Efficacy and safety of 48 weeks of enfuvirtide 180 mg once-daily dosing versus 90 mg twice-daily dosing in HIV-infected patients

Transdermal Delivery of Enfuvirtide in a Porcine Model Using a Low-Frequency, Low-Power Ultrasound Transducer Patch

Ultrasound-mediated transdermal delivery is a promising parenteral administration method for large-molecule or unstable medications. This study evaluated skin health and systemic delivery when administering enfuvirtide, an injectable anti-retroviral medication, over a 1-mo period in a porcine model using a low-frequency cymbal transducer. Three groups received twice-daily treatments: (i) enfuvirtide injection control (n = 12); (ii) saline ultrasound control (n = 6); and (iii) enfuvirtide ultrasound treatment (n = 13). Ultrasound parameters were as follows: 30-min exposure, 90 mW/cm², 24-26 kHz and 15% duty cycle. No statistical difference in trans-epidermal water loss, a measure of skin health and function, was seen between ultrasound-treated and control skin sites for either saline (p = 0.50) or enfuvirtide (p = 0.29) groups. Average trough plasma concentrations of enfuvirtide were 0.6 ± 0.2 and 2.8 ± 0.8 μg/mL for ultrasound and injection, respectively. Tolerability and efficacy results indicate that chronic, low-frequency ultrasound exposure can be a practical means for transdermal delivery of medications such as enfuvirtide.

Lower pill burden and once-daily antiretroviral treatment regimens for HIV infection: A meta-analysis of randomized controlled trials

Once-daily compared with twice-daily antiretroviral therapy regimens increased adherence; however, the difference was modest and not associated with a difference in virological suppression. In addition, higher pill burden was associated with lower rates of virological suppression, whether once- or twice-daily regimens.

Background. Contemporary antiretroviral treatment regimens are simpler than in the past, with lower pill burden and once-daily dosing frequency common. We performed a meta-analysis of randomized controlled trials (RCTs) to investigate the impact of pill burden and once-daily vs twice-daily dosing on ART adherence and virological outcomes.

Methods. A literature search of 4 electronic databases through 31 March 2013 was used. RCTs comparing once-daily vs twice-daily ART regimens that also reported on adherence and virological suppression were included. Study design, study population characteristics, intervention, outcome measures, and study quality were extracted. Study quality was rated using the Cochrane risk-of-bias tool.

Results. Nineteen studies met our inclusion criteria (N = 6312 adult patients). Higher pill burden was associated with both lower adherence rates (P = .004) and worse virological suppression (P < .0001) in both once-daily and twice-daily subgroups, although the association with adherence in the once-daily subgroup was not statistically significant. The average adherence was modestly higher in once-daily regimens than twice-daily regimens (weighted mean difference = 2.55%; 95% confidence interval [CI], 1.23 to 3.87; P = .0002). Patients on once-daily regimens did not achieve virological suppression more frequently than patients on twice-daily regimens (relative risk [RR] = 1.01; 95% CI, 0.99 to 1.03; P = .50). Both adherence and viral load suppression decreased over time, but adherence decreased less with once-daily dosing than with twice-daily dosing.

Conclusions. Lower pill burden was associated with both better adherence and virological suppression. Adherence, but not virological suppression, was slightly better with once- vs twice-daily regimens.

Treatment simplification in HIV-infected adults as a strategy to prevent toxicity, improve adherence, quality of life and decrease healthcare costs

Since the advent of highly active antiretroviral therapy (HAART), the treatment of human immunodeficiency virus (HIV) infection has become more potent and better tolerated. While the current treatment regimens still have limitations, they are more effective, more convenient, and less toxic than regimens used in the early HAART era, and new agents, formulations and strategies continue to be developed. Simplification of therapy is an option for many patients currently being treated with antiretroviral therapy (ART). The main goals are to reduce pill burden, improve quality of life and enhance medication adherence, while minimizing short- and long-term toxicities, reducing the risk of virologic failure and maximizing cost-effectiveness. ART simplification strategies that are currently used or are under study include the use of once-daily regimens, less toxic drugs, fixed-dose coformulations and induction-maintenance approaches. Improved adherence and persistence have been observed with the adoption of some of these strategies. The role of regimen simplification has implications not only for individual patients, but also for health care policy. With increased interest in ART regimen simplification, it is critical to study not only implications for individual tolerability, toxicity, adherence, persistence and virologic efficacy, but also cost, scalability, and potential for dissemination and implementation, such that limited human and financial resources are optimally allocated for maximal efficiency, coverage and sustainability of global HIV/AIDS treatment.

Twice-daily versus once-daily antiretroviral therapy and coformulation strategies in HIV-infected adults: benefits, risks, or burden?

The recent development of once-daily antiretroviral agents and fixed-dose combination formulations has been an important development in antiretroviral regimen simplification. Recent studies indicate that once-daily antiretroviral regimens improve adherence, especially in antiretroviral-naïve patients and in difficult-to-treat populations, such as the homeless or marginally housed. However, there are potential risks with the higher peak and lower trough plasma drug concentrations that may result from certain once-daily formulations. Due to the multifactorial and complex nature of adherence behavior, clinicians' efforts to improve patient adherence should not be limited to prescribing once-daily regimens, but should also consider social support, side effect management, and adherence support tools, such as pillbox organizers and other targeted interventions. Additional research will clarify the benefits of once-daily and fixed-dose combination regimens on clinical and virologic outcomes. Comprehensive cost-benefit analysis of regimen simplification could help facilitate evidence-based decisions regarding antiretroviral regimen choices.

A single tablet regimen is associated with higher adherence and viral suppression than multiple tablet regimens in HIV+ homeless and marginally housed people

BACKGROUND

Although, single-tablet regimen (STR) efavirenz, emtricibine, and tenofovir disoproxil fumarate (EFV/FTC/TDF) may be appealing in HIV-infected persons who are at high risk for nonadherence, the degree to which this simplified formulation affects adherence is not known. The virologic effectiveness of this STR in a potentially nonadherent population remains a concern, given the rapid selection of drug resistance seen with these drugs.

METHOD

We performed a prospective observational study assessing adherence and virologic response to EFV/FTC/TDF STR among a cohort of homeless and marginally housed individuals. We compared adherence and viral suppression to historical controls followed in the same cohort.

RESULTS

Adherence was higher in EFV/FTC/TDF STR regimen compared to non-one-pill-once-daily therapy (P = 0.006) after controlling for multiple confounders. Viral suppression (HIV RNA <50 copies/ml) was greater in EFV/ FTC/TDF STR than non-one-pill-once-daily regimens (69.2 versus 46.5%; P = 0.02), but there was no difference in viral suppression after controlling for adherence.

CONCLUSION

Once-daily EFV/TNF/FTC STR appears to be a reasonable option for individuals with multiple barriers to adherence. Randomized clinical trials addressing various therapeutic strategies for this patient population are needed.

The fusion inhibitor enfuvirtide in recent antiretroviral strategies

PURPOSE OF REVIEW

The purpose of this review is to discuss recent pharmacological, virological, and clinical data that concern enfuvirtide usage in different antiretroviral combinations.

RECENT FINDINGS

Randomized, recent trials in multidrug-experienced patients suggest that antiretroviral combinations with enfuvirtide have excellent virological responses with new antiretroviral compounds, including darunavir, etravirine, raltegravir, vicriviroc, and maraviroc. Trials confirm long-term safety, in spite of moderate injection-site reactions or pain, and lack of significant interactions. Preliminary data suggest that switching from enfuvirtide to raltegravir is effective and using enfuvirtide in prophylaxis of mother-to-child transmission is well tolerated. To administer enfuvirtide in an intensification strategy in antiretroviral-naïve or experienced populations may accelerate virological decline.

SUMMARY

Dosage adaptations to renal insufficiency are not necessary with enfuvirtide. Spinal fluid concentrations and ombilic cord passage are negligible. Durability of virological responses with enfuvirtide in combinations has been confirmed, in spite of injection-site reactions and twice daily subcutaneous administration. Enfuvirtide should be used with at least one other fully active drug in optimized background therapy in multidrug-experienced populations, a possible exception being with entry inhibitors, which may further benefit from the addition of a third active drug. Data concerning enfuvirtide in antiretroviral combinations show accelerated viral load decline, and the possibility of switching from enfuvirtide to raltegravir without modification of optimized background therapy.

Reassessment of enfuvirtide's role in the management of HIV-1 infection

BACKGROUND

The development of new protease inhibitors, new non-nucleoside reverse transcriptase inhibitors and novel therapeutic drug classes has dramatically changed the approach to managing HIV-1 patients with multidrug resistant virus. This has led many clinicians to reevaluate the clinical utility of enfuvirtide.

OBJECTIVES

To summarize recent literature on enfuvirtide and to reassess enfuvirtide's role in the management of HIV-1 infection.

METHODS

MEDLINE (1990 to February Week 2 2008) and EMBASE (1990 to 2008 week 8) databases were searched using the following terms: 'enfuvirtide', 'Fuzeon', 'T20', 'HIV fusion inhibitors', and 'HIV entry inhibitor'; limits: English language. Reference lists of articles deemed relevant were hand searched for additional publications. Significant abstracts from recent international HIV conferences were also identified.

CONCLUSION

Enfuvirtide can optimize the response to new combinations of HIV-1 drug regimens in multiresistant patients. Its inclusion as an active agent is effective but use is impacted by its high cost, inconvenient route of administration and cosmetic side-effect profile.