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Background: Pediatric brain tumors (PBT) stand as the leading cause of cancer‐related deaths in children. Chemoradiation protocols have improved survival rates, even for non‐resectable tumors. Nonetheless, radiation therapy carries the risk of numerous adverse effects that can have long‐lasting, detrimental effects on the quality of life for survivors. The pursuit of chemotherapeutics that could obviate the need for radiotherapy remains ongoing. Several anti‐tumor agents, including sunitinib, valproic acid, carboplatin, and panobinostat, have shown effectiveness in various malignancies but have not proven effective in treating PBT. The presence of the blood–brain barrier (BBB) plays a pivotal role in maintaining suboptimal concentrations of anti‐cancer drugs in the central nervous system (CNS). Ongoing research aims to modulate the integrity of the BBB to attain clinically effective drug concentrations in the CNS. However, current findings on the interaction of exogenous chemical agents with the BBB remain limited and do not provide a comprehensive explanation for the ineffectiveness of established anti‐cancer drugs in PBT. Methods: We conducted our search for chemotherapeutic agents associated with the blood–brain barrier (BBB) using the following keywords: Chemotherapy in Cancer, Chemotherapy in Brain Cancer, Chemotherapy in PBT, BBB Inhibition of Drugs into CNS, Suboptimal Concentration of CNS Drugs, PBT Drugs and BBB, and Potential PBT Drugs. We reviewed each relevant article before compiling the information in our manuscript. For the generation of figures, we utilized BioRender software. Focus: We focused our article search on chemical agents for PBT and subsequently investigated the role of the BBB in this context. Our search criteria included clinical trials, both randomized and non‐randomized studies, preclinical research, review articles, and research papers. Finding: Our research suggests that, despite the availability of potent chemotherapeutic agents for several types of cancer, the effectiveness of these chemical agents in treating PBT has not been comprehensively explored. Additionally, there is a scarcity of studies examining the role of the BBB in the suboptimal outcomes of PBT treatment, despite the effectiveness of these drugs for other types of tumors. [ABSTRACT FROM AUTHOR]

AZD7442 (Evusheld) is a combination of two human anti‐severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2) monoclonal antibodies (mAbs), tixagevimab (AZD8895) and cilgavimab (AZD1061). Route of administration is an important consideration to improve treatment access. We assessed pharmacokinetics (PKs) of AZD7442 absorption following 600 mg administered intramuscularly (i.m.) in the thigh compared with 300 mg intravenously (i.v.) in ambulatory adults with symptomatic COVID‐19. PK analysis included 84 of 110 participants randomized to receive i.m. AZD7442 and 16 of 61 randomized to receive i.v. AZD7442. Serum was collected prior to AZD7442 administration and at 24 hours and 3, 7, and 14 days later. PK parameters were calculated using noncompartmental methods. Following 600 mg i.m., the geometric mean maximum concentration (Cmax) was 38.19 μg/mL (range: 17.30–60.80) and 37.33 μg/mL (range: 14.90–58.90) for tixagevimab and cilgavimab, respectively. Median observed time to maximum concentration (Tmax) was 7.1 and 7.0 days for tixagevimab and cilgavimab, respectively. Serum concentrations after i.m. dosing were similar to the i.v. dose (27–29 μg/mL each component) at 3 days. The area under the concentration‐time curve (AUC)0–7d geometric mean ratio was 0.9 for i.m. vs. i.v. Participants with higher weight or body mass index were more likely to have lower concentrations with either route. Women appeared to have higher interparticipant variability in concentrations compared with men. The concentrations of tixagevimab and cilgavimab after administration i.m. to the thigh were similar to those achieved with i.v. after 3 days from dosing. Exposure in the i.m. group was 90% of i.v. over 7 days. Administration to the thigh can be considered to provide consistent mAb exposure and improve access. [ABSTRACT FROM AUTHOR]

Combination antiretroviral therapy (ART) can suppress plasma HIV‐RNA to < 50 copies/mL, decrease HIV transmission, reduce mortality, and improve quality of life for people living with HIV. ART cannot, however, eliminate HIV from an infected individual. The primary barrier to cure HIV infection is the multiple reservoir sites, including adipose tissue, bone marrow, central nervous system, liver, lungs, male and female reproductive system, secondary lymph nodes, and gut‐associated lymphoid tissue, established 1 to 2 weeks after acquisition of HIV. Additional challenges include understanding the mechanism(s) by which HIV is maintained at low or undetectable levels and developing treatments that will eradicate or produce a sustained suppression of virus without ART. To date, the most extensive clinical investigations of cure strategies have been the shock‐and‐kill approach using histone deacetylase inhibitors (HDACis) to induce reactivation of latent HIV. Despite evidence for HIV latency reversal, HDACis alone have not decreased the size of the latent reservoir. Clinical pharmacologic explanations for these results include a low inhibitory quotient (i.e., low potency) within the reservoir sites and intrinsic (e.g., sex differences and reservoir size) and extrinsic (physiochemical and pharmacokinetic drug characteristics) factors. We offer an outline of desired clinical pharmacologic attributes for therapeutics intended for clinical HIV cure research and call for research teams to have early and ongoing involvement of clinical pharmacologists. We believe such a collective effort will provide a solid scientific basis and hope for reaching the goal of a cure for HIV infection. [ABSTRACT FROM AUTHOR]

Dyskinesia induced by long‐term L‐Dopa (LID) therapy in Parkinson disease is associated with altered striatal function whose molecular bases remain unclear. Here, a transcriptomic approach was applied for comprehensive analysis of distinctively regulated genes in striatal tissue, their specific pathways, and functional‐ and disease‐associated networks in a rodent model of LID. This approach has identified transforming growth factor beta type 1 (TGFβ1) as a highly upregulated gene in dyskinetic animals. TGFβ1 pathway is a top aberrantly regulated pathway in the striatum following LID development based on differentially expressed genes (> 1.5 fold change and P < 0.05). The induction of TGFβ1 pathway specific genes, TGFβ1, INHBA, AMHR2 and PMEPA1 was also associated with regulation of NPTX2, PDP1, SCG2, SYNPR, TAC1, TH, TNNT1 genes. Transcriptional network and upstream regulator analyses have identified AKT‐centered functional and ERK‐centered disease networks revealing the association of TGFβ1, IL‐1β and TNFα with LID development. Therefore, results support that TGFβ1 pathway is a major contributor to the pathogenic mechanisms of LID. [ABSTRACT FROM AUTHOR]

The secondary lymphoid tissues (LT), lymph nodes (LN) and gut‐associated lymphoid tissue are the primary sites of HIV replication and where the latent pool of virus is maintained. We compared the pharmacokinetics of tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) in LT of 13 HIV‐infected persons receiving a TDF‐containing antiretroviral regimen who subsequently switched to a TAF‐containing regimen. Study participants were on stable antiretroviral therapy for ≥12 months with plasma HIV‐RNA < 48 copies/mL for 6 months before enrollment and entry CD4 cell counts > 300 cells/µL. Intracellular concentrations of tenofovir‐diphosphate (TFV‐DP) and emtricitabine‐triphosphate (FTC‐TP) were quantified in PBMCs and in mononuclear cells obtained from LN, ileum and rectal tissues. With TAF, the TFV‐DP concentrations in PBMCs and LN were 7.3‐fold and 6.4‐fold higher (ratios of geometric means of TAF to TDF), respectively, compared with TDF; ileal and rectal concentrations, however, were lower with geometric mean ratios of 0.14 and 0.18, respectively. A statistically significant relationship was observed between PBMC and LN concentrations of TFV‐DP. During TDF‐containing therapy, the expected effect of cobicistat to increase TFV plasma concentrations was observed, as were higher TFV‐DP concentrations in PBMCs and mononuclear cells from LN, ileum and rectal tissues. The higher TFV‐DP concentrations achieved with TAF in the LN provides the first human correlate of the observation in animals that TAF produced higher tenofovir LN concentrations. The ability to increase LN concentrations allows investigations of whether antiretroviral regimens with improved LN pharmacokinetics elicit a more complete virologic response in that compartment. [ABSTRACT FROM AUTHOR]

Adherence with antiretroviral therapy is important for preventing disease progression and HIV transmission. The co‐encapsulated pill sensor system sends a signal through a cutaneous patch and allows real‐time monitoring of pill ingestion. A 16‐week pilot study used a sensor system in 15 HIV‐infected individuals with real‐time monitoring of pill‐taking with a personalized short message system text. System acceptability was assessed by survey at weeks 4, 8, 12, and 16. Follow‐up occurred in 80% of subjects through 8 weeks. The system effectively collected measures of pill ingestion, which triggered text message reminders. Only 2 of 14 participants stated that co‐encapsulated pills were "unable to take" or "poorly tolerated." At least 75% of respondents stated at each visit that the patch was very or somewhat comfortable. With regard to text message reminders, only 10–15% of the participants at any visit did not find the messages to be helpful. Larger studies will define the utility of this system to assess antiretroviral adherence relative to standard measures. [ABSTRACT FROM AUTHOR]

The roles of the NAT2 genotype and enzyme maturation on isoniazid pharmacokinetics were investigated in South African infants with perinatal HIV exposure enrolled in a randomized, double-blind, controlled trial of isoniazid for prevention of tuberculosis disease and latent infection. Plasma concentration-time measurements of isoniazid from 151 infants (starting at 3-4 months of age) receiving isoniazid 10 to 20 mg/kg/d orally during the course of the 24-month study were incorporated in a population analysis along with NAT2 genotype, body weight, age, and sex. The results showed a different NAT2 enzyme maturation profile for each of the 3 acetylation groups, with the 70-kg body weight–normalized typical apparent clearance for the fast and intermediate acetylators increasing from 14.25 L/h and 10.88 L/h at 3 months of age to 22.84 L/h and 15.58 L/h at 24 months of age, respectively, with no significant change in the apparent clearance of the slow group during this period. A hypothesis is proposed to explain the genotype-dependent enzyme maturation processes for the NAT2 enzyme. [ABSTRACT FROM PUBLISHER]

Study Objective To determine whether the absorption of four antiretroviral agents-raltegravir, etravirine, emtricitabine, and tenofovir-is compromised when administered by gastrostomy tube. Design Pharmacokinetic analysis. Setting University medical center. Patient A 52-year-old African-American man coinfected with advanced multidrug-resistant human immunodeficiency virus ( HIV) and chronic hepatitis B, who was receiving treatment with raltegravir, etravirine, emtricitabine, and tenofovir, and developed ulcerative esophagitis with perforation, requiring a gastrostomy tube. Measurements and Main Results Due to the patient's esophageal perforations, all nutrition and drug therapy had to be provided by gastrostomy tube. As his antiretroviral regimen of raltegravir, etravirine, and emtricitabine-tenofovir was not available in liquid or powder formulations, the oral tablets were crushed or dispersed and mixed with water, then administered by gastrostomy tube. To ensure that the absorption of the drugs was sufficient for antiretroviral response, plasma samples were collected at 2 hours and 12 hours after dosing, and drug concentrations were quantitated by using validated assays. The 2- and 12-hour postdose plasma concentrations were 1220 and 446 ng/ml for raltegravir, 212 and 274 ng/ml for etravirine, 1148 and 164 ng/ml for emtricitabine, and 320 and 94 ng/ml for tenofovir, respectively. The patient's plasma concentrations were then compared with those in published pharmacokinetic studies of oral regimens administered to HIV-infected persons and healthy volunteers. Overall, the plasma concentrations of the antiretrovirals administered by gastrostomy tube were similar to published values. No drug toxicities were observed in this patient. Conclusion These pharmacokinetic data suggest that absorption of raltegravir, etravirine, emtricitabine, and tenofovir was not compromised when the drugs were administered by gastrostomy tube. These findings provide a basis for further investigation of the pharmacokinetics, safety, tolerance, and antiretroviral response to raltegravir, etravirine, and emtricitabine-tenofovir when the oral route of administration is not possible. [ABSTRACT FROM AUTHOR]

The authors compared the pharmacokinetics of lopinavir (LPV) and ritonavir (RTV) between women and men. This 2-step, multicenter, pharmacokinetic study enrolled human immunodeficiency virus (HIV)–infected adults on lopinavir/ritonavir (LPV/r) capsules (400/100 mg bid) plus 1 or more nucleoside reverse transcriptase inhibitors. All participants underwent 12-hour pharmacokinetic sampling. The pharmacokinetic sampling was repeated in participants receiving the LPV/r tablet formulation. Step 1 enrolled 37 women and 40 men; step 2 included 42 participants from step 1 plus 35 new participants (39 women and 38 men). LPV pharmacokinetics in women and men were not significantly different with either formulation. Women had significantly higher median RTV AUC0-12 h with both the soft-gel capsule (SGC) and tablet formulations (SGC: 5395 vs 4119 ng·h/mL, P = .026; tablet: 5310 vs 3941 ng·h/mL, P = .012), higher median Cmax (SGC: 802 vs 635 ng/mL, P = .032; tablet: 773 vs 570 ng/mL, P = .006), and lower median CL/F (SGC: 18.54 vs 24.31 L/h, P = .026; tablet: 18.83 vs 25.37 L/h, P = .012). RTV CL/F was slower in women after weight adjustment with both formulations. The pharmacokinetics of LPV in the SGC and tablet formulations are comparable in HIV-infected patients. Women had higher RTV AUC0-12 h and lower CL/F with both formulations. The mechanism of the sex difference in RTV CL/F warrants elucidation. [ABSTRACT FROM PUBLISHER]

Efavirenz, a nonnucleoside reverse transcriptase inhibitor, is a highly effective and widely prescribed antiretroviral agent. It is recommended as first-line treatment of human immunodeficiency virus (HIV) infection. The standard dose of efavirenz is 600 mg/day; however, adverse central nervous system effects limit its use. Few data citing use of efavirenz at lower doses have been published. We describe a 35-year-old man with HIV infection whose virologic suppression was maintained after 18 months of treatment with efavirenz 400 mg/day. Genetic testing for cytochrome P450 (CYP) 2B6 showed that the patient was a heterozygous variant; patients with this polymorphism tend to have higher plasma efavirenz concentrations and slower plasma efavirenz clearance (prolonged elimination half-lives). Therapeutic drug monitoring also supported the dose reduction in this patient. Even with the 400-mg dose, the patient's plasma trough concentrations exceeded the upper limit of the therapeutic range. However, as he remained completely asymptomatic with this dose, no further dose reduction was necessary. This case report provides evidence that reduced efavirenz doses may be effective in the treatment of HIV infection. In addition, this case demonstrates that pharmacogenetic and pharmacokinetic testing combined with therapeutic drug monitoring may be used to guide reduced-dose, efavirenz-based therapy. [ABSTRACT FROM AUTHOR]

Food can change drug concentrations by several mechanisms, including some that are independent of absorption effects. This study tests the hypothesis that a meal decreases zidovudine (ZDV) concentration in blood plasma independent of an effect on drug absorption. The study was conducted as a substudy nested in a larger protocol in which ZDV was given to 7 healthy men by continuous infusion for 5 days starting on day 1. The subjects received only a standardized breakfast meal on day 2 and were fasted on day 3 until the 8-hour sampling period each day was finished. Blood samples were collected through an indwelling cannula in the arm contralateral to the ZDV infusion at the same time of day on both days. It was found that food decreased the blood plasma ZDV concentration at 1 hour postprandial by 14% (5.0%-22%; geometric mean change with 95% confidence interval). This decrease recovered by 6 hours postprandial. Similar changes were seen with the ZDV primary metabolite, zidovudine glucuronide. The authors conclude that food decreases blood plasma ZDV concentrations independent of any absorption effects. This effect may be due to the increased hepatic metabolism because feeding increases hepatic blood flow and because ZDV has a high hepatic extraction ratio with low affinity to blood plasma proteins. [ABSTRACT FROM PUBLISHER]

The effects of proton pump inhibitors on the pharmacokinetics of atazanavir and amprenavir (administered as fosamprenavir) were rigorously evaluated in healthy volunteers in two studies, but formal studies in persons infected with human immunodeficiency virus (HIV) are lacking. We describe a 65-year-old man with HIV who underwent a 12-hour intensive pharmacokinetic study while receiving esomeprazole with atazanavir-ritonavir and subsequently, an 8-hour study while receiving esomeprazole with fosamprenavir-ritonavir. Consistent with the data in healthy volunteers, a major interaction between esomeprazole and atazauavir-ritonavir was observed in this patient--marked reductions in atazanavir trough plasma concentration and in the area under the concentration-time curve from 0-24 hours--whereas an interaction between esomeprazole and fosamprenavir-ritonavir was not apparent in this patient. [ABSTRACT FROM AUTHOR]

Study Objective. To evaluate and describe the parameters and characteristics of different drug regimens in children infected with human immunodeficiency virus (HIV). Design. Randomized, open-label, multicenter study. Setting. Pediatric HIV research clinics in the United States and Puerto Rico. Patients. Twenty-one H1V-infected children, aged 3-14 years, who were clinically stable and treated with the same antiretroviral therapy for 16 weeks or longer. Intervention. In step 1, children were randomized to receive one of three treatment regimens: zidovudine plus lamivudine, ritonavir plus zidovudine and lamivudine, or ritonavir plus stavudine. Patients originally assigned to the zidovudine plus lamivudine group in step 1 were eligible to progress to step 2 if their HIV RNA values at week 12, 24, or 36 were 10,000 copies/ml or greater but 100,000 copies/ml or less. In step 2 they received a regimen of ritonavir plus stavudine and nevirapine. Measurements and Main Results. Seven children were randomized to each of the three treatment regimens. Concentrations of the agents were quantitated at steady state after observed doses, and the pharmacokinetic parameters were determined. Nevirapine concentrations were not determined. One child was excluded from analysis because pharmacokinetic parameters could not be estimated. Ritonavir oral clearance was slower in the pooled cohort of children who received stavudine compared with zidovudine and lamivudine. Stavudine oral clearance was marginally faster when combined with ritonavir and nevirapine compared with only ritonavir. Conclusion. Therapy for HIV is complex, and pharmacodynamic data indicate that relationships exist between systemic concentrations of antiretroviral drugs and virologic response. Careful drug interaction studies have not been conducted for all treatment regimens, and it will not be surprising if unexpected interactions are found. Pharmacokinetic studies to address... [ABSTRACT FROM AUTHOR]

To understand whether disease caused by the human immunodeficiency virus (HIV) affects zidovudine disposition, we compared the drug's pharmacokinetics in six healthy volunteers; six persons with the acquired immunodeficiency syndrome (AIDS) and no evidence of gastrointestinal (nausea, vomiting, diarrhea), renal (elevated blood urea nitrogen, serum creatinine), or hepatic (elevated liver function tests) disease; and three patients with AIDS and hepatic disease. After a single oral dose of zidovudine, serial blood samples were analyzed for drug concentration by radioimmunoassay. A one-compartment oral absorption model was fit to the concentration-time data. The absorption rate constant (4.05 vs 2.11 hr−1) and time to maximum concentration (0.61 vs 1.03 hr) were significantly different in healthy volunteers versus patients with AIDS without hepatic disease. Differences in half-life, oral clearance, and area under the curve were not statistically significant. In the three patients with AIDS plus hepatic disease, clearance was reduced an average of 63%, and area under the curve was increased by a factor of 2.3. These comparative pharmacokinetic data do not support profound differences between zidovudine's disposition in healthy volunteers and individuals with AIDS; however, the differences and trends that were observed may represent an effect of HIV disease. Although the presence of hepatic disease clearly indicates a need to modify individual dosages, these pharmacokinetic data may have more generalized implications for zidovudine dosing as the relationships between drug concentration and therapeutic or toxic effects are clarified. [ABSTRACT FROM AUTHOR]