Maximum likelihood estimation of renal transporter ontogeny profiles for pediatric PBPK modeling.

Optimal treatment of infants with many renally cleared drugs must account for maturational differences in renal transporter (RT) activity. Pediatric physiologically-based pharmacokinetic (PBPK) models may incorporate RT activity, but this requires ontogeny profiles for RT activity in children, especially neonates, to predict drug disposition. Therefore, RT expression measurements from human kidney postmortem cortical tissue samples were normalized to represent a fraction of mature RT activity. Using these data, maximum likelihood estimated the distributions of RT activity across the pediatric age spectrum, including preterm and term neonates. PBPK models of four RT substrates (acyclovir, ciprofloxacin, furosemide, and meropenem) were evaluated with and without ontogeny profiles using average fold error (AFE), absolute average fold error (AAFE), and proportion of observations within the 5-95% prediction interval. Novel maximum likelihood profiles estimated ontogeny distributions for the following RT: OAT1, OAT3, OCT2, P-gp, URAT1, BCRP, MATE1, MRP2, MRP4, and MATE-2 K. Profiles for OAT3, P-gp, and MATE1 improved infant furosemide and neonate meropenem PBPK model AFE from 0.08 to 0.70 and 0.53 to 1.34 and model AAFE from 12.08 to 1.44 and 2.09 to 1.36, respectively, and improved the percent of data within the 5-95% prediction interval from 48% to 98% for neonatal ciprofloxacin simulations, respectively. Even after accounting for other critical population-specific maturational differences, novel RT ontogeny profiles substantially improved neonatal PBPK model performance, providing validated estimates of maturational differences in RT activity for optimal dosing in children.

Pre-medication protocols for the prevention of paclitaxel-induced infusion related reactions: a systematic review and meta-analysis.

BACKGROUND: Prophylaxis against infusion-related reactions (IRR) from paclitaxel with steroids and antihistamines is a standard of care due to high rates of IRR. This systematic review and meta-analysis aimed to comprehensively summarize the evidence behind various prophylaxis strategies. METHODS: EMBASE, MEDLINE, PubMed, and the Cochrane Register of Controlled Trials were searched (1946 to May 14, 2021). The primary outcomes were Grade 3/4 IRR and any-grade IRR. Secondary outcomes included treatment delay or discontinuation and adverse events secondary to pre-medications. RESULTS: Of the 1285 unique citations, 26 studies were selected: 11 studies for quantitative analysis and 15 studies for qualitative analysis. Studies included randomized controlled trials and observational studies (n = 25-281). There was a non-significant benefit in favour of oral steroids starting 12 h prior to paclitaxel administration versus intravenous steroids immediately prior to paclitaxel administration for grade 3/4 IRRs, with a risk difference (RD) of 2% [95%CI 0 to 5%], any-grade IRR with a RD of 4% [95%CI: -1% to 9%] and treatment discontinuation with a RD of 1% [95%CI -1% to 2%]. For de-escalation strategies, a point-estimate for any-grade IRR was 0.44% [95% CI, 0 to 0.02, p = 0.98] and for grade 3/4 IRR was 3.1% (95% CI, 0.02 to 0.07, p = 0.11). CONCLUSION: Although studies have high risk of bias and risk, differences between steroid routes of administration were small, there was a non-significant trend in favour of oral steroids. De-escalation strategies after two previous successful paclitaxel infusions have an overall low incidence rate of severe IRR and warrant further prospective clinical trials. Insufficient evidence remains to recommend for or against other interventions for the prevention of paclitaxel IRR.

Management of anticoagulation in patients with metastatic castration-resistant prostate cancer receiving abiraterone + prednisone.

PURPOSE: Abiraterone has been proven to be an effective agent used in the management of metastatic castration-resistant prostate cancer, significantly improving overall and progression-free survival. Due to the pharmacodynamic and pharmacokinetic properties of abiraterone, concurrent use with anticoagulation may pose a challenge for clinicians. Thrombosis within the cancer setting continues to increase patient mortality; therefore, appropriate anticoagulation through the use of a management algorithm can reduce adverse events and increase quality of life. METHODS: A review of the literature was preformed by a medical oncologist, haematologist and pharmacists to identify relevant randomized controlled trials, meta-analyses and retrospective studies. Major society guidelines were reviewed to further aid in developing the anticoagulation protocol for non-valvular atrial fibrillation and venous thromboembolism within this patient population. After reviewing the literature, a clinical framework was designed to aid clinicians in the management of those patients receiving abiraterone concurrently with an anticoagulant. RESULTS: In this review, we describe the potential interactions between abiraterone and various anticoagulants and provide management strategies based on the most recent literature for atrial fibrillation, venous thromboembolism and mechanical heart valves to avoid potential drug-drug interactions. CONCLUSION: Abiraterone therapy has become a mainstay of the management of advanced prostate cancer and is often used over prolonged years. In this review, we have summarized a framework of how to use abiraterone in men with prostate cancer on anticoagulants. Evidence available to date suggests that patients with an indication for anticoagulation such as atrial fibrillation, venous thromboembolism and mechanical heart valves can be treated safely with abiraterone in the appropriate setting, with appropriate monitoring.