Pre-exposure prophylaxis of non-HIV viral infections and the role of long-acting antivirals.

Viruses cause a large burden of human infectious diseases. During the past 50 years, antivirals have been developed to treat many pathogenic viruses, including herpesviruses, retroviruses, hepatitis viruses, and influenza. Besides being used as treatment, antivirals have shown efficacy for preventing certain viral infections. Following the success in the HIV field, a renewed interest has emerged on the use of antivirals as prophylaxis for other viruses. The development of formulations with extended half-life has pushed further this consideration in persons at risk for a wide range of viral infections. In this way, long-acting antivirals might behave as "chemovaccines" when classical vaccines do not exist, cannot be recommended, immune responses are suboptimal, escape mutants emerge, and/or immunity wanes. Five main caveats would temper its use, namely, selection of drug resistance, drug interactions, short- and long-term side effects, potential teratogenicity in women of child-bearing age, and high cost. Herein, we discuss the prospects for long-acting antivirals as prophylaxis of human viral infections other than HIV.

Rebound in sexually transmitted infections after the COVID-19 pandemic.

Sexually transmitted infections (STIs) have become the second in the global rating of infectious diseases after respiratory infections. Globally, over 1 million, new STI is diagnosed every day. Although four conditions are the most representative and of obligatory declaration (gonorrhea, syphilis, chlamydia, and human immunodeficiency virus [HIV]), there are many other prevalent STI, including trichomona, herpes simplex, papillomavirus, and viral hepatitis. Herein, we perform a narrative and retrospective review, analyzing information from public databases from distinct Spanish government institutions. STI significantly declined in Spain during 2020 as a result of lockdown and social isolation measures dictated in response to the COVID-19 pandemic. After releasing restrictions, a major STI rebound occurred in 2021. Increases were 49% for gonorrhea, 45% for HIV, 39% for chlamydia, and 32% for syphilis. Based on nationwide statistics, we build a narrative review of the recent STI surge after COVID-19. In summary, we propose a holistic approach to confront the current re-emergence of STI. On one hand, new innovative medical advances must be implemented, including new rapid tests, novel vaccines, pre-exposure prophylaxis beyond HIV, and long-acting antivirals. On the other hand, information to citizens needs to be reformulated with interventions aimed to build a healthier society, alike it has been undertaken with tobacco, alcohol, diet, and lifestyle. STI determines important sexual, reproductive, and maternal-child health consequences. To promote human well-being or flourishing, the education of adolescents and young adults should be aligned with human ecology. Therefore, it is urgent to address new approaches in sexual health that represent a clear benefit for individual persons and society. In this way, favoring a cultural evolution aimed to delay the age of first sexual intercourse and the avoidance of multiple sex partners should be prioritized.

Oral antivirals for the prevention and treatment of SARS-CoV-2 infection.

Vaccines and antivirals are the classical weapons deployed to contain, prevent, and treat life-threatening viral illnesses. Specifically, for SARS-CoV-2 infection, vaccines protect against severe COVID-19 disease manifestations and complications. However, waning immunity and emergence of vaccine escape mutants remains a growing threat. This is highlighted by the current surge of the omicron COVID-19 variant. Thus, there is a race to find treatment alternatives. We contend that oral small molecule antivirals that halt SARSCoV- 2 infection are essential. Compared to currently available monoclonal antibodies and remdesivir, where parenteral administration is required, oral antivirals offer treatments in an outpatient setting with dissemination available on a larger scale. In response to this need at 2021's end, regulatory agencies provided emergency use authorization for both molnupiravir and nirmatrelvir. These medicines act on the viral polymerase and protease, respectively. Each is given for 5 days and can reduce disease progression by 30% and 89%, respectively. The advent of additional oral antivirals, the assessment of combination therapies, the formulation of extended-release medications, and their benefit for both early treatment and prophylaxis will likely transform the landscape of the COVID-19 pandemic.

Advances in hepatitis B therapeutics.

Despite the availability of both effective preventive vaccines and oral antivirals, over 250 million people are chronically infected with the hepatitis B virus (HBV). Globally, chronic hepatitis B is the leading cause of hepatocellular carcinoma, which represents the third cause of cancer mortality, accounting for nearly 1 million annual deaths. Current oral nucleos(t)ide therapy with tenofovir or entecavir suppresses serum HBV-DNA in most treated patients, but rarely is accompanied by HBsAg loss. Thus, treatment has to be given lifelong to prevent viral rebound. A broad spectrum of antivirals that block the HBV life cycle at different steps are in clinical development, including entry inhibitors, cccDNA disrupters/silencers, translation inhibitors, capsid assembly modulators, polymerase inhibitors and secretion inhibitors. Some of them exhibit higher potency than current oral nucleos(t)ides. Drugs in more advanced stages of clinical development are bulevirtide, JNJ-6379, ABI-H0731, ARO-HBV and REP-2139. To date, only treatment with ARO-HBV and with REP-2139 have resulted in HBsAg loss in a significant proportion of patients. Combination therapies using distinct antivirals and/or immune modulators are expected to maximize treatment benefits. The current goal is to achieve a 'functional cure', with sustained serum HBsAg after drug discontinuation. Ultimately, the goal of HBV therapy will be virus eradication, an achievement that would require the elimination of the cccDNA reservoir within infected hepatocytes.

AIDS Clinical Research in Spain-Large HIV Population, Geniality of Doctors, and Missing Opportunities.

The first cases of AIDS in Spain were reported in 1982. Since then over 85,000 persons with AIDS have been cumulated, with 60,000 deaths. Current estimates for people living with HIV are of 145,000, of whom 20% are unaware of it. This explains the still high rate of late HIV presenters. Although the HIV epidemic in Spain was originally driven mostly by injection drug users, since the year 2000 men having sex with men (MSM) account for most new incident HIV cases. Currently, MSM represent over 80% of new yearly HIV diagnoses. In the 80s, a subset of young doctors and nurses working at Internal Medicine hospital wards became deeply engaged in attending HIV-infected persons. Before the introduction of antiretrovirals in the earlier 1990s, diagnosis and treatment of opportunistic infections was their major task. A new wave of infectious diseases specialists was born. Following the wide introduction of triple combination therapy in the late 1990s, drug side effects and antiretroviral resistance led to built a core of highly devoted HIV specialists across the country. Since then, HIV medicine has improved and currently is largely conducted by multidisciplinary teams of health care providers working at hospital-based outclinics, where HIV-positive persons are generally seen every six months. Antiretroviral therapy is currently prescribed to roughly 75,000 persons, almost all attended at clinics belonging to the government health public system. Overall, the impact of HIV/AIDS publications by Spanish teams is the third most important in Europe. HIV research in Spain has classically been funded mostly by national and European public agencies along with pharma companies. Chronologically, some of the major contributions of Spanish HIV research are being in the field of tuberculosis, toxoplasmosis, leishmaniasis, HIV variants including HIV-2, drug resistance, pharmacology, antiretroviral drug-related toxicities, coinfection with viral hepatitis, design and participation in clinical trials with antiretrovirals, immunopathogenesis, ageing, and vaccine development.

Drug interactions in HIV-infected patients treated for hepatitis C.

INTRODUCTION: The introduction of direct-acting antivirals (DAA) has revolutionized the hepatitis C field. Most hepatitis C patients can now be cured, including those coinfected with HIV. However, drug-drug interactions (DDI) between DAA and antiretrovirals (ARV) should be known to prevent either toxicity due to drug overexposure or treatment failures due to low drug concentrations. Areas covered: Clinically significant DDI may be classified as major (when co-administration should be contraindicated) or minor (when they require close monitoring, changes in drug dosage or in timing). Strategies for preventing and managing DDI influence response rates in HIV/HCV-coinfected patients. Pharmacokinetic evidence of interactions from clinical trials and reports from real-world experience are discussed. Expert opinion: The most frequent DDI between DAA and ARV affect drug metabolism by CYP450 induction/inhibition, leading to abnormal drug exposures. Throughout this mechanism interact HCV and HIV boosted protease inhibitors, and most non-nucleoside HCV and HIV polymerase inhibitors. In contrast, HIV and HCV nucleos(t)ide analogue polymerase inhibitors, most HCV NS5A inhibitors and HIV integrase inhibitors (e.g., dolutegravir), do not or only marginally affect CYP450, and therefore are relatively free of DDI. Exposure to some HIV and HCV nucleos(t)ide analogues (e.g., tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters (e.g., P-glycoprotein) and requires special attention in patients with renal insufficiency.

Treatment of hepatitis C with new fixed dose combinations.

INTRODUCTION: The advent of oral direct-acting antivirals (DAA) has revolutionized the hepatitis C virus (HCV) therapeutic landscape providing cure rates over 90%. However, a subset of patients remains at higher risk for treatment failure, including those infected with: i) genotype 3 and cirrhosis; ii) resistance-associated substitutions (RAS) occurring either as natural polymorphisms or selected after prior DAA failure; and iii) poor drug adherence associated with social disabilities (homeless, psychiatric illnesses, injection drug use, alcoholism, etc.). Whereas discovery of new DAA with increased antiviral activity across all genotypes and over RAS may enhance efficacy, development of fixed dose combinations (FDC) may be the best way to improve drug adherence in difficult-to-treat HCV populations. Areas covered: Three FDC regimens are in the last steps of clinical development for treating hepatitis C. Two distinct nucleotide analogues that inhibit the HCV polymerase, sofosbuvir and uprifosbuvir, are part of the FDC from Gilead and Merck, respectively. The AbbVie dual FDC does not include a polymerase inhibitor. All three new FDC include second-generation NS3 protease inhibitors and NS5A inhibitors active across all HCV genotypes and over common RAS. Expert opinion: Hepatitis C cure rates over 95% are expected with all three next-coming DAA, even in the most difficult-to-treat and/or cure patient populations. These regimens would be particularly needed for the growing number of prior DAA failures. Co-formulations and 8-week shorter treatment lengths will help to overcome drug adherence challenges in certain populations.

HIV Pre-Exposure Prophylaxis - Is it just about pills?

The increasing use of antiretrovirals for averting HIV infection before potential exposure is under debate. Whereas there is no doubt about the benefit of using Truvada® (tenofovir plus emtricitabine) to reduce HIV acquisition in uninfected persons who have sex with HIV-infected stable partners, concerns are rising about the increasing rate of sexually transmitted infections in subjects engaged in sex with multiple partners, due to misinterpreted self-security.

Prevention and management of treatment failure to new oral hepatitis C drugs.

INTRODUCTION: Chronic hepatitis C virus (HCV) infection has become a curable disease. Sustained virologic response rates above 90% have been achieved with recommended direct-acting antiviral (DAA) combinations in most registration trials. However, outcomes in real-world patients are lower. In patients experiencing DAA failure, resistance-associated variants (RAVs) are almost universally selected. At this time it is unclear when and how to re-treat hepatitis C in patients with prior DAA failure. AREAS COVERED: The rate of DAA failure and predictors of lack of treatment response using distinct DAA combinations are analyzed. We discuss the management of HCV treatment failure and the impact of RAVs on re-treatment strategies. EXPERT OPINION: Failure to DAA combinations occurs more often in chronic hepatitis C patients with baseline predictors of poor response, such as those with RAVs, genotypes 3 or 1a, advanced liver cirrhosis, elevated serum HCV-RNA and perhaps HIV coinfection. Impaired antiviral efficacy is more frequent when multiple factors are present. On-treatment predictors of DAA failure are poor drug adherence and development of side effects. Extending the length of therapy, adding ribavirin and/or using DAA from other drug families may allow successful re-treatment of most prior DAA failures.

High serum HCV RNA in chronic hepatitis C patients coinfected with HIV despite successful antiretroviral therapy.

BACKGROUND: Baseline serum HCV RNA predicts treatment success in chronic hepatitis C patients. Thresholds at 0.8, 2, 4 and 6 million IU/ml discriminate treatment outcomes using distinct antiviral regimens. Compared to the general population, immunosuppressed individuals exhibit greater viral load values. This has been confirmed in HIV-HCV-coinfected patients, although little is known about the influence of antiretroviral therapy. METHODS: Serum HCV RNA results recorded from all chronic hepatitis C patients who consecutively attended at our clinic were analysed. RESULTS: A total of 813 patients with detectable HCV RNA were identified. HIV coinfection was present in 78.7%, of whom 91% were on antiretroviral therapy. Overall, 467 (57%), 273 (34%), 170 (21%) and 127 (16%) had HCV RNA >0.8, >2, >4 and >6 million IU/ml, respectively. These high viral load values were found in 60%/36%/23%/18% of HIV-positive versus 47%/25%/11%/6% of HIV-negative individuals (P<0.01), respectively. In multivariate analysis, the greatest HCV RNA values were only significantly associated with HIV coinfection and HCV genotypes-1 or -4. Greater HCV RNA values were paradoxically found in HIV patients on than off antiretroviral therapy. CONCLUSIONS: Serum HCV RNA values above 0.8, 2, 4 and 6 million IU/ml are roughly seen in 47%, 25%, 11% and 6% of chronic hepatitis C monoinfected patients, respectively. Despite being on antiretroviral therapy, the corresponding figures are 1.3- to 3.0-fold greater in HIV-HCV-coinfected patients, who may benefit less frequently from shorter oral HCV treatment lengths.

New hepatitis C therapies for special patient populations.

INTRODUCTION: Chronic hepatitis C virus (HCV) infection has become a curable disease. More than 90% sustained virologic response rates have been obtained with 8-24 weeks of treatment with distinct combinations of direct-acting antivirals (DAA) in most registration trials. However, outcomes in real-world patients tend to be lower and treatment of special patient populations is often challenging. AREAS COVERED: We address the treatment of chronic hepatitis C with DAA in major special patient populations, such as HIV-positive persons, transplant recipients, patients with advanced cirrhosis, renal insufficiency, hepatitis B or D coinfection, injection drug users (IDUs) and prior DAA failures. EXPERT OPINION: Drug interactions between DAA and medications given to persons with HIV infection or transplant recipients can result in treatment failure and adverse events. Severe organ dysfunction as in kidney insufficiency or decompensated cirrhosis may lead to DAA overexposure and toxicities. Dysfunctional social circumstances and behavior are associated to poor drug adherence and increased risk for HCV re-infection in active IDUs. Finally, DAA response might be impaired by viral interference in patients with hepatitis B or D coinfection or drug resistance in HCV either at baseline or after prior DAA failures.

Hepatitis C cure with antiviral therapy--benefits beyond the liver.

Liver disease is the major complication of chronic HCV infection. However, extrahepatic complications are common (50-75%), including mixed cryoglobulinaemia and B-cell lymphomas. Given that chronic hepatitis C has become curable using expensive oral direct-acting antivirals (DAAs), it seems worth revisiting the whole spectrum and burden of disease in HCV carriers.Herein, we update the most clinically significant medical complications associated with chronic hepatitis C and the evidence of benefits that would derive from a wide use of curative DAA therapies.Chronic HCV infection is associated with a broad spectrum of clinical conditions, including distinct rheumatic disorders (polyarthritis, sicca syndrome), lymphoproliferative conditions (mixed cryoglobulinaemia, monoclonal gammapathies and B-cell lymphomas) and damage at other organs due to persistent systemic inflammation, leading to renal, bone, neurological and/or cardiovascular disease. Eradication of HCV with DAAs is associated with amelioration and/or resolution of most liver-related and extrahepatic complications. Ultimately, gains in quality of life and survival favour treating everyone with hepatitis C regardless of liver fibrosis stage.

Rate and predictors of serum HCV-RNA >6 million IU/mL in patients with chronic hepatitis C.

BACKGROUND: Baseline serum HCV-RNA predicts sustained virological response in chronic hepatitis C patients treated with antiviral therapy. A threshold at 6 million IU/mL has been proposed to best discriminate treatment outcomes on sofosbuvir-based regimens. In comparison with the general population, immunosuppressed individuals exhibit greater viral load values. OBJECTIVES: To estimate the rate and predictors of serum HCV-RNA above 6 millionIU/mL in chronic hepatitis C patients on care outside clinical trials. STUDY DESIGN: Serum HCV-RNA values recorded from all chronic hepatitis C patients consecutively attended at our clinic during the last decade were analyzed. Testing had been performed using the COBAS TaqMan HCV test v2.0. RESULTS: A total of 816 individuals with detectable serum HCV-RNA were identified. The main characteristics of this population were as follows: mean age 48.6 years-old; 73.4% males; mean ALT 82.6IU/L; mean HCV-RNA 6.02logIU/mL; 80.6% HCV genotypes 1 or 4; 34.9% advanced liver fibrosis; 35.4% IL28B-CC alleles. HIV coinfection in 78.7%, of whom 91% were on antiretroviral therapy. Overall, 127 (15.6%) had serum HCV-RNA values >6 millionIU/mL. This high viremia was found in 18.2% of HIV-positive versus 5.7% of HIV-negative subjects (p<0.001). In multivariate analysis, serum HCV-RNA >6 millionIU/mL was only significantly associated with HIV coinfection (OR: 4.03; 95% CI: 1.98-8.19, p<0.01) and HCV genotypes 1 or 4 (OR: 1.88; 95% CI: 1.05-3.37, p=0.03). CONCLUSIONS: Serum HCV-RNA >6 millionIU/mL is roughly seen in 6% of chronic hepatitis C monoinfected patients, and increases up to 18% in HIV coinfection.

Dual antiviral therapy for HIV and hepatitis C - drug interactions and side effects.

INTRODUCTION: Roughly 20% of HIV-positive persons worldwide are coinfected with hepatitis C virus (HCV). The recent advent of direct-acting antivirals (DAA) that cure most hepatitis C patients has attracted much attention. Knowledge on drug interactions between DAA and antiretrovirals (ARV) may allow maximizing antiviral efficacy while minimizing drug-related toxicities. AREAS COVERED: We review the most frequent side effects and clinically significant drug interactions between DAA and ARV. We further discuss how they can be prevented and managed in HIV/HCV-coinfected patients. EXPERT OPINION: The safety profile of current DAA and the most recently approved ARV is quite favorable. Interactions between DAA and ARV could be frequent in clinical practice. The most common drug interactions affect drug metabolism by inducing or inhibiting the cytochrome P450 system, leading to abnormal drug exposures. Throughout this mechanism HCV and HIV protease inhibitors interact, especially when co-formulated with ritonavir as a pharmacoenhancer, and non-nucleoside HCV and HIV polymerase inhibitors. In contrast, HIV and HCV nucleos(t)ide polymerase inhibitors, and most HCV NS5A inhibitors (i.e., ledipasvir) and HIV integrase inhibitors (i.e., dolutegravir), do not or only marginally affect CYP450, and therefore are free of significant drug interactions. Exposure to HIV and HCV nucleos(t)ide analogues (i.e., tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters (i.e., P-glycoprotein).

Emerging challenges in managing hepatitis B in HIV patients.

Roughly 10 % of HIV-positive individuals worldwide have concomitant chronic hepatitis B virus (HBV) infection, with large differences between geographical regions and/or risk groups. Hepatitis B is a preventable infection with vaccines. However, it cannot be eradicated once acquired, resembling HIV and in contrast with HCV. In developed countries, hepatitis B exhibits particular features in the HIV population. First, HBV infection is less frequently misdiagnosed than in the general population. Second, nucleos(t)ide analogs active against HBV are widely used as part of antiretroviral combinations and are taken by most HIV patients. Lastly, as the HIV population ages given the success of antiretroviral therapy, non-AIDS co-morbidities are becoming a major cause of disease, for which specific drugs are required, increasing the risk of interactions and hepatotoxicity. Furthermore, concern on HBV reactivation is rising as immunosuppressive drug therapies are increasingly been used for cancers and other non-malignant conditions. In this scenario, new challenges are emerging in the management of hepatitis B in HIV-positive individuals. Among them, major interest is focused on failures to suppress HBV replication, HBV breakthroughs and reactivations, the meaning of isolated anti-HBc, screening for liver cancer, and the complexity arising when hepatitis viruses C and/or D are additionally present. This review will focus on these challenges and the major advances in HBV coinfection in HIV.

Drug interactions with new hepatitis C oral drugs.

INTRODUCTION: Chronic hepatitis C virus (HCV) infection has recently become a curable disease with antiviral therapy. The knowledge of drug interactions using direct-acting antivirals (DAA) may permit maximizing antiviral efficacy and avoiding drug-related toxicities. Ageing in the chronic hepatitis C population, along with added co-morbidities that require other medications, has increased the attention on drug interactions using DAA. AREAS COVERED: This review provides an update of the most clinically significant pharmacokinetic and pharmacodynamic drug interactions occurring between currently available DAA and other medications. The review also revisits how drug interactions with DAA can be prevented and managed. EXPERT OPINION: Interactions between DAA and other drugs are frequent in clinical practice. The most frequent drug interactions modify drug metabolism by inducing or inhibiting the cytochrome P450, leading to abnormal drug exposures. Through this mechanism HCV protease inhibitors, especially when co-formulated with ritonavir as pharmacoenhancer, and non-nucleoside HCV polymerase inhibitors interact with other medications. In contrast, NS5B nucleos(t)ide analog inhibitors (i.e., sofosbuvir) and some HCV NS5A inhibitors (i.e., ledipasvir), which do not or only marginally affect CYP450, are relatively free of significant pharmacokinetic interactions. However, exposure to HCV nucleos(t)ide analogs may be influenced by induction/inhibition of drug transporters (i.e., P-glycoprotein) as well as by pharmacodynamic interference with other nucleos(t)ide analogs used as antivirals or cancer drugs. Drug interactions for some NS5A inhibitors (i.e., daclatasvir) are generally moderate and can be managed with dose adjustments.