A new era of antiretroviral drug toxicity

Prevalence and Factors Associated With Frailty Among Older Adults Living With HIV Compared to Their Uninfected Peers From the Kenyan Coast

Objectives: a) To document the prevalence and correlates of frailty among older adults living with HIV (OALWH) and their uninfected peers, and b) Investigate HIV status as an independent predictor of frailty. Methods: This cross-sectional study was conducted between 2020 and 2021 at the Kenyan coast among 440 older adults aged ≥50 years (257 OALWH). Frailty was assessed using the Reported Edmonton Frail Scale. Logistic regression was used to examine the correlates of frailty. Results: The prevalence of frailty was significantly higher among OALWH (24%) than their uninfected peers (13%). HIV seropositivity was not independently associated with frailty. Sleeping difficulties, ageism, higher waist/hip ratio, visiting traditional healers, HIV treatment change/interruption, prolonged illness following HIV diagnosis, and self-reported diabetes were significantly associated with higher odds of frailty. Residing in larger households, having higher income, having friends, being male and light physical activities were significantly associated with reduced odds of frailty. Conclusion: The prevalence of frailty is elevated among OALWH; however, factors other than HIV are predominant, particularly psychosocial factors. Multicomponent interventions are needed to prevent/delay and manage frailty in this setting.

Raltegravir plus abacavir/lamivudine in virologically suppressed HIV-1-infected patients: 48-week results of the KIRAL study

Background

Long-term combination antiretroviral therapy often results in toxicity/tolerability problems, which are one of the main reasons for switching treatment. Despite the favorable profile of raltegravir (RAL), data on its combination with abacavir/lamivudine (ABC/3TC) are scarce. Based on clinical data, we evaluated this regimen as a switching strategy.

Design

Multicenter, non-controlled, retrospective study including all virologically suppressed HIV-1-infected patients who had switched to RAL+ABC/3TC.

Methods

We evaluated effectiveness (defined as maintenance of HIV-1-RNA <50 copies/mL at 48 weeks) safety, tolerability, laboratory data, and CD4+ count at week 48 of this switching strategy.

Results

The study population comprised 467 patients. Median age was 49 years (IQR: 45–53). Males accounted for 75.4%. Median CD4+ count at baseline was 580 cells/μL (IQR, 409). The main reasons for switching were toxicity/tolerability problems (197; 42.2%) and physician’s criteria (133; 28.5%). At week 48, HIV-1 RNA remained at <50 copies/mL in 371/380 (97.6%; 95%CI: 96.4–99.0) when non-virological failure was censured. Virological failure was recorded in 1.9% patients and treatment failure in 20.5% of patients (96/467 [95%CI, 16.9–24.2]). The main reasons for treatment failure included switch to fixed-dose combination regimens (31; 6.6%), toxicity/poor tolerability (27; 5.8%), and physician’s decision (17; 3.6%). A total of 73 adverse events were detected in 64 patients (13.7%). These resolved in 43 patients (67.2%). Of the 33 cases related or likely related to treatment, 30 were Grade-1 (90.9%). CD4+ count and renal, hepatic, and lipid profiles remained clinically stable over the 48 weeks.

Conclusions

Our findings suggest that RAL+ABC/3TC could be an effective, safe/tolerable, and low-toxicity option for virologically suppressed HIV-1-infected patients.

Chronic Kidney Disease and Antiretroviral Therapy in HIV-Positive Individuals: Recent Developments

Chronic kidney disease (CKD) has emerged as an important health concern in HIV-positive individuals. Preventing long-term kidney toxicity from an antiretroviral therapy is therefore critical. Selected antiretroviral agents, especially tenofovir disoproxil fumarate (TDF) and some ritonavir-boosted protease inhibitors (PI/rs), have been associated with increased risk of CKD. However, the CKD risk attributable to these agents is overall small, especially in those with low baseline risk of CKD and normal renal function. CKD risk in HIV-positive individuals can be further minimized by timely identification of those with worsening renal function and discontinuation of potentially nephrotoxic agents. Clinicians can use several monitoring tools, including the D:A:D risk score and routine measurements of estimated glomerular filtration (eGFR) and proteinuria, to identify high-risk individuals who may require an intervention. Tenofovir alafenamide (TAF), a TDF alternative, promises to be safer in terms of TDF-associated kidney and bone toxicity. While the short-term data on TAF does indicate lower eGFR decline and lower risk of proteinuria (vs. TDF), long-term data on renal safety of TAF are still awaited. Promising results have also emerged from recent trials on alternative dual-therapy antiretroviral regimens which exclude the nucleoside(tide) reverse transcriptase class as well as possibly the PI/rs, thereby reducing the drug burden, and possibly the toxicity. However, long-term safety or benefits of these dual-therapy regimens are still unclear and will need to be studied in future prospective studies. Finally, addressing risk factors such as hypertension and diabetes will continue to be important in this population.

Modifying Antiretroviral Therapy in Virologically Suppressed HIV-1-Infected Patients

HIV-1-infected patients with suppressed plasma viral loads often require changes to their antiretroviral (ARV) therapy to manage drug toxicity and intolerance, to improve adherence, and to avoid drug interactions. In patients who have never experienced virologic failure while receiving ARV therapy and who have no evidence of drug resistance, switching to any of the acceptable US Department of Health and Human Services first-line therapies is expected to maintain virologic suppression. However, in virologically suppressed patients with a history of virologic failure or drug resistance, it can be more challenging to change therapy while still maintaining virologic suppression. In these patients, it may be difficult to know whether the discontinuation of one of the ARVs in a suppressive regimen constitutes the removal of a key regimen component that will not be adequately supplanted by one or more substituted ARVs. In this article, we review many of the clinical scenarios requiring ARV therapy modification in patients with stable virologic suppression and outline the strategies for modifying therapy while maintaining long-term virologic suppression.

Drug transporters in tissues and cells relevant to sexual transmission of HIV: Implications for drug delivery

Efflux and uptake transporters of drugs are key regulators of the pharmacokinetics of many antiretroviral drugs. A growing body of literature has revealed the expression and functionality of multiple transporters in female genital tract (FGT), colorectal tissue, and immune cells. Drug transporters could play a significant role in the efficacy of preventative strategies for HIV-1 acquisition. Pre-exposure prophylaxis (PrEP) is a promising strategy, which utilizes topically (vaginally or rectally), orally or other systemically administered antiretroviral drugs to prevent the sexual transmission of HIV to receptive partners. The drug concentration in the receptive mucosal tissues and target immune cells for HIV is critical for PrEP effectiveness. Hence, there is an emerging interest in utilizing transporter information to explain tissue disposition patterns of PrEP drugs, to interpret inter-individual variability in PrEP drug pharmacokinetics and effectiveness, and to improve tissue drug exposure through modulation of the cervicovaginal, colorectal, or immune cell transporters. In this review, the existing literature on transporter expression, functionality and regulation in the transmission-related tissues and cells is summarized. In addition, the relevance of transporter function for drug delivery and strategies that could exploit transporters for increased drug concentration at target locales is discussed. The overall goal is to facilitate an understanding of drug transporters for PrEP optimization.

Transcriptional profiling suggests that Nevirapine and Ritonavir cause drug induced liver injury through distinct mechanisms in primary human hepatocytes

Drug induced liver injury (DILI), a major cause of pre- and post-approval failure, is challenging to predict pre-clinically due to varied underlying direct and indirect mechanisms. Nevirapine, a non-nucleoside reverse transcriptase inhibitor (NNRTI) and Ritonavir, a protease inhibitor, are antiviral drugs that cause clinical DILI with different phenotypes via different mechanisms. Assessing DILI in vitro in hepatocyte cultures typically requires drug exposures significantly higher than clinical plasma Cmax concentrations, making clinical interpretations of mechanistic pathway changes challenging. We previously described a system that uses liver-derived hemodynamic blood flow and transport parameters to restore primary human hepatocyte biology, and drug responses at concentrations relevant to in vivo or clinical exposure levels. Using this system, primary hepatocytes from 5 human donors were exposed to concentrations approximating clinical therapeutic and supra-therapeutic levels of Nevirapine (11.3 and 175.0 μM) and Ritonavir (3.5 and 62.4 μM) for 48 h. Whole genome transcriptomics was performed by RNAseq along with functional assays for metabolic activity and function. We observed effects at both doses, but a greater number of genes were differentially expressed with higher probability at the toxic concentrations. At the toxic doses, both drugs showed direct cholestatic potential with Nevirapine increasing bile synthesis and Ritonavir inhibiting bile acid transport. Clear differences in antigen presentation were noted, with marked activation of MHC Class I by Nevirapine and suppression by Ritonavir. This suggests CD8+ T cell involvement for Nevirapine and possibly NK Killer cells for Ritonavir. Both compounds induced several drug metabolizing genes (including CYP2B6, CYP3A4 and UGT1A1), mediated by CAR activation in Nevirapine and PXR in Ritonavir. Unlike Ritonavir, Nevirapine did not increase fatty acid synthesis or activate the respiratory electron chain with simultaneous mitochondrial uncoupling supporting clinical reports of a lower propensity for steatosis. This in vitro study offers insights into the disparate direct and immune-mediated toxicity mechanisms underlying Nevirapine and Ritonavir toxicity in the clinic.

The road ahead: working towards effective clinical translation of biomedical HIV prevention strategies

ABSTRACT 

Emerging evidence from several randomized controlled trials show that antiretroviral-based biomedical HIV prevention interventions are efficacious in preventing HIV if they are taken as directed, and could potentially reduce the number of new HIV infections globally. Strategies such as treatment as prevention and use of oral pre-exposure prophylaxis for HIV prevention have shown great promise, yet have raised important implementation concerns around awareness and acceptance, delivery, adherence, side effects, risk compensation, cost–effectiveness and drug resistance. In order to address these issues, a number of treatment as prevention and pre-exposure prophylaxis demonstration projects have been initiated to assess the feasibility of introducing these interventions in ‘real-world’ settings. These projects will be instrumental in determining best practices for optimal delivery and sustainability of these HIV prevention interventions. The road to effective translation to clinical setting is promising, but comes with challenges which are not insurmountable.