Rilpivirine, emtricitabine and tenofovir alafenamide: single-tablet combination for the treatment of HIV-1 infection in selected patients

Brief Report: No Difference in Urine Tenofovir Levels in Patients Living With HIV on Unboosted Versus Dose-Adjusted Boosted Tenofovir Alafenamide

BACKGROUND

Tenofovir alafenamide (TAF) is increasingly used in HIV treatment, with or without agents that require pharmacologic boosters such as ritonavir/cobicistat. Boosters increase TAF levels, so the TAF dose is lowered in single-pill combinations. We hypothesized that individuals on dose-adjusted boosted TAF would have similar urine tenofovir (TFV) concentrations to those on unboosted TAF.

SETTING/METHODS

We collected urine samples from patients with HIV on TAF, with evidence of virologic suppression and high self-reported adherence at 2 San Francisco clinics from June 2019 to January 2020. We measured urine TFV levels by liquid chromatography/tandem mass spectrometry and used linear regression to compare natural log-transformed urine TFV levels for patients on boosted versus unboosted TAF.

RESULTS

Our analysis included 30 patients on unboosted TAF (25 mg daily TAF) and 15 on boosted TAF (12 on 10 mg daily TAF and 3 on 25 mg daily TAF). Patients on unboosted vs. boosted TAF had similar baseline age, weight, sex, and creatinine. In unadjusted univariate linear regression, there were no significant differences in urine TFV levels based on presence/absence of boosting after TAF dose reduction to 10 mg (geometric mean ratio 1.07; 95% confidence interval: 0.53 to 2.16). This finding was unchanged in adjusted analysis.

CONCLUSIONS

No significant differences in urine TFV levels were seen for patients on unboosted vs. boosted dose-reduced TAF. These results have important implications for our forthcoming point-of-care urine immunoassay for TAF, implying that separate adherence cutoffs will not be necessary for patients on boosters and dose-reduced TAF. A single POC TAF immunoassay will, thus, support monitoring on most TAF-based antiretroviral therapy.

The Increase of HIV-1 Infection, Neurocognitive Impairment, and Type 2 Diabetes in The Rio Grande Valley

The Human Immunodeficiency Virus (HIV-1) infection remains a persistent predicament for the State of Texas, ranking seventh among the most documented HIV cases in the United States. In this regard, the Rio Grande Valley (RGV) in South Texas is considered as one of the least investigated areas of the state with respect to HIV infection and HIV associated comorbidities. Considering the 115% increase in average HIV incidence rates per 100,000 within the RGV from 2007-2015, it is worth characterizing this population with respect to their HIV-1 infection, HIV-1 Associated Neurocognitive Disorders (HAND), and the association of treatment with combined antiretroviral therapy (cART). Moreover, the increased rate of Type-2 Diabetes (T2D) in the RGV population is intertwined with that of HIV-1 infection facing challenges due to the lack of knowledge about prevention to inadequate access to healthcare. Hence, the role of T2D in the development of HAND among the people living with HIV (PLWH) in the RGV will be reviewed to establish a closer link between T2D and HAND in cART-treated patients of the RGV.

Co-crystals, Salts or Mixtures of Both? The Case of Tenofovir Alafenamide Fumarates

Tenofovir alafenamide fumarate (TAF) is the newest prodrug of tenofovir that constitutes several drug products used for the treatment of HIV/AIDS. Although the solid-state properties of its predecessor tenofovir disoproxil fumarate have been investigated and described in the literature, there are no data in the scientific literature on the solid state properties of TAF. In our report, we describe the preparation of two novel polymorphs II and III of tenofovir alafenamide monofumarate (TA MF2 and TA MF3). The solid-state structure of these compounds was investigated in parallel to the previously known tenofovir alafenamide monofumarate form I (TA MF1) and tenofovir alafenamide hemifumarate (TA HF). Interestingly, the single-crystal X-ray diffraction of TA HF revealed that this derivative exists as a co-crystal form. In addition, we prepared a crystalline tenofovir alafenamide free base (TA) and its hydrochloride salt (TA HCl), which enabled us to determine the structure of TA MF derivatives using ¹⁵N-ssNMR (¹⁵N-solid state nuclear magnetic resonance). Surprisingly, we observed that TA MF1 exists as a mixed ionization state complex or pure salt, while TA MF2 and TA MF3 can be obtained as pure co-crystal forms.

Dolutegravir/rilpivirine for the treatment of HIV-1 infection

Much progress has been made in the development of antiretroviral therapies (ARTs) for HIV-1 infection. Beginning a little over a decade ago, single tablet combination regimens (STRs) became available, and subsequently, newer STR formulations with improved safety profiles have emerged. Recently, there is a growing interest in regimen simplification with the primary goal of further reducing long-term toxicities of ART and improving medication adherence. Dolutegravir/rilpivirine (DTG/RPV) was approved by the US Food and Drug Administration (FDA) as the first dual antiretroviral STR for the maintenance therapy of HIV-1 infection. Following an extensive review of all published papers on RPV and DTG, administered alone and in combination, extracted from databases including PubMed, Google scholar, and EMBASE, as well as drug package inserts and conference abstracts and proceedings, this review discusses the chemical properties and composition, pharmacodynamics and pharmacokinetic properties, clinical trial efficacy and safety data, as well as important drug-drug interactions associated with DTG/RPV. An expert opinion section discusses ideal candidates for DTG/RPV in the context of available but limited data and in comparison to currently available and emerging ART alternatives.

Microfabricated devices for oral drug delivery

Oral administration of drugs is most convenient for patients and therefore the ultimate goal when developing new medication. The physical barriers in the body, low pH of the stomach and degradation by enzymes in the gastrointestinal tract are a few of the obstacles to succeeding with oral drug delivery. Microfabricated devices show promise to overcome some of these hindrances and thereby improve the bioavailability of drugs after oral administration. There is an increasing focus on microfabricated oral drug delivery systems, and so far there have been three main groups of designs: patch-like structures, microcontainers and microwells. Here, we review the newest development in top-down microfabricated devices for oral drug delivery with coverage of the aspects of design, choice of material and fabrication techniques. Furthermore, the drug loading techniques and methods for testing are discussed. In addition, we discuss the future perspectives for microfabricated devices.