Lopinavir/ritonavir monotherapy or plus zidovudine and lamivudine in antiretroviral-naive HIV-infected patients

Risk factors for loss of virological suppression in patients receiving lopinavir/ritonavir monotherapy for maintenance of HIV suppression

Background

Risk factors for loss of virological response in patients receiving lopinavir/ritonavir (LPV/r) monotherapy as maintenance treatment have not been determined.

Methods

In 121 patients enrolled in the OK and OK04 clinical trials assigned to receive monotherapy with LPV/r, we attempted to identify factors associated with loss of virological suppression at 48 weeks, defined as confirmed serum HIV type-1 RNA>50 copies/ml, with missing data or changes caused by toxicity censored. Univariate and multivariate Cox proportional hazard models were used to calculate hazard ratios for the risk of loss of virological suppression.

Results

At week 48, 15 patients experienced loss of virological suppression. Probability of loss of virological suppression was 12.7%. Less than 9 months of maintenance of virological suppression prior to monotherapy, a lower baseline haemoglobin and low adherence measured by self-reported total missed doses in the week prior to study visit were associated with loss of virological suppression in the univariate analyses. Independent factors associated with loss of virological suppression by multivariate analyses were ≥2 visits with self-reported missed doses in the week prior to the study visit, a lower baseline haemoglobin and a nadir CD4+ T-cell count <100 cells/μl

Conclusions

Suboptimal adherence, lower baseline haemoglobin and a nadir CD4+ T-cell count <100 cells/μl were the main risk factors for losing virological suppression in patients randomized to monotherapy with LPV/r.

HIV monotherapy with ritonavir-boosted protease inhibitors: a systematic review

OBJECTIVE

To assess the efficacy of ritonavir-boosted protease inhibitor monotherapy.

DESIGN AND METHODS

Systematic review of all protease inhibitor-monotherapy studies published in peer-reviewed journals or presented at conferences to date. Data of randomized controlled trials were pooled to yield common odds ratios.

RESULTS

Twenty-two protease inhibitor-monotherapy studies were identified. In the intent-to-treat analysis, 395 out of 582 (67.9%) patients had undetectable HIV-RNA at the end of follow-up. In the six randomized controlled trials (all lopinavir/ritonavir monotherapy), the risk of therapy failure was greater on monotherapy: 121 out of 364 (33.2%) patients on monotherapy against 64 out of 280 (22.9%) patients on HAART [pooled odds ratio 1.48 (95% confidence interval 1.02-2.13, P = 0.037)]. Regarding patients with successfully resuppressed HIV-RNA upon (re-)introducing nucleoside reverse transcriptase inhibitors (NRTIs) as nonfailures, the risk of therapy failure was comparable: 98 out of 364 (26.9%) against 64 out of 280 (22.9%) patients [odds ratio 1.05 (95% confidence interval 0.72-1.53, P = 0.81)].

CONCLUSION

The overall efficacy of ritonavir-boosted protease inhibitor monotherapy is inferior to HAART. The efficacy improves in patients started on monotherapy after suppressed HIV-RNA for at least 6 months. Ten percent of patients have viral rebound with HIV-RNA levels between 50 and 500 copies/ml. Possible explanations are lack of HIV suppression in particular cells or compartments, alternative resistance mechanisms, and nonadherence. Once proven that reintroduction of NRTIs, in patients with loss of viral suppression, is safe and effective, a broader use of simplification of HAART to protease inhibitor monotherapy might be justified. This review supports that the majority of patients with prolonged viral suppression on HAART can successfully be treated with protease inhibitor monotherapy. Arguments for this strategy are NRTI/NNRTI side effects, NRTI/NNRTI resistance, and costs.

Simplification Strategies to Reduce Antiretroviral drug Exposure: Progress and Prospects

Current US guidelines for initial therapy of HIV type-1 (HIV-1) infection recommend daily, lifelong treatment with a combination of three antiretroviral drugs consisting of two nucleoside analogue reverse transcriptase inhibitors and a non-nucleoside reverse transcriptase inhibitor or a protease inhibitor. Although this approach has been successful in reducing morbidity and mortality from HIV-1 infection, concerns remain about adverse events from chronic drug exposure, the requirement for daily medication adherence, the risk of HIV-1 drug resistance and high treatment costs. The availability of antiretrovirals that are coformulated and dosed once daily have reduced pill burden and have simplified dosing schedules, but have not lowered drug exposure or cost. These limitations have stimulated research into drug-sparing strategies including intermittent therapy and simplified maintenance regimens. Randomized clinical trials have shown greater mortality with intermittent therapy compared with continuous therapy leading to rejection of this strategy. Pilot studies of simplified maintenance therapy with a ritonavir-boosted protease inhibitor alone have shown more promise, although concerns remain. This article reviews progress in the simplification of antiretroviral therapy, recent clinical trial results and prospects for the future.

Prognostic factors for virological response in antiretroviral therapy-naive patients in the MONARK Trial randomized to ritonavir-boosted lopinavir alone

Background

MONARK is a pilot randomized trial comparing the safety and efficacy of lopinavir/ritonavir (LPV/r) monotherapy to a standard triple-drug regimen as initial therapy. The primary endpoint was virological response (VR) defined as viral load (VL)<400 copies/ml at week 24 and VL<50 copies/ml at week 48. The objective of this study was to determine prognostic factors of VR in patients receiving LPV/r monotherapy.

Methods

Baseline characteristics, including demographics, HIV type-1 (HIV-1) subtype (B versus non-B), early VR up to week 4, LPV trough concentrations and compliance were investigated as prognostic factors for VR in patients receiving LPV/r monotherapy. Logistic regression was used to search for variables significantly associated with the occurrence of VR.

Results

VR was achieved in 53 out of 83 patients randomized to the LPV/r arm. The on-treatment analysis, using a multivariate model, indicated that having VL<400 copies/ml at week 4 and harbouring HIV-1 subtype B were independently associated with an increased probability of VR. No difference in early VL reduction was evidenced between patients harbouring B or non-B subtypes. The latter patients had more difficulty in adherence to therapy than the former patients. The intention-to-treat analysis showed similar results.

Conclusions

HIV-1 RNA measured at baseline or at week 4 and HIV-1 subtype (B versus non-B) were independent predictive factors of VR in patients starting therapy with LPV/r alone. Although based on a small sample size, results of this study showed that adherence to therapy is lower in patients harbouring non-B subtypes and appears to be a key factor of VR in the context of protease inhibitor monotherapy.

Lopinavir/ritonavir in the treatment of HIV-1 infection: a review

Lopinavir/ritonavir is the first and only coformulated HIV-1 protease inhibitor (PI). Large clinical trials have demonstrated lopinavir/ritonavir's clinical efficacy in both antiretroviral-naïve and -experienced patients. The immunologic and virologic benefits of treatment with this agent have been proven in HIV-infected adults, adolescents, and children. Smaller studies support the use of lopinavir/ritonavir monotherapy as a therapeutic option in certain patients. The drug is characterized by a high genetic barrier to resistance, and appears to be more forgiving of non-adherence than earlier, unboosted PIs. The most frequent side effects observed are diarrhea, nausea, and vomiting. These gastrointestinal adverse effects are generally mild to moderate. Metabolic derangements, including hyperlipidemia and glucose intolerance, have also been observed in lopinavir/ritonavir recipients. As the menu of available antiretroviral agents continues to expand, lopinavir/ritonavir remains a proven and effective drug for the treatment of HIV infection.

Ritonavir-boosted darunavir: a powerful option for treatment-experienced HIV-1-infected patients

Darunavir is a HIV protease inhibitor with potent activity in vitro against a broad range of HIV-1 strains and isolates containing multiple protease inhibitor resistance-associated mutations. Its bioavailability increases when co-administered with low-dose ritonavir, or if taken with a meal. Darunavir (in combination with ritonavir) has been approved for treatment of antiretroviral drug-experienced patients with limited therapeutic options. Clinical trials demonstrated significant efficacy with darunavir/ritonavir 600/100 mg twice daily plus optimized background regimens, with sustained response after 48 weeks and no major safety and tolerability concerns. Clinical trials assessing its efficacy in earlier treatment failure have been favorable, however, its role in the treatment of naive patients has not yet been defined.

A 96-week comparison of lopinavir-ritonavir combination therapy followed by lopinavir-ritonavir monotherapy versus efavirenz combination therapy

Antiretroviral-naive HIV-1-infected volunteers received zidovudine/lamivudine plus either lopinavir/ritonavir (n=104) or efavirenz (n=51). Lopinavir/ritonavir-treated subjects demonstrating 3 consecutive monthly HIV-1 RNA levels <50 copies/mL started lopinavir/ritonavir monotherapy. In previous-failure=failure analysis, 48% (lopinavir/ritonavir) and 61% (efavirenz) maintained HIV-1 RNA at <50 copies/mL through week 96, (P= .17; 95% confidence interval [CI] for the difference, -29% to 4%); in noncompletion=failure analysis, 60% (lopinavir/ritonavir) and 63% (efavirenz) maintained HIV-1 RNA at <50 copies/mL at week 96 (P= .73; 95% CI for the difference, -19% to 13%). Significant sparing of peripheral lipoatrophy was noted in the lopinavir/ritonavir simplification strategy. This study has provided important information for future studies using treatment simplified to lopinavir/ritonavir monotherapy.

Effect of Lopinavir/Ritonavir Monotherapy on Quality of Life and Self-Reported Symptoms among Antiretroviral-Naive Patients: Results of the MONARK Trial

Background

Standard-of-care for HIV-infected patients consists of combining three antiretroviral drugs. However, other therapeutic strategies could be beneficial given long-term toxicity and quality of life (QOL) issues associated with taking multiple antiretroviral drugs for many years. In the prospective, open label, randomized, pilot monotherapy antiretroviral Kaletra® (MONARK) trial among antiretroviral-naive patients, lopinavir/ritonavir (LPV/r) monotherapy was found to be less suppressive for HIV RNA than a standard triple-drug therapy of LPV/r plus zidovudine/lamivudine (on-treatment analysis after 48 weeks). We present data from the MONARK trial concerning QOL and patient-reported symptoms.

Methods

Patient-reported symptoms were collected at baseline and at weeks 4, 12, 24 and 48 using a list of 22 symptoms. QOL was assessed at baseline, week 24 and week 48 using the six-domain World Health Organization QOL short form questionnaire for HIV-infected individuals including an evaluation of global health perception.

Results

Patients treated with the standard triple-drug therapy reported significantly more symptoms over 48 weeks of treatment than patients treated with LPV/r monotherapy (incidence rate ratio [95% confidence interval] 1.3 [1.1, 1.6] P=0.001 and 1.4 [1.2, 1.7] P=0.0004 for the total number of symptoms and the number of symptoms causing discomfort, respectively). No baseline differences and no significant changes were observed in the six QOL scores. The percentage of patients with a positive perception of their global health status increased significantly in the monotherapy arm from 32% at baseline to 67% at week 48 ( P<0.0001).

Conclusions

These results suggest that the number of self-reported symptoms could be used as a treatment-sensitive measure of patients’ well-being in clinical trials.