response to HAART, as well as long-term efficacy, depends strongly on a few fundamental parameters that can easily be assessed in a clinical setting. There is a need for effective suppression of HIV replication over decades, and these factors should be considered early in treatment planning to identify patients with an unfavourable profile of risk factors for treatment failure.

Duration of highly active antiretroviral therapy regimens

The median duration of highly active antiretroviral therapy (HAART) regimens was reported to be 11.8 months in one US study, but that study included both treatment-experienced and treatment-naive patients. The duration of initial HAART regimens for treatment-naive patients alone has not been reported. We selected 405 antiretroviral-naive patients who were seen at the University of Alabama at Birmingham HIV Outpatient Clinic from 1 January 1996 through 9 October 2001, and we assessed the duration of initial and successive HAART regimens in this group. Any antiretroviral medication change, excluding dosage changes, that lasted >or=14 days was considered to indicate the start of a new regimen. The median duration of regimens was determined by Kaplan-Meier analysis, and proportional hazards regression was used to identify factors associated with shorter duration of initial regimen. The median duration of initial regimens was 1.6 years, and medication toxicity-associated events were the cause of one-half of discontinuations. Only a history of opportunistic infection and injection drug use were significantly associated with shorter regimen duration.

[Adherence to antiretroviral drug therapy. A systematic review]

BACKGROUND

We performed a systematic review of the medical literature in order to determine the level of adherence to antiretroviral therapy and its relation with the social, demographic, and clinical characteristics of patients.

METHOD

Systematic search of published primary studies in MEDLINE, EMBASE and IME and review of reports presented in main congresses related to infectious diseases and AIDS. Observational and intervention studies carried out in adult patients between 1990 and the first semester of 2001 were selected following descriptive and quality criteria. Both English language and Spanish language reports were analyzed.

RESULTS

30 studies fulfilled previously established requirements. Most studies show high adherence levels between 50% and 80% patients, with a range between 28% and 82%. In univariate or multivariate analyses, factors associated with worse adherence levels were as follows: females, younger people, low education level, low income, active drug consumption, lack of self-perception of the efficacy of antiretroviral agents, stress and lack of motivation, high number of tablets and complexity of administration guidelines. Most prospective studies show a good correlation between adherence and control of HIV infection determined by the measurement of the viral load.

CONCLUSIONS

The number of primary studies with methodological quality is limited and future works must be performed under strict design conditions. Most studies show that a high proportion of patients, between 20% and 50%, do not have optimal levels of adherence. Patients with higher adherence levels exhibit greater clinical effectivity. Social, demographic, psychological and other factors related to the lack of adherence must be taken into account in order to improve the compliance in these patients.

Impact of discontinuation of initial protease inhibitor therapy on further virological response in a cohort of human immunodeficiency virus-infected patients

Although discontinuation of antiretroviral drug therapy is common, the impact on outcome in routine clinical practice is unknown. The Antiprotéases Cohorte (APROCO) Cohort Study enrolled 1281 patients at the time they started a protease inhibitor (PI)-containing regimen from 1997 through 1999. After a median duration of follow-up of 20 months, 51% of patients had discontinued their initial PI. Prospectively recorded reasons for discontinuation were intolerance (52% of patients), poor adherence (22%), and failure of therapy (15%). In a multivariate logistic regression analysis, only discontinuation due to poor adherence was associated with a lower frequency of human immunodeficiency virus RNA level in plasma of <500 copies/mL 12 months after initiation of therapy (odds ratio, 0.27 vs. no change; P<.0001); discontinuation due to intolerance was not associated with virological response (odds ratio, 0.89; P=.58). Patients experiencing intolerance should be reassured that changing therapy will probably not be harmful. Multidisciplinary efforts should concentrate on ways to avoid discontinuation of treatment for adherence reasons.

Adherence to highly active antiretroviral therapy in the real world: experience of twelve English HIV units

In order to describe how human immunodeficiency virus (HIV) clinics in and around London are trying to optimize their patients' adherence to highly active antiretroviral therapy (HAART), we performed a survey of practice and policy in the clinics using a postal questionnaire. Clinics were also asked to review up to 10 randomly selected case notes of patients receiving HAART and complete a questionnaire on each about how adherence was encouraged and assessed. Twelve clinics took part in the project and surveyed the notes of 89 patients. The results show that several clinics define adequate adherence as taking more than 95% of prescribed doses although there was no uniform definition across the participating units. Adherence was encouraged through simplifying HAART regimens, providing dose-dispensing boxes and alarms, arranging early follow-up for patients starting treatment, and offering continuing support through specific health care workers. Adequate discussion and provision of written information was seen as an important aid to adherence but the case note survey showed evidence of deficiencies in this area in approximately 40% of patients. Assessed levels of adherence were less than 95% in 27% of patients. The main reasons for suboptimal adherence were found to be lack of motivation to take treatment by the patients, high pill burden, and drug side effects although there were several other contributing factors. This study shows that the HIV units take HAART adherence seriously but there are several deficiencies in putting policy into practice.

A Randomized Clinical Trial Comparing Nelfinavir Or Nevirapine Associated to Zidovudine/Lamivudine in HIV-Infected Naive Patients (The Combine Study)

Background

Non-nucleoside reverse transcriptase inhibitor-containing regimens may be a valid alternative to protease inhibitor-containing regimens for initial antiretroviral therapy, but to date few studies comparing these two strategies have been performed.

Objective

To evaluate the efficacy and safety of nelfinavir or nevirapine associated to zidovudine/lamivudine in HIV-infected naive patients.

Design

Randomized, open-label, multicentre trial.

Setting

Twelve centres in Spain (9) and Argentina (3).

Patients

One hundred and forty-two HIV-infected naive patients without AIDS.

Interventions

Patients received combivir (zidovudine 300 mg/lamivudine 150 mg, twice-daily) plus either nelfinavir (1250 mg) twice-daily (zidovudine/lamivudine/nelfinavir, n=70) or nevirapine (200 mg) twice-daily (zidovudine/lamivudine/nevirapine, n=72), and were followed for 12 months. The primary endpoint was the proportion of patients with a plasma HIV-1 RNA (pVL) of less than 200 copies/ml by PCR at 12 months. pVL of less than 20 copies/ml (PCR), changes in CD4 counts, clinical progression and adverse events were also evaluated. Efficacy was assessed using intent-to-treat (ITT) (missing=failure) and on-treatment analysis.

Results

At 12 months in the ITT analysis the proportion of patients with pVL below 200 copies/ml was 60% (95% CI 48.5–71.5) in the zidovudine/lamivudine/nelfinavir arm and 75% (95% CI 65–85) in the zidovudine/lamivudine/nevirapine arm ( P=0.06), and the proportion below 20 copies/ml was 50% (95% CI 38.3–61.7) and 65% (95% CI 54.2–76.2), respectively ( P=0.06). No differences were found when comparing the subgroup of patients with baseline pVL of more than 100 000 copies/ml. A gain of +173 and +162 CD4 cells/mm3, respectively, was observed. Zidovudine/lamivudine/nelfinavir was discontinued in 21% of patients, and zidovudine/lamivudine/ nevirapine in 25%, due to toxicity ( P>0.2).

Conclusions

Our results suggest that zidovudine/ lamivudine/nevirapine is at least as effective as zidovudine/lamivudine/nelfinavir as first-line therapy for HIV disease.

Low body weight and type of protease inhibitor predict discontinuation and treatment-limiting adverse drug reactions among HIV-infected patients starting a protease inhibitor regimen: consistent results from a randomized trial and an observational cohort

OBJECTIVES

To assess predictors for discontinuation and treatment-limiting adverse drug reactions (TLADR) among patients starting their first protease inhibitor (PI).

METHODS

Data on patients starting a PI regimen (indinavir, ritonavir, ritonavir/saquinavir and saquinavir hard gel) in a randomized trial (RAS, n = 318) and an observational cohort (OBC, n = 505) were used to document reasons for discontinuation and TLADR. Risk factors for discontinuation of the initial PI/developing TLADR were assessed in Cox models.

RESULTS

A total of 43 (RAS) and 48% (OBC) discontinued the initial PI therapy within less than 2 years. In both populations TLADR were the most common reason for discontinuation. The incidence of TLADR in RAS was: 8.5 (indinavir), 66.0 (ritonavir), 15.6 (saquinavir hard gel) per 100 person-years of follow-up (P < 0.001). Body weight and type of PI initiated were independent risk factors for treatment discontinuation and TLADR in both groups. In OBC, the risk of developing TLADR increased by 12% per 5 kg lower body weight when starting the PI regimen [the relative hazard (RH) was 1.12 (95% confidence interval: 1.05-1.19) per 5 kg lighter], and starting ritonavir was associated with a three- to sixfold higher risk of TLADR relative to other PI regimens. Very similar results were documented in RAS [RH for body weight was 1.18 (1.07-1.29)].

CONCLUSIONS

Nearly half of the patients stopped treatment with the initial PI, most commonly as a result of adverse drug reactions. Low body weight and initiation of ritonavir relative to other PIs were associated with an increased risk of TLADRs. Very consistent results were found in a randomized trial and an observational cohort.

Saquinavir soft-gel capsule: an updated review of its use in the management of HIV infection

Saquinavir is a potent and highly selective HIV protease inhibitor. Initially formulated as a hard-gel capsule (HGC), saquinavir was the first protease inhibitor available commercially for the treatment of patients with HIV infection. The limited oral bioavailability of saquinavir HGC has been improved significantly with the introduction of a soft-gel capsule (SGC) formulation. Saquinavir SGC displays greater than dose-proportional pharmacokinetics and mean area under the plasma concentration-time curve (AUC) values are 8- to 10-fold higher with saquinavir SGC 1200 mg 3 times daily than with the HGC formulation 600 mg 3 times daily, the recommended dosages of the 2 formulations. In combination with other protease inhibitors (particularly "low dose" ritonavir), the oral bioavailability of saquinavir (as either the HGC or SGC formulation) is markedly increased, allowing for reduced dosing frequency and/or dosage. The efficacy and tolerability of once- or twice-daily saquinavir SGC/"low dose" ritonavir combinations are currently being evaluated in patients with HIV infection. Data (up to 48 weeks) from noncomparative and comparative clinical trials evaluating saquinavir SGC-containing combination regimens in adult patients with HIV infection, support and strengthen the clinical efficacy profile of the drug that was demonstrated in initial trials. In antiretroviral therapy-naive and -experienced patients, saquinavir SGC combined with > or =2 nucleoside reverse transcriptase inhibitors (NRTIs), or nelfinavir, or nelfinavir plus 2 NRTIs or nonnucleoside reverse transcriptase inhibitors (NNRTIs), markedly improved immunological and virological surrogate markers (increased mean CD4+ cell counts and decreased mean plasma HIV RNA levels) of HIV infection. Saquinavir SGC demonstrated a trend to greater antiviral efficacy (measured by improvements in surrogate markers) than the HGC formulation (not statistically significant); a significantly greater proportion of patients treated with saquinavir SGC had plasma HIV RNA levels <400 copies/ml than patients receiving the HGC formulation. In the first direct comparison of 2 protease inhibitors, saquinavir SGC plus 2 NRTIs demonstrated similar antiviral efficacy to indinavir plus 2 NRTIs in patients with HIV infection (almost all of whom were antiretroviral therapy-naive); at 24 weeks, a significantly greater increase in CD4+ cell count from baseline was obtained in the saquinavir SGC group compared with the indinavir group, although this difference was not apparent at week 32. Triple therapy with saquinavir SGC plus 2 NRTIs was as effective as nelfinavir-containing triple therapy, or quadruple therapy (saquinavir SGC plus 2 NRTIs plus nelfinavir) in markedly suppressing HIV RNA levels in antiretroviral therapy-experienced or -naive patients. Saquinavir SGC is generally well tolerated. Gastrointestinal disturbances (generally nausea, diarrhoea, abdominal pain, vomiting and dyspepsia of moderate or greater intensity) are the most common adverse events associated with saquinavir SGC-containing therapy. In comparative trials, saquinavir SGC-containing therapy was as well tolerated as indinavir- and nelfinavir-containing therapy; although there were no statistical differences between treatment groups, the incidence of diarrhoea was lower in patients receiving saquinavir SGC compared with nelfinavir, saquinavir SGC plus nelfinavir (all combined with 2 NRTIs) or saquinavir SGC plus nelfinavir without additional therapy. Compared with the HGC formulation, saquinavir SGC appears to be associated with a higher overall incidence of adverse events.

CONCLUSIONS

Clinical trial data have shown that as part of triple or quadruple combination therapy, saquinavir SGC is an effective and generally well tolerated protease inhibitor in antiretroviral therapy-naive or -experienced patients with HIV infection. (ABSTRACT TRUNCATED)