Background: People with HIV (PWH) have benefited tremendously from effective antiretroviral(ARV) treatments. However, PWH are at increased risk for other viral infections transmitted in the same way as HIV (such as hepatitis C and MPox) or that are opportunistic (e.g. cytomegalovirus). These coinfections contribute significantly to morbidity and mortality among PWH and require effective treatments to optimize patient outcomes. However, their management is complicated by drug-drug interactions (DDIs) with ARVs.

Metabolism pathways and DDIs between approved ARVs and selected antiviral agents used for the treatment of common and clinically relevant viral coinfections are discussed. Literature review included search of published papers, conference abstracts (IAS, CROI, IDWeek, EACS, Glasgow) as well as unpublished data from approved drug prescribing information and regulatory submissions sourced from PubMed, Google, and Google Scholar available between June 30 1981 through June 1, 2024.

Management of drug interactions is essential for maintaining efficacy and safety of ARV and other co-administered antiviral therapies. Longer acting agents are now available for treatment of HIV and this lengthens the period during which drug interactions may occur. Emerging novel nanoparticle-carrier targeted hepatitis C and HIV treatments may mitigate, if not eliminate, their propensity for drug-drug interactions.

Highly active antiretroviral therapy has led to a significant increase in the life expectancy of people living with HIV. The trade-off is that HIV-infected patients often suffer from comorbidities that require additional treatment, increasing the risk of Drug-Drug Interactions (DDIs), the clinical relevance of which has often not been determined during registration trials of the drugs involved. Therefore, it is important to identify potential clinically relevant DDIs in order to establish the most appropriate therapeutic approaches. This review aims to summarize and analyze data from studies published over the last two decades on DDI-related adverse clinical outcomes involving anti-HIV drugs and those used to treat comorbidities. Several studies have examined the pharmacokinetics and tolerability of different drug combinations. Protease inhibitors, followed by nonnucleoside reverse transcriptase inhibitors and integrase inhibitors have been recognized as the main players in DDIs with antivirals used to control co-infection, such as Hepatitis C virus, or with drugs commonly used to treat HIV comorbidities, such as lipid-lowering agents, proton pump inhibitors and anticancer drugs. However, the studies do not seem to be consistent with regard to sample size and follow-up, the drugs involved, or the results obtained. It should be noted that most of the available studies were conducted in healthy volunteers without being replicated in patients. This hampered the assessment of the clinical burden of DDIs and, consequently, the optimal pharmacological management of people living with HIV.

The World Health Organization proposed targets to eliminate hepatitis C virus (HCV) by 2030, aiming to treat ≥80% of people with HCV, decreasing new chronic infections by 90% and liver-related mortality by 65%. While children/adolescents represent a minority of cases, the true burden is underestimated. Advances in drug development have resulted in simplified treatments that are well-tolerated, effective, and pangenotypic in activity. Sofosbuvir/velpatasvir, a combined nucleotide analog NS5B polymerase inhibitor and NS5A inhibitor, respectively, is approved for HCV treatment for individuals ≥3 years, supported by safety data using lower-dose, novel formulations.

This review discusses chemistry, pharmacokinetics/pharmacodynamics, dosing, efficacy, and safety of sofosbuvir/velpatasvir highlighting pediatric data. Literature review included publications/conference abstracts from PubMed, Google, and Google Scholar. Information from key clinical trials/regulatory approvals is reviewed.

Sofosbuvir/velpatasvir is a safe and effective therapy for the treatment of pangenotypic chronic HCV infection with limited cases of virologic relapse and adverse events among pediatric populations aged 3 years and older. However, the tolerability among children less than 6 years could be improved by alternative formulations, if not, shorter treatment durations. An aspirational role of direct-acting antivirals (DAAs) that should be explored is for the prevention of infection in exposed and at-risk pediatric populations.

The clinical outcomes of antiretroviral drugs may be modified through drug interactions; thus, it is important to update the drug interactions in people living with HIV (PLHIV).

To update clinically relevant drug interactions in PLHIV on antiretroviral therapy with novel drug interactions published from 2017 to 2022.

A systematic review in Medline/PubMed database from July 2017 to December 2022 using the Mesh terms antiretroviral agents and drug interactions or herb-drug interactions or food-drug interactions. Publications with drug interactions in humans, in English or Spanish, and with full-text access were retrieved. The clinical relevance of drug interactions was grouped into five levels according to the gravity and probability of occurrence.

A total of 366 articles were identified, with 219 (including 87 citation lists) were included, which allowed for the identification of 471 drug interaction pairs; among them, 291 were systematically reported for the first time. In total 42 (14.4%) and 137 (47.1%) were level one and two, respectively, and 233 (80.1%) pairs were explained with the pharmacokinetic mechanism. Among these 291 pairs, protease inhibitors (PIs) and ritonavir/cobicistat-boosted PIs, as well as integrase strand transfer inhibitors (InSTIs), with 70 (24.1%) and 65 (22.3%) drug interaction pairs of levels one and two, respectively, were more frequent.

In PLHIV on antiretroviral therapy, we identify 291 drug interaction pairs systematically reported for the first time, with 179 (61.5%) being assessed as clinically relevant (levels one and two). The pharmacokinetic mechanism was the most frequently identified. PIs, ritonavir/cobicistat-boosted PIs, and InSTIs were the antiretroviral groups with the highest number of clinically relevant drug interaction pairs (levels one and two).

The treatment of patients infected with the hepatitis C virus (HCV) has been revolutionised by the development of direct-acting antiviral agents (DAAs) that target specific HCV proteins involved in viral replication. The first DAAs were associated with clinical problems such as adverse drug reactions and pharmacokinetic drug-drug interactions (DDIs). Current FDA/EMA-approved treatments are combinations of DAAs that simultaneously target the HCV N5A-protein, the HCV N5B-polymerase and the HCV NS3/4A-protease. Adverse events and DDIs are less likely with these DAA combinations but several DDIs of potential clinical significance remain. Much of the available information on the interaction of DAAs with CYP drug-metabolising enzymes and influx and efflux transporters is contained in regulatory summaries and is focused on DDIs of likely clinical importance. Important DDIs perpetrated by current DAAs include increases in the pharmacokinetic exposure to statins and dabigatran. Some mechanistic information can be deduced. Although the free concentrations of DAAs in serum are very low, a number of these DDIs are likely mediated by the inhibition of systemic influx transporters, especially OATP1B1/1B3. Other DDIs may arise by DAA-mediated inhibition of intestinal efflux transporters, which increases the systemic concentrations of some coadministered drugs. Conversely, DAAs are victims of DDIs mediated by cyclosporin, ketoconazole, omeprazole and HIV antiretroviral drug combinations, especially when boosted by ritonavir and, to a lesser extent, cobicistat. In addition, concurrent administration of inducers, such as rifampicin, carbamazepine and efavirenz, decreases exposure to some DAAs. Drug-drug interactions that increase the accumulation of HCV N3/4A-protease inhibitors like grazoprevir may exacerbate hepatic injury in HCV patients.

Hepatitis C virus (HCV) infection is more prevalent in people living with HIV-AIDS (PLHA) and portends a poorer prognosis. Pharmacokinetic studies suggest the absence of significant interaction between velpatasvir and dolutegravir which has been recently recommended as part of preferred first-line antiretroviral therapy (ART) regimens by WHO. However, clinical data on the use of velpatasvir-based regimen in PLHA taking dolutegavir is lacking. Hence, we aimed to assess the efficacy and safety of sofosbuvir and velpatasvir (SOF + VEL) in HCV and HIV coinfected patients on dolutegravir-based ART. Forty-five consecutive PLHA with HCV coinfection on dolutegravir-based ART were prospectively enrolled. All patients were treated SOF + VEL for 12 weeks. Complete haemogram, liver and renal function tests were assessed at baseline, 4 weeks and at end of treatment. Sustained virological response (SVR) was assessed at 12 weeks after end of treatment. The majority were males (95.5%) with a mean age of 32.8 ± 12.3 years. Cirrhosis was present in 6 (13.3%) patients. All patients completed 12 weeks of therapy with SOF + VEL, but SVR could not be assessed in two patients. Forty-two (97.7%) of the remaining 43 patients attained SVR-12. SVR-12 rate was 97.7% and 93.3% by per protocol and intention to treat analysis, respectively. No grade III/IV adverse events were reported, and there was no worsening of blood counts, liver or renal function test parameters. The pan-genotypic regimen of SOF + VEL is safe and effective in PLHA with HCV coinfection who are on dolutegravir-based ART.

The life expectancy of people living with HIV (PLWHIV) has significantly improved in recent decades, mostly due to antiretroviral (ARV) therapy. Aging can affect the pharmacokinetics of drugs and, as a consequence, increase the risk of drug interactions and toxicity that may impact treatment. The aim of this study was to carry out a systematic review of the literature on the effect of aging on ARV pharmacokinetics.

Searches were performed in the BVS, EMBASE and PUBMED databases until November 2022. All studies available in English, Spanish and Portuguese investigating the pharmacokinetics of ARV approved by the US Food and Drug Administration (FDA) from 2005 to 2020 were selected. Peer-reviewed publications were included if they met all criteria: adults (≥ 18 years of age) living with or without HIV; report any pharmacokinetic parameter or plasma concentration of at least one of the following ARVs: tenofovir alafenamide fumarate (TAF); doravirine (DOR), rilpivirine (RIL) and etravirine (ETR); darunavir (DRV), tipranavir (TPV) and fostemsavir (FTR); dolutegravir (DTG), raltegravir (RAL), bictegravir (BIC) and elvitegravir (EVG); maraviroc (MVC); ibalizumab (IBA); cobicistat (COBI). Pharmacokinetic parameters were reported stratified per age group: young adults (aged 18-49 years) or older (age ≥ 50 years) and all studies were evaluated for quality. The review protocol was registered in the PROSPERO database (registration number CRD42021236432).

Among 97 studies included, 20 reported pharmacokinetic evaluation in older individuals (age ≥ 50 years). Twenty five percent of the articles were phase I randomized clinical trials with HIV-negative participants and non-compartmental pharmacokinetic analysis presenting the parameters area under the curve (AUC) and peak drug concentration (Cmax). Seven age-stratified studies evaluated BIC, ETR, DRV, DTG, DOR and RAL. We found publications with discordant results for ETR and DTG pharmacokinetics in different age groups. DRV exposure was highly variable but modestly increased in aging PLWHIV. In contrast, no influence of age on BIC, DOR and RAL exposure was observed. A variability in pharmacokinetic parameters could be observed for the other ARVs (TAF and MVC) in different age groups.

Exposure to DRV increases modestly with age, while exposure to BIC, DOR and RAL appears to be unaffected by age. As the available evidence to confirm a potential effect of aging on ARV pharmacokinetics is limited, further studies are necessary.

The direct-acting antiviral agents (DAAs) have revolutionized the treatment of Hepatitis C Virus (HCV) infection. However, a simple and feasible treatment strategy with high efficacy and safety for HCV in patients coinfected with Human Immunodeficiency Virus (HIV) remains an unmet medical need, especially in areas with limited health resource. This study aims to assess the efficacy and safety of 12 weeks of treatment with sofosbuvir and velpatasvir in patients with chronic HCV/HIV-1 coinfection.

We conducted a multicenter, single-arm, open-label study in China, which involved chronic HCV/HIV-1 coinfected patients who are receiving an antiretroviral regimen of a combination tablet consisting of elvitegravir, cobicistat, emtricitabine, tenofovir alafenamide, (EVG/c/FTC/TAF) once daily. Patients with liver cirrhosis or experienced to DAAs treatment were excluded. All patients received combined sofosbuvir (400 mg) and velpatasvir (100 mg) tablet once daily for 12 weeks regardless of HCV genotype. The primary efficacy endpoint was sustained virologic response, defined as HCV RNA <15 IU/mL at 12 weeks after completion of treatment (SVR12). The primary safety endpoint was the proportion of patients who prematurely discontinued treatment because of adverse events. Safety and efficacy data were analyzed with an intention-to-treat (ITT) population (last observation carried forward) and per-protocol (PP) population. This trial is registered on ChiCTR.org.cn with number being ChiCTR1800020246.

Of the 243 patients enrolled, 78% were male, 9% had been previously treated for HCV with interferon, and none had pre-defined cirrhosis, although 8% had Fibrosis 4 score (FIB-4) >3.25. A total of 233 patients completed 12-week post-treatment follow-up. Overall, 227/233 patients (97%) achieved SVR12: 100% (63/63) in those with HCV genotype 1, 67% (2/3) in those with genotype 2, 95% (84/88) in those with genotype 3, 99% (78/79) in those with genotype 6. Rates of SVR12 were lower among those with baseline FIB-4 >3.25 than those without (78% [14/18] vs. 99% [211/212], P < 0.001). HIV-1 suppression was not compromised. The most common adverse events were upper respiratory tract infection (5%), cough (3%), abnormal renal function (2%), abnormal liver function (2%), constipation (2%), urinary tract infection (2%) and sleep disorders (2%). No participant discontinued treatment because of adverse events or death.

Twelve weeks of treatment with sofosbuvir/velpatasvir provide high rates of SVR and is well-tolerated in patients coinfected with HIV-1 and HCV regardless of HCV genotypes. Non-invasive liver fibrosis score may help to further distinguish patients at greater likelihood of a suboptimal response.

The 13th Five Year Plan of the Ministry of Science and Technology of China for the prevention and treatment of major infectious diseases such as AIDS and viral hepatitis, the National Key Research and Development Program of China, Medical Key Discipline Program of Guangzhou-Viral Infectious Diseases (2021-2023), Basic research program on people's Livelihood Science and technology of Guangzhou, and National Natural Science Foundation of China.

Antiretroviral therapy is the recognized treatment for human immunodeficiency virus (HIV) infection involving several antiviral agents. Even though highly active antiretroviral therapy has been proven to be very effective in suppressing HIV replication, the antiretroviral drugs, belonging to different pharmacological classes, present quite complex pharmacokinetic properties such as extensive drug metabolism and transport by membrane-associated drug carriers. Moreover, due to uncomplications or complications in HIV-infected populations, an antiretroviralbased multiple-drug coadministration therapy strategy is usually applied for treatment effect, thus raising the possibility of drug-drug interactions between antiretroviral drugs and common drugs such as opioids, stains, and hormonal contraceptives. Herein, thirteen classical antiretroviral drugs approved by US Food and Drug Administration were summarized. Besides, relative drug metabolism enzymes and transporters known to interact with those antiretroviral drugs were detailed and described. Furthermore, one after the summarized antiretroviral drugs, the drug-drug interactions between two antiretroviral drugs or antiretroviral drug - conventional medical drugs of the past decade were discussed and summarized. This review is intended to deepen the pharmacological understanding of antiretroviral drugs and promote more secure clinical applications for antiretroviral drugs to treat HIV.

Both HCV and HIV are highly prevalent infections with current estimates of 57 and 38 million people infected worldwide, respectively. Oral antivirals can be curative for HCV and rescue HIV patients from disease progression. Dual therapy in coinfected patients requires expertise.

Four major issues challenge dual HCV and HIV treatment, including overlapping drug-related side effects, hepatitis B reactivation, immune reconstitution inflammatory syndromes (IRIS), and drug-drug interactions (DDI). A search was conducted in PubMed from January 2010 to March 2023.

The advent of second-generation direct-acting antivirals (DDA) that depict higher antiviral potency, fewer side effects, pangenotypic activity and are co-formulated has expanded the indication of HCV therapy and particularly in HIV-coinfected individuals. Sequential initiation of antiretrovirals (ARV) followed by DAA is generally preferred to start dual treatment concomitantly. Close monitoring of rare episodes of HBV reactivation and IRIS is warranted. The most frequent DDI between DAA and ARV affect drug metabolism by CYP450 induction/inhibition, leading to abnormal drug exposures. Throughout this mechanism interact most HCV and HIV protease inhibitors and non-nucleoside polymerase inhibitors. Exposure to some HIV and HCV nucleos(t)ide analogues (e.g. tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters and requires special attention in patients with renal insufficiency.

Background and Objectives: Hepatitis C virus (HCV) is a major cause of liver disease worldwide. People who inject drugs (PWIDs) constitute the majority of patients with HCV infection in the United States and Central Asia. There are several obstacles to treating HCV infection in PWIDs because PWIDs are often accompanied by concurrent infection, low compliance, substance abuse, and risky behavior. The aim of the study is to compare the efficacies of direct-acting antiviral (DAA) therapy for HCV infection in PWIDs and those without opioid injection. Materials and Methods: In this retrospective cohort study, we included 53 PWIDs with HCV infections treated on site in a methadone program and 106 age- and sex-matched patients with HCV infections who had no history of opioid injection (ratio of 1:2). All eligible subjects received anti-HCV treatment by DAA agents in our hospital from March 2018 to December 2020. The charts of these patients were carefully reviewed for demographic data, types of DAA agents, and treatment outcomes. The primary outcome measure was sustained virological response (SVR). Results: PWIDs and non-drug users had different HCV genotype profiles (p = 0.013). The former had higher proportions of genotype 3 (18.9% vs. 7.5%) and genotype 6 (24.5% vs. 14.2%) than the latter. The two patient groups had comparable rates of complete drug refilling (100.0% vs. 91.1%) and frequency of loss to follow-up (3.8% vs. 0.9%). However, PWIDs had a lower SVR rate of DAA treatment than non-drug users (92.2% vs. 99.0%; p = 0.04). Further analysis showed that both human immunodeficiency virus (HIV) coinfection and history of PWID were risk factors associated with treatment failure. The subjects with coinfection with HIV had lower SVR rates than those without HIV infection (50.0% vs. 96.5%; p = 0.021). Conclusions: PWIDs with HCV infections have higher proportions of HCV genotype 3 and genotype 6 than non-drug users with infections. DAA therapy can achieve a high cure rate (>90%) for HCV infection in PWID, but its efficacy in PWID is lower than that in non-drug users.

The nephrotoxicity of sofosbuvir (SOF) on human immunodeficiency virus and hepatitis C virus (HIV/HCV)-coinfected patients receiving antiretroviral therapy (ART) remains controversial. We prospectively compared the estimated glomerular filtration rate (eGFR) changes in 167 patients receiving SOF-based direct-acting antivirals (DAAs) who also received tenofovir disoproxil fumarate (TFV)-based (n = 116) and TFV-free ART (n = 51). The eGFR was assessed by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, and the eGFR changes between ART regimens were compared by the generalized estimated equation. During DAA treatment, participants on TFV-based ART had a higher eGFR decline than those on TFV-free ART (slope coefficient difference: -0.82 ml/min/1.73 m2 /month [95% CI: -1.21 to -0.43]; p < 0.001), whereas the eGFR changes did not differ between groups (slope coefficient difference: 0.13 ml/min/1.73 m2 /month [95% CI: -0.32 to 0.58]; p = 0.42) after discontinuing DAAs. Participants on TFV TDF-based ART had a higher eGFR decline than those on TFV alafenamide fumarate (TAF)-based ART (slope coefficient difference: -0.31 ml/min/1.73 m2 /month [95% CI: -0.50 to -0.12]; p = 0.01). After discontinuing DAAs, the eGFR changes did not differ between groups (slope coefficient difference: 0.06 ml/min/1.73 m2 /month [95% CI: -0.98 to 1.10]; p = 0.91). In conclusion, HIV/HCV-coinfected patients on TFV-based ART had a slight eGFR decline compared to those on TFV-free ART during SOF-based DAA therapy. A similar trend between TDF-based and TAF-based ART was also observed. Because the differences of eGFR changes are limited, the physicians should not discourage the use of SOF-based DAAs in HIV-positive patients on TFV-based ART.

Combined antiretroviral treatments have significantly improved the morbidity and mortality related to HIV infection, thus transforming HIV infection into a chronic disease; however, the efficacy of antiretroviral treatments is highly dependent on the ability of infected individuals to adhere to life-long drug combination therapies. A major milestone in HIV treatment is the marketing of the long-acting intramuscular antiretroviral drugs cabotegravir and rilpivirine, allowing for infrequent drug administration, with the potential to improve adherence to therapy and treatment satisfaction. Intramuscular administration of cabotegravir and rilpivirine leads to differences in pharmacokinetics and drug-drug interaction (DDI) profiles compared with oral administration. A notable difference is the long elimination half-life with intramuscular administration, which reaches 5.6-11.5 weeks for cabotegravir and 13-28 weeks for rilpivirine, compared with 41 and 45 h, respectively, with their oral administration. Cabotegravir and rilpivirine have a low potential to cause DDIs, however these drugs can be victims of DDIs. Cabotegravir is mainly metabolized by UGT1A1, and rilpivirine is mainly metabolized by CYP3A4, therefore these agents are susceptible to DDIs with inhibitors, and particularly inducers of drug-metabolizing enzymes. Intramuscular administration of cabotegravir and rilpivirine has the advantage of eliminating DDIs occurring at the gastrointestinal level, however interactions can still occur at the hepatic level. This review provides insight on the intramuscular administration of drugs and summarizes the pharmacology of long-acting cabotegravir and rilpivirine. Particular emphasis is placed on DDI profiles after oral and intramuscular administration of these antiretroviral drugs.

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease, with approximately 71 million chronically infected individuals worldwide. Clinical care for patients with HCV-related liver disease has advanced considerably thanks to an enhanced understanding of the pathophysiology of the disease, as well as developments in diagnostic procedures and improvements in therapy and prevention. These therapies make it possible to eliminate hepatitis C as a major public health threat, as per the World Health Organization target, although the timeline and feasibility vary from region to region. These European Association for the Study of the Liver recommendations on treatment of hepatitis C describe the optimal management of patients with recently acquired and chronic HCV infections in 2020 and onwards.

In this review, we examine the pharmacokinetics and clinically relevant drug interactions of the newer generation direct-acting antivirals (DAAs) for the treatment of chronic hepatitis C, specifically sofosbuvir/velpatasvir (Epclusa®), sofosbuvir/velpatasvir/voxilaprevir (Vosevi®), glecaprevir/pibrentasvir (Maviret®), and elbasvir/grazoprevir (Zepatier®). We searched MEDLINE (1948-January 2020), Embase (1964-January 2020), Google, and GoogleScholar using the terms pharmacokinetics, drug interaction, drug metabolism, sofosbuvir, velpatasvir, Epclusa, voxilaprevir, Vosevi, glecaprevir, pibrentasvir, Maviret, elbasvir, grazoprevir, and Zepatier, from inception to January 13, 2020. The search was limited to randomized controlled trials, in vitro studies, prospective and retrospective human studies, drug monographs, abstracts, and conference proceedings. All relevant published literature on pharmacokinetic and pharmacodynamic interactions involving DAAs were reviewed and the data extracted. Numerous clinically relevant drug-drug interactions (DDIs) were identified with the newer generation DAAs and commonly prescribed drugs. NS3/4A protease inhibitors are more likely to be involved in DDIs, followed by NS5A inhibitors and NS5B polymerase inhibitor. The majority of clinically relevant DDIs are predictable, according to known pharmacokinetic, pharmacodynamics, and physicochemical properties of DAAs; however, in select cases, unpredictable DDIs do occur. As expected, many drug interactions exist between newer generation DAAs and commonly prescribed medications. While the majority of clinically relevant interactions are predictable, many require therapeutic dose adjustment or careful selection of non-interacting drugs. In select cases, severe and unpredictable drug interactions can occur. Clinicians should consult hepatitis C virus pharmacotherapy experts and tertiary drug interaction resources when initiating DAA therapy in patients taking other medications.

Ledipasvir/sofosbuvir and sofosbuvir/velpatasvir have been approved worldwide for the treatment of chronic hepatitis C virus (HCV) infection. Although both have been approved in China, there are currently no data on their pharmacokinetic profiles in Chinese individuals. Two studies investigated the pharmacokinetic properties, safety, and tolerability of ledipasvir/sofosbuvir and sofosbuvir/velpatasvir, respectively, in healthy Chinese subjects.

Two Phase I, open-label, single- and multiple-dose studies were conducted in healthy Chinese subjects. Ledipasvir/sofosbuvir (90/400 mg) or sofosbuvir/velpatasvir (400/100 mg), respectively, was administered orally once daily under fasted conditions. Subjects received a single dose (day 1) and multiple doses (days 8-17 [ledipasvir/sofosbuvir]; days 8-14 [sofosbuvir/velpatasvir]). Plasma pharmacokinetic parameters were estimated by using noncompartmental models, and safety was assessed through clinical evaluation and monitoring of adverse events.

Fourteen subjects were enrolled in each study (7 men, 7 women each; mean age, 30 years [ledipasvir/sofosbuvir] and 29 years [sofosbuvir/velpatasvir]). The pharmacokinetic parameters for sofosbuvir, GS-566500, GS-331007, and ledipasvir or velpatasvir were similar to historical values in non-Chinese subjects. Consistent with the t_1/2 of ledipasvir relative to 24-h dosing, accumulation of 177% (AUC) and 107% (C_max) was observed. There was no significant accumulation of velpatasvir, sofosbuvir, GS-566500, or GS-331007. Both drugs were generally well tolerated; no serious adverse events or discontinuations due to adverse events were reported.

Overall, ledipasvir/sofosbuvir and sofosbuvir/velpatasvir exhibited pharmacokinetic and safety profiles in healthy Chinese subjects similar to those in non-Chinese subjects in historical studies, supporting their use in the Chinese population with HCV infection. ChinaDrugTrials.org.cn identifiers: CTR20160149 (ledipasvir/sofosbuvir); CTR20160602 (sofosbuvir/velpatasvir).

Cobicistat (COBI), a CYP3A inhibitor, is a pharmacokinetic enhancer that increases exposures of the HIV protease inhibitors (PIs) atazanavir (ATV) and darunavir (DRV). The potential drug interaction between COBI-boosted PIs and hormonal contraceptives, which are substrates of intestinal efflux transporters and extensively metabolized by CYP enzymes, glucuronidation and sulfation, was evaluated.

This was a Phase I, open-label, two cohort (n=18/cohort), fixed-sequence study in healthy females that evaluated the drug-drug interaction (DDI) between multiple-dose ATV+COBI or DRV+COBI and single-dose drospirenone/ethinyl estradiol (EE). DDIs were evaluated using 90% confidence intervals of the geometric least-squares mean ratios of the test (drospirenone/EE+boosted PI) versus reference (drospirenone/EE) using lack of DDI boundaries of 70-143%. Safety was assessed throughout the study.

29/36 participants completed the study. Relative to drospirenone/EE alone, drospirenone area under the plasma concentration versus time curve extrapolated to infinity (AUC_inf) was 1.6-fold and 2.3-fold higher, and maximum observed plasma concentration (C_max) was unaltered, upon coadministration with DRV+COBI and ATV+COBI, respectively. EE AUC_inf decreased 30% with drospirenone/EE + DRV+COBI and was unchanged with ATV+COBI + drospirenone/EE, relative to drospirenone/EE alone. Study treatments were generally well tolerated. The majority of adverse events were mild and consistent with known safety profiles of the compounds.

Consistent with COBI-mediated CYP3A inhibition, drospirenone exposure increased following coadministration with COBI-containing regimens, with a greater increase with ATV+COBI. Thus, clinical monitoring for drospirenone-associated hyperkalaemia is recommended with DRV+COBI and ATV+COBI should not be used with drospirenone. Lower EE exposure with DRV+COBI may be attributed to inductive effects of DRV on CYP enzymes and/or intestinal efflux transporters (that is, P-gp) involved in EE disposition.

It has been estimated by the World Health Organization (WHO) that over 71 million people were infected with the hepatitis C virus (HCV) in 2015. Since then, a number of highly effective direct-acting antiviral (DAA) regimens have been licensed for the treatment of chronic HCV infection: sofosbuvir/daclatasvir, sofosbuvir/ledipasvir, elbasvir/grazoprevir, sofosbuvir/velpatasvir, glecaprevir/pibrentasvir, and sofosbuvir/velpatasvir/voxilaprevir. With these treatment regimens, almost all chronic HCV-infected patients, even including prior DAA failures, can be treated effectively and safely. It is therefore likely that further development of DAAs will be limited. In this descriptive review we provide an overview of the clinical pharmacokinetic characteristics of currently available DAAs by describing their absorption, distribution, metabolism, and excretion. Potential drug-drug interactions with the DAAs are briefly discussed. Furthermore, we summarize what is known about the pharmacodynamics of the DAAs in terms of efficacy and safety. We briefly discuss the relationship between the pharmacokinetics of the DAAs and efficacy or toxicity in special populations, such as hard to cure patients and patients with liver cirrhosis, liver transplantation, renal impairment, hepatitis B virus or HIV co-infection, bleeding disorders, and children. The aim of this overview is to educate/update prescribers and pharmacists so that they are able to safely and effectively treat HCV-infected patients even in the presence of underlying co-infections or co-morbidities.

Objectives: There are scarce data on the combination of dolutegravir (DTG) plus rilpivirine (RPV) in the real world, including patients with hepatitis C virus (HCV) coinfection, toxicity or previous failure, or at risk for severe drug-drug interactions (DDIs). Methods: Prospective cohort study of virologically suppressed HIV-1 infected patients, without resistance to DTG or RPV, switched to this dual regimen because of toxicity or risk of DDIs (NCT02491242). Results: Overall, 102 patients (mean age 54 years, 28% women) were included. Fifty-seven were coinfected with HCV (fibrosis grade 4 in 27 cases, 1 liver transplantation). Seven patients had chronic kidney disease (1 renal transplantation). At week 48, only 1 virologic failure occurred (<1%), and 6 patients (6%) left the regimen (3 with central nervous system adverse events, 1 each due to pregnancy, metformin interaction, and lost to follow up). Thus, the overall treatment success rates were 93% (95% CI, 88%-98%; ITT-e, snapshot analysis) and 96% (95% CI, 92%-99%; per protocol analysis). The CD4/CD8 ratio increased slightly (median, +0.03). Triglycerides levels improved significantly (-18.8%, p < 0.01). The creatinine-based estimated glomerular filtration rate decreased by a mean of -8.4 ml/min/1.73 m², but tubular renal parameters improved. A paired dual X-ray absorptiometry scan showed a mild improvement in spine (mean, +1.15%; -0.57 to +3.3%) and in femoral neck bone mineral density (mean, +0.4%; -3.3% to +2.57%). Conclusions: In the clinical setting, switching to the combination of DTG plus rilpivirine in virologically suppressed HIV-1 patients is effective and safe, and improves lipid, renal and bone evolution.

Data on anti-HCV therapy in patients on dialysis is still evolving. Sofosbuvir is mainly eliminated through the renal route and there is controversy about its use in these patients.

We describe a 53-year-old male patient with HCV genotype 3 and human immunodeficiency type 1 (HIV) infection on chronic dialysis. HIV infection was diagnosed in 1987 and since July 2007 the patient was compliant with his antiretroviral therapy (ART) and had an undetectable plasma HIV viral load on all follow-up measurements. The patient was known to have HCV infection since 1997 but has never been treated for chronic hepatitis C. Because of progressive renal impairment dialysis started in 2005.

Before anti-HCV treatment commenced the patient liver transient elastography (FibroScan) indicated F3 fibrosis (stiffness, 11.6 kPa) and his HCV RNA viral load was 320,798 IU/mL (Abbott RealTime HCV assay).

Fixed dose combination of sofosbuvir/velpatasvir (400 mg/100 mg) for 11 weeks.

Twelve weeks after treatment cessation HCV RNA was undetectable, hence the patient achieved a sustained virologic response. The drugs were well tolerated and the patient did not report any side effects.

Sofosbuvir/velpatasvir may be an option for HCV genotype 3 infection in patients coinfected with HIV on long-term dialysis.

The advent of direct-acting antiviral agents (DAAs) has transformed the hepatitis C virus (HCV) therapeutic landscape in terms of efficacy and safety, with a cure rate of more than 90%. However, an important potential for drug-drug interactions (DDIs) is expected with these combinations, particularly in patients with other comorbidities (e.g. HIV co-infection, cardiovascular diseases). Each DAA can be a substrate, an inhibitor and/or an inducer of metabolic enzymes and drug efflux transporters. DAAs can act as both victims and perpetrators of DDIs and can sometimes increase the risk and/or intensity of side effects or limit the efficacy of treatment. Therefore, knowledge and management of DDIs with DAAs should be considered a key issue of HCV therapy. This review describes the pharmacokinetic profile of currently used and recommended DAA regimens and summarizes available data regarding DDIs to optimize HCV treatment in clinical practice.

Several safe and highly effective direct-acting antiviral (DAA) drugs for chronic hepatitis C virus (HCV) have been developed and greatly increase the number of therapeutic options available to successfully treat HCV infection. However, because treatment regimens contain at least two drugs (e.g., elbasvir and grazoprevir, glecaprevir and pibrentasvir, or sofosbuvir with daclatasvir, simeprevir, ledipasvir, or velpatasvir) and up to five drugs (ombitasvir/paritaprevir/ritonavir plus dasabuvir with or without ribavirin), the potential for drug-drug interactions (DDIs) becomes an important consideration for HCV-infected individuals with comorbidities that require concomitant medications, such as human immunodeficiency virus/HCV coinfection or immunosuppression after liver transplantation. This review details the pharmacokinetics and DDI potential of approved DAAs for the treatment of HCV infection.