Bone mineral density in HIV-negative men participating in a tenofovir pre-exposure prophylaxis randomized clinical trial in San Francisco

Is pre-exposure prophylaxis effective for preventing HIV infection in men who have sex with men?

INTRODUCTION

Increasing rates of HIV infection remain of concern, especially for high-risk groups such as men who have sex with men. Oral pre-exposure prophylaxis has emerged as an alternative to prevention. However, doubts persist in patients and physicians about its effectiveness.

METHODS

To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach.

RESULTS AND CONCLUSIONS

We identified six systematic reviews including twelve studies overall, of which six were randomized trials. We concluded the use of oral pre-exposure prophylaxis reduces the probability of HIV infection in men who have sex with men, has few or no adverse effects, and is a measure with a good balance between benefits, risks and costs.

Recent advances in pre-exposure prophylaxis for HIV

Although pre-exposure prophylaxis (PrEP)-the use of antiretroviral drugs by non-infected people to prevent the acquisition of HIV-is a promising preventive option, important public health questions remain. Daily oral emtricitabine (FTC)-tenofovir disoproxil fumarate (TDF) is highly efficacious in preventing the acquisition of HIV in people at risk as a result of a range of different types of sexual exposure. There is good evidence of efficacy in women and men, and when men who have sex with men use event based dosing. Studies have been conducted in several countries and epidemics. Because adherence to this treatment varies greatly there are questions about its public health benefit. Oral FTC-TDF is extremely safe, with minimal impact on kidney, bone, or pregnancy outcomes, and there is no evidence that its effectiveness has been reduced by risk compensation during open label and programmatic follow-up. It is too early to assess the impact of this treatment on the incidence of sexually transmitted infections (STIs) at a population level. Many challenges remain. Access to pre-exposure prophylaxis is limited and disparities exist, including those governed by race and sex. Different pricing and access models need to be explored to avoid further widening inequalities. The optimal combination prevention program needs to be defined, and this will depend on local epidemiology, service provision, and cost effectiveness. This review updates the evidence base for pre-exposure prophylaxis regarding its effectiveness, safety, and risk compensation.

Brief Report: Recovery of Bone Mineral Density After Discontinuation of Tenofovir-Based HIV Pre-exposure Prophylaxis

BACKGROUND

Oral tenofovir disoproxil fumarate (TDF) for HIV prevention and treatment is associated with decreases in bone mineral density (BMD). Previous reports suggest that these changes may be reversible after discontinuation of TDF.

SETTING

A metabolic substudy of 498 participants in a randomized, placebo-controlled HIV prevention trial of oral coformulated TDF with emtricitabine (TDF/FTC, Truvada) for HIV pre-exposure prophylaxis (PrEP) enrolling a global sample of men who have sex with men and trans women.

METHODS

Participants underwent dual X-ray absorptiometry to quantify bone mineral density (BMD) in the hip and spine during PrEP and at 2 visits after stopping (median of 23 and 79 weeks post-PrEP, respectively). Results are stratified by pharmacologic measure of TDF/FTC adherence.

RESULTS

There was no significant difference in change in hip/spine BMD at any time point between placebo and those with low adherence. Adherent participants had a mean (standard error) BMD change at TDF/FTC discontinuation of -1.02% (0.24) in the hip and -1.84% (0.36) in the spine. After stop, annualized BMD increases of 1.13% per year (0.27) in hip and 1.81% per year (0.36) in spine BMD were observed in adherent participants compared with 0.19% (0.16) and 0.74% (0.21) in the placebo group, respectively (P = 0.003, both comparisons). On average, BMD returned to baseline levels by 1 year after PrEP stop. Recovery was consistent across age, baseline BMD z-score, and treatment duration.

CONCLUSIONS

Mean BMD returns to baseline levels within 12-18 months after TDF-based PrEP discontinuation in both hip and spine with consistency across participant subgroups.

CLINICAL TRIALS REGISTRATION

clinicaltrials.gov NCT00458393.

A Review of HIV Pre-Exposure Prophylaxis: The Female Perspective

When taken consistently, pre-exposure prophylaxis (PrEP) against human immunodeficiency virus (HIV) with once daily tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) has been shown to safely reduce the incidence of HIV infection in high-risk individuals by more than 90%. Yet, according to the Centers for Disease Control and Prevention, there were about 2.1 million new cases of HIV reported worldwide in 2015. Undoubtedly, there is significant room for improvement to prevent the transmission of HIV. Research to date has been heavily focused on the high-risk men who have sex with men (MSM) population, yet, many women worldwide remain at high risk of HIV transmission. PrEP offers women a protection method that is discrete, does not require partner consent, and may be compatible with both contraception or conception as desired. However, women often remain under-represented in HIV prevention literature and are reported to have lower real-world uptake in comparison to men. Furthermore, clinical trials that do focus on the female population demonstrate mixed efficacy results that highlight the adherence challenges in this population. It is essential to identify factors that contribute to PrEP non-adherence as well as barriers to preventative treatment. This review will discuss the clinical evidence behind PrEP in women, current barriers to use afflicting this population, pharmacotherapy considerations for the female patient, alternative and future agents, and the current real-world application of PrEP.

HIV preexposure prophylaxis for adolescents and young adults

PURPOSE OF REVIEW

The review describes the evidence for HIV preexposure prophylaxis (PrEP) with daily combined tenofovir disoproxil fumarate and emtricitabine for adolescents and young adults. Current recommendations are described, as are the unique medical, socioeconomic, and legal considerations regarding the use of PrEP for youth.

RECENT FINDINGS

PrEP with daily oral tenofovir disoproxil fumarate-emtricitabine has been shown to help prevent new HIV infection among adults at substantial risk. Evidence suggests a protective benefit of PrEP for youth at risk for HIV, although low adherence is emerging as a barrier to effective use.

SUMMARY

Effective use of antiretrovirals for PrEP represents a seminal development in HIV prevention efforts. Improving access and adherence to PrEP for youth has the potential to substantially reduce the incidence of HIV in this population.

An HIV Preexposure Prophylaxis Demonstration Project and Safety Study for Young MSM

BACKGROUND

Young men who have sex with men (YMSM) are a key population for implementation of preexposure prophylaxis (PrEP) interventions. This open-label study examined adherence to PrEP and assessed sexual behavior among a diverse sample of YMSM in 12 US cities.

METHODS

Eligible participants were 18- to 22-year-old HIV-uninfected MSM who reported HIV transmission risk behavior in the previous 6 months. Participants were provided daily tenofovir disoproxil fumarate/emtricitabine (Truvada). Study visits occurred at baseline, monthly through week 12, and then quarterly through week 48. Dried blood spots were serially collected for the quantification of tenofovir diphosphate (TFV-DP).

RESULTS

Between March and September 2013, 2186 individuals were approached and 400 were found to be preliminarily eligible. Of those 400, 277 were scheduled for an in-person screening visit and 200 were enrolled (mean age = 20.2; 54.5% black, 26.5% Latino). Diagnosis of sexually transmitted infections, including urethral and rectal chlamydial/gonococcal infection and syphilis, at baseline was 22% and remained high across visits. At week 4, 56% of participants had TFV-DP levels consistent with ≥4 pills per week. By week 48, 34% of participants had TFV-DP levels consistent with ≥4 pills per week, with a noticeable drop-off occurring at week 24. Four HIV seroconversions occurred on study (3.29/100 person-years). Condomless sex was reported by >80% of participants, and condomless anal sex with last partner was associated with higher TFV-DP levels.

CONCLUSIONS

Acceptability of PrEP was high, and most participants achieved protective drug levels during monthly visits. As visit frequency decreased, so did adherence. YMSM in the United States may need PrEP access in youth-friendly settings with tailored adherence support and potentially augmented visit schedules.

Bone Age and Mineral Density Assessments Using Plain Roentgenograms in Tenofovir-exposed Infants in Malawi and Brazil Enrolled in HIV Prevention Trials Network 057

BACKGROUND

Tenofovir disoproxil fumarate (TDF) use during pregnancy has been increasing, and studies linking bone toxicity with exposure to TDF have raised concern for its use in infants.

METHODS

Hand/wrist and spine radiographs were obtained at 3 days and 12 weeks of age in infants born to HIV-infected pregnant women enrolled in the HIV Prevention Trials Network 057 pharmacokinetic study of TDF conducted in Malawi and Brazil assigned to 3 TDF dosing cohorts. In cohort 1, mothers received 600 mg of TDF during labor. In cohort 2, infants received 4 mg/kg dose on days 0, 3 and 5. In cohort 3, a 900 mg maternal dose was given during labor, followed by a 6 mg/kg infant dose on days 0, 3 and 5 of life.

RESULTS

Across all 3 cohorts, 89 infants had radiographs performed at either time point, and 85 had radiographs performed at both time points. Metaphyseal lucency was present in 1 case in Brazil and 2 in Malawi. Fifteen percent of infants from Brazil and 9% of infants from Malawi presented bone age discrepancies. No other abnormalities were identified in Brazil, whereas in Malawi, there were 7 more cases of wrist osteopenia, 2 of spine osteopenia and 3 other abnormalities.

CONCLUSION

Bone abnormalities were not uncommon in the overall cohort of HIV-exposed infants. Because of very limited study drug exposure at the time of birth, it is unlikely that TDF was associated with these findings. Untreated maternal HIV disease and/or maternal nutritional status could potentially be related to fetal bone development. This association should be explored in future cohort studies.

Pre-Exposure Prophylaxis: A Narrative Review of Provider Behavior and Interventions to Increase PrEP Implementation in Primary Care

Since FDA approval of HIV pre-exposure prophylaxis (PrEP) for HIV prevention, attention has been focused on PrEP implementation. The CDC estimates that 1.2 million U.S. adults might benefit from PrEP, but only a minority are using PrEP, so there is a significant unmet need to increase access for those at risk for HIV. Given the large numbers of individuals who have indications for PrEP, there are not enough practicing specialists to meet the growing need for providers trained in providing PrEP. Moreover, since PrEP is a preventive intervention for otherwise healthy individuals, primary care providers (PCPs) should be primary prescribers of PrEP. There are important clinical considerations that providers should take into account when planning to prescribe PrEP, which are highlighted in the clinical case discussed. A growing body of research also suggests that some providers may be cautious about prescribing PrEP because of concerns regarding its "real-world" effectiveness, anticipated unintended consequences associated with its use, and ambiguity as to who should prescribe it. This review summarizes findings from studies that have assessed prescriber behavior regarding provision of PrEP, and offers recommendations on how to optimize PrEP implementation in primary care settings. Development and dissemination of educational interventions for PCPs and potential PrEP users are needed, including improved methods to assist clinicians in identifying appropriate PrEP candidates, and programs to promote medication adherence and access to social and behavioral health services. PCPs are well-positioned to prescribe PrEP and coordinate health-related services to improve the sexual health of their patients, but tailored educational programs are needed.

Bone health in HIV and hepatitis B or C infections

Chronic infections with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV) add to age-dependent bone loss and may contribute to lower bone strength in the elderly. In this review, we report recent highlights on the epidemiology of bone fragility in chronic viral infections with HIV, HCV and HBV, its physiopathology and discuss the interference of antiviral therapies with bone metabolism. Chronic infections influence bone through the interactions between risk factors for bone fragility and falls (which are highly prevalent in infected patients), virus activity and antiviral drugs. HIV-infected patients are at increased risk of fracture and the risk is higher in cases of co-infection with HIV and untreated chronic viral hepatitis. In HIV patients, the majority of bone loss occurs during virus activity and at initiation of antiretroviral therapy (ART). However, long-term elderly HIV-infected patients on successful ART display bone microstructure alterations only partially captured by dual energy X-ray absorptiometry (DXA). Bone loss is associated with an increase of bone resorption, reflecting the upregulation of the receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) pathways via a crosstalk between virus activity, inflammation and the immune system. The use of some antiviral drugs, such as tenofovir (controlling both HBV and HIV infections) or protease inhibitors, may be associated with higher bone toxicity. The reduction of tenofovir plasma concentrations with the implementation of tenofovir alafenamide (TAF) attenuates bone mineral density (BMD) loss but it remains unknown whether it will contribute to reducing fracture risk in long-term HIV-treated patients. Moreover, to what extent the new direct-acting agents for treatment of HCV, including nucleotide inhibitors and protease inhibitors, may affect bone health similarly as ART in HIV should be investigated.

Successful Implementation of HIV Preexposure Prophylaxis: Lessons Learned From Three Clinical Settings

The past 3 years have marked a transition from research establishing the safety and efficacy of HIV preexposure prophylaxis (PrEP) to questions about how to optimize its implementation. Until recently, PrEP was primarily offered as part of randomized controlled trials or open-label studies. These studies highlighted the key components of PrEP delivery, including regular testing for HIV and other sexually transmitted infections (STIs), adherence and risk-reduction support, and monitoring for renal toxicity. PrEP is now increasingly provided in routine clinical settings. This review summarizes models for PrEP implementation from screening through initiation and follow-up, focusing on the strengths and weaknesses of three delivery systems: a health maintenance organization, an STI clinic, and a primary care practice. These early implementation experiences demonstrate that PrEP can be successfully delivered across a variety of settings and highlight strategies to streamline PrEP delivery in clinical practice.

HIV and Bone Complications: Understudied Populations and New Management Strategies

The higher risk of osteoporosis and fracture associated with HIV infection and certain antiretrovirals has been well established and the need for risk stratification among older adults increasingly recognized. This review focuses upon emerging data on bone complications with HIV/HCV coinfection, in children and adolescents, and with pre-exposure prophylaxis (PrEP), as well as new management strategies to minimize the negative effects of ART on bone.

Osteoporosis in postmenopausal women living with HIV

The widespread availability of effective antiretroviral therapy (ART) has transformed HIV from a life-limiting condition to one with near-normal life expectancy. HIV is associated with an increased risk of osteopenia and osteoporosis, with people living with HIV (PLHIV) potentially experiencing these conditions at a younger age than their HIV-negative counterparts. The mechanisms driving bone disease in HIV are complex and include: an increased prevalence of traditional risk factors; other comorbid conditions; and HIV-associated factors such as viral effects, systemic inflammation, and ART-related factors. One-third of PLHIV in the United Kingdom are female, and increasing numbers of women living with HIV (WLHIV) are reaching menopausal age. Oestrogen decline in the context of an elevated background risk of poor bone health results in WLHIV being at greater risk of osteoporosis than women without HIV. European HIV guidelines therefore recommend routine screening of postmenopausal WLHIV using FRAX^© for clinical risk factors, with or without bone mineral density scanning. Data support the use of calcium and vitamin D supplementation, and bisphosphonates in the treatment of osteoporosis in PLHIV. Additionally, some patients with confirmed osteoporosis may benefit from a switch to an ART agent with a better bone safety profile. However, there remains a notable paucity of data on HIV and menopause, including the impact of hormone replacement therapy on the bone health of WLHIV. In conclusion, it is important that clinicians are aware that postmenopausal WLHIV are a group at particular risk of bone disease, who require proactive screening and advice about preventative measures.

Effectiveness and safety of oral HIV preexposure prophylaxis for all populations

OBJECTIVE

Preexposure prophylaxis (PrEP) offers a promising new approach to HIV prevention. This systematic review and meta-analysis evaluated the evidence for use of oral PrEP containing tenofovir disoproxil fumarate as an additional HIV prevention strategy in populations at substantial risk for HIV based on HIV acquisition, adverse events, drug resistance, sexual behavior, and reproductive health outcomes.

DESIGN

Rigorous systematic review and meta-analysis.

METHODS

A comprehensive search strategy reviewed three electronic databases and conference abstracts through April 2015. Pooled effect estimates were calculated using random-effects meta-analysis.

RESULTS

Eighteen studies were included, comprising data from 39 articles and six conference abstracts. Across populations and PrEP regimens, PrEP significantly reduced the risk of HIV acquisition compared with placebo. Trials with PrEP use more than 70% demonstrated the highest PrEP effectiveness (risk ratio = 0.30, 95% confidence interval: 0.21-0.45, P < 0.001) compared with placebo. Trials with low PrEP use did not show a significantly protective effect. Adverse events were similar between PrEP and placebo groups. More cases of drug-resistant HIV infection were found among PrEP users who initiated PrEP while acutely HIV-infected, but incidence of acquiring drug-resistant HIV during PrEP use was low. Studies consistently found no association between PrEP use and changes in sexual risk behavior. PrEP was not associated with increased pregnancy-related adverse events or hormonal contraception effectiveness.

CONCLUSION

PrEP is protective against HIV infection across populations, presents few significant safety risks, and there is no evidence of behavioral risk compensation. The effective and cost-effective use of PrEP will require development of best practices for fostering uptake and adherence among people at substantial HIV risk.

Drug safety evaluation of oral tenofovir disoproxil fumarate-emtricitabine for pre-exposure prophylaxis for human immunodeficiency virus infection

INTRODUCTION

Tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) are nucleoside reverse transcriptase inhibitors approved as pre-exposure prophylaxis (PrEP) against human immunodeficiency virus (HIV). Prophylactic TDF-based regimens have been shown to reduce the risk of HIV infection by 74 to 92% among participants with detectable drug levels. Adverse events observed in clinical trials include nausea, elevated creatinine and liver enzymes, and decreased bone mineral density.

AREAS COVERED

This article reviews the pharmacology, pharmacokinetics, and the safety profile of TDF and FTC used as PrEP for HIV infection.

EXPERT OPINION

TDF-FTC can have a large impact in preventing HIV infections among high risk individuals when taken daily. Although TDF-FTC is associated with adverse events, they can be minimized with clinician-guided monitoring.

Antiretroviral Drugs for Treatment and Prevention of HIV Infection in Adults: 2016 Recommendations of the International Antiviral Society-USA Panel

IMPORTANCE

New data and therapeutic options warrant updated recommendations for the use of antiretroviral drugs (ARVs) to treat or to prevent HIV infection in adults.

OBJECTIVE

To provide updated recommendations for the use of antiretroviral therapy in adults (aged ≥18 years) with established HIV infection, including when to start treatment, initial regimens, and changing regimens, along with recommendations for using ARVs for preventing HIV among those at risk, including preexposure and postexposure prophylaxis.

EVIDENCE REVIEW

A panel of experts in HIV research and patient care convened by the International Antiviral Society-USA reviewed data published in peer-reviewed journals, presented by regulatory agencies, or presented as conference abstracts at peer-reviewed scientific conferences since the 2014 report, for new data or evidence that would change previous recommendations or their ratings. Comprehensive literature searches were conducted in the PubMed and EMBASE databases through April 2016. Recommendations were by consensus, and each recommendation was rated by strength and quality of the evidence.

FINDINGS

Newer data support the widely accepted recommendation that antiretroviral therapy should be started in all individuals with HIV infection with detectable viremia regardless of CD4 cell count. Recommended optimal initial regimens for most patients are 2 nucleoside reverse transcriptase inhibitors (NRTIs) plus an integrase strand transfer inhibitor (InSTI). Other effective regimens include nonnucleoside reverse transcriptase inhibitors or boosted protease inhibitors with 2 NRTIs. Recommendations for special populations and in the settings of opportunistic infections and concomitant conditions are provided. Reasons for switching therapy include convenience, tolerability, simplification, anticipation of potential new drug interactions, pregnancy or plans for pregnancy, elimination of food restrictions, virologic failure, or drug toxicities. Laboratory assessments are recommended before treatment, and monitoring during treatment is recommended to assess response, adverse effects, and adherence. Approaches are recommended to improve linkage to and retention in care are provided. Daily tenofovir disoproxil fumarate/emtricitabine is recommended for use as preexposure prophylaxis to prevent HIV infection in persons at high risk. When indicated, postexposure prophylaxis should be started as soon as possible after exposure.

CONCLUSIONS AND RELEVANCE

Antiretroviral agents remain the cornerstone of HIV treatment and prevention. All HIV-infected individuals with detectable plasma virus should receive treatment with recommended initial regimens consisting of an InSTI plus 2 NRTIs. Preexposure prophylaxis should be considered as part of an HIV prevention strategy for at-risk individuals. When used effectively, currently available ARVs can sustain HIV suppression and can prevent new HIV infection. With these treatment regimens, survival rates among HIV-infected adults who are retained in care can approach those of uninfected adults.

Correlates of PrEP Indication in a Multi-Site Cohort of Young HIV-Uninfected Transgender Women

Transgender women are at high risk of HIV infection, with younger transgender women (YTW) particularly vulnerable. Pre-Exposure Prophylaxis (PrEP) has shown efficacy in reducing HIV acquisition, but little is known about PrEP indication or initiation among YTW. Baseline data from 180 YTW age 18-29 years enrolled in Project LifeSkills, an on-going HIV prevention intervention for YTW, were analyzed to examine factors associated with PrEP indication. The sample (mean age = 23.4, SD = 3.2) was comprised largely of women of color (69 %) and of low socioeconomic status (71 % unemployed). Overall, 62 % met criteria for PrEP indication, but only 5 % reported ever taking PrEP. Factors associated with increased odds of PrEP indication were: PrEP interest (aOR 3.24; 95 % CI 1.44, 7.33), number of recent anal sex partners (aOR 1.23; 95 % CI 1.04, 1.46), and lower collective self-esteem scores (aOR 0.67; 95 % CI 0.47, 0.94). Despite high levels of PrEP indication, there remain low levels of PrEP awareness and uptake among YTW.

Correlates of PrEP Indication in a Multi-Site Cohort of Young HIV-Uninfected Transgender Women

Transgender women are at high risk of HIV infection, with younger transgender women (YTW) particularly vulnerable. Pre-Exposure Prophylaxis (PrEP) has shown efficacy in reducing HIV acquisition, but little is known about PrEP indication or initiation among YTW. Baseline data from 180 YTW age 18-29 years enrolled in Project LifeSkills, an on-going HIV prevention intervention for YTW, were analyzed to examine factors associated with PrEP indication. The sample (mean age = 23.4, SD = 3.2) was comprised largely of women of color (69 %) and of low socioeconomic status (71 % unemployed). Overall, 62 % met criteria for PrEP indication, but only 5 % reported ever taking PrEP. Factors associated with increased odds of PrEP indication were: PrEP interest (aOR 3.24; 95 % CI 1.44, 7.33), number of recent anal sex partners (aOR 1.23; 95 % CI 1.04, 1.46), and lower collective self-esteem scores (aOR 0.67; 95 % CI 0.47, 0.94). Despite high levels of PrEP indication, there remain low levels of PrEP awareness and uptake among YTW.

The Safety of Tenofovir-Emtricitabine for HIV Pre-Exposure Prophylaxis (PrEP) in Individuals With Active Hepatitis B

Background:

Pre-exposure prophylaxis (PrEP) with daily oral emtricitabine and tenofovir disoproxil fumarate (FTC/TDF) prevents HIV infection. The safety and feasibility of HIV PrEP in the setting of hepatitis B virus (HBV) infection were evaluated.

Methods:

The Iniciativa Profilaxis Pre-Exposición study randomized 2499 HIV-negative men and transgender women who have sex with men to once-daily oral FTC/TDF versus placebo. Hepatitis serologies and transaminases were obtained at screening and at the time PrEP was discontinued. HBV DNA was assessed by polymerase chain reaction, and drug resistance was assessed by population sequencing. Vaccination was offered to individuals susceptible to HBV infection.

Results:

Of the 2499 participants, 12 (0.5%; including 6 randomized to FTC/TDF) had chronic HBV infection. After stopping FTC/TDF, 5 of the 6 participants in the active arm had liver function tests performed at follow-up. Liver function tests remained within normal limits at post-stop visits except for a grade 1 elevation in 1 participant at post-stop week 12 (alanine aminotransferase = 90, aspartate aminotransferase = 61). There was no evidence of hepatic flares. Polymerase chain reaction of stored samples showed that 2 participants in the active arm had evidence of acute HBV infection at enrollment. Both had evidence of grade 4 transaminase elevations with subsequent resolution. Overall, there was no evidence of TDF or FTC resistance among tested genotypes. Of 1633 eligible for vaccination, 1587 (97.2%) received at least 1 vaccine; 1383 (84.7%) completed the series.

Conclusions:

PrEP can be safely provided to individuals with HBV infection if there is no evidence of cirrhosis or substantial transaminase elevation. HBV vaccination rates at screening were low globally, despite recommendations for its use, yet uptake and efficacy were high when offered.

Bone Mineral Density Changes Among Young, Healthy African Women Receiving Oral Tenofovir for HIV Preexposure Prophylaxis

BACKGROUND

Limited data exist on effect of tenofovir disoproxil fumarate (TDF) when used for preexposure prophylaxis (PrEP) on bone mineral density (BMD) in HIV-negative women. We evaluated the effect of daily oral TDF and emtricitabine/TDF compared with placebo on BMD among women enrolled in an HIV-1 PrEP trial.

METHODS

HIV-uninfected women in Uganda and Zimbabwe had BMD measurements of lumbar spine (LS) and total hip (TH) by dual-energy x-ray absorptiometry at baseline and every 24 weeks for 48 weeks of active treatment and for 48 weeks after discontinuation of study medication. Plasma tenofovir levels were assessed every 12 weeks for the first 48 weeks.

RESULTS

Of 518 women enrolled, 432 had dual-energy x-ray absorptiometry results at baseline and week 48. In the primary analysis, no significant differences in percent BMD change in hip or spine between arms observed, likely because of low product adherence. Among the subset with tenofovir detection in 75%-100% of plasma samples, the mean percent BMD change from baseline to week 48 in the LS was 1.4% lower for TDF or emtricitabine/TDF recipients than for placebo (P = 0.002) and TH BMD was 0.9% lower (P = 0.018). BMD changes from end of active treatment to 48 weeks were significantly greater in the active arm participants compared with placebo participants with a net difference of approximately +0.9% at the LS (P = 0.007) and +0.7% (P = 0.003) at the TH.

CONCLUSIONS

TDF-containing oral PrEP resulted in small but significant reversible decreases in hip and spine BMD among young African women.

Bone mineral density decline according to renal tubular dysfunction and phosphaturia in tenofovir-exposed HIV-infected patients

INTRODUCTION

The mechanisms underlying the effect of tenofovir disoproxil fumarate (TDF) on the decline of bone mineral density (BMD) have not been established, especially the effect of renal tubular dysfunction.

METHODS

Longitudinal study of 90 patients with two successive dual X-ray absorptiometry scans after evaluation of serum and urinary parameters (proteinuria, albuminuria, phosphaturia, uricosuria, glycosuria, β-2-microglobulin, and retinol-binding protein).

RESULTS

After a median of 38 months on TDF, osteopenia at spine and hip was observed in 49 and 48%, and osteoporosis in 9 and 2%, respectively. There was a lineal correlation between BMD at femoral neck and time on TDF (Spearman's rho = -0.27; P = 0.01). One or more tubular abnormalities were observed in 80% of cases (hyperphosphaturia, 50%). A lower BMD correlated with phosphaturia (r = -0.25; P = 0.03), even with phosphataemia within normal limits. In fact, patients with previous improvement in phosphaturia had better BMD at inclusion (Spearman's rho = -0.33; P < 0.01). A second dual X-ray absorptiometry, after a median of 40.8 months (33.8-45.1; 627.7 patients-year on TDF), showed additional BMD reduction at hip in 50% of cases (36% with bone loss >3%), a decline associated with phosphaturia (β, -0.31; P = 0.01) or number of tubular abnormalities (β, -0.41; P = 0.01), but also with use of boosted protease inhibitors (β, -0.47; P = 0.03) and BMD at inclusion (β, -0.33; P = 0.03).

CONCLUSION

Chronic abnormal phosphaturia explains, at least in part, progressive bone loss during TDF therapy. These data suggest that tubular dysfunction leads to an altered equilibrium between phosphataemia, phosphaturia, and bone as mechanism of progressive BMD decline.

[Impact of long-term highly active antiretroviral therapy on bone metabolism in AIDS patients]

OBJECTIVE

To evaluate the influence of long-term highly active antiretroviral therapy (HAART) on bone metabolism in patients with acquired immune deficiency syndrome (AIDS).

METHODS

A total of 82 AIDS patients who received HAART in the First Affiliated Hospital of Zhejiang University Medical School during January 2012 and May 2016 were enrolled in the study. Patients were divided into TDF group (n=41) and AZT group (n=41), and glomerular filtration rate (GFR), serum calcium, serum phosphate and serum ALP levels in 6, 12, 18, 24 and 30-month during the treatment were analyzed in both groups.

RESULTS

Both TDF-based and AZT-based therapies significantly improved CD4(+) T-cell levels of the patients, and no significant difference was observed between the groups. Compared with the baseline, GFR [(120.71±62.85) vs(110.08±39.18) mL/min] and serum phosphate [(1.25±0.19) vs(1.22±0.21) mmol/L] levels rose after 6-month treatment in TDF group, but the difference was not statistically significant (P>0.05); Serum ALP [99.0(79.5-124.0) U/L vs 80.0(60.5-96.0) U/L] and serum calcium [(2.32±0.12) vs(2.25±0.17) mmol/L] levels rose significantly (P<0.05). As treatment continued, the levels of GFR, serum calcium and serum phosphate declined, while the serum ALP number was still increasing. After 30 months of HAART, the level of serum calcium [(2.16±0.15) vs(2.25±0.17) mmol/L], serum phosphate [(1.06±0.17) vs(1.22±0.21) mmol/L], GFR [(98.13±30.43) vs (110.08±39.18) mL/min] declined significantly (P<0.05) in TDF group, while serum ALP [110.0(98.5-120.5) U/L vs 80.0(60.5-96.0) U/L, P<0.05] increased. In AZT group, serum calcium and serum ALP levels rose and GFR level was declined (P<0.05), while serum phosphate level was not significantly changed during the treatment (P>0.05). Compared with AZT group, there were greater changes on the levels of GFR, serum calcium, serum phosphate and serum ALP in TDF group.

CONCLUSION

HAART is effective for patients with AIDS, and TDF-based therapy may have significant impact on bone metabolism of the patients, which needs close monitoring and timely intervention or adjustment if necessary.

Southern African guidelines on the safe use of pre-exposure prophylaxis in persons at risk of acquiring HIV-1 infection

The Southern African HIV Clinicians Society published its first set of oral pre-exposure prophylaxis (PrEP) guidelines in June 2012 for men who have sex with men (MSM) who are at risk of HIV infection. With the flurry of data that has been generated in PrEP clinical research since the first guideline, it became evident that there was a need to revise and expand the PrEP guidelines with new evidence of safety and efficacy of PrEP in several populations, including MSM, transgender persons, heterosexual men and women, HIV-serodiscordant couples and people who inject drugs. This need is particularly relevant following the World Health Organization (WHO) Consolidated Treatment Guidelines released in September 2015. These guidelines advise that PrEP is a highly effective, safe, biomedical option for HIV prevention that can be incorporated with other combination prevention strategies in Southern Africa, given the high prevalence of HIV in the region. PrEP should be tailored to populations at highest risk of HIV acquisition, whilst further data from studies in the region accrue to guide optimal deployment to realise the greatest impact regionally. PrEP may be used intermittently during periods of perceived HIV acquisition risk, rather than continually and lifelong, as is the case with antiretroviral treatment. Recognition and accurate measurement of potential risk in individuals and populations also warrants discussion, but are not extensively covered in these guidelines.

Symptoms, Side Effects and Adherence in the iPrEx Open-Label Extension

BACKGROUND

Blinded clinical trials have reported a modest and transient "start-up syndrome" with initiation of tenofovir-based pre-exposure prophylaxis (PrEP). We evaluate this phenomenon and its effect on adherence in an open-label PrEP study.

METHODS

In the iPrEx open-label extension (OLE) study, an 18-month open-label, multi-site PrEP cohort taking daily oral co-formulated tenofovir/emtricitabine, we examined the prevalence and duration of PrEP-associated symptoms and their effect on adherence, assessed by drug levels in dried blood spots tested monthly for the first 3 months.

RESULTS

Symptom reports peaked within the first month, with 39% reporting potentially PrEP-related symptoms compared to 22% at baseline. Symptoms largely resolved to pre-PrEP levels by 3 months.Symptoms varied substantially in frequency by study site (range in 1-month symptoms: 11% to 70%). Nongastrointestinal (GI) symptoms were not associated with adherence (odds ratio [OR] = 1.2, 95% confidence interval [CI], .4-3.7); however, GI-associated symptoms in the first 4 weeks were inversely associated with adherence at 4 weeks (OR = 0.47, 95% CI, .23-.96). Reports of GI symptoms were associated with 7% (95% CI, 4%-11%) of suboptimal adherence in this cohort.

CONCLUSIONS

PrEP-associated symptoms in the open-label setting occur in a minority of users and largely resolve within 3 months. GI symptoms are associated with a modest reduction in PrEP adherence, but good adherence is possible even in the presence of frequent symptom reports.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.govNCT00458393.

Antiretrovirals for primary HIV prevention: the current status of pre- and post-exposure prophylaxis

In light of the 2 million HIV infections that occur globally each year, there is a need to optimize strategies that integrate biomedical and behavioral approaches to HIV prevention. Post-exposure prophylaxis (PEP) immediately after acute high-risk exposures and pre-exposure prophylaxis (PrEP) for those who engage in recurrent high-risk behaviors are promising bio-behavioral approaches to decreasing HIV transmission. Guidelines have recommended PEP for occupational and non-occupational exposures for over 15 years, but uptake of PEP has been limited, partly as a result of insufficient awareness of this intervention among persons at highest risk for acquiring HIV. However, since the publication of large randomized clinical trials demonstrating the efficacy of PrEP, and the dissemination of guidelines endorsing its use, there is a renewed focus on bio-behavioral prevention. Numerous studies have recently assessed the acceptability of bio-behavioral prevention programs among diverse populations or described experiences implementing these programs in "real-world" settings. As research and clinical data informing optimal utilization of PEP and PrEP are rapidly accumulating, this review provides a timely summary of recent progress in bio-behavioral prevention. By contextualizing the most noteworthy recent findings regarding PEP and PrEP, this review seeks to inform the successful implementation of these promising prevention approaches.

High Prevalence of Low Bone Mineral Density and Substantial Bone Loss over 4 Years Among HIV-Infected Persons in the Era of Modern Antiretroviral Therapy

HIV-infected persons are living longer on combination antiretroviral therapy (cART) but experiencing more comorbidities including low bone mineral density (BMD). Using data from the Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (SUN Study), we determined the prevalence of low BMD (T-score below one standard deviation of the reference mean) and compared it with matched controls from the National Health and Nutrition Examination Survey (NHANES). We also assessed 4-year longitudinal BMD changes among participants virologically suppressed on cART. Of 653 participants included in this analysis (77% male, 29% black, median age 41 years, median CD4(+) cell count 464 cells/mm(3), 89% with HIV RNA <400 copies/ml), 51% and 10% had baseline osteopenia and osteoporosis, respectively. Low BMD at the femoral neck was significantly more prevalent than for the NHANES controls (47% versus 29%, p<0.001). Lower body mass index, nonwhite race, longer tenofovir exposure, older age, being unemployed or retired, and lower apolipoprotein E were independently associated with baseline osteoporosis. Among 170 participants virologically suppressed on cART and with longitudinal BMD data, 31% experienced substantial bone loss (≥5% BMD decline from baseline) over 4 years. Female sex, current smoking, and longer stavudine use were more common among participants who had substantial bone loss, although these variables failed to reach statistical significance. Low BMD was highly prevalent among HIV-infected persons. One-third of participants experienced substantial bone loss despite cART, suggesting the need for monitoring and potential clinical interventions.

Safety of oral tenofovir disoproxil fumarate-based pre-exposure prophylaxis for HIV prevention

INTRODUCTION

Tenofovir disoproxil fumarate (TDF)-based pre-exposure prophylaxis is a novel HIV prevention strategy for individuals at increased sexual risk for HIV infection. For any biomedical prevention intervention, the bar for tolerating adverse effects in healthy persons is high compared to therapeutic interventions.

AREAS COVERED

We provide a concise summary of the clinical safety of TDF-based pre-exposure prophylaxis with focus on TDF-related effects on tolerability, kidney function, bone density, HIV resistance, sexual and reproductive health. The evidence base for this review is derived from a literature search of both randomized and observational studies evaluating efficacy and safety of TDF-based PrEP, TDF alone or in combination with emtricitabine, identified from PUBMED and EMBASE electronic databases, clinicaltrials.gov and major HIV conferences.

EXPERT OPINION

TDF-based pre-exposure prophylaxis is a potent intervention against HIV acquisition when taken which is generally safe and well tolerated. The risk of the small, non-progressive, and reversible decline in glomerular filtration rate and bone mineral density as well as the potential selection for drug resistance associated with PrEP are outweighed, at the population level and broadly for individuals, by PrEP's substantial reduction in the risk of HIV infection.

Bone Disease in HIV: Recommendations for Screening and Management in the Older Patient

Availability of potent antiretroviral therapy (ART) has resulted in markedly improved survival for people with human immunodeficiency virus (HIV) infection, as well as an aging HIV population. Increasing morbidity from age-related conditions has resulted in the need to understand the complex roles HIV and its treatment play in the pathogenesis of these conditions. Bone disease and fragility fractures are conditions that occur more frequently in HIV. It is therefore recommended that risk assessment for fragility fracture using the Fracture Risk Assessment Tool (FRAX(®)) algorithm, and low bone mass by dual energy X-ray absorptiometry (DXA) scan, be performed in all patients with HIV infection over the age of 50 years and in those with a history of fragility fracture, and should be repeated every 2-3 years. Because many HIV experts believe that HIV infection and its treatment is a secondary cause of osteoporosis, it should be included as such in the FRAX(®) assessment tool. Management of osteoporosis in HIV infection should follow the same guidelines as that in the general population. Attention to lifestyle factors, including vitamin D replacement, should be emphasized. Whether cessation of tenofovir- or protease inhibitor-based ART regimens should be considered prior to bisphosphonate treatment is currently unknown and should only occur in patients with active alternative ART regimens. The use of bisphosphonates has been shown to be safe and effective in HIV patients, and while there is limited data on second-line osteoporosis regimens, there is no reason to suggest they would not be effective in people with HIV.

Pre-exposure prophylaxis to prevent HIV infection: current status, future opportunities and challenges

As the global incidence of HIV exceeds 2 million new infections annually, effective interventions to decrease HIV transmission are needed. Randomized, placebo-controlled studies have demonstrated that daily oral antiretroviral pre-exposure prophylaxis (PrEP) with a fixed-dose combination tablet containing tenofovir disoproxil fumarate and emtricitabine can significantly reduce HIV incidence among diverse at-risk populations. In these studies, the efficacy of PrEP was correlated with levels of adherence. Official guidelines recommend provision of PrEP to people at greatest risk of HIV acquisition, and demonstration projects suggest that high levels of uptake and adherence are possible outside of controlled studies. However, several potential barriers to implementing PrEP remain. These challenges include low awareness and utilization of PrEP by at-risk individuals, uncertainty about adherence in 'real-world' settings, the majority of healthcare providers being untrained in PrEP provision, limited data about potential adverse effects from long-term use of tenofovir-emtricitabine, high costs of PrEP medications, and stigma associated with PrEP use and the behaviors that would warrant PrEP. Innovative pharmacologic chemoprophylactic approaches could provide solutions to some of these challenges. Less-than-daily oral dosing regimens and long-acting injectable medications could reduce pill burdens and facilitate adherence, and local delivery of PrEP medications to genital compartments via gels, rings and films may limit systemic drug exposure and potential toxicities. As the portfolio of chemoprophylactic agents and delivery systems expands to meet the diverse sexual health needs and product preferences of individuals who may benefit from PrEP, it is hoped that antiretroviral chemoprophylaxis could become an acceptable, feasible, and highly effective addition to existing HIV prevention strategies.

HIV pre-exposure prophylaxis (PrEP): a review of current knowledge of oral systemic HIV PrEP in humans

PURPOSE

Despite established HIV prevention strategies and broadly available diagnostic strategies in developed western countries, rates of HIV new infections remain high. Alternative strategies for HIV prevention, particularly among men who have sex with men (MSM), are crucial. HIV pre-exposure prophylaxis (PrEP) has been discussed as one additional option that this review seeks to explore.

METHODS

An online search identifying PrEP-relevant literature from 1st January 2010 to 1st August, 2015 was performed.

RESULTS

The iPrEx study, first published in 2010, demonstrated a reduction in relative risk (RRR) of HIV seroconversion of 44 % for continuous PrEP with tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) in MSM. The efficacy of PrEP has been confirmed for continuous PrEP in the PROUD study and for intermittent PrEP in the IPERGAY study (RRR = 86 % in both studies). The PrEP was well tolerated in all studies, and the evolution of HIV resistance has been low. Compensatory increased sexual risk behavior was not observed in recent studies. In contrast to the high efficacy of risk reduction for HIV transmission in MSM, the results of TDF PrEP and TDF/FTC PrEP studies using microbicidal agents or pills among heterosexual women were different (RRR 6-75 %).

CONCLUSIONS

Continuous and intermittent PrEP demonstrated high efficacy in preventing HIV seroconversion, notably among MSM. PrEP was well tolerated. Adherence was critical for high efficacy in all studies. Further studies to evaluate implementation strategies and cost-effectiveness in different risk populations are needed as well as drug approval in Europe.

Lower Newborn Bone Mineral Content Associated With Maternal Use of Tenofovir Disoproxil Fumarate During Pregnancy

BACKGROUND

Fetal bone effects of maternal tenofovir use have not been well studied. We sought to compare whole-body bone mineral content (BMC) of newborns exposed vs not exposed to tenofovir in utero.

METHODS

We enrolled participants from April 2011 to June 2013 at 14 US clinical sites. Singleton infants of women with human immunodeficiency virus (HIV) infection who took tenofovir in late pregnancy (tenofovir-exposed) or no tenofovir during pregnancy (tenofovir-unexposed) were enrolled during late pregnancy or within 72 hours of birth. Infants born before 36 weeks gestation or with confirmed HIV infection were excluded. Whole-body BMC was measured in the first month of life and compared with that of the tenofovir-exposed and tenofovir-unexposed newborns, unadjusted and adjusted for covariates.

RESULTS

Seventy-four tenofovir-exposed and 69 tenofovir-unexposed infants had evaluable BMC measurements. Tenofovir-exposed mothers were more likely to be married (31% vs 22%; P = .04) and to use boosted protease inhibitors (84% vs 62%; P = .004). Tenofovir-exposed newborns did not differ from unexposed newborns on mean gestational age (38.2 vs 38.1 weeks) or mean length (-0.41 vs -0.18) or weight (-0.71 vs -0.48) Z-scores. The mean (standard deviation) BMC of tenofovir-exposed infants was 12% lower than for unexposed infants (56.0 [11.8] vs 63.8 [16.6] g; P = .002). The adjusted mean bone mineral content was 5.3 g lower (95% confidence interval, -9.5, -1.2; P = .013) in the tenofovir-exposed infants.

CONCLUSIONS

Maternal tenofovir use is associated with significantly lower neonatal BMC. The duration and clinical significance of this finding should be evaluated in longitudinal studies.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov NCT01310023.

Role of oral pre-exposure prophylaxis (PrEP) in current and future HIV prevention strategies

Treatment as prevention is expected to have a major role in reducing HIV incidence, but other prevention interventions will also be required to bring the epidemic under control, particularly among key populations. One or more forms of pre-exposure prophylaxis (PrEP) will likely play a critical role. Oral PrEP with emtricitabine-tenofovir (Truvada®) is currently available in the US and some other countries, but uptake has been slow. We review the concerns that have contributed to this slow uptake and discuss current and future research in this critical area of HIV prevention research.

Meconium Tenofovir Concentrations and Growth and Bone Outcomes in Prenatally Tenofovir Exposed HIV-Uninfected Children

BACKGROUND

Maternal tenofovir disoproxil fumarate (TDF) treatment among HIV-infected pregnant women results in fetal tenofovir (TFV) exposure. Fetal TFV toxicity was demonstrated in animals, but most clinical investigations have not observed toxicity in humans.

METHODS

We evaluated HIV-exposed, uninfected infants in the Surveillance Monitoring for Antiretroviral Therapy Toxicities cohort of the Pediatric HIV/AIDS Cohort Study whose mothers were prescribed TDF for ≥ 8 third trimester weeks. Infant dual-energy X-ray absorptiometry scans were obtained at 0-4 weeks to measure whole body bone mineral content. Meconium TFV concentrations were quantified by liquid chromatography-tandem mass spectrometry.

RESULTS

Fifty-eight TFV-exposed infants had meconium TFV quantified. Detectable concentrations were 11-48,100 ng/g; 3 infants had undetectable concentrations. Maternal TDF prescription duration ranged from 8 to 41 gestational weeks; infant gestational ages were 36-41 weeks. Meconium TFV concentrations were not correlated with TFV exposure duration or timing and did not vary by concomitant prescription of protease inhibitors. Increased meconium TFV concentrations were associated with greater gestational ages (ρ = 0.29, P = 0.03) and lower maternal plasma HIV RNA before delivery (ρ = -0.29, P = 0.04). Meconium TFV concentrations were not associated with infant weight, length (n = 58) or bone mineral content (n = 49).

CONCLUSIONS

For the first time, we explored associations between meconium TFV concentrations and infant growth and bone measurements; we did not observe a meconium concentration-dependent relationship for these infant outcomes. These findings support other clinical research failing to show dose-response relationships for growth and bone outcomes among intrauterine TFV-exposed infants. High meconium TFV concentrations correlated with low maternal viral load, suggesting maternal TDF adherence significantly contributes to meconium TFV concentrations.

Low bone mineral density and risk of incident fracture in HIV-infected adults

BACKGROUND

Prevalence rates of low bone mineral density (BMD) and bone fractures are higher among HIV-infected adults compared with the general United States (US) population, but the relationship between BMD and incident fractures in HIV-infected persons has not been well described.

METHODS

Dual energy X-ray absorptiometry (DXA) results of the femoral neck of the hip and clinical data were obtained prospectively during 2004-2012 from participants in two HIV cohort studies. Low BMD was defined by a T-score in the interval >-2.5 to <-1.0 (osteopenia) or ≤-2.5 (osteoporosis). We analysed the association of low BMD with risk of subsequent incident fractures, adjusted for sociodemographics, other risk factors and covariables, using multivariable proportional hazards regression.

RESULTS

Among 1,006 participants analysed (median age 43 years [IQR 36-49], 83% male, 67% non-Hispanic white, median CD4(+) T-cell count 461 cells/mm(3) [IQR 311-658]), 36% (n=358) had osteopenia and 4% (n=37) osteoporosis; 67 had a prior fracture documented. During 4,068 person-years of observation after DXA scanning, 85 incident fractures occurred, predominantly rib/sternum (n=18), hand (n=14), foot (n=13) and wrist (n=11). In multivariable analyses, osteoporosis (adjusted hazard ratio [aHR] 4.02, 95% CI 2.02, 8.01) and current/prior tobacco use (aHR 1.59, 95% CI 1.02, 2.50) were associated with incident fracture.

CONCLUSIONS

In this large sample of HIV-infected adults in the US, low baseline BMD was significantly associated with elevated risk of incident fracture. There is potential value of DXA screening in this population.

Reduced bone mineral density among ART-naive male patients with HIV in China

Aims: To evaluate the prevalence and associated factors of reduced bone mineral density (BMD) among antiretroviral therapy (ART) naive HIV-infected male patients in China. Methods: We compared BMD between HIV-infected male patients and healthy controls. Risk factors of reduced BMD were studied using multivariable linear regression. Results: Reduced BMD rate of chronic HIV infection patients was higher. HIV infection was independently associated with decreased BMD after adjusting for demographic factors. Older age, lower BMI and men who have sex with men (MSM) were revealed as the risk factors of lower BMD in HIV-infected male patients. Conclusion: Reduced BMD rate of HIV-infected patients was high. Policies are needed for prevention and treatment.

Vitamin D and Calcium Attenuate Bone Loss With Antiretroviral Therapy Initiation: A Randomized Trial

BACKGROUND

Antiretroviral therapy initiation for HIV-1 infection is associated with 2% to 6% loss of bone mineral density (BMD).

OBJECTIVE

To evaluate the effect of vitamin D3 plus calcium supplementation on bone loss associated with antiretroviral therapy initiation.

DESIGN

48-week prospective, randomized, double-blind, placebo-controlled study. (ClinicalTrials.gov: NCT01403051).

SETTING

39 AIDS Clinical Trials Group units.

PATIENTS

Adults with antiretroviral therapy-naive HIV.

MEASUREMENTS

BMD by dual-energy x-ray absorptiometry, 25-hydroxyvitamin D levels, and other laboratory assessments.

RESULTS

165 eligible patients were randomly assigned (79 received vitamin D3 plus calcium and 86 received placebo). The study groups were well-balanced at baseline: 90% were men, 33% were non-Hispanic black, and the median CD4 count was 0.341 × 109 cells/L. At 48 weeks, the percentage of decline in total hip BMD was smaller in the vitamin D3 plus calcium group than in the placebo group: Medians were -1.36% (interquartile range [IQR], -3.43% to 0.50%) and -3.22% (IQR, -5.56% to -0.88%), respectively (P = 0.004). Similar results were seen at the lumbar spine. At 48 weeks, 90% of patients achieved HIV-1 RNA levels less than 50 copies/mL. Levels of 25-hydroxyvitamin D3 increased with vitamin D3 plus calcium but not with placebo: Median change was 61.2 nmol/L (IQR, 36.4 to 94.3) versus 1.7 nmol/L (IQR, -13.2 to 10.7) (P < 0.001). Overall, 103 patients (62%) reported 1 or more adverse event, with similar distribution between groups; no cases of hypercalcemia and 1 case of nephrolithiasis were reported in the placebo group.

LIMITATION

No international sites were included, and follow-up was only 48 weeks.

CONCLUSION

Vitamin D3 plus calcium supplementation mitigates the BMD loss seen with initiation of efavirenz/emtricitabine/tenofovir disoproxil fumarate.

Tenofovir: What We Have Learnt After 7.5 Million Person-Years of Use

Tenofovir was licensed for use in patients with HIV in 2001 and since then has become a firmly established anti-retroviral in both guidelines and routine practice. Data have been presented from many pivotal studies—informing on its efficacy, use, and adverse features—and there are also over 7.5 million patient-years of experience to date. We explore the data on this nucleotide reverse transcriptase inhibitor in HIV presented since 2008—focusing on efficacy, side effects, and utility.

Pre-exposure prophylaxis for sexually-acquired HIV risk management: a review

Despite significant efforts, the rate of new HIV infections worldwide remains unacceptably high, highlighting the need for new HIV prevention strategies. HIV pre-exposure prophylaxis (PrEP) is a new approach that involves the ongoing use of antiretroviral medications by HIV-negative individuals to reduce the risk of HIV infection. The use of daily tenofovir/emtricitabine as oral PrEP was found to be effective in multiple placebo-controlled clinical trials and approved by the United States Food and Drug Administration. In addition, the Centers for Disease Control and Prevention in the United States and the World Health Organization have both released guidelines recommending the offer of oral PrEP to high-risk populations. The scale-up of PrEP is underway, but several implementation questions remain unanswered. Demonstration projects and open-label extensions of placebo-controlled trials are ongoing and hope to contribute to our understanding of PrEP use and delivery outside the randomized controlled trial setting. Evidence is beginning to emerge from these open-label studies and will be critical for guiding PrEP scale-up. Outside of such studies, PrEP uptake has been slow and several client- and provider-related barriers are limiting uptake. Maximizing the public health impact of PrEP will require rollout to be combined with interventions to promote uptake, support adherence, and prevent increases in risk behavior. Additional PrEP strategies are currently under investigation in placebo-controlled clinical trials and may be available in the future.

Effects of Emtricitabine/Tenofovir on Bone Mineral Density in HIV-Negative Persons in a Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Daily preexposure prophylaxis (PrEP) with oral emtricitabine and tenofovir disoproxil fumarate (FTC/TDF) decreases the risk of human immunodeficiency virus (HIV) acquisition. Initiation of TDF decreases bone mineral density (BMD) in HIV-infected people. We report the effect of FTC/TDF on BMD in HIV-seronegative men who have sex with men and in transgender women.

METHODS

Dual-energy X-ray absorptiometry was performed at baseline and 24-week intervals in a substudy of iPrEx, a randomized, double-blind, placebo-controlled trial of FTC/TDF PrEP. Plasma and intracellular tenofovir concentrations were measured in participants randomized to FTC/TDF.

RESULTS

In 498 participants (247 FTC/TDF, 251 placebo), BMD in those randomized to FTC/TDF decreased modestly but statistically significantly by 24 weeks in the spine (net difference, -0.91% [95% confidence interval {CI}, -1.44% to -.38%]; P = .001) and hip (-0.61% [95% CI, -.96% to -.27%], P = .001). Changes within each subsequent 24-week interval were not statistically significant. Changes in BMD by week 24 correlated inversely with intracellular tenofovir diphosphate (TFV-DP), which was detected in 53% of those randomized to FTC/TDF. Net BMD loss by week 24 in participants with TFV-DP levels indicative of consistent dosing averaged -1.42% ± 29% and -0.85% ± 19% in the spine and hip, respectively (P < .001 vs placebo). Spine BMD tended to rebound following discontinuation of FTC/TDF. There were no differences in fractures (P = .62) or incidence of low BMD.

CONCLUSIONS

In HIV-uninfected persons, FTC/TDF PrEP was associated with small but statistically significant decreases in BMD by week 24 that inversely correlated with TFV-DP, with more stable BMD thereafter.

CLINICAL TRIALS REGISTRATION

NCT00458393.

HIV-related metabolic comorbidities in the current ART era

Despite effective antiretroviral therapy (ART), HIV-infected individuals have residual chronic immune activation that contributes to the pathogenesis of HIV infection. This immune system dysregulation is a pathogenic state manifested by very low naïve T-cell numbers and increased terminally differentiated effector cells that generate excessive proinflammatory cytokines with limited functionality. Immune exhaustion leaves an individual at risk for accelerated aging-related diseases, including renal dysfunction, atherosclerosis, diabetes mellitus, and osteoporosis. We highlight research that clarifies the role of HIV, ART, and other factors that contribute to the development of these diseases among HIV-infected persons.

Clinical Treatment Options Infectious Diseases: Update on PrEP Implementation, Adherence, and Advances in Delivery

Pre-exposure prophylaxis (PrEP) is an effective and evidence-based HIV-prevention option and is recommended for individuals with substantial risk for HIV infection [1]. Randomized controlled trials have demonstrated that daily oral PrEP dramatically reduces the risk of HIV infection when it is taken as directed. Concerns regarding widespread emergence of antiretroviral resistance attributable to PrEP and behavioral disinhibition have to date not been observed in clinical trials and open-label demonstration projects. PrEP has great potential as part of an HIV risk reduction strategy and barriers to wider implementation including community education, prescriber availability, and elimination of financial barriers should be aggressively pursued. Adherence is critical to PrEP efficacy and has varied across study populations; developing and refining ways of measuring and supporting adherence is essential to the success of PrEP. Evaluation of long-acting medications and alternative formulations for PrEP is underway and may lead to the wider implementation and impact of PrEP.

Long-term treatment with tenofovir in Asian-American chronic hepatitis B patients is associated with abnormal renal phosphate handling

BACKGROUND

Increased risk of defective urinary phosphate reabsorption and osteoporosis has been reported in HIV and chronic hepatitis B (CHB) patients treated with tenofovir disoproxil fumarate (TDF).

AIMS

Goals of this study were to evaluate the prevalence of renal phosphate wasting and abnormal bone mineral density in CHB patients taking TDF compared to CHB patients treated with entecavir (ETV) and untreated CHB patients.

METHODS

This is a cross-sectional study of 146 consecutive Asian-American CHB patients who were treatment naïve (n = 60) or treated with either TDF (n = 42) or ETV (n = 44). Proximal tubular handling of phosphate was assessed by the maximal rate of tubular reabsorption of phosphate (TmPO4) divided by glomerular filtration rate (GFR) (TmPO4/GFR). Bone mineral density (BMD) was measured using dual X-ray absorptiometry.

RESULTS

TmPO4/GFR was similar among CHB patients treated with TDF compared to untreated patients and patients taking ETV. However, among patients treated with ≥18 months of TDF or ETV, prevalence of abnormal TmPO4/GFR was higher among patients treated with TDF compared to ETV (48.5 % (16/33) vs. 12.5 % (3/24), p = 0.005). Overall prevalence of osteoporosis in this cohort of CHB patients was 14 %, with no significant difference between the three groups. Renal phosphate handling did not correlate with osteoporosis.

CONCLUSIONS

Chronic hepatitis B patients treated with ≥18 months of TDF experienced an increased risk of proximal tubular dysfunction. TDF did not increase the risk of osteoporosis. Longitudinal studies are needed to confirm these findings.

Skeletal health in adults with HIV infection

Concern has been raised that HIV infection, its treatment, or both adversely affect skeletal health. Cross-sectional studies show that bone mineral density (BMD) is 3-5% lower in patients infected with HIV than in uninfected controls, but patients with HIV infection are, on average, 5 kg lighter than uninfected people. After this weight difference is accounted for, BMD differences are smaller and not clinically relevant. Longitudinal studies show short-term BMD loss of 2-4% over 1-2 years when antiretroviral therapy is started, followed by longer periods of BMD increase or stability. Losses are greatest with treatment regimens that contain tenofovir. Patients infected with HIV have slightly higher fracture rates than controls, but the increased risk of fracture is substantially attenuated by adjustment for traditional risk factors for fracture. These reassuring findings suggest that management of skeletal health in HIV should follow guidelines for the general population. In general, effective antiretroviral treatment and avoidance of undernutrition are the two most important factors for maintenance of skeletal health in patients infected with HIV.

PrEP awareness and perceived barriers among single young men who have sex with men

Pre-exposure prophylaxis (PrEP) has the potential to help reduce new HIV infections among young men who have sex with men (YMSM). Using a cross-sectional survey of YMSM (N=1,507; ages 18-24), we gauged YMSM's PrEP awareness and PrEP-related beliefs regarding side effects, accessibility, and affordability. Overall, 27% of the sample had heard about PrEP; 1% reported ever using PrEP prior to sex. In a multivariate logistic regression, we found that YMSM were more likely to have heard about PrEP if they were older, more educated, were residentially unstable in the prior 30 days, had insurance, or reported having at least one sexually transmitted infection in their lifetime. We found no differences by race/ethnicity, history of incarceration, or recent sexual risk behavior. In multivariate linear regression models, Black and Latino YMSM were more likely than Whites to state they would not use PrEP because of side effect concerns. YMSM were more likely to indicate that they would not be able to afford PrEP if they did not have insurance or if they had a prior sexually transmitted infection, PrEP rollout may be hindered due to lack of awareness, as well as perceived barriers regarding its use. We propose strategies to maximize equity in PrEP awareness and access if it is to be scaled up among YMSM.

Low bone mineral density in patients with well-suppressed HIV infection: association with body weight, smoking, and prior advanced HIV disease

BACKGROUND

Human immunodeficiency virus (HIV) and combination antiretroviral therapy (cART) may both contribute to the higher prevalence of osteoporosis and osteopenia in HIV-infected individuals.

METHODS

Using dual-energy X-ray absorptiometry, we compared lumbar spine, total hip, and femoral neck bone mineral density (BMD) in 581 HIV-positive (94.7% receiving cART) and 520 HIV-negative participants of the AGEhIV Cohort Study, aged ≥45 years. We used multivariable linear regression to investigate independent associations between HIV, HIV disease characteristics, ART, and BMD.

RESULTS

The study population largely consisted of men who have sex with men (MSM). Osteoporosis was significantly more prevalent in those with HIV infection (13.3% vs 6.7%; P<.001). After adjustment for body weight and smoking, being HIV-positive was no longer independently associated with BMD. Low body weight was more strongly negatively associated with BMD in HIV-positive persons with a history of a Centers for Disease Control and Prevention class B or C event. Interestingly, regardless of HIV status, younger MSM had significantly lower BMD than older MSM, heterosexual men, and women.

CONCLUSIONS

The observed lower BMD in treated HIV-positive individuals was largely explained by both lower body weight and more smoking. Having experienced symptomatic HIV disease, often associated with weight loss, was another risk factor. The low BMD observed in younger MSM remains unexplained and needs further study.

Oral pre-exposure prophylaxis (PrEP) for prevention of HIV in serodiscordant heterosexual couples in the United States: opportunities and challenges

Oral HIV pre-exposure prophylaxis (PrEP) is a promising new biomedical prevention approach in which HIV-negative individuals are provided with daily oral antiretroviral medication for the primary prevention of HIV-1. Several clinical trials have demonstrated efficacy of oral PrEP for HIV prevention among groups at high risk for HIV, with adherence closely associated with level of risk reduction. In the United States (US), three groups have been prioritized for initial implementation of PrEP-injection drug users, men who have sex with men at substantial risk for HIV, and HIV-negative partners within serodiscordant heterosexual couples. Numerous demonstration projects involving PrEP implementation among MSM are underway, but relatively little research has been devoted to study PrEP implementation in HIV-serodiscordant heterosexual couples in the US. Such couples face a unique set of challenges to PrEP implementation at the individual, couple, and provider level with regard to PrEP uptake and maintenance, adherence, safety and toxicity, clinical monitoring, and sexual risk behavior. Oral PrEP also provides new opportunities for serodiscordant couples and healthcare providers for primary prevention and reproductive health. This article provides a review of the critical issues, challenges, and opportunities involved in the implementation of oral PrEP among HIV-serodiscordant heterosexual couples in the US.

Assessment of bone mineral density in tenofovir-treated patients with chronic hepatitis B: can the fracture risk assessment tool identify those at greatest risk?

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is an established nucleotide analogue in the treatment of chronic hepatitis B. Bone mineral density loss has been described in TDF-treated patients with human immunodeficiency virus infection, but limited data exist for patients with chronic hepatitis B. Dual X-ray absorptiometry (DEXA) was used to determine bone mineral density changes in TDF-exposed patients. We evaluated the accuracy of the Fracture Risk Assessment Tool (FRAX) as an alternative to DEXA in clinical practice.

METHODS

A total of 170 patients were studied: 122 were exposed to TDF, and 48 were controls. All patients underwent DEXA, and demographic details were recorded. FRAX scores (before and after DEXA) were calculated.

RESULTS

TDF was associated with a lower hip T score (P = .02). On univariate and multivariate analysis, advancing age, smoking, lower body mass index, and TDF exposure were independent predictors of low bone mineral density. In addition, the pre-DEXA FRAX score was an accurate predictor of the post-DEXA FRAX treatment recommendation (100% sensitivity and 83% specificity), area under the curve 0.93 (95% CI, .87-.97, P < .001).

CONCLUSIONS

TDF-treated patients with chronic hepatitis B have reduced bone mineral density, but the reduction is limited to 1 anatomical site. Age and advanced liver disease are additional contributing factors, underlining the importance of multifactorial fracture risk assessment. FRAX can accurately identify those at greatest risk of osteoporotic fracture.

An overview of antiretroviral pre-exposure prophylaxis of HIV infection

Despite improvements in access to antiretroviral therapy and the use of simplified dosing regimens, HIV infection is still an important global public health problem. As a consequence, significant research efforts have been focused on the development of strategies to prevent the acquisition of HIV infection. These efforts have begun to produce results. The HPTN-052 study demonstrated the effectiveness of treating infected individuals as a means to prevent onward transmission of HIV infection. In addition, Phase 2B/3 studies have shown that the use of oral and topical antiretroviral pre-exposure prophylaxis (PrEP) can significantly reduce the acquisition of HIV infection in serodiscordant couples, young women in sub-Saharan Africa, men who have sex with men, and intravenous drug users. Despite these successes, challenges remain. Adherence to daily PrEP is variable, and some large studies have failed to demonstrate the effectiveness of PrEP in reducing HIV acquisition. Novel PrEP technologies, including sustained delivery intravaginal rings and long-acting injectable products, are being developed to try and circumvent adherence problems associated with daily PrEP regimens. The purpose of this article is to briefly summarize recent progress in the development of antiretroviral PrEP.