Increase in serum bilirubin in HIV/hepatitis-C virus-coinfected patients on atazanavir therapy following initiation of pegylated-interferon and ribavirin

Heme-Induced Macrophage Phenotype Switching and Impaired Endogenous Opioid Homeostasis Correlate with Chronic Widespread Pain in HIV

Chronic widespread pain (CWP) is associated with a high rate of disability and decreased quality of life in people with HIV-1 (PWH). We previously showed that PWH with CWP have increased hemolysis and elevated plasma levels of cell-free heme, which correlate with low endogenous opioid levels in leukocytes. Further, we demonstrated that cell-free heme impairs β-endorphin synthesis/release from leukocytes. However, the cellular mechanisms by which heme dampens β-endorphin production are inconclusive. The current hypothesis is that heme-dependent TLR4 activation and macrophage polarization to the M1 phenotype mediate this phenomenon. Our novel findings showed that PWH with CWP have elevated M1-specific macrophage chemokines (ENA-78, GRO-α, and IP-10) in plasma. In vitro, hemin-induced polarization of M0 and M2 macrophages to the M1 phenotype with low β-endorphins was mitigated by treating cells with the TLR4 inhibitor, TAK-242. Similarly, in vivo phenylhydrazine hydrochloride (PHZ), an inducer of hemolysis, injected into C57Bl/6 mice increased the M1/M2 cell ratio and reduced β-endorphin levels. However, treating these animals with the heme-scavenging protein hemopexin (Hx) or TAK-242 reduced the M1/M2 ratio and increased β-endorphins. Furthermore, Hx attenuated heme-induced mechanical, heat, and cold hypersensitivity, while TAK-242 abrogated hypersensitivity to mechanical and heat stimuli. Overall, these results suggest that heme-mediated TLR4 activation and M1 polarization of macrophages correlate with impaired endogenous opioid homeostasis and hypersensitivity in people with HIV.

Heme attenuates beta-endorphin levels in leukocytes of HIV positive individuals with chronic widespread pain

The prevalence of chronic widespread pain (CWP) in people with HIV is high, yet the underlying mechanisms are elusive. Leukocytes synthesize the endogenous opioid, β-endorphin, within their endoplasmic reticulum (ER). When released into plasma, β-endorphin dampens nociception by binding to opioid receptors on sensory neurons. We hypothesized that the heme-dependent redox signaling induces ER stress, which attenuates leukocyte β-endorphins levels/release, thereby increasing pain sensitivity in people with HIV. Results demonstrated that HIV positive individuals with CWP had increased plasma methemoglobin, erythrocytes membrane oxidation, hemolysis, and low plasma heme scavenging enzyme, hemopexin, compared to people with HIV without CWP and HIV-negative individuals with or without pain. In addition, the leukocytes from people with HIV with CWP had attenuated levels of the heme metabolizing enzyme, heme oxygenase-1, which metabolizes free heme to carbon-monoxide and biliverdin. These individuals also had elevated ER stress, and low β-endorphin in leukocytes. In vitro, heme exposure or heme oxygenase-1 deletion, decreased β-endorphins in murine monocytes/macrophages. Treating cells with a carbon-monoxide donor or an ER stress inhibitor, increased β-endorphins. To mimic hemolytic effects in a preclinical model, C57BL/6 mice were injected with phenylhydrazine hydrochloride (PHZ). PHZ increased cell-free heme and ER stress, decreased leukocyte β-endorphin levels and hindpaw mechanical sensitivity thresholds. Treatment of PHZ-injected mice with hemopexin blocked these effects, suggesting that heme-induced ER stress and a subsequent decrease in leukocyte β-endorphin is responsible for hypersensitivity in people with HIV.

CIHR Canadian HIV Trials Network Coinfection and Concurrent Diseases Core Research Group: 2016 Updated Canadian HIV/Hepatitis C Adult Guidelines for Management and Treatment

Background. Hepatitis C virus (HCV) coinfection occurs in 20-30% of Canadians living with HIV and is responsible for a heavy burden of morbidity and mortality. Purpose. To update national standards for management of HCV-HIV coinfected adults in the Canadian context with evolving evidence for and accessibility of effective and tolerable DAA therapies. The document addresses patient workup and treatment preparation, antiviral recommendations overall and in specific populations, and drug-drug interactions. Methods. A standing working group with HIV-HCV expertise was convened by The Canadian Institute of Health Research HIV Trials Network to review recently published HCV antiviral data and update Canadian HIV-HCV Coinfection Guidelines. Results. The gap in sustained virologic response between HCV monoinfection and HIV-HCV coinfection has been eliminated with newer HCV antiviral regimens. All coinfected individuals should be assessed for interferon-free, Direct Acting Antiviral HCV therapy. Regimens vary in content, duration, and success based largely on genotype. Reimbursement restrictions forcing the use of pegylated interferon is not acceptable if optimal patient care is to be provided. Discussion. Recommendations may not supersede individual clinical judgement. Treatment advances published since December 2015 are not considered in this document.

Hyperbilirubinaemia in HIV-HCV co-infected patients on antiretroviral therapy: drug effect or liver disease severity?

Objective

Hyperbilirubinaemia (HB) is common in HIV and hepatitis C virus (HIV–HCV) co-infected patients and poses a unique challenge in management as it may be due to medications such as the protease inhibitors (PIs) or to hepatic dysfunction. There are no data on the relationship of HB to liver histology and PI use in this population. Clinicians caring for these patients are faced with the difficult task of determining whether increasing serum bilirubin is due to drug effects or progression of liver disease.

Methods

To address this gap in knowledge, we performed a retrospective analysis of 344 consecutive HIV–HCV co-infected patients undergoing liver biopsy to identify factors associated with HB. Demographic, clinical, laboratory data were collected. Advanced fibrosis was defined as bridging fibrosis or cirrhosis. Those with hepatitis B virus, hepatic decompensation or hepatocellular carcinoma were excluded.

Results

The prevalence of HB (range 1.3–9.4) was 33% and more common in those on a PI (46%) than those who were not (10%; p≤0.001) and mostly in those on indinavir (40%) or atazanavir (46%). Of the patients on these PIs, HB was not associated with fibrosis grade, demographics, or other clinical variables. Conversely, in those not on a PI, HB was associated with fibrosis grade (p≤0.0001) after adjusting for other clinical and demographic variables.

Conclusions

In the setting of indinavir or atazanavir use, HB is common and unrelated to underlying disease severity and the medications can be continued safely. Conversely, HB in HIV–HCV co-infected patients not on a PI is due to their underlying liver disease and suggests these patients require closer monitoring.

Telaprevir-based therapy for treatment of HIV-1 and hepatitis C virus co-infected patients: An early access programme

OBJECTIVES

HPC3005 is a multicentre, open-label, telaprevir trial in HCV/HIV coinfected patients with severe fibrosis or compensated cirrhosis.

METHODS

Patients were treated with telaprevir 750 mg every 8 h (1125 mg if on efavirenz) plus pegylated interferon-alpha (PEG-IFN, 180 μg once-weekly) and ribavirin (RBV, 800 mg/day) for 12 weeks, followed by 36 weeks of PEG-IFN/RBV.

RESULTS

Mean age was 44 years, 97/118 patients were male and all were Caucasian, 68 had severe fibrosis and 50 had cirrhosis. Seventy-eight had HCV RNA levels ≥800 000 IU/mL, 72 had HCV genotype 1a, baseline HIV RNA was <50 copies/mL in 112 patients. Overall, 114/118 patients continued antiretroviral treatment, 4 were untreated. Seventy-five patients received tenofovir and 74 emtricitabine; in addition 53 received atazanavir/ritonavir, 43 raltegravir, and 24 efavirenz. By intention-to-treat, 78 (66%) patients achieved SVR24. Nineteen discontinued telaprevir, 8 for virological endpoint, 5 for adverse events (2 anaemia, 2 rash, 1 asthenia), 5 for non-compliance and 1 withdrew consent. The most common adverse events were anaemia (36 patients), thrombocytopaenia (33), rash (26), bilirubin increase (17), and neutropenia (16).

CONCLUSIONS

In this early access programme in coinfected patients with severe fibrosis or cirrhosis, 66% of patients achieved SVR. The most common adverse events were haematological.

CLINICAL TRIAL NUMBER

NCT01500616.

Treatment of Hepatitis C in HIV-Infected Patients: Moving Towards an Era of All Oral Regimens

Hepatitis C (HCV)-related liver disease has become one of the leading causes of death in HIV patients. With the development of new direct-acting antivirals for HCV, treatment regimens have become shorter, more effective, and easier to tolerate without interferon. However, cost may be a significant impediment to the widespread use of these newer agents in both resource-rich and resource-poor settings. In HIV patients, treatment for HCV is not always as straightforward compared with HCV monoinfected patients due to potential drug-drug interactions. In this article, we will examine by genotypes the FDA approved direct-acting antivirals, as well as those in clinical trials that will soon be FDA-approved focusing on data in HCV/HIV co-infection. Preferred agents for HCV treatment and potential drug-drug interactions with antiretroviral therapy (ART) will be highlighted.

Sofosbuvir for chronic hepatitis C virus infection genotype 1-4 in patients coinfected with HIV

BACKGROUND

Chronic hepatitis C virus (HCV) infection is a major cause of morbidity and mortality among HIV-infected patients. Sofosbuvir is a first-in-class HCV NS5B inhibitor with potent pan-genotypic antiviral activity. We report a 2-part study that assessed the efficacy and safety of sofosbuvir in HCV/HIV-coinfected patients. Part A examined potential drug interactions between sofosbuvir and antiretrovirals (efavirenz, emtricitabine, tenofovir, zidovudine, lamivudine, atazanavir, ritonavir, darunavir, and raltegravir). Part B was a pilot study of sofosbuvir plus peginterferon-ribavirin administered for 12 weeks.

METHODS

We enrolled noncirrhotic patients with chronic HCV infection (genotype, 1-6) and stable HIV. Part A followed a 5-cohort, open-label, multiple-dose, single-sequence design; part B followed an open-label, single-arm design. The primary end point of part B was sustained virologic response (defined as undetectable HCV RNA) 12 weeks after end of treatment (SVR12). This study is registered with ClinicalTrials.gov, number NCT01565889.

FINDINGS

Thirty-eight patients were enrolled in part A and 23 in part B. In part A, no clinically significant drug interactions were observed between sofosbuvir and any of the antiretrovirals evaluated. In part B, 21 (91.3%) patients achieved SVR12. Two patients relapsed but none experienced on-treatment HCV virologic failure. Two patients discontinued study treatment because of adverse events (altered mood and anemia). No serious adverse events, HIV viral breakthrough, or decreases in CD4 percentage were reported in either part A or part B.

INTERPRETATION

Sofosbuvir may be coadministered safely with many commonly used antiretrovirals. The addition of sofosbuvir to peginterferon-ribavirin was highly effective as assessed by SVR in HCV/HIV-coinfected patients.

Sofosbuvir plus ribavirin for treatment of hepatitis C virus in patients co-infected with HIV (PHOTON-2): a multicentre, open-label, non-randomised, phase 3 study

BACKGROUND

Although interferon-free regimens are approved for patients co-infected with HIV and genotype-2 or genotype-3 hepatitis C virus (HCV), interferon-based regimens are still an option for those co-infected with HIV and HCV genotypes 1 or 4. These regimens are limited by clinically significant toxic effects and drug interactions with antiretroviral therapy. We aimed to assess the efficacy and safety of an interferon-free, all-oral regimen of sofosbuvir plus ribavirin in patients with HIV and HCV co-infection.

METHODS

We did this open-label, non-randomised, uncontrolled, phase 3 study at 45 sites in seven European countries and Australia. We enrolled patients (aged ≥18 years) co-infected with stable HIV and chronic HCV genotypes 1-4, including those with compensated cirrhosis. Once-daily sofosbuvir (400 mg) plus twice-daily ribavirin (1000 mg in patients with bodyweights <75 kg and 1200 mg in those with weights ≥75 kg) was given for 24 weeks to all patients except treatment-naive patients with genotype-2 HCV, who received a 12-week regimen. The primary efficacy endpoint was sustained virological response 12 weeks after treatment. We did analysis by modified intention to treat. This study is registered with ClinicalTrials.gov, number NCT01783678.

FINDINGS

Between Feb 7, 2013, and July 29, 2013, we enrolled 275 eligible patients, of whom 262 (95%) completed treatment; 274 patients were included in the final analysis. Overall rates of sustained virological response 12 weeks after treatment were 85% (95% CI 77-91) in patients with genotype-1 HCV, 88% (69-98) in patients with genotype-2 HCV, 89% (81-94) in patients with genotype-3 HCV, and 84% (66-95) in patients with genotype-4 HCV. Response rates in treatment-naive patients with HCV genotypes 2 or 3 (89% [95% CI 67-99] and 91% [81-97], respectively) were similar to those in treatment-experienced patients infected with those genotypes (83% [36-100] and 86% [73-94], respectively). There was no emergence of sofosbuvir-resistance mutations in patients with HCV viral relapse. Six (2%) patients discontinued treatment because of adverse events. The most common adverse events were fatigue, insomnia, asthenia, and headache. Four (1%) patients had serious adverse events regarded as related to study treatment. Additionally, four (1%) patients receiving antiretroviral treatment had a transient HIV viral breakthrough; however, none required changes in antiretroviral regimen.

INTERPRETATION

Sofosbuvir and ribavirin provided high rates of sustained virological response after 12 weeks of treatment in treatment-naive and treatment-experienced patients co-infected with HIV and HCV genotypes 1-4. The characteristics of this interferon-free combination regimen make sofosbuvir plus ribavirin a useful treatment option for this patient population.

FUNDING

Gilead Sciences.

Sofosbuvir and ribavirin for hepatitis C in patients with HIV coinfection

IMPORTANCE

Treatment of hepatitis C virus (HCV) infection in patients also infected with human immunodeficiency virus (HIV) has been limited due to drug interactions with antiretroviral therapies (ARTs) and the need to use interferon.

OBJECTIVE

To determine the rates of HCV eradication (sustained virologic response [SVR]) and adverse events in patients with HCV-HIV coinfection receiving sofosbuvir and ribavirin treatment.

DESIGN, SETTING, AND PARTICIPANTS

Open-label, nonrandomized, uncontrolled phase 3 trial conducted at 34 treatment centers in the United States and Puerto Rico (August 2012-November 2013) evaluating treatment with sofosbuvir and ribavirin among patients with HCV genotypes 1, 2, or 3 and concurrent HIV. Patients were required to be receiving ART with HIV RNA values of 50 copies/mL or less and a CD4 T-cell count of more than 200 cells/μL or to have untreated HIV infection with a CD4 T-cell count of more than 500 cells/μL. Of the treatment-naive patients, 114 had HCV genotype 1 and 68 had HCV genotype 2 or 3, and 41 treatment experienced participants who had been treated with peginterferon-ribavirin had HCV genotype 2 or 3, for a total of 223 participants.

INTERVENTIONS

Treatment-naive patients with HCV genotype 2 or 3 received 400 mg of sofosbuvir and weight-based ribavirin for 12 weeks and treatment-naive patients with HCV genotype 1 and treatment-experienced patients with HCV genotype 2 or 3 received the same treatment for 24 weeks.

MAIN OUTCOMES AND MEASURES

The primary study outcome was the proportion of patients with SVR (serum HCV <25 copies/mL) 12 weeks (SVR12) after cessation of HCV therapy.

RESULTS

Among treatment-naive participants, 87 patients (76%) of 114 (95% CI, 67%-84%) with genotype 1, 23 patients (88%) of 26 with genotype 2 (95% CI, 70%-985), and 28 patients (67%) of 42 with genotype 3 (95% CI, 51%-80%) achieved SVR12. Among treatment-experienced participants, 22 patients (92%) of 24 with genotype 2 (95% CI, 73%-99%) and 16 patients (94%) of 17 (95% CI, 71%-100%) achieved SVR12. The most common adverse events were fatigue, insomnia, headache, and nausea. Seven patients (3%) discontinued HCV treatment due to adverse events. No adverse effect on HIV disease or its treatment was observed.

CONCLUSIONS AND RELEVANCE

In this open-label, nonrandomized, uncontrolled study, patients with HIV who were coinfected with HCV genotype 1, 2, or 3 who received the oral, interferon-free combination of sofosbuvir and ribavirin for 12 or 24 weeks had high rates of SVR12. Further studies of this oral regimen in diverse populations of coinfected patients are warranted.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01667731.

Hepatitis C virus infection in patients with HIV-1: epidemiology, natural history and management

Hepatitis C virus (HCV)-related liver diseases have contributed to increased morbidity and mortality in HIV-1-infected individuals in the era of effective antiretroviral therapy. HCV transmission patterns have changed among the HIV co-infected population during the last decade, with acute HCV infection emerging worldwide. HIV infection accelerates the progression of HCV-related liver diseases and consequently cirrhosis, liver failure, and hepatocellular carcinoma. However, the current standard treatment of HCV infection with pegylated interferon plus ribavirin results in only a limited viral response. Furthermore, cumbersome pill regimens, antiretroviral related hepatotoxicity, and drug interactions of HCV and HIV regimens complicate therapy strategies. Fortunately, in the near future, new direct-acting anti-HCV agents will widen therapeutic options for HCV/HIV co-infection. Liver transplantation is also gradually accepted as a therapeutic option for end stage liver disease of HCV/HIV co-infected patients.

Update on Hepatitis C Virus and HIV Coinfection

Chronic hepatitis C virus (HCV) infection has historically been difficult to treat in the HIV-infected population, owing to generally poor responses to interferon-based therapies. The recent rapid development of directly acting antiviral agents (DAAs) against HCV has the potential to revolutionize treatment of this infection in the HIV population by improving tolerability and outcome, and, ultimately, reducing the significant burden of liver-related morbidity and mortality in this population. Clinical trials to address the safety and efficacy of novel DAAs in the HCV/HIV coinfected population are ongoing, and show much promise. The rapidity of current drug discovery in the field of HCV is both impressive and daunting for clinicians who will have to master these drugs. Going forward, the inclusion of individuals from this large and growing patient population in clinical trials will be of paramount importance.

[Consensus Statement by GeSIDA/National AIDS Plan Secretariat on antiretroviral treatment in adults infected by the human immunodeficiency virus (Updated January 2013)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the GeSIDA/National AIDS Plan Secretariat (Grupo de Estudio de Sida and the Secretaría del Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations and the evidence which support them are based on a modification of the criteria of Infectious Diseases Society of America.

RESULTS

cART is recommended in patients with symptoms of HIV infection, in pregnant women, in serodiscordant couples with high risk of transmission, in hepatitisB co-infection requiring treatment, and in HIV nephropathy. cART is recommended in asymptomatic patients if CD4 is <500cells/μl. If CD4 are >500cells/μl cART should be considered in the case of chronic hepatitisC, cirrhosis, high cardiovascular risk, plasma viral load >100.000 copies/ml, proportion of CD4 cells <14%, neurocognitive deficits, and in people aged >55years. The objective of cART is to achieve an undetectable viral load. The first cART should include 2 reverse transcriptase inhibitors (RTI) nucleoside analogs and a third drug (a non-analog RTI, a ritonavir boosted protease inhibitor, or an integrase inhibitor). The panel has consensually selected some drug combinations, for the first cART and specific criteria for cART in acute HIV infection, in tuberculosis and other HIV related opportunistic infections, for the women and in pregnancy, in hepatitisB or C co-infection, in HIV-2 infection, and in post-exposure prophylaxis.

CONCLUSIONS

These new guidelines update previous recommendations related to first cART (when to begin and what drugs should be used), how to monitor, and what to do in case of viral failure or adverse drug reactions. cART specific criteria in comorbid patients and special situations are similarly updated.

Antiviral drugs and the treatment of hepatitis C

With effective treatment of HIV-1, hepatitis C virus (HCV) has become increasingly recognized as a major cause of morbidity and mortality in this population. Rapid progression of liver disease and cirrhosis has been documented in HIV/HCV co-infected individuals, particularly with lower CD4-counts (< 200/μL). Therefore, HCV treatment has become a priority for many clinicians, despite the presence of many. An important issue among HIV/HCV co-infected patients is the selection of antiretroviral therapy (ART) during treatment with pegylated interferon, ribavirin (RBV), plus new HCV protease inhibitors. Extensive drug-drug interactions (DDI) and overlapping drug-associated adverse events can impact the outcome of HCV therapy. In this review, we focus on the important data and studies regarding optimizing antiretroviral regimens before starting HCV treatment in HIV/HCV co-infected patients to increase the chance of sustained virologic response (SVR).

[Consensus document of Gesida and Spanish Secretariat for the National Plan on AIDS (SPNS) regarding combined antiretroviral treatment in adults infected by the human immunodeficiency virus (January 2012)]

This consensus document has been prepared by a panel consisting of members of the AIDS Study Group (Gesida) and the Spanish Secretariat for the National Plan on AIDS (SPNS) after reviewing the efficacy and safety results of clinical trials, cohort and pharmacokinetic studies published in medical journals, or presented in medical scientific meetings. Gesida has prepared an objective and structured method to prioritise combined antiretroviral treatment (cART) in naïve patients. Recommendations strength (A, B, C) and the evidence which supports them (I, II, III) are based on a modification of the Infectious Diseases Society of America criteria. The current antiretroviral treatment (ART) of choice for chronic HIV infection is the combination of three drugs. ART is recommended in patients with symptomatic HIV infection, in pregnancy, in serodiscordant couples with high transmission risk, hepatitis B fulfilling treatment criteria, and HIV nephropathy. Guidelines on ART treatment in patients with concurrent diagnosis of HIV infection and an opportunistic type C infection are included. In asymptomatic patients ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts <350 cells/μL; 2) when CD4 counts are between 350 and 500 cells/μL, therapy will be recommended and only delayed if patient is reluctant to take it, the CD4 are stabilised, and the plasma viral load is low; 3) therapy could be deferred when CD4 counts are above 500 cells/μL, but should be considered in cases of cirrhosis, chronic hepatitis C, high cardiovascular risk, plasma viral load >10(5) copies/mL, proportion of CD4 cells <14%, and in people aged >55 years. ART should include 2 reverse transcriptase inhibitors nucleoside analogues and a third drug (non-analogue reverse transcriptase inhibitor, ritonavir boosted protease inhibitor or integrase inhibitor). The panel has consensually selected and given priority to using the Gesida score for some drug combinations, some of them co-formulated. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures, but an undetectable viral load may be possible nowadays. Adverse events are a fading problem of ART. Guidelines in acute HIV infection, in women, in pregnancy, and to prevent mother-to-child transmission and pre- and post-exposition prophylaxis are commented upon. Management of hepatitis B or C co-infection, other co-morbidities, and the characteristics of ART in HIV-2 infection are included.

Treatment of hepatitis C virus infection in adults and children: updated Swedish consensus recommendations

Swedish recommendations for the treatment of hepatitis C virus (HCV) infection were updated at a recent expert meeting. Therapy for acute HCV infection should be initiated if spontaneous resolution does not occur within 12 weeks. The recommended standard-of-care therapy for chronic HCV genotype 1 infection is an HCV protease inhibitor in combination with peginterferon (peg-IFN) and ribavirin. Treatment is strongly recommended in patients with bridging fibrosis and cirrhosis, whereas in patients with less advanced fibrosis, deferring therapy may be preferential in light of likely therapeutic improvements in the near future. Patients with chronic genotype 2/3 infection should generally be treated with peg-IFN and ribavirin for 24 weeks. In patients with a very rapid viral response (i.e. HCV RNA below 1000 IU/ml on day 7), or favourable baseline characteristics and undetectable HCV RNA week 4, treatment can be shortened to 12-16 weeks, provided that no dose reductions are needed.

Directly acting antivirals for hepatitis C and antiretrovirals: potential for drug-drug interactions

PURPOSE OF REVIEW

Boceprevir and telaprevir are directly acting antivirals (DAAs) that have recently been licensed for treatment of hepatitis C virus (HCV) infection. Data in both untreated and previously treated patients indicate a significantly increased sustained virological response (SVR) compared with that observed with conventional therapy. However, the advent of DAA therapy poses specific challenges for HCV treatment in terms of managing drug-drug interactions (DDIs). This review aims to provide a comprehensive summary of DDI with the recently licensed DAAs, including pharmacokinetic data and current recommendations made by the manufacturers and with particular reference to antiretrovirals. Potential for DDIs with the DAAs in clinical development and the mechanisms of interaction are also discussed.

RECENT FINDINGS

Targeted pharmacokinetic drug interaction studies have demonstrated that both boceprevir and telaprevir are potent inhibitors of the metabolic enzyme cytochrome P4503A4, making them perpetrators of interactions with co-administered medications which are metabolized by this enzyme. In addition, co-administered medications may affect plasma levels of boceprevir and telaprevir via various mechanisms, some of which remain to be fully elucidated.

SUMMARY

As a result of DDIs, the concomitant use of some medicines with DAA will be contraindicated, whereas other combinations may require caution, monitoring, or dose modification of the co-administered drug. Management of DDIs with these novel agents will pose a new challenge, and prescriber awareness of the potential for DDIs is fundamental for safe prescribing. Online resources are likely to play a key role in prescriber education and clinical decision-making.

Challenges and opportunities for hepatitis C drug development in HIV-hepatitis C virus-co-infected patients

The approval of the first direct-acting antivirals (DAAs) against the hepatitis C virus (HCV) has been eagerly expected for treating chronic hepatitis C in HIV individuals given that progression to cirrhosis and end-stage liver disease occurs faster in the co-infected population. The appropriate and judicious use of DAAs may provide cure to a large number of HIV-HCV patients. On the contrary, the widespread use of DAAs will occasionally be off-label or under unsatisfactory medical conditions, which may result in undesirable toxicities, drug interactions or selection of drug resistance in HCV. As a result of using first-generation DAAs in HIV-HCV-co-infected patients, a growing proportion of the remaining hepatitis C individuals will be those harboring non-HCV 1 genotypes or drug-resistant HCV variants. Over time, the largest reservoir of HCV genotype 1 patients will accumulate in resource-poor nations where access to hepatitis C therapy has been elusive and HIV treatment remains the primary health issue for the co-infected population.

Atazanavir/ritonavir-based combination antiretroviral therapy for treatment of HIV-1 infection in adults

In the past 15 years, improvements in the management of HIV infection have dramatically reduced morbidity and mortality. Similarly, rapid advances in antiretroviral medications have resulted in the possibility of life-long therapy with simple and tolerable regimens. Protease inhibitors have been important medications in regimens of combination antiretroviral therapy for the treatment of HIV. One of the recommended and commonly used therapies in this class is once-daily-administered atazanavir, pharmacologically boosted with ritonavir (atazanavir/r). Clinical studies and practice have shown these drugs, in combination with other antiretroviral agents, to be potent, safe and easy to use in a variety of settings. Atazanavir/r has minimal short-term toxicity, including benign bilirubin elevation, and has less potential for long-term complications of hyperlipidemia and insulin resistance compared with other protease inhibitors. A high genetic barrier to resistance and a favorable resistance profile make it an excellent option for initial HIV treatment or as the first drug utilized in the protease inhibitors class. Atazanavir/r is also currently being studied in novel treatment strategies, including combinations with new classes of antiretrovirals to assess nucleoside reverse transcriptase inhibitor-sparing regimens. In this article we review atazanavir/r as a treatment for HIV infection and discuss the latest information on its pharmacology, efficacy and toxicity.

Impact of early elevation of serum bilirubin during treatment with pegylated interferon and ribavirin in patients with chronic hepatitis C

AIM

  Hemolytic anemia is a well-known adverse effect of interferon and ribavirin combination treatment. Herein, we analyzed the impact of early elevation of serum bilirubin level as a marker for predicting severe anemia during treatment.

METHODS

  We studied 245 chronic hepatitis C patients who received pegylated interferon and ribavirin combination treatment, and divided them using two different threshold levels: (i) elevation of total bilirubin of 0.5 mg/dL or more within 1 week of starting treatment; and (ii) drop of hemoglobin (Hb) by 3 g/dL or more within 4 weeks of starting treatment. We compared the dynamics in each group and then investigated independent factors for predicting a severe Hb drop (≥3 g/dL) at 4 weeks after beginning treatment and dose reduction of ribavirin.

RESULTS

  Total bilirubin levels at 1 week were significantly higher in patients with a Hb drop of 3 g/dL or more as compared to those with a drop of less than 3 g/dL (P < 0.0001). Hb levels at 4 weeks were significantly lower in the group of 0.5 mg/dL or more increase of total bilirubin levels than in the group with a less than 0.5 mg/dL increase (P < 0.0001). Therefore, elevation of total bilirubin after 1 week of treatment was shown to be an independent factor for predicting severe Hb drop (≥3 g/dL) at 4 weeks (P < 0.0001), and dose reduction of ribavirin during treatment (P = 0.0321).

CONCLUSION

  Early elevation of serum bilirubin level was found to be a possible predictive marker of both a severe drop of Hb in the early phase of treatment and dose reduction of ribavirin.

[AIDS Study Group/Spanish AIDS Plan consensus document on antiretroviral therapy in adults with human immunodeficiency virus infection (updated January 2010)]

OBJECTIVE

This consensus document is an update of antiretroviral therapy recommendations for adult patients with human immunodeficiency virus infection.

METHODS

To formulate these recommendations a panel made up of members of the Grupo de Estudio de Sida (Gesida, AIDS Study Group) and the Plan Nacional sobre el Sida (PNS, Spanish AIDS Plan) reviewed the advances in the current understanding of the pathophysiology of human immunodeficiency virus (HIV) infection, the efficacy and safety of clinical trials, and cohort and pharmacokinetic studies published in biomedical journals or presented at scientific meetings. Three levels of evidence were defined according to the data source: randomized studies (level A), cohort or case-control studies (level B), and expert opinion (level C). The decision to recommend, consider or not to recommend ART was established in each situation.

RESULTS

Currently, the treatment of choice for chronic HIV infection is the combination of three drugs of two different classes, including 2 nucleosides or nucleotide analogs (NRTI) plus 1 non-nucleoside (NNRTI) or 1 boosted protease inhibitor (PI/r), but other combinations are possible. Initiation of ART is recommended in patients with symptomatic HIV infection. In asymptomatic patients, initiation of ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts below 350 cells/microl; 2) When CD4 counts are between 350 and 500 cells/microl, therapy should be started in case of cirrhosis, chronic hepatitis C, high cardiovascular risk, HIV nephropathy, HIV viral load above 100,000 copies/ml, proportion of CD4 cells under 14%, and in people aged over 55; 3) Therapy should be deferred when CD4 are above 500 cells/microl, but could be considered if any of previous considerations concurs. Treatment should be initiated in case of hepatitis B requiring treatment and should be considered for reduce sexual transmission. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures but undetectable viral loads maybe possible with the new drugs even in highly drug experienced patients. Genotype studies are useful in these situations. Drug toxicity of ART therapy is losing importance as benefits exceed adverse effects. Criteria for antiretroviral treatment in acute infection, pregnancy and post-exposure prophylaxis are mentioned as well as the management of HIV co-infection with hepatitis B or C.

CONCLUSIONS

CD4 cells counts, viral load and patient co-morbidities are the most important reference factors to consider when initiating ART in asymptomatic patients. The large number of available drugs, the increased sensitivity of tests to monitor viral load, and the ability to determine viral resistance is leading to a more individualized therapy approach in order to achieve undetectable viral load under any circumstances.

Atazanavir: a review of its use in the management of HIV-1 infection

Atazanavir (Reyataz), a protease inhibitor (PI), is approved in many countries for use as a component of antiretroviral therapy (ART) regimens for the treatment of adult, and in some countries in paediatric, patients with HIV-1 infection. ART regimens containing ritonavir-boosted atazanavir improved virological and immunological markers in adult patients with HIV-1 infection, and had similar efficacy to regimens containing lopinavir/ritonavir in treatment-naive and treatment-experienced patients. In addition, unboosted atazanavir was noninferior to ritonavir-boosted atazanavir in treatment-naive patients. Atazanavir is administered once daily and has a low capsule burden. Atazanavir, whether unboosted or boosted, was generally well tolerated and appeared to be associated with less marked metabolic effects, including less alteration of lipid levels, than other PIs. These properties mean that boosted atazanavir, and unboosted atazanavir in patients unable to tolerate ritonavir, continues to have a role as a component of ART regimens in patients with HIV-1 infection.

HIV protease inhibitors: recent clinical trials and recommendations on use

BACKGROUND

HIV protease inhibitors (PIs) are potent antiretroviral drugs that represent a pivotal component of highly active antiretroviral therapy (HAART). PIs have evolved over the years to gain in potency, convenience, tolerability and genetic barrier to resistance.

OBJECTIVE

Updated summary of evidence-based information about the efficacy and safety of PIs on initial, simplification and rescue interventions in HIV patients.

METHODS

Review of available data reported in peer-reviewed journals, medical conferences and treatment guidelines.

RESULTS

Due to their characteristics, PIs are, and will remain, a cornerstone component in most lines of antiretroviral therapy. The antiviral activity, tolerability and convenience of PIs have improved significantly in recent years. Differences between compounds within this class may favour their use in specific situations, such as the friendly metabolic profile of atazanavir in patients with cardiovascular disease or the high genetic barrier of darunavir or tipranavir in heavily pretreated individuals with HIV.