Analysis of Pharmacovigilance Databases for Dolutegravir Safety in Pregnancy.

BACKGROUND: The Botswana Tsepamo study reported neural tube defects (NTDs) in 4 of 426 (0.94%) infants of women receiving preconception dolutegravir (DTG) antiretroviral therapy (ART) vs 14 of 11 300 (0.12%) receiving preconception non-DTG ART. Data are needed to investigate this potential safety signal. Clinicians, patients, and pharmaceutical companies can report adverse drug reactions (ADRs) to pharmacovigilance databases. Data from ADRs reported to various pharmacovigilance databases were searched for NTDs. METHODS: Four pharmacovigilance databases (World Health Organization [WHO] VigiAccess; United Kingdom Medicines Health Regulatory Authority [UK MHRA]; European Medicines Agency [EMA] EudraVigilance; US Food and Drug Administration Adverse Event Reporting System [FAERS]) with online data availability were analyzed for NTD reports for 4 integrase inhibitors (DTG, raltegravir, elvitegravir, bictegravir), 2 protease inhibitors (darunavir, atazanavir), and 2 nonnucleoside reverse transcriptase inhibitors (nevirapine, efavirenz). Reports in the system organ class "congenital or familial disorders" were searched for NTDs. RESULTS: NTDs have been reported among infants born from women taking a wide range of antiretrovirals in 4 pharmacovigilance databases (WHO VigiAccess, 116 reactions; UK MHRA, 8 cases; EMA EudraVigilance, 20 cases; FAERS, 44 cases). Six NTDs were identified for DTG across the pharmacovigilance databases. Cases were very hard to interpret, given the lack of clear denominators. CONCLUSIONS: Pharmacovigilance databases have many limitations, most importantly lack of a clear denominator for patients exposed to the drug of interest and duplicate cases that are difficult to identify. Given widespread use of new antiretroviral drugs worldwide and anticipated use of new drugs, prospective follow-up of pregnant women and birth surveillance studies such as Tsepamo are critically needed.

Immediate Versus Deferred Switching From a Boosted Protease Inhibitor-based Regimen to a Dolutegravir-based Regimen in Virologically Suppressed Patients With High Cardiovascular Risk or Age ≥50 Years: Final 96-Week Results of the NEAT022 Study.

Background: Both immediate and deferred switching from a ritonavir-boosted protease inhibitor (PI/r)-based regimen to a dolutegravir (DTG)-based regimen may improve lipid profile. Methods: European Network for AIDS Treatment 022 Study (NEAT022) is a European, open-label, randomized trial. Human immunodeficiency virus (HIV)-infected adults aged ≥50 years or with a Framingham score ≥10% were eligible if HIV RNA was <50 copies/mL. Patients were randomized to switch from PI/r to DTG immediately (DTG-I) or to deferred switch at week 48 (DTG-D). Week 96 endpoints were proportion of patients with HIV RNA <50 copies/mL, percentage change of lipid fractions, and adverse events (AEs). Results: Four hundred fifteen patients were randomized: 205 to DTG-I and 210 DTG-D. The primary objective of noninferiority at week 48 was met. At week 96, treatment success rate was 92.2% in the DTG-I arm and 87% in the DTG-D arm (difference, 5.2% [95% confidence interval, -.6% to 11%]). There were 5 virological failures in the DTG-I arm and 5 (1 while on PI/r and 4 after switching to DTG) in the DTG-D arm without selection of resistance mutations. There was no significant difference in terms of grade 3 or 4 AEs or treatment-modifying AEs. Total cholesterol and other lipid fractions (except high-density lipoprotein) significantly (P < .001) improved both after immediate and deferred switching to DTG overall and regardless of baseline PI/r strata. Conclusions: Both immediate and deferred switching from a PI/r to a DTG regimen in virologically suppressed HIV-infected patients ≥50 years old or with a Framingham score ≥10% was highly efficacious and well tolerated, and improved the lipid profile. Clinical Trials Registration: NCT02098837 and EudraCT: 2013-003704-39.

Latent tuberculosis infection screening and treatment in HIV: insights from evaluation of UK practice.

Latent TB infection (LTBI) screening and treatment in HIV-positive individuals in the UK is advocated by the British HIV Association (BHIVA) and National Institute for Health and Care Excellence (NICE), although each recommends differing strategies. We undertook an evaluation of UK practice, relating the responses to the local HIV/TB disease burden. 162 of 188 (86%) UK geographical areas responded; only 93/162 (57.4%) offer LTBI testing with considerable heterogeneity in practice, and no difference in HIV/TB burden between areas offering testing and those who do not. Only 33/93 (35.5%) and 6/93 (6.5%) reported full compliance with BHIVA and NICE guidance respectively. A uniform national guideline is required.

HIV-1 drug resistance mutations emerging on darunavir therapy in PI-naive and -experienced patients in the UK.

BACKGROUND: Darunavir is considered to have a high genetic barrier to resistance. Most darunavir-associated drug resistance mutations (DRMs) have been identified through correlation of baseline genotype with virological response in clinical trials. However, there is little information on DRMs that are directly selected by darunavir in clinical settings. OBJECTIVES: We examined darunavir DRMs emerging in clinical practice in the UK. PATIENTS AND METHODS: Baseline and post-exposure protease genotypes were compared for individuals in the UK Collaborative HIV Cohort Study who had received darunavir; analyses were stratified for PI history. A selection analysis was used to compare the evolution of subtype B proteases in darunavir recipients and matched PI-naive controls. RESULTS: Of 6918 people who had received darunavir, 386 had resistance tests pre- and post-exposure. Overall, 2.8% (11/386) of these participants developed emergent darunavir DRMs. The prevalence of baseline DRMs was 1.0% (2/198) among PI-naive participants and 13.8% (26/188) among PI-experienced participants. Emergent DRMs developed in 2.0% of the PI-naive group (4 mutations) and 3.7% of the PI-experienced group (12 mutations). Codon 77 was positively selected in the PI-naive darunavir cases, but not in the control group. CONCLUSIONS: Our findings suggest that although emergent darunavir resistance is rare, it may be more common among PI-experienced patients than those who are PI-naive. Further investigation is required to explore whether codon 77 is a novel site involved in darunavir susceptibility.

Dolutegravir versus raltegravir in antiretroviral-experienced, integrase-inhibitor-naive adults with HIV: week 48 results from the randomised, double-blind, non-inferiority SAILING study.

BACKGROUND: Dolutegravir (GSK1349572), a once-daily HIV integrase inhibitor, has shown potent antiviral response and a favourable safety profile. We evaluated safety, efficacy, and emergent resistance in antiretroviral-experienced, integrase-inhibitor-naive adults with HIV-1 with at least two-class drug resistance. METHODS: ING111762 (SAILING) is a 48 week, phase 3, randomised, double-blind, active-controlled, non-inferiority study that began in October, 2010. Eligible patients had two consecutive plasma HIV-1 RNA assessments of 400 copies per mL or higher (unless >1000 copies per mL at screening), resistance to two or more classes of antiretroviral drugs, and had one to two fully active drugs for background therapy. Participants were randomly assigned (1:1) to once-daily dolutegravir 50 mg or twice-daily raltegravir 400 mg, with investigator-selected background therapy. Matching placebo was given, and study sites were masked to treatment assignment. The primary endpoint was the proportion of patients with plasma HIV-1 RNA less than 50 copies per mL at week 48, evaluated in all participants randomly assigned to treatment groups who received at least one dose of study drug, excluding participants at one site with violations of good clinical practice. Non-inferiority was prespecified with a 12% margin; if non-inferiority was established, then superiority would be tested per a prespecified sequential testing procedure. A key prespecified secondary endpoint was the proportion of patients with treatment-emergent integrase-inhibitor resistance. The trial is registered at ClinicalTrials.gov, NCT01231516. FINDINGS: Analysis included 715 patients (354 dolutegravir; 361 raltegravir). At week 48, 251 (71%) patients on dolutegravir had HIV-1 RNA less than 50 copies per mL versus 230 (64%) patients on raltegravir (adjusted difference 7·4%, 95% CI 0·7 to 14·2); superiority of dolutegravir versus raltegravir was then concluded (p=0·03). Significantly fewer patients had virological failure with treatment-emergent integrase-inhibitor resistance on dolutegravir (four vs 17 patients; adjusted difference -3·7%, 95% CI -6·1 to -1·2; p=0·003). Adverse event frequencies were similar across groups; the most commonly reported events for dolutegravir versus raltegravir were diarrhoea (71 [20%] vs 64 [18%] patients), upper respiratory tract infection (38 [11%] vs 29 [8%]), and headache (33 [9%] vs 31 [9%]). Safety events leading to discontinuation were infrequent in both groups (nine [3%] dolutegravir, 14 [4%] raltegravir). INTERPRETATION: Once-daily dolutegravir, in combination with up to two other antiretroviral drugs, is well tolerated with greater virological effect compared with twice-daily raltegravir in this treatment-experienced patient group. FUNDING: ViiV Healthcare.

Has the time come to abandon efavirenz for first-line antiretroviral therapy?

Efavirenz has been recommended as a preferred third agent together with two nucleos(t)ides for first-line combination antiretroviral therapy (ART) for >15 years. The availability of efavirenz in a fixed-dose combination makes it very attractive. However, because of (i) adverse events associated with efavirenz, (ii) a poorer overall efficacy of efavirenz compared with newer antiretrovirals, (iii) the ranking of efavirenz as FDA Pregnancy Category D and (iv) the relatively high prevalence of transmitted drug-resistance mutations, there is a need to reconsider the role of efavirenz in first-line ART. We review the available evidence that challenges efavirenz's current position in first-line HIV treatment guidelines. Apart from its animal teratogenic potential, and moderate neuropsychiatric adverse events associated with its use, efavirenz has recently been associated with an increased risk of suicidality when compared with other antiretroviral drugs. Most importantly, efavirenz has demonstrated overall inferior efficacy to various comparator drugs, which include rilpivirine, raltegravir and dolutegravir, in antiretroviral-naive patients. Furthermore, epidemiological data indicate that the prevalence of non-nucleoside reverse transcriptase inhibitor resistance has reached 5%-8% in various parts of the world, and minority transmitted non-nucleoside reverse transcriptase inhibitor resistance-associated mutations can have a negative impact on the outcome of first-line efavirenz-based ART. Based on considerations of efficacy, toxicity and resistance, it is time to reconsider the routine use of efavirenz in ART. This, of course, presupposes that other antiretrovirals will be available in place of efavirenz, and may not be applicable in certain developing country settings where this is not the case.

Efficacy of short-term monotherapy with maraviroc, a new CCR5 antagonist, in patients infected with HIV-1.

We assessed the efficacy and safety of 10-d monotherapy with the orally administered CCR5 antagonist maraviroc in 63 HIV-1-positive individuals prescreened for the absence of CXCR4-using virus. Maximum reduction in viral load occurred at a median of 10-15 d, with a mean reduction of >or=1.6 log(10) copies/ml at all twice daily doses >or=100 mg. These results provide proof of concept that CCR5 antagonism is a viable antiretroviral therapeutic approach.

Use of Systemic Therapies for Treatment of Psoriasis in People Living with Controlled HIV: Inference-Based Guidance from a Multidisciplinary Expert Panel.

BACKGROUND: People living with human immunodeficiency virus (PLHIV) have a similar prevalence of psoriasis as the general population, though incidence and severity correlate with HIV viral load. Adequately treating HIV early renders the infection a chronic medical condition and allows PLHIV with a suppressed viral load (PLHIV-s) to live normal lives. Despite this, safety concerns and a lack of high-level data have hindered the use of systemic psoriasis therapies in PLHIV-s. OBJECTIVES: We aim to provide a structured framework that supports healthcare professionals and patients discussing the risks and benefits of systemic psoriasis therapy in PLHIV-s. Our goal was to address the primary question, are responses to systemic therapies for the treatment of psoriasis in PLHIV-s similar to those in the non-HIV population? METHODS: We implemented an inference-based approach relying on indirect evidence when direct clinical trial data were absent. In this instance, we reviewed indirect evidence supporting inferences on the status of immune function in PLHIV. Recommendations on systemic treatment for psoriasis in PLHIV were derived using an inferential heuristic. RESULTS: We identified seven indirect indicators of immune function informed by largely independent bodies of evidence: (1) functional assays, (2) vaccine response, (3) life expectancy, (4) psoriasis manifestations, (5) rate of infections, (6) rate of malignancies, and (7) organ transplant outcomes. CONCLUSIONS: Drug-related benefits and risks when treating a patient with systemic psoriasis therapies are similar for non-HIV patients and PLHIV with a suppressed viral load and normalized CD4 counts. Prior to initiating psoriasis treatment in PLHIV, HIV replication should be addressed by an HIV specialist. Exercise additional caution for patients with a suppressed viral load and discordant CD4 responses on antiretroviral therapy.

People living with human immunodeficiency virus (PLHIV) develop psoriasis as often as everyone else. We asked: what are effective and safe treatments when PLHIV need systemic therapy (pills or injections) for their psoriasis?HIV infection attacks the immune system. When HIV is not treated, the immune system declines. A less effective immune system makes it harder for the body to fight infections and certain cancers. Psoriasis is a skin condition caused by overactive immune cells. Effective psoriasis treatments reduce immune-cell activity. There are some concerns that treatments for psoriasis may not work and could worsen infections or cancers.To answer the question, we gathered 11 dermatologists and 4 HIV specialists. We reviewed the international scientific literature on PLHIV and psoriasis. The absence of direct evidence and volume of information to review made the process challenging. The end results were worthwhile.We concluded that people who are diagnosed early and take antiretroviral therapy to control their HIV infection (PLHIV-c) can live long, healthy lives. Accordingly, we determined that PLHIV-c can likely expect the same safety and efficacy for systemic psoriasis treatments as the general population. Treatment decisions should be made on a case-by-case basis through consultation with the patient and treating physician(s).Pillars of modern medicine are evidence-based care and collaborative decision-making. Too often, neither care provider nor patient are adequately informed. We have tried to fill one information gap for PLHIV and psoriasis. This process may help answer questions in other disease populations where direct evidence is scarce or absent.

Long-term CD4+ T-cell count evolution after switching from regimens including HIV nucleoside reverse transcriptase inhibitors (NRTI) plus protease inhibitors to regimens containing NRTI plus non-NRTI or only NRTI.

BACKGROUND: Data regarding CD4+ recovery after switching from protease inhibitor (PI)-based regimens to regimens not containing PI are scarce. METHODS: Subjects with virological success on first-PI-regimens who switched to NNRTI therapy (NNRTI group) or to nucleoside reverse transcriptase (NRTI)-only (NRTI group) were studied. The effect of the switch on the ongoing CD4+ trend was assessed by two-phase linear regression (TPLR), allowing us to evaluate whether a change in the CD4+ trend (hinge) occurred and the time of its occurrence. Furthermore, we described the evolution of the frequencies in CD4-count classes across four relevant time-points (baseline, before and immediately after the switch, and last visit). Finally, we explored whether the CD4+ counts evolved differently in patients who switched to NNRTI or NRTI-only regimens by considering: the overall CD4+ trends, the time to CD4+≥ 500/mm3 after the switch, and the area-under-the-curve (AUC) of the CD4+ after the switch. RESULTS: Eight hundred and ninety-six patients, followed for a median of 2,121 days, were included. At TPLR, hinges occurred in 581/844 (68.9%), but in only 40/581 (6.9%) within a time interval (180 days) compatible with a possible relationship to the switch; furthermore, in 19/40 cases, CD4+ counts appeared to decrease after the hinges. In comparison with the NNRTI group, the NRTI group showed CD4+ count greater at baseline (P = 0.0234) and before the switch (P ≤ 0.0001), superior CD4+ T-cell increases after HAART was started, lower probability of not achieving CD4+ ≥ 500/mm3 (P = 0.0024), and, finally, no significant differences in the CD4+ T-cell AUC after the switch after adjusting for possible confounders (propensity score and pre-switch AUC). Persistence at CD4+ < 200/mm3 was observed in 34/435 (7.5%) patients, and a decrease below this level was found in only 10/259 (3.9%) with baseline CD4+ ≥ 350/mm3. CONCLUSIONS: Switching from first-line PI to NNRTI- or NRTI-based regimens did not seem to impair CD4+ trend over long-term follow-up. Although the greater CD4+ increases in patients who switched to the NRTI-only regimen was due to higher CD4+ counts before the switch, several statistical analyses consistently showed that switching to this regimen did not damage the ongoing immune-reconstitution. Lastly, the observation that CD4+ T-cell counts remained low or decreased in the long term despite virological success merits further investigation.

Tenofovir alafenamide vs. tenofovir disoproxil fumarate: an updated meta-analysis of 14 894 patients across 14 trials.

BACKGROUND: Both tenofovir disoproxil fumarate (TDF)/emtricitabine and tenofovir alafenamide (TAF)/emtricitabine demonstrate excellent efficacy and safety overall, but concerns remain over specific changes in markers of bone and renal function. Lower plasma tenofovir concentrations are seen with TAF and in unboosted regimens. We assess TAF vs. TDF safety with and without booster coformulation. METHODS: A previous systematic review was updated with recent clinical trials. TAF vs. TDF efficacy and safety were compared in boosted and unboosted subgroups. Efficacy was measured by viral suppression. Key safety endpoints included all adverse events, serious adverse events, Grades 3-4 adverse events and adverse event discontinuation. Further specific renal and bone markers were also assessed. RESULTS: A total of 14 clinical trials comparing TDF and TAF regimens were identified. A significant difference (P = 0.0004) in efficacy was shown in the boosted subgroup in favour of TAF, but no difference was seen in the unboosted subgroup. There were no significant differences between TAF and TDF for any of the key safety endpoints analysed. No differences were seen for the bone markers analysed. No difference was found for renal tubular events. There was a difference in risk for discontinuation due to renal adverse events when boosted (P = 0.03), but none when unboosted. CONCLUSION: Across all main safety endpoints, no differences between TAF and TDF are seen. Boosted TDF regimens were associated with lesser comparative efficacy than boosted TAF and a higher risk of renal event discontinuation. However, modern antiretroviral regimens are more commonly unboosted. This study finds no difference in efficacy or safety in unboosted TAF vs. TDF.

Tenofovir DF, emtricitabine, and efavirenz vs. zidovudine, lamivudine, and efavirenz for HIV.

BACKGROUND: Durable suppression of replication of the human immunodeficiency virus (HIV) depends on the use of potent, well-tolerated antiretroviral regimens to which patients can easily adhere. METHODS: We conducted an open-label, noninferiority study involving 517 patients with HIV infection who had not previously received antiretroviral therapy and who were randomly assigned to receive either a regimen of tenofovir disoproxil fumarate (DF), emtricitabine, and efavirenz once daily (tenofovir-emtricitabine group) or a regimen of fixed-dose zidovudine and lamivudine twice daily plus efavirenz once daily (zidovudine-lamivudine group). The primary end point was the proportion of patients without baseline resistance to efavirenz in whom the HIV RNA level was less than 400 copies per milliliter at week 48 of the study. RESULTS: Through week 48, significantly more patients in the tenofovir-emtricitabine group reached and maintained the primary end point of less than 400 copies of HIV RNA per milliliter than did those in the zidovudine-lamivudine group (84 percent vs. 73 percent, respectively; 95 percent confidence interval for the difference, 4 to 19 percent; P=0.002). This difference excludes the inferiority of the tenofovir DF, emtricitabine, and efavirenz regimen, indicating a significantly greater response with this regimen. Significant differences were also seen in the proportion of patients with HIV RNA levels of less than 50 copies per milliliter (80 percent in the tenofovir-emtricitabine group vs. 70 percent in the zidovudine-lamivudine group; 95 percent confidence interval for the difference, 2 to 17 percent; P=0.02) and in increases in CD4 cell counts (190 vs. 158 cells per cubic millimeter, respectively; 95 percent confidence interval for the difference, 9 to 55; P=0.002). More patients in the zidovudine-lamivudine group than in the tenofovir-emtricitabine group had adverse events resulting in discontinuation of the study drugs (9 percent vs. 4 percent, respectively; P=0.02). In none of the patients did the K65R mutation develop. CONCLUSIONS: Through week 48, the combination of tenofovir DF and emtricitabine plus efavirenz fulfilled the criteria for noninferiority to a fixed dose of zidovudine and lamivudine plus efavirenz and proved superior in terms of virologic suppression, CD4 response, and adverse events resulting in discontinuation of the study drugs. (ClinicalTrials.gov number, NCT00112047.)

Global access of rifabutin for the treatment of tuberculosis - why should we prioritize this?

INTRODUCTION: Rifabutin, a rifamycin of equivalent potency to rifampicin, has several advantages in its pharmacokinetic and toxicity profile, particularly in HIV co-infected patients on combined antiretroviral therapy (cART). In this commentary, we evaluate evidence supporting increased global use of rifabutin and highlight key recommendations for action. DISCUSSION: Although extrapolation of data from HIV uninfected patients would suggest non-inferiority, there has been no randomized controlled study comparing rifabutin versus rifampicin in the outcomes of relapse-free cure, in drug susceptible tuberculosis (TB), in HIV co-infected patients on currently utilized cART regimens or in paediatric populations. An important advantage of rifabutin is that compared to the dose adjustments required with rifampicin, it can be co-administered with the integrase strand transfer inhibitors raltegravir or dolutegravir without the need for dose adjustments. This strategy would be easier to implement in a programmatic setting and would save costs. We have assessed cost incentives to utilize rifabutin and have estimated generic costs for a range of rifabutin dosage scenarios. Where facilities are present for drug re-challenge and monitoring for drug toxicity and cross-reactivity, rifabutin offers a switch alternative for adverse drug reactions (ADR)s attributed to rifampicin. This would negate the need to prolong treatment in the absence of a rifamycin as part of short-course multidrug therapy. There is evidence of incomplete cross-resistance to rifampicin and rifabutin. Rifabutin may be useful in rifampicin-resistant TB, in an estimated 20% of cases, based on phenotypic or genotypic rifabutin susceptibility testing. CONCLUSIONS: Rifabutin should be available globally as a first-line rifamycin in HIV co-infected individuals and as a switch option in cases of rifampicin associated ADRs. Further studies are needed to ascertain the utility of rifabutin in rifampicin-resistant rifabutin-susceptible TB.

Optimizing responses to drug safety signals in pregnancy: the example of dolutegravir and neural tube defects.

INTRODUCTION: The unexpected identification of a neural tube defect (NTD) safety signal with preconception dolutegravir (DTG) exposure in the Botswana Tsepamo birth outcomes study brought into sharp focus the need for reliable data on use of new antiretrovirals in pregnancy, improved pharmacovigilance systems to evaluate safety of new drugs being introduced into populations including women of reproductive potential, and balanced risk-benefit messaging when a safety signal is identified. DISCUSSION: The Tsepamo study NTD safety signal and accompanying regulatory responses led to uncertainty about the most appropriate approach to DTG use among women of reproductive potential, affecting global DTG roll-out plans, and limiting DTG use in adolescent girls and women. It also revealed a tension between a public health approach to antiretroviral treatment (ART) and individual choice, and highlighted difficulties interpreting and messaging an unexpected safety signal with uncertainty about risk. This difficulty was compounded by the lack of high-quality data on pregnancy outcomes from women receiving ART outside the Tsepamo surveillance sites and countries other than Botswana, resulting in a prolonged period of uncertainty while data on additional exposures are evaluated to refute or confirm the initial safety signal. We discuss principles for evaluating and introducing new drugs in the general population that would ensure collection of appropriate data to inform drug safety in adolescent girls and women of reproductive potential and minimize confusion about drug use in this population when a safety signal is identified. CONCLUSIONS: The response to a signal suggesting a possible safety risk for a drug used in pregnancy or among women who may become pregnant needs to be rapid and comprehensive. It requires the existence of appropriately designed surveillance systems with broad population coverage; data analyses that examine risk-benefit trade-offs in a variety of contexts; guidance to transform this risk-benefit balance into effective and agreed-upon policy; involvement of the affected community and other key stakeholders; and a communication plan for all levels of knowledge and complexity. Implementation of this proposed framework for responding to safety signals is needed to ensure that any drug used in pregnancy can be rapidly and appropriately evaluated should a serious safety alert arise.

Renal safety of tenofovir alafenamide vs. tenofovir disoproxil fumarate: a pooled analysis of 26 clinical trials.

OBJECTIVE: Compared with tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF) has been associated with improvement in markers of renal dysfunction in individual randomized trials; however, the comparative incidence of clinically significant renal events remains unclear. DESIGN: We used a pooled data approach to increase the person-years of drug exposure analysed, maximizing our ability to detect differences in clinically significant outcomes. METHODS: We pooled clinical renal safety data across 26 treatment-naive and antiretroviral switch studies to compare the incidence of proximal renal tubulopathy and discontinuation due to renal adverse events between participants taking TAF-containing regimens vs. those taking TDF-containing regimens. We performed secondary analyses from seven large randomized studies (two treatment-naive and five switch studies) to compare incidence of renal adverse events, treatment-emergent proteinuria, changes in serum creatinine, creatinine clearance, and urinary biomarkers (albumin, beta-2-microglobulin, and retinol binding protein-to-creatinine ratios). RESULTS: Our integrated analysis included 9322 adults and children with HIV (n = 6360 TAF, n = 2962 TDF) with exposure of 12 519 person-years to TAF and 5947 to TDF. There were no cases of proximal renal tubulopathy in participants receiving TAF vs. 10 cases in those receiving TDF (P < 0.001), and fewer individuals on TAF (3/6360) vs. TDF (14/2962) (P < 0.001) discontinued due to a renal adverse event. Participants initiating TAF-based vs. TDF-based regimens had more favourable changes in renal biomarkers through 96 weeks of therapy. CONCLUSION: These pooled data from 26 studies, with over 12 500 person-years of follow-up in children and adults, support the comparative renal safety of TAF over TDF.

Single- and multiple-dose pharmacokinetics of etravirine administered as two different formulations in HIV-1-infected patients.

BACKGROUND: An open-label, randomized, crossover study to evaluate the pharmacokinetics of two different formulations of etravirine after single and multiple dosing. METHODS: Treatment-experienced HIV-1-infected patients with viral load <50 copies/ml continued their current antiretroviral regimen and added etravirine twice daily for 7 days with a morning intake on day 8. Etravirine was administered following food as either 800 mg twice daily of the Phase II formulation or 100 mg or 200 mg twice daily of the Phase III formulation. A 12 h pharmacokinetic assessment was performed on days 1 and 8. RESULTS: After single- and multiple-dose administration, the exposure to etravirine was lower with 100 mg twice daily and higher with 200 mg twice daily compared with 800 mg twice daily. On day 8, the mean (+/-SD) area under the plasma concentration-time curve over 12 h (AUC0-12 h) was 1,284 (+/-958) ng x h/ml when etravirine was administered as 100 mg twice daily (n=33), 3,713 (+/-2,069) ng x h/ml when administered as 200 mg twice daily (n=27) and 2,607 (+/-2,135) ng x h/ml when administered as 800 mg twice daily (n=32). Both formulations and all doses of etravirine tested were generally safe and well tolerated. CONCLUSIONS: The range of exposure to etravirine was comparable between 200 mg twice daily dose and 800 mg twice daily. The Phase III formulation of etravirine significantly improves the bioavailability of etravirine over the Phase II formulation with reduced interpatient variability in etravirine pharmacokinetics.

Pharmacokinetic analysis to assess forgiveness of boosted saquinavir regimens for missed or late dosing.

OBJECTIVES: One potential concern of once-daily protease inhibitor administration is low trough concentrations and ultimately the 'forgiveness' or robustness in comparison with the originally licensed twice-daily dose. To give an estimation of 'forgiveness', we determined the length of time plasma drug concentrations were below target in HIV-infected patients receiving saquinavir/ritonavir regimens. METHODS: Seventy-seven pharmacokinetic profiles (saquinavir/ritonavir 1000/100 mg twice daily, n = 34; 1600/100 mg once daily, n = 26; 2000/100 mg once daily, n = 17) from five studies were combined, presented as twice- and once-daily percentiles (P10-P90) and compared. At percentiles where trough concentrations fell below the alleged minimum effective concentration (MEC; 100 ng/mL), the length of time below MEC was determined. RESULTS: Saquinavir concentrations were below MEC at P10 for 0.7 h for twice-daily saquinavir/ritonavir when compared with 8.6 and 6.6 h for 1600/100 and 2000/100 mg once daily, respectively. At P25, 1600/100 mg once daily produced suboptimal concentrations for 5.5 h in contrast to 0.5 h for 2000/100 mg once daily. CONCLUSIONS: Here, we provide substantive data that indicate once-daily saquinavir, in particular 1600/100 mg, is not as robust as the twice-daily regimen based on a population of UK patients; this raises concern over late or missed doses. However, pharmacokinetic data can only ever be a guide to the impact on long-term efficacy.

Population pharmacokinetics of ritonavir-boosted saquinavir regimens in HIV-infected individuals.

OBJECTIVES: The aim of this study was to develop and validate a population pharmacokinetic model in order to describe ritonavir-boosted saquinavir concentrations dosed twice and once daily in human immunodeficiency virus (HIV)-infected patients from the UK, Uganda and Thailand and to identify factors that may influence saquinavir pharmacokinetics. METHODS: Pharmacokinetic data from 10 clinical studies were combined. Non-linear mixed effects modelling (NONMEM version V) was applied to determine the saquinavir pharmacokinetic parameters, interindividual/interoccasion variability (IIV/IOV) and residual error. Various covariates potentially related to saquinavir pharmacokinetics were explored, and the final model was validated by means of 95% prediction interval and testing the predictive performance of the model with data not included in the model-building process. RESULTS: Ninety-seven patients were included from the UK (n = 52), Uganda (n = 18) and Thailand (n = 27), contributing 347 saquinavir profiles (1-14 profiles per patient). A one-compartment model with zero-order absorption and lag-time best described the data with IIV/IOV on apparent oral clearance (CL/F) and volume of distribution (V/F) and with IIV on duration and absorption lag-time. The ritonavir area under the curve over the dosing interval was significantly associated with saquinavir CL/F and V/F. A typical patient from the UK had approximately 1.5- and 3-fold higher saquinavir CL/F compared with patients from Uganda (89.0 versus 49.8 L/h) and Thailand (89.0 versus 26.7 L/h), respectively. CONCLUSIONS: A model to characterize ritonavir-boosted saquinavir pharmacokinetics in HIV-infected adults has been developed and validated. The model could be used for dosage adaptation following therapeutic drug monitoring and to assess patients' suitability for once-daily boosted saquinavir therapy.

A novel probe drug interaction study to investigate the effect of selected antiretroviral combinations on the pharmacokinetics of a single oral dose of maraviroc in HIV-positive subjects.

AIMS: Maraviroc (UK-427 857), an antagonist of the CCR5 receptor with potent anti-HIV activity, was recently approved for use in treatment-experienced patients infected with CCR5-tropic HIV-1. The aim of this study was to evaluate the effect of selected commonly used antiretroviral therapy (ART) combinations on the pharmacokinetics of a single oral dose of maraviroc 300 mg in HIV-positive subjects compared with historical controls. METHODS: In this study, four cohorts of HIV-positive patients (n = 8 each) receiving one of the following combination therapies were recruited: cohort 1--efavirenz + Combivir (lamivudine/zidovudine); cohort 2--efavirenz + didanosine + tenofovir; cohort 3--nevirapine + lamivudine + tenofovir; cohort 4--Kaletra (lopinavir/ritonavir) + stavudine + lamivudine. Subjects continued on their prescribed ART and also received a single oral dose of maraviroc 300 mg. Serial blood samples and urine for determination of maraviroc pharmacokinetics were collected over 12 h postdose. Plasma pharmacokinetic parameters from this study were compared with historical data generated in HIV-positive subjects receiving maraviroc monotherapy in a Phase IIa study. RESULTS: A total of 29 subjects were recruited (eight each in cohorts 1-3, and five in cohort 4). The geometric mean ratios for AUC(12) and C(max) for each treatment group compared with maraviroc monotherapy were: 47% and 67% (cohort 1); 48% and 76% (cohort 2); 101% and 154% (cohort 3); and 265% and 180% (cohort 4), respectively. T(max) was similar in all treatment groups. Mean values for renal clearance ranged from 8.2 l h(-1) (cohort 1) to 13.2 l h(-1) (cohort 4). There were no renal clearance data collected in the comparator study. CONCLUSIONS: The results of this study support those previously seen in healthy volunteer studies that showed that efavirenz reduces maraviroc exposure, whereas lopinavir/ritonavir increases maraviroc exposure. These data also suggest that nevirapine does not lead to a clinically significant effect on maraviroc pharmacokinetics.