Cabotegravir and rilpivirine long acting injectables in a pregnant woman living with HIV.

This case report describes bimonthly LAI CAB/RPV prior to and throughout pregnancy. CAB concentration was comparable to non-pregnant individuals, RPV was 70-75% lower. No virologic failure orvertical transmission occurred. Despite placental transfer, no congenital malformations were noted. Bimonthly CAB/RPV LAI may not be suitable for pregnant women and monitoring of exposed infants is warranted.

Twice-Daily Dosing of Dolutegravir in Infants on Rifampicin Treatment: A Pharmacokinetic Substudy of the EMPIRICAL Trial.

BACKGROUND: We evaluated dolutegravir pharmacokinetics in infants with human immunodeficiency virus (HIV) receiving dolutegravir twice daily (BID) with rifampicin-based tuberculosis (TB) treatment compared with once daily (OD) without rifampicin. METHODS: Infants with HIV aged 1-12 months, weighing ≥3 kg, and receiving dolutegravir BID with rifampicin or OD without rifampicin were eligible. Six blood samples were taken over 12 (BID) or 24 hours (OD). Dolutegravir pharmacokinetic parameters, HIV viral load (VL) data, and adverse events (AEs) were reported. RESULTS: Twenty-seven of 30 enrolled infants had evaluable pharmacokinetic curves. The median (interquartile range) age was 7.1 months (6.1-9.9), weight was 6.3 kg (5.6-7.2), 21 (78%) received rifampicin, and 11 (41%) were female. Geometric mean ratios comparing dolutegravir BID with rifampicin versus OD without rifampicin were area under curve (AUC)0-24h 0.91 (95% confidence interval, .59-1.42), Ctrough 0.95 (0.57-1.59), Cmax 0.87 (0.57-1.33). One infant (5%) receiving rifampicin versus none without rifampicin had dolutegravir Ctrough <0.32 mg/L, and none had Ctrough <0.064 mg/L. The dolutegravir metabolic ratio (dolutegravir-glucuronide AUC/dolutegravir AUC) was 2.3-fold higher in combination with rifampicin versus without rifampicin. Five of 82 reported AEs were possibly related to rifampicin or dolutegravir and resolved without treatment discontinuation. Upon TB treatment completion, HIV viral load was <1000 copies/mL in 76% and 100% of infants and undetectable in 35% and 20% of infants with and without rifampicin, respectively. CONCLUSIONS: Dolutegravir BID in infants receiving rifampicin resulted in adequate dolutegravir exposure, supporting this treatment approach for infants with HIV-TB coinfection.

Dolutegravir as First- or Second-Line Treatment for HIV-1 Infection in Children.

BACKGROUND: Children with human immunodeficiency virus type 1 (HIV-1) infection have limited options for effective antiretroviral treatment (ART). METHODS: We conducted an open-label, randomized, noninferiority trial comparing three-drug ART based on the HIV integrase inhibitor dolutegravir with standard care (non-dolutegravir-based ART) in children and adolescents starting first- or second-line ART. The primary end point was the proportion of participants with virologic or clinical treatment failure by 96 weeks, as estimated by the Kaplan-Meier method. Safety was assessed. RESULTS: From September 2016 through June 2018, a total of 707 children and adolescents who weighed at least 14 kg were randomly assigned to receive dolutegravir-based ART (350 participants) or standard care (357). The median age was 12.2 years (range, 2.9 to 18.0), the median weight was 30.7 kg (range, 14.0 to 85.0), and 49% of the participants were girls. By design, 311 participants (44%) started first-line ART (with 92% of those in the standard-care group receiving efavirenz-based ART), and 396 (56%) started second-line ART (with 98% of those in the standard-care group receiving boosted protease inhibitor-based ART). The median follow-up was 142 weeks. By 96 weeks, 47 participants in the dolutegravir group and 75 in the standard-care group had treatment failure (estimated probability, 0.14 vs. 0.22; difference, -0.08; 95% confidence interval, -0.14 to -0.03; P = 0.004). Treatment effects were similar with first- and second-line therapies (P = 0.16 for heterogeneity). A total of 35 participants in the dolutegravir group and 40 in the standard-care group had at least one serious adverse event (P = 0.53), and 73 and 86, respectively, had at least one adverse event of grade 3 or higher (P = 0.24). At least one ART-modifying adverse event occurred in 5 participants in the dolutegravir group and in 17 in the standard-care group (P = 0.01). CONCLUSIONS: In this trial involving children and adolescents with HIV-1 infection who were starting first- or second-line treatment, dolutegravir-based ART was superior to standard care. (Funded by ViiV Healthcare; ODYSSEY ClinicalTrials.gov number, NCT02259127; EUDRACT number, 2014-002632-14; and ISRCTN number, ISRCTN91737921.).

Availability and stock-outs of paediatric antiretroviral treatment formulations at health facilities in Kenya and Uganda.

INTRODUCTION: The large number of deaths among children with HIV is driven by poor antiretroviral treatment (ART) coverage among this cohort. The aim of the study was to assess the availability and stock-outs of paediatric and adult ART formulations in Kenya and Uganda across various regions and types of health facilities. METHODS: A survey on availability and stock-outs of paediatric ART at health facilities was adapted from the standardized Health Action International-WHO Medicine Availability Monitoring Tool. All preferred and limited-use formulations, and three phased-out formulations according to the 2021 WHO optimal formulary list were included in the survey, as well as a selection of adult ART formulations suitable for older children, adolescents, and adults. Availability data were collected in June-July 2022 and stock-out data were obtained over the previous year from randomly selected public and private-not-for-profit (PNFP) facilities registered to dispense paediatric ART across six districts per country. All data were analysed descriptively. RESULTS: In total, 144 health facilities were included (72 per country); 110 were public and 34 PNFP facilities. Overall availabilities of preferred paediatric ART formulations were 52.2% and 63.5% in Kenya and Uganda, respectively, with dolutegravir (DTG) 10 mg dispersible tablets being available in 70.2% and 77.4% of facilities, respectively, and abacavir/lamivudine dispersible tablets in 89.8% and 98.2% of facilities. Of note, availability of both formulations was low (37.5% and 62.5%, respectively) in Kenyan PNFP facilities. Overall availabilities of paediatric limited-use products were 1.1% in Kenya and 1.9% in Uganda. At least one stock-out of a preferred paediatric ART formulation was reported in 40.0% of Kenyan and 74.7% of Ugandan facilities. Nevirapine solution stock-outs were reported in 43.1% of Ugandan facilities, while alternative formulations for postnatal HIV prophylaxis were not available. CONCLUSIONS: Recommended DTG-based first-line ART for children across all ages was reasonably available at health facilities in Kenya and Uganda, with the exception of Kenyan PNFP facilities. Availability of paediatric ART formulations on the limited-use list was extremely low across both countries. Stock-outs were reported regularly, with the high number of reported stock-outs of neonatal ART formulations in Uganda being most concerning.

Outcomes of Bariatric Surgery in People With Human Immunodeficiency Virus: A Retrospective Analysis From the ATHENA Cohort.

BACKGROUND: The implications of bariatric surgery (BS) on virologic and metabolic outcomes in people with human immunodeficiency virus (HIV; PWH) on antiretroviral therapy (ART) are unknown. METHODS: Here, we report a retrospective analysis up to 18 months post-BS in PWH from the AIDS Therapy evaluation in The Netherlands (ATHENA) cohort with data from all dutch HIV treating Centers. Primary end points were a confirmed virologic failure (2 consecutive HIV-RNA measurements >200 copies/mL) and the percentage of patients who achieved >20% total body weight loss up to 18 months post-BS. Switches from baseline ART and trough plasma concentrations of antiretrovirals were also reported post-BS. Metabolic parameters and medication usage were compared pre- and post-BS. RESULTS: Fifty-one patients were included. One case of confirmed virologic failure and 3 cases with viral blips were detected in this cohort up to 18 months post-BS. Eighty-five percent of patients achieved >20% total body weight loss at 18 months post-BS, with a mean difference from baseline (95% confidence interval) of -33.5% (-37.7% to -29.3%). Trough plasma concentrations of measured antiretroviral agents were all above minimum effective concentrations, except for 1 sample of darunavir. Lipid profiles, but not serum creatinine and blood pressure, improved significantly (P < .01) post-BS. Total medications and obesity-related comedications declined from 203 to 103 and from 62 to 25, respectively, at 18 months post-BS. CONCLUSIONS: BS was an effective intervention for weight loss and lipid control in PWH using ART in this cohort with no clear link to poor virologic outcomes.

Pharmacokinetic Data of Dolutegravir in Second-line Treatment of Children With Human Immunodeficiency Virus: Results From the CHAPAS4 Trial.

BACKGROUND: Dolutegravir (DTG), combined with a backbone of 2 nucleoside reverse transcriptase inhibitors, is currently the preferred first-line treatment for human immunodeficiency virus (HIV) in childhood. CHAPAS4 is an ongoing randomized controlled trial investigating second-line treatment options for children with HIV. We did a nested pharmacokinetic (PK) substudy within CHAPAS4 to evaluate the DTG exposure in children with HIV taking DTG with food as part of their second-line treatment. METHODS: Additional consent was required for children on DTG enrolled in the CHAPAS4 trial to participate in this PK substudy. Children weighing 14-19.9 kg took 25 mg DTG as dispersible tablets and children ≥20 kg took 50 mg film-coated tablets. Steady-state 24-hour DTG plasma concentration-time PK profiling was done at t = 0 and 1, 2, 4, 6, 8, 12, and 24 hours after observed DTG intake with food. Reference adult PK data and pediatric data from the ODYSSEY trial were used primarily for comparison. The individual target trough concentration (Ctrough) was defined as 0.32 mg/L. RESULTS: Thirty-nine children on DTG were included in this PK substudy. The geometric mean (GM) area under the concentration-time curve over the dosing interval (AUC0-24h) was 57.1 hours × mg/L (coefficient of variation [CV%], 38.4%), which was approximately 8% below the average AUC0-24h in children in the ODYSSEY trial with comparable dosages, but above the adult reference. The GM (CV%) Ctrough was 0.82 mg/L (63.8%), which was comparable to ODYSSEY and adult reference values. CONCLUSIONS: This nested PK substudy shows that the exposure of DTG taken with food in children on second-line treatment is comparable with that of children in the ODYSSEY trial and adult references. Clinical Trials Registration.ISRCTN22964075.

First Pharmacokinetic Data of Tenofovir Alafenamide Fumarate and Tenofovir With Dolutegravir or Boosted Protease Inhibitors in African Children: A Substudy of the CHAPAS-4 Trial.

BACKGROUND: We evaluated the pharmacokinetics of tenofovir alafenamide fumarate (TAF) and tenofovir in a subset of African children enrolled in the CHAPAS-4 trial. METHODS: Children aged 3-15 years with human immunodeficiency virus infection failing first-line antiretroviral therapy were randomized to emtricitabine/TAF versus standard-of-care nucleoside reverse transcriptase inhibitor combination, plus dolutegravir, atazanavir/ritonavir, darunavir/ritonavir, or lopinavir/ritonavir. Daily emtricitabine/TAF was dosed according to World Health Organization (WHO)-recommended weight bands: 120/15 mg in children weighing 14 to <25 kg and 200/25 mg in those weighing ≥25 kg. At steady state, 8-9 blood samples were taken to construct pharmacokinetic curves. Geometric mean (GM) area under the concentration-time curve (AUC) and the maximum concentration (Cmax) were calculated for TAF and tenofovir and compared to reference exposures in adults. RESULTS: Pharmacokinetic results from 104 children taking TAF were analyzed. GM (coefficient of variation [CV%]) TAF AUClast when combined with dolutegravir (n = 18), darunavir/ritonavir (n = 34), or lopinavir/ritonavir (n = 20) were 284.5 (79), 232.0 (61), and 210.2 (98) ng*hour/mL, respectively, and were comparable to adult reference values. When combined with atazanavir/ritonavir (n = 32), TAF AUClast increased to 511.4 (68) ng*hour/mL. For each combination, tenofovir GM (CV%) AUCtau and Cmax remained below reference values in adults taking 25 mg TAF with a boosted protease inhibitors. CONCLUSIONS: In children, TAF combined with boosted PIs or dolutegravir and dosed according to WHO-recommended weight bands provides TAF and tenofovir concentrations previously demonstrated to be well tolerated and effective in adults. These data provide the first evidence for use of these combinations in African children. CLINICAL TRIALS REGISTRATION: ISRCTN22964075.

Drug interaction potential of high-dose rifampicin in patients with pulmonary tuberculosis.

Accumulating evidence supports the use of higher doses of rifampicin for tuberculosis (TB) treatment. Rifampicin is a potent inducer of metabolic enzymes and drug transporters, resulting in clinically relevant drug interactions. To assess the drug interaction potential of higher doses of rifampicin, we compared the effect of high-dose rifampicin (40 mg/kg daily, RIF40) and standard-dose rifampicin (10 mg/kg daily, RIF10) on the activities of major cytochrome P450 (CYP) enzymes and P-glycoprotein (P-gp). In this open-label, single-arm, two-period, fixed-order phenotyping cocktail study, adult participants with pulmonary TB received RIF10 (days 1-15), followed by RIF40 (days 16-30). A single dose of selective substrates (probe drugs) was administered orally on days 15 and 30: caffeine (CYP1A2), tolbutamide (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), midazolam (CYP3A), and digoxin (P-gp). Intensive pharmacokinetic blood sampling was performed over 24 hours after probe drug intake. In all, 25 participants completed the study. Geometric mean ratios (90% confidence interval) of the total exposure (area under the concentration versus time curve, RIF40 versus RIF10) for each of the probe drugs were as follows: caffeine, 105% (96%-115%); tolbutamide, 80% (74%-86%); omeprazole, 55% (47%-65%); dextromethorphan, 77% (68%-86%); midazolam, 62% (49%-78%), and 117% (105%-130%) for digoxin. In summary, high-dose rifampicin resulted in no additional effect on CYP1A2, mild additional induction of CYP2C9, CYP2C19, CYP2D6, and CYP3A, and marginal inhibition of P-gp. Existing recommendations on managing drug interactions with rifampicin can remain unchanged for the majority of co-administered drugs when using high-dose rifampicin. Clinical Trials registration number NCT04525235.

Adherence to prescription medication during pregnancy: Do pregnant women use pharmacological treatment as prescribed?

AIMS: Pregnant women are hypothesized to have low adherence to prescribed medication, because of concerns about harmful effects on the unborn child. However, very little is known about the actual adherence to prescribed medication during pregnancy. We determined to what extent women follow treatment recommendations regarding prescribed medication use in mid-pregnancy. METHODS: Dutch women participating in the PRIDE Study completed a 6-week diary on medication use. Additionally, pharmacy records were obtained. For each medication dispensed, we determined 3 measures of adherence: (i) whether use was reported in the diary (actual use); (ii) difference between dispensing date and date of first reported use (initiation time); and (iii) proportion of days with at least the correct number of doses taken (implementation adherence). RESULTS: During the 6-week study period, 235 of 816 women (29%) were dispensed medication. Actual use was highest for medications used for chronic conditions (88%; 95% confidence interval [95% CI] 81-93), followed by medication for pregnancy-related conditions (79%; 95% CI 71-86) and medication for occasional and short-time use (69%; 95% CI 60-77). We observed a ≥1-day delay in treatment initiation for 42% of medications dispensed for the first time in the study period. Mean implementation adherence was 74.2% (95% CI 69.3-79.2) for medications that were actually used. CONCLUSION: Although actual use of medications dispensed was high, many pregnant women did not adhere to treatment recommendations. This nonadherence may impact maternal and child health and lead to overestimation of medication use in studies in perinatal pharmacoepidemiology relying on administrative databases.

Tenofovir Alafenamide Plasma Concentrations Are Reduced in Pregnant Women Living With Human Immunodeficiency Virus (HIV): Data From the PANNA Network.

BACKGROUND: Tenofovir alafenamide (TAF), a prodrug of tenofovir (TFV), is included in the majority of the recommended first-line antiretroviral regimens for patients living with human immunodeficiency virus (HIV), but there are limited data on TAF use in pregnant women. We aimed to examine the plasma pharmacokinetics of TAF and TFV in pregnant women from Europe. METHODS: Pregnant women living with HIV were included from treatment centers across Europe, and intensive pharmacokinetic sampling in the third trimester and postpartum was performed. Pharmacokinetic parameters of TAF and TFV were determined with noncompartmental analysis. The proportion of women with a TAF area under the curve (AUClast) below the target of 53.1 ng∗h/mL was determined. Clinical efficacy and safety outcome parameters were reported. RESULTS: In total, 20 pregnant women living with HIV were included. At the third trimester, geometric mean TAF AUClast and Cmax were decreased by 46% and 52%, respectively, compared with postpartum. TFV AUC0-24h, Cmax, and Ctrough decreased by 33%, 30%, and 34%, respectively. The proportion of women with a TAF AUClast < 53.1 ng∗h/mL was 6% at third trimester and 0% postpartum. One out of 20 women had a viral load > 50 copies/mL at third trimester and no mother-to-child transmission occurred. CONCLUSIONS: TAF plasma concentrations were reduced by about half in women living with HIV during third trimester of pregnancy but remained above the predefined efficacy target in the majority of the pregnant women. TFV concentrations were reduced by approximately 30% during third trimester. Despite the observed exposure decrease, high virologic efficacy was observed in this study.

'I fear my partner will abandon me': the intersection of late initiation of antenatal care in pregnancy and poor ART adherence among women living with HIV in South Africa and Uganda.

BACKGROUND: Many women in sub-Saharan Africa initiate antenatal care (ANC) late in pregnancy, undermining optimal prevention of mother-to-child-transmission (PMTCT) of HIV. Questions remain about whether and how late initiation of ANC in pregnancy is related to adherence to antiretroviral therapy (ART) in the era of national dolutegravir roll-out. METHODS: This study employed a qualitative design involving individual interviews and focus group discussions conducted between August 2018 and March 2019. We interviewed 37 pregnant and lactating women living with HIV selected purposively for early or late presentation to ANC from poor urban communities in South Africa and Uganda. Additionally, we carried out seven focused group discussions involving 67 participants in both countries. Data were analysed thematically in NVivo12. RESULTS: Women described common underlying factors influencing both late ANC initiation and poor ART adherence in South Africa and Uganda. These included poverty and time constraints; inadequate health knowledge; perceived low health risk; stigma of HIV in pregnancy; lack of disclosure; and negative provider attitudes. Most late ANC presenters reported relationship problems, lack of autonomy and the limited ability to dialogue with their partners to influence household decisions on health and resource allocation. Perception of poor privacy and confidentiality in maternity clinics was rife among women in both study settings and compounded risks associated with early disclosure of pregnancy and HIV. Women who initiated ANC late and were then diagnosed with HIV appeared to be more susceptible to poor ART adherence. They were often reprimanded by health workers for presenting late which hampered their participation in treatment counselling and festered provider mistrust and subsequent disengagement in care. Positive HIV diagnosis in late pregnancy complicated women's ability to disclose their status to significant others which deprived them of essential social support for treatment adherence. Further, it appeared to adversely affect women's mental health and treatment knowledge and self-efficacy. CONCLUSIONS: We found clear links between late initiation of ANC and the potential for poor adherence to ART based on common structural barriers shaping both health seeking behaviours, and the adverse impact of late HIV diagnosis on women's mental health and treatment knowledge and efficacy. Women who present late are a potential target group for better access to antiretrovirals that are easy to take and decrease viral load rapidly, and counselling support with adherence and partner disclosure. A combination of strengthened health literacy, economic empowerment, improved privacy and patient-provider relationships as well as community interventions that tackle inimical cultural practices on pregnancy and unfair gender norms may be required.

"It's only fatness, it doesn't kill": a qualitative study on perceptions of weight gain from use of dolutegravir-based regimens in women living with HIV in Uganda.

BACKGROUND: Dolutegravir (DTG)-based regimens have been recommended by the WHO as the preferred first-line and second-line HIV treatment in all populations. Evidence suggests an association with weight gain, particularly among black women. Our study investigated perceptions of weight gain from DTG-based regimen use on body image and adherence of antiretroviral therapy in women living with HIV (WLHIV) in Uganda. METHODS: Between April and June 2021, we conducted semi-structured interviews involving 25 WLHIV (adolescents, women of reproductive potential and post-menopausal women) and 19 healthcare professionals (clinicians, nurses, ART managers and counsellors) purposively selected from HIV clinics in Kampala. The interviews explored perceptions of body weight and image; experiences and management of weight related side effects associated with DTG; and knowledge and communication of DTG-related risks. Data was analysed thematically in NVivo 12 software. RESULTS: Our findings indicate WLHIV in Uganda commonly disliked thin body size and aspired to gain moderate to high level body weight to improve their body image, social standing and hide their sero-positive status. Both WLHIV and healthcare professionals widely associated weight gain with DTG use, although it was rarely perceived as an adverse event and was unlikely to be reported or to alter medication adherence. Clinical management and pharmacovigilance of DTG-related weight gain were hampered by the limited knowledge of WLHIV of the health risks of being over-weight and obesity; lack of diagnostic equipment and resources; and limited clinical guidance for managing weight gain and associated cardiovascular and metabolic comorbidities. CONCLUSIONS: The study highlights the significance of large body-size in promoting psychosocial wellbeing in WLHIV in Uganda. Although weight gain is recognized as a side effect of DTG, it may be welcomed by some WLHIV. Healthcare professionals should actively talk about and monitor for weight gain and occurrence of associated comorbidities to facilitate timely interventions. Improved supply of diagnostic equipment and support with sufficient guidance for managing weight gain for healthcare professionals in Uganda are recommended.

The Effect of Pregnancy on the Pharmacokinetics of Total and Unbound Dolutegravir and Its Main Metabolite in Women Living With Human Immunodeficiency Virus.

BACKGROUND: Pharmacokinetic and efficacy data on dolutegravir in pregnant women living with human immunodeficiency virus (HIV) are still limited but needed to support its use as one of the preferred antiretroviral agents. METHODS: Within the multicenter Pharmacokinetics of ANtiretroviral agents in HIV-infected pregNAnt women (PANNA) study, pregnant women living with HIV and using dolutegravir once daily (50 mg, with food) underwent 24-hour pharmacokinetic profiling in their third trimester and postpartum. Dolutegravir exposure in the third trimester was considered adequate if geometric mean unbound, pharmacologically active, minimal plasma concentrations (Cmin, unbound) and ≥90% of individual Cmin, unbound levels were >0.85 µg/L, the proposed 90% inhibitory concentration for unbound dolutegravir. Geometric mean ratios (GMRs) with 90% confidence intervals (CIs) for comparison of total and unbound pharmacokinetic parameters in the third trimester and postpartum were calculated, including the metabolic ratio for dolutegravir-glucuronide. Safety and virological data were collected. RESULTS: Seventeen women (76% black) were enrolled (25 evaluable pharmacokinetic profiles; 15 in the third trimester, 10 in postpartum). In the third trimester, geometric mean (coefficient of variation, %) Cmin, unbound was 2.87 (87) µg/L and 93% of individual Cmin, unbound levels were >0.85 µg/L. The GMR (90% CI) in the third trimester vs postpartum was 0.86 (.68-1.10) for area under the curve (AUC0-24h), and for Cmax, 0.93 (.77-1.13). GMR (90% CI) for the trough concentrations was 0.71 (.49-1.02), based on total dolutegravir concentrations. Four serious adverse events were reported, unlikely related to dolutegravir. The HIV polymerase chain reaction test was negative in 14/17 infants (result unknown for 3 infants). CONCLUSIONS: Pharmacokinetic changes for dolutegravir in late pregnancy are not clinically relevant and support the use of dolutegravir 50 mg once daily with food in pregnancy. CLINICAL TRIALS REGISTRATION: NCT00825929.

Clinically Significant Lower Elvitegravir Exposure During the Third Trimester of Pregnant Patients Living With Human Immunodeficiency Virus: Data From the Pharmacokinetics of ANtiretroviral agents in HIV-infected pregNAnt women (PANNA) Network.

This phase 4 study investigated the influence of pregnancy on the pharmacokinetics of elvitegravir/cobicistat in 14 women with human immunodeficiency virus type 1. The results support the recommendation against elvitegravir/cobicistat use during pregnancy, as the elvitegravir concentration at the end of the dosing interval (Ctrough) was reduced by 77%, with 85% of pregnant women having a Ctrough below the effective concentration (EC90). Clinical Trials Registration. NCT00825929.

Suboptimal Dosing of Fluconazole in Critically Ill Patients: Time To Rethink Dosing.

Fluconazole is frequently used for the treatment of invasive Candida infections in critically ill patients. However, alterations in renal functions might influence fluconazole clearance. Therefore, our objective was to study the impact of renal function on the population pharmacokinetics of fluconazole in critically ill patients with various degrees of renal function or undergoing continuous renal replacement therapy (CRRT). This was an open-label, multicenter observational study. Critically ill patients receiving fluconazole were included. Baseline and clinical data were collected. At days 3 and 7 of enrollment, blood samples were drawn for pharmacokinetic curves. Additionally, daily trough samples were taken. A nonlinear mixed-effects model was built, followed by Monte Carlo simulations for assessment of exposure to various dosages of fluconazole. Nineteen patients were included with a median age of 64.4 (range, 23 to 81) years and median weight of 82.0 (range, 44.0 to 119.5) kg. A linear two-compartment model best described fluconazole pharmacokinetics and demonstrated higher clearance than expected in critically ill patients. Simulations showed that daily dosages of 600 mg and 800 mg are needed for intensive care unit (ICU) patients with normal renal function and patients on CRRT, respectively, to achieve the EUCAST-recommended target fAUC (area under the concentration-time curve for the free, unbound fraction of the drug)/MIC ratio of 100. In conclusion, fluconazole clearance is highly variable in ICU patients and is strongly dependent on renal function and CRRT. Trough concentrations correlated well with the AUC, opening up opportunities for tailored dosing using therapeutic drug monitoring. We recommend doses of 400 mg for patients with poor to moderate renal function, 600 mg for patients with adequate renal function, and 800 mg for patients treated with CRRT. (This study has been registered at ClinicalTrials.gov under identifier NCT02666716.).

Pharmacokinetic similarity demonstrated after crushing of the elbasvir/grazoprevir fixed-dose combination tablet for HCV infection.

BACKGROUND: Finding a suitable treatment for HCV patients with swallowing disorders is still a major challenge. In practice, direct-acting antivirals are crushed without knowledge of adequate absorption. Crushing can alter drug exposure, possibly leading to treatment failure, development of resistance or toxicity. Currently, there is no information about crushing of the fixed-dose combination tablet of elbasvir/grazoprevir; therefore, crushing of this tablet is not recommended. OBJECTIVES: To investigate the influence of crushing on the pharmacokinetics of the elbasvir/grazoprevir fixed-dose combination tablet. METHODS: We conducted an open-label, two-period, randomized, cross-over, Phase I, single-dose trial in 11 healthy adult volunteers. Subjects randomly received whole-tablet elbasvir/grazoprevir or crushed and suspended elbasvir/grazoprevir in a fasted state. Pharmacokinetic similarity criteria (90% CIs lie within 70%-143% acceptance range) were used for AUC0-∞ and AUC0-72. RESULTS: Mean plasma concentration-time curves of elbasvir and grazoprevir showed similar pharmacokinetic profiles. The primary pharmacokinetic parameters AUC0-∞ and AUC0-72 of elbasvir and grazoprevir after intake of a crushed tablet were on average 12%-16% higher compared with the whole tablet, but 90% CIs were all within the predefined boundaries of pharmacokinetic similarity. Crushing leads to a higher Cmax of grazoprevir (42%); no significant difference was found between treatments with regard to the Cmax of elbasvir. No serious adverse events were reported during the trial. CONCLUSIONS: Pharmacokinetic similarity could be demonstrated for a crushed and suspended tablet compared with a whole tablet, without impacting drug safety or efficacy. Crushed and suspended administration of elbasvir/grazoprevir can be used in patients with swallowing disorders.

Pharmacokinetics of antiretroviral and tuberculosis drugs in children with HIV/TB co-infection: a systematic review.

INTRODUCTION: Management of concomitant use of ART and TB drugs is difficult because of the many drug-drug interactions (DDIs) between the medications. This systematic review provides an overview of the current state of knowledge about the pharmacokinetics (PK) of ART and TB treatment in children with HIV/TB co-infection, and identifies knowledge gaps. METHODS: We searched Embase and PubMed, and systematically searched abstract books of relevant conferences, following PRISMA guidelines. Studies not reporting PK parameters, investigating medicines that are not available any longer or not including children with HIV/TB co-infection were excluded. All studies were assessed for quality. RESULTS: In total, 47 studies met the inclusion criteria. No dose adjustments are necessary for efavirenz during concomitant first-line TB treatment use, but intersubject PK variability was high, especially in children <3 years of age. Super-boosted lopinavir/ritonavir (ratio 1:1) resulted in adequate lopinavir trough concentrations during rifampicin co-administration. Double-dosed raltegravir can be given with rifampicin in children >4 weeks old as well as twice-daily dolutegravir (instead of once daily) in children older than 6 years. Exposure to some TB drugs (ethambutol and rifampicin) was reduced in the setting of HIV infection, regardless of ART use. Only limited PK data of second-line TB drugs with ART in children who are HIV infected have been published. CONCLUSIONS: Whereas integrase inhibitors seem favourable in older children, there are limited options for ART in young children (<3 years) receiving rifampicin-based TB therapy. The PK of TB drugs in HIV-infected children warrants further research.

Importance of Prospective Studies in Pregnant and Breastfeeding Women Living With Human Immunodeficiency Virus.

Recently, the US Food and Drug Administration and European Medicines Agency issued warnings on the use of dolutegravir and darunavir/cobicistat for treatment of pregnant women living with human immunodeficiency virus (HIV). It took 3-5 years to identify the risks associated with the use of these antiretroviral drugs, during which time pregnant women were exposed to these drugs in clinical care, outside of controlled clinical trial settings. Across all antiretroviral drugs, the interval between registration of new drugs and first data on pharmacokinetics and safety in pregnancy becoming available is around 6 years. In this viewpoint, we provide considerations for clinical pharmacology research to provide safe and effective treatment of pregnant and breastfeeding women living with HIV and their children. These recommendations will lead to timelier availability of safety and pharmacokinetic information needed to develop safe treatment strategies for pregnant and breastfeeding women living with HIV, and are applicable to other chronic disease areas requiring medication during pregnancy.

Protein binding of rifampicin is not saturated when using high-dose rifampicin.

BACKGROUND: Higher doses of rifampicin are being investigated as a means to optimize response to this pivotal TB drug. It is unknown whether high-dose rifampicin results in saturation of plasma protein binding and a relative increase in protein-unbound (active) drug concentrations. OBJECTIVES: To assess the free fraction of rifampicin based on an in vitro experiment and data from a clinical trial on high-dose rifampicin. METHODS: Protein-unbound rifampicin concentrations were measured in human serum spiked with increasing total concentrations (up to 64 mg/L) of rifampicin and in samples obtained by intensive pharmacokinetic sampling of patients who used standard (10 mg/kg daily) or high-dose (35 mg/kg) rifampicin up to steady-state. The performance of total AUC0-24 to predict unbound AUC0-24 was evaluated. RESULTS: The in vitro free fraction of rifampicin remained unaltered (∼9%) up to 21 mg/L and increased up to 13% at 41 mg/L and 17% at 64 mg/L rifampicin. The highest (peak) concentration in vivo was 39.1 mg/L (high-dose group). The arithmetic mean percentage unbound to total AUC0-24in vivo was 13.3% (range = 8.1%-24.9%) and 11.1% (range = 8.6%-13.6%) for the standard group and the high-dose group, respectively (P = 0.214). Prediction of unbound AUC0-24 based on total AUC0-24 resulted in a bias of -0.05% and an imprecision of 13.2%. CONCLUSIONS: Plasma protein binding of rifampicin can become saturated, but exposures after high-dose rifampicin are not high enough to increase the free fraction in TB patients with normal albumin values. Unbound rifampicin exposures can be predicted from total exposures, even in the higher dose range.

Effect of diabetes mellitus on TB drug concentrations in Tanzanian patients.

BACKGROUND: Diabetes mellitus (DM) is associated with poor TB treatment outcome. Previous studies examining the effect of DM on TB drug concentrations yielded conflicting results. No studies have been conducted to date in an African population. OBJECTIVES: To compare exposure to TB drugs in Tanzanian TB patients with and without DM. PATIENTS AND METHODS: A prospective pharmacokinetic study was performed among 20 diabetic and 20 non-diabetic Tanzanian TB patients during the intensive phase of TB treatment. Plasma pharmacokinetic parameters of isoniazid, rifampicin, pyrazinamide and ethambutol were compared using an independent-sample t-test on log-transformed data. Multiple linear regression analysis was performed to assess the effects of DM, gender, age, weight, HIV status and acetylator status on exposure to TB drugs. RESULTS: A trend was shown for 25% lower total exposure (AUC0-24) to rifampicin among diabetics versus non-diabetics (29.9 versus 39.9 mg·h/L, P=0.052). The AUC0-24 and peak concentration (Cmax) of isoniazid were also lower in diabetic TB patients (5.4 versus 10.6 mg·h/L, P=0.015 and 1.6 versus 2.8 mg/L, P=0.013). Pyrazinamide AUC0-24 and Cmax values were non-significantly lower among diabetics (P=0.08 and 0.09). In multivariate analyses, DM remained an independent predictor of exposure to isoniazid and rifampicin, next to acetylator status for isoniazid. CONCLUSIONS: There is a need for individualized dosing of isoniazid and rifampicin based on plasma concentration measurements (therapeutic drug monitoring) and for clinical trials on higher doses of these TB drugs in patients with TB and DM.