Short-course daily isoniazid and rifapentine for latent tuberculosis infection in people living with HIV who received coformulated bictegravir/emtricitabine/tenofovir alafenamide

Clinical considerations and pharmacokinetic interactions between HIV and tuberculosis therapeutics

INTRODUCTION

Tuberculosis (TB) is a leading infectious disease cause of mortality worldwide, especially for people living with human immunodeficiency virus (PLWH). Treating TB in PLWH can be challenging due to numerous drug interactions.

AREAS COVERED

This review discusses drug interactions between antitubercular and antiretroviral drugs. Due to its clinical importance, initiation of antiretroviral therapy in patients requiring TB treatment is discussed. Special focus is placed on the rifamycin class, as it accounts for the majority of interactions. Clinically relevant guidance is provided on how to manage these interactions. An additional section on utilizing therapeutic drug monitoring (TDM) to optimize drug exposure and minimize toxicities is included.

EXPERT OPINION

Antitubercular and antiretroviral coadministration can be successfully managed. TDM can be used to optimize drug exposure and minimize toxicity risk. As new TB and HIV drugs are discovered, additional research will be needed to assess for clinically relevant drug interactions.

Treatment Responses to Integrase Strand-transfer Inhibitor-containing Antiretroviral Regimens in Combination With Short-course Rifapentine-based Regimens for Latent Tuberculosis Infection Among People With HIV

BACKGROUND

Real-world experience with combinations of short-course rifapentine-based regimens and integrase strand-transfer inhibitor-containing antiretroviral therapy (ART) in management of latent tuberculous infection (LTBI) is limited among people with human immunodeficiency virus (PWH).

METHODS

From August 2019 to October 2022, PWH receiving 3 months of weekly rifapentine plus isoniazid (3HP) or 1 month of daily rifapentine plus isoniazid (1HP) in combination with ART were included. The primary outcome was virologic response within 12 months after LTBI treatment; secondary outcomes included treatment completion rate and safety of LTBI regimens.

RESULTS

During the study period, 479 PWH (94.6% male; median age, 43 years) were included: 142 received 1HP and bictegravir (BIC)-containing regimens (1HP/BIC group), 46 1HP and dolutegravir (DTG)-containing regimens (1HP/DTG group), 38 3HP and BIC-containing regimens (3HP/BIC group), 214 3HP and DTG-containing regimens (3HP/DTG group), 17 1HP and other ART regimens (1HP/others group), and 22 3HP/other ART regimens (3HP/others group). In the intention-to-treat analysis, the proportions of PWH maintaining plasma HIV-1 RNA <200 copies/mL within 12 months after LTBI treatment completion were 96.5% (1HP/BIC), 100% (1HP/DTG), 100% (3HP/BIC), 95.8% (3HP/DTG), 100% (1HP/others), and 100% (3HP/others). The overall completion rates were >80% for all treatment groups, whereas >50% of the included PWH experienced any adverse event. LTBI regimens and ART combinations were not associated with virologic response and completion rate.

CONCLUSIONS

Combinations of short-course rifapentine-based regimens and integrase strand-transfer inhibitor-containing ART maintained viral suppression for most PWH within 12 months of LTBI treatment completion with low rates of grade 3 or higher adverse events.

US Guidelines Fall Short on Short-Course Tuberculosis-Preventive Therapy

The provision of tuberculosis-preventive therapy (TPT) to vulnerable populations is critical for global control. Shorter-course TPT regimens are highly effective and improve completion rates. Despite incorporation of 1 month of rifapentine and isoniazid into global guidelines, current US TPT guidelines do not include this as a recommended regimen, but should.

Biktarvy for the treatment of HIV infection: Progress and prospects

Bictegravir (BIC), a second-generation integrase strand-transfer inhibitor (INSTI) with high resilience to INSTI-resistance mutations, is integrated as a key component of Biktarvy® - a fixed-dose once-daily triple-drug regimen of bictegravir (BIC), emtricitabine (FTC) plus tenofovir alafenamide (TAF). Based on the accumulated evidence from HIV clinical trials and real-world studies, the clinical effectiveness of BIC + FTC + TAF has been proven non-inferior to other fixed-dose once-daily combinations such as dolutegravir + FTC + TAF and dolutegravir + abacavir + lamivudine. Biktarvy also shows limited drug-drug interactions and a high barrier to drug resistance. According to recent HIV guidelines, BIC + FTC + TAF is recommended as initial and long-term therapy for the treatment of HIV infection. For the pre-exposure prophylaxis, tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF) remains advisable, but BIC may be possibly added to TDF or TAF. In the development of a long-acting once-monthly regimen, the novel nano-formulation of BIC + FTC + TAF could be possibly developed in the future.

Broadening access to tenofovir alafenamide for the treatment and prevention of HIV-1 infection

INTRODUCTION

Tenofovir alafenamide (TAF), a prodrug of tenofovir, achieves higher intracellular concentrations of tenofovir-diphosphate and 90% lower plasma concentrations of tenofovir compared to tenofovir disoproxil fumarate (TDF). TAF is associated with improved renal and bone safety outcomes.

AREAS COVERED

We review the efficacy and safety of TAF-containing regimens in adults and pediatrics. We highlight safety data during pregnancy, drug interactions during co-administration with tuberculosis treatment, and critical knowledge gaps to be addressed for the successful implementation of TAF in low- and middle-income countries. We performed a search on MEDLINE PubMed and conference websites for relevant articles published from January 2010 to March 2023.

EXPERT OPINION

Current evidence demonstrates that TAF has similar efficacy and tolerability, superior bone and renal safety, and higher rates of dyslipidemia and weight gain, compared with TDF. However, there are several knowledge gaps, in specific sub-populations, that require action. Emerging data suggests that TAF is safe during pregnancy, although fuller safety data to support TAF use in pregnancy is needed. Similarly, there is a lack of evidence that TAF can be used in combination with rifamycin-based tuberculosis treatment in PWH and TB. Further studies are needed to fill knowledge gaps and support the wider rollout of TAF.

Recent advances on dual inhibitors targeting HIV reverse transcriptase associated polymerase and ribonuclease H

Reverse transcriptase (RT) plays an indispensable role in the replication of human immunodeficiency virus (HIV) through its associated polymerase and ribonuclease H (RNase H) activities during the viral RNA genome transformation into proviral DNA. Due to the fact that HIV is a highly mutagenic virus and easily resistant to single-target RT inhibitors, dual inhibitors targeting HIV RT associated polymerase and RNase H have been developed. These dual inhibitors have the advantages of increasing efficacy, reducing drug resistance, drug-drug interactions, and cytotoxicity, as well as improving patient compliance. In this review, we summarize recent advances in polymerase/RNase H dual inhibitors focusing on drug design strategies, and structure-activity relationships and share new insights into developing anti-HIV drugs.

Evaluation of drug-drug interaction between rilpivirine and rifapentine using PBPK modelling

Tuberculosis remains the leading cause of death among people living with HIV. Rifapentine is increasingly used to treat active disease or prevent reactivation, in both cases given either as weekly or daily therapy. However, rifapentine is an inducer of CYP3A4, potentially interacting with antiretrovirals like rilpivirine. This in silico study investigates the drug-drug interaction (DDI) magnitude between daily oral rilpivirine 25 mg with either daily 600 mg or weekly 900 mg rifapentine. A physiologically based pharmacokinetic (PBPK) model was built in Simbiology (Matlab R2018a) to simulate the drug-drug interaction. The simulated PK parameters from the PBPK model were verified against reported clinical data for rilpivirine and rifapentine separately, daily rifapentine with midazolam, and weekly rifapentine with doravirine. The simulations of concomitant administration of rifapentine with rilpivirine at steady-state lead to a maximum decrease on AUC0-24 and Ctrough by 83% and 92% on day 5 for the daily rifapentine regimen and 68% and 92% for the weekly regimen on day 3. In the weekly regimen, prior to the following dose, AUC0-24 and Ctrough were still reduced by 47% and 53%. In both simulations, the induction effect ceased 2 weeks after the interruption of rifapentine's treatment. A daily double dose of rilpivirine after initiating rifapentine 900 mg weekly was simulated but failed to compensate the drug-drug interaction. The drug-drug interaction model suggested a significant decrease on rilpivirine exposure which is unlikely to be corrected by dose increment, thus coadministration should be avoided.

Care cascade of tuberculosis infection treatment for people living with HIV in the era of antiretroviral therapy scale-up

Testing and treatment of tuberculosis infection (TBI) are recommended for people living with HIV (PLWH). We aimed to evaluate the care cascade of TBI treatment among PLWH in the era of antiretroviral therapy (ART) scale-up. This retrospective study included adult PLWH undergoing interferon-gamma release assay (IGRA)-based TBI screening during 2019–2021. PLWH testing IGRA-positive were advised to receive directly-observed therapy for TBI after active TB disease was excluded. The care cascade was evaluated to identify barriers to TBI management. Among 7951 PLWH with a median age of 38 years and CD4 count of 616 cells/mm³, 420 (5.3%) tested positive and 38 (0.5%) indeterminate for IGRA. The TBI treatment initiation rate was 73.6% (309/420) and the completion rate was 91.9% (284/309). More than 80% of PLWH concurrently received short-course rifapentine-based regimens and integrase strand transfer inhibitor (InSTI)-containing ART. The main barrier to treatment initiation was physicians’ concerns and patients’ refusal (85.6%). The factors associated with treatment non-completion were older age, female, anti-HCV positivity, and higher plasma HIV RNA. Our observation of a high TBI completion rate among PLWH is mainly related to the introduction of short-course rifapentine-based regimens in the InSTI era, which can be the strategy to improve TBI treatment uptake.