Full Validation and Application to Clinical Research of a High-Performance Liquid Chromatography Method for the Assessment of Urinary 3-Indoxyl Sulfate in Pediatric Patients with Hematopoietic Stem Cell Transplant.

3-indoxyl sulfate (3-IS) results from a hepatic transformation of indole, a tryptophan degradation product produced by commensal gut bacteria. The metabolite has shown promise as a biomarker of dysbiosis and clinical outcomes following hematopoietic stem cell transplant (HSCT) in adults. Nonetheless, there is a paucity of data regarding microbiome health and outcomes in the pediatric HSCT setting. We developed and thoroughly validated an affordable high-performance liquid chromatography/fluorescence detector (HPLC-FLD) method to quantify 3-IS in urine for use in the pediatric setting. Chromatographic separation was achieved on a C18 column (250 × 4.6 mm × 5 µm) with a mobile phase consisting of pH 4.0 acetic acid-triethylamine buffer and acetonitrile (88:12, v/v), eluted isocratically at 1 mL/min. 3-IS fluorescence detection was set at excitation/emission of 280 and 375, respectively. The method was fully validated according to FDA-specified limits including selectivity, linearity (0.10 to 10.00 mg/L, r2 > 0.997), intra- and inter-day accuracy, and precision. 3-IS stability was confirmed after three freeze-thaw cycles, for short- and medium-term on a benchtop and at 4 °C and for long-term up to 60 days at -20 °C. The validated method was used to quantify 3-IS in urine samples from HSCT pediatric patients.

The importance of basic and translational research in caring for children with malignant solid tumors in Latin America.

Objective: Basic and translational research in pediatric cancer are essential to improve patient care. To critically assess the developments achieved in these areas in Latin America, we systematically reviewed information published between 2013 and 2023. Methods: Studies of basic and translational research performed by investigators in Latin America evaluating pediatric malignant solid and central nervous system tumors were retrieved from PubMed. Original articles published in English between 2013 and 2023 were included. Collaborations among Latin American authors or among Latin American authors working with researchers from other continents were also included. Studies were excluded if they focused only on adults or on basic research in tumor biology not specifically related to the tumor types analyzed in this review. Results: A total of 550 articles were retrieved, but after removal of duplicates, 514 articles were included in the analysis, the majority of which were authored by researchers affiliated with institutions in Argentina, Brazil and Mexico. These countries also had the highest number of collaborations on original articles published with authors from Europe and North America. Argentina had the highest number of collaborations on original publications, with coauthors from Brazil and Uruguay. The median impact factor of the 244 journals in which articles were published was 3.5. The most commonly studied tumors were osteosarcomas, neuroblastomas and medulloblastomas; the most commonly studied areas were molecular analysis, tumor cell biology and biomarkers. Conclusions: In Latin America, research in pediatric oncology is on the agenda, despite a notable disparity in publication rates and frequency of collaboration between countries. There is a need to strengthen scientific collaboration within Latin America and with countries from other continents to promote research and to develop novel treatment strategies that reflect the local needs of children in Latin America who have solid tumors and brain cancer.

Feasibility of steroid-free tacrolimus-basiliximab immunosuppression in pediatric liver transplantation and predictors for steroid requirement.

Avoidance of steroids in pediatric liver transplantation may reduce toxicity and morbidity. The aim of this study was to analyze the feasibility of a steroid-free tacrolimus-basiliximab immunosuppression scheme, the risk factors associated with steroid requirement, and safety parameters. Patients who underwent liver transplantation for biliary atresia between 2011 and 2019 were included and followed for 6 months after transplantation. Immunosuppression consisted of tacrolimus-based treatment with basiliximab induction. Steroid-free survival was estimated, and risk factors for steroid requirement were evaluated using multivariate Cox regression analysis. A total of 76 patients were included, of whom 42 (55.3%) required steroids (>14 d) due to biopsy-proven acute rejection (47.6%, n = 20), instability in liver function tests (35.7%, n = 15), tacrolimus-related adverse drug reactions (14.3%, n = 6), or other reasons (bronchospasm episode, n = 1). Steroid-free survival was 45.9% (95% CI, 35.9-58.8). Independent factors associated with steroid requirement included tortuosity in tacrolimus trough levels (≥1.76 vs. <1.76: HR 5.8, 95% CI, 2.6-12.7; p < 0.001) and mean tacrolimus trough levels (≥ 6.4 ng/mL vs. < 6.4 ng/mL: HR 0.4, 95% CI, 0.2-0.7; p = 0.002). The rate of bacterial and viral infections was comparable between patients with and without steroids, although in the former group, cytomegalovirus infection developed earlier ( p = 0.03). Patients receiving steroids had higher total cholesterol, LDL, and HDL levels ( p < 0.05) during follow-up, but no changes in the height Z-score were observed 1 year after transplantation. Basiliximab induction in combination with tacrolimus-based treatment avoided steroid requirements in 45% of the patients. Tacrolimus variability and trough levels below 6.4 ng/mL independently increased the risk of steroid requirement. Further efforts should be focused on personalizing immunosuppressive treatment.

The importance of basic and translational research in caring for children with malignant solid tumors in Latin America / La importancia de la investigación básica y aplicada para la atención de pacientes pediátricos con tumores sólidos malignos en América Latina / A importância da pesquisa básica e translacional no tratamento de crianças com tumores sólidos malignos na América Latina

ABSTRACT Objective. Basic and translational research in pediatric cancer are essential to improve patient care. To critically assess the developments achieved in these areas in Latin America, we systematically reviewed information published between 2013 and 2023. Methods. Studies of basic and translational research performed by investigators in Latin America evaluating pediatric malignant solid and central nervous system tumors were retrieved from PubMed. Original articles published in English between 2013 and 2023 were included. Collaborations among Latin American authors or among Latin American authors working with researchers from other continents were also included. Studies were excluded if they focused only on adults or on basic research in tumor biology not specifically related to the tumor types analyzed in this review. Results. A total of 550 articles were retrieved, but after removal of duplicates, 514 articles were included in the analysis, the majority of which were authored by researchers affiliated with institutions in Argentina, Brazil and Mexico. These countries also had the highest number of collaborations on original articles published with authors from Europe and North America. Argentina had the highest number of collaborations on original publications, with coauthors from Brazil and Uruguay. The median impact factor of the 244 journals in which articles were published was 3.5. The most commonly studied tumors were osteosarcomas, neuroblastomas and medulloblastomas; the most commonly studied areas were molecular analysis, tumor cell biology and biomarkers. Conclusions. In Latin America, research in pediatric oncology is on the agenda, despite a notable disparity in publication rates and frequency of collaboration between countries. There is a need to strengthen scientific collaboration within Latin America and with countries from other continents to promote research and to develop novel treatment strategies that reflect the local needs of children in Latin America who have solid tumors and brain cancer.

RESUMEN Objetivo. La investigación básica y aplicada en el campo de la oncología pediátrica es fundamental para mejorar la atención al paciente. Con el objetivo de realizar una evaluación crítica de los avances logrados en este campo en América Latina, hemos realizado una revisión sistemática de la información publicada entre el 2013 y el 2023. Metodología. Se recopilaron de PubMed los artículos de investigación básica y traslacional publicados por investigadores de América Latina en los que se evaluaron tumores malignos sólidos y del sistema nervioso central en la población infantil. Se incluyeron artículos originales publicados en inglés entre el 2013 y el 2023. También se incluyeron artículos fruto de la colaboración científica entre autores e investigadores de América Latina y otros continentes. Se excluyeron aquellos estudios que se centraron solo en personas adultas o en la investigación básica en biología tumoral no relacionada específicamente con los tipos de tumores analizados en esta revisión. Resultados. Se encontraron 550 artículos en total. Después de eliminar los artículos duplicados, se incluyeron 514 artículos en la revisión, la mayoría de los cuales fueron escritos por investigadores vinculados a centros de investigación de Argentina, Brasil y México. También procedieron de estos tres países la mayor parte de los artículos originales escritos en colaboración con autores de Europa y América del Norte. Argentina tuvo el mayor número de colaboraciones en publicaciones originales, con coautores de Brasil y Uruguay. La mediana del índice de impacto de las 244 revistas en las que se publicaron los artículos fue de 3,5. Los tumores más estudiados fueron osteosarcomas, neuroblastomas y meduloblastomas. Los temas más estudiados fueron el análisis molecular, la biología de las células tumorales y los biomarcadores. Conclusiones. La investigación en oncología pediátrica forma parte de la agenda de investigación de América Latina, si bien hay una disparidad notoria en las tasas de publicación y la frecuencia de la colaboración entre países. Es necesario fortalecer la colaboración científica dentro de América Latina y con los países de otros continentes para promover la investigación y desarrollar estrategias de tratamiento novedosas que respondan a las necesidades locales de los niños y niñas de América Latina que tienen tumores sólidos o cáncer del sistema nervioso central.

RESUMO Objetivo. A pesquisa básica e translacional em câncer pediátrico é essencial para melhorar o atendimento dos pacientes. No intuito de realizar uma avaliação crítica dos avanços alcançados nessa área na América Latina, fez-se uma revisão sistemática de informações publicadas entre 2013 e 2023. Métodos. Pesquisas básicas e translacionais realizadas por pesquisadores da América Latina que avaliaram tumores sólidos malignos e tumores do sistema nervoso central em crianças foram obtidas da base de dados PubMed. Foram incluídos artigos originais publicados em inglês entre 2013 e 2023. Também foram incluídas colaborações entre autores latino-americanos ou entre autores latino-americanos que trabalham com pesquisadores de outros continentes. Estudos que tratavam apenas de adultos ou pesquisas básicas sobre biologia tumoral não especificamente relacionadas aos tipos de tumor analisados nesta revisão foram excluídos. Resultados. No total, a busca recuperou 550 artigos da base de dados. Após a remoção dos artigos duplicados, foram incluídos 514 artigos na análise, a maioria de autoria de pesquisadores de instituições da Argentina, do Brasil e do México. Esses países também tiveram o maior número de colaborações em artigos originais publicados com autores da Europa e da América do Norte. A Argentina teve o maior número de colaborações em publicações originais, com coautores do Brasil e do Uruguai. O fator de impacto mediano dos 244 periódicos nos quais os artigos foram publicados era de 3,5. Os tumores mais estudados foram osteossarcomas, neuroblastomas e meduloblastomas; as áreas mais estudadas foram análise molecular, biologia de células tumorais e biomarcadores. Conclusões. Na América Latina, a pesquisa em oncologia pediátrica está na ordem do dia, apesar de uma evidente disparidade nos índices de publicação e na frequência de colaboração entre os países. É necessário fortalecer a colaboração científica dentro da América Latina e com países de outros continentes a fim de promover a pesquisa e desenvolver novas estratégias de tratamento que reflitam as necessidades locais das crianças latino-americanas com tumores sólidos e câncer cerebral.

Establishment and Comprehensive Characterization of a Novel Preclinical Platform of Metastatic Retinoblastoma for Therapeutic Developments.

Purpose: Although there have been improvements in the management of metastatic retinoblastoma, most patients do not survive, and all patients suffer from multiple short- and long-term treatment toxicities. Reliable and informative models to assist clinicians are needed. Thus we developed and comprehensively characterized a novel preclinical platform of primary cell cultures and xenograft models of metastatic retinoblastoma to provide insights into the molecular biology underlying metastases and to perform drug screening for the identification of hit candidates with the highest potential for clinical translation. Methods: Orbital tumor, bone marrow, cerebrospinal fluid, and lymph node tumor infiltration specimens were obtained from seven patients with metastatic retinoblastoma at diagnosis, disease progression, or relapse. Tumor specimens were engrafted in immunodeficient animals, and primary cell lines were established. Genomic, immunohistochemical/immunocytochemical, and pharmacological analysis were performed. Results: We successfully established five primary cell lines: two derived from leptomeningeal, two from orbital, and one from lymph node tumor dissemination. After the intravitreal or intraventricular inoculation of these cells, we established cell-derived xenograft models. Both primary cell lines and xenografts accurately retained the histological and genomic features of the tumors from which they were derived and faithfully recapitulated the dissemination patterns and pharmacological sensitivity observed in the matched patients. Conclusions: Ours is an innovative and thoroughly characterized preclinical platform of metastatic retinoblastoma developed for the understanding of tumor biology of this highly aggressive tumor and has the potential to identify drug candidates to treat patients who currently lack effective treatment options.

Population Pharmacodynamic Modelling of the CD19+ Suppression Effects of Rituximab in Paediatric Patients with Neurological and Autoimmune Diseases.

BACKGROUND: Limited pharmacotherapy and the failure of conventional treatments in complex pathologies in children lead to increased off-label use of rituximab. We aimed to characterize the time course of CD19+ B lymphocytes (CD19+) under treatment with intravenous rituximab in children with neurologic and autoimmune diseases and to evaluate the impact of covariates (i.e., demographics, diagnosis and substitution between innovator and biosimilar product) on rituximab pharmacodynamics and disease activity. METHODS: Pre- and post-drug infusion CD19+ in peripheral blood were prospectively registered. A population pharmacodynamic model describing the time course of CD19+ was developed with NONMEM v7.4. Simulations of three different rituximab regimens were performed to assess the impact on CD19+. Logistic regression analysis was performed to identify predictors of clinical response recorded through disease activity scores. RESULTS: 281 measurements of CD19+ lymphocyte counts obtained from 63 children with neurologic (n = 36) and autoimmune (n = 27) diseases were available. The time course of CD19+ was described with a turn-over model in which the balance between synthesis and degradation rates is disrupted by rituximab, increasing the latter process. The model predicts half-lives (percent coefficient of variation, CV(%)) of rituximab and CD19+ of 11.6 days (17%) and 173.3 days (22%), respectively. No statistically significant effect was found between any of the studied covariates and model parameters (p > 0.05). Simulations of different regimens showed no clinically significant differences in terms of CD19+ repopulation times. A trend towards a lack of clinical response was observed in patients with lower CD19+ repopulation times and higher areas under the CD19+ versus time curve. CONCLUSIONS: Rituximab pharmacodynamics was described in a real-world setting in children suffering from autoimmune and neurologic diseases. Diagnosis, substitution between innovator rituximab and its biosimilars or type of regimen did not affect rituximab-induced depletion of CD19+ nor the clinical response in this cohort of patients. According to this study, rituximab frequency and dosage may be chosen based on clinical convenience or safety reasons without affecting CD19+ repopulation times. Further studies in larger populations are required to confirm these results.

Treatment of graft versus host disease with photopheresis interferes in voriconazole therapeutic drug monitoring: A case study.

Extracorporeal photopheresis is an established procedure for refractory graft-versus-host disease, a major complication associated with notable morbidity and mortality in patients with allogeneic hematopoietic stem cell transplant. Despite being implemented over a decade ago, there is scant information about potential interactions or analytical interferences with concomitant drugs in this polymedicated population. Here we report the case of a pediatric patient diagnosed with cutaneous steroid-refractory acute graft-versus-host disease after unrelated allogeneic hematopoietic stem cell transplant that was treated with photopheresis. Analytical quantification of voriconazole by HPLC-PDA the day following photopheresis treatment did not permit therapeutic drug monitoring (TDM) due to the presence of interference at the voriconazole retention time. Following investigations, it was demonstrated that the interference is likely attributable to a psoralen-based compound. The interference was not present when samples were obtained prior to photopheresis, enabling TDM. This case underscores the relevance of communication among the members of the treating team to perform reliable TDM, especially in routine clinical practice of pediatric patients with complex diseases undergoing innovative treatments. This finding is relevant to voriconazole quantification by HPLC-PDA, frequently used in laboratories based in middle-income countries.

Pharmacokinetics of Orbital Topotecan After Ophthalmic Artery Chemosurgery and Intravenous Infusion in the Swine Model.

Purpose: Surgery, multiagent systemic chemotherapy, and radiation are used for patients with orbital retinoblastoma but are associated with unacceptable short- and long-term toxicity (including death). We studied orbital and systemic exposure of topotecan in the swine model after ophthalmic artery chemosurgery (OAC) and intravenous (IV) delivery. Methods: Landrace pigs (n = 3) underwent 30-minute OAC of topotecan (4 mg), and samples were serially obtained from the femoral artery and from a microdialysis probe inserted into the lateral rectus muscle sheath of the infused eye as a surrogate of the orbital irrigation. Animals were recovered, and, after a wash-out period, plasma and microdialysate samples from the contralateral eye were collected after a 30-minute IV infusion of topotecan (4 mg). Samples were quantified by high-performance liquid chromatography, and population pharmacokinetic analysis was conducted using MonolixSuite. Results: After OAC, median topotecan exposure in the orbit was 5624 ng × h/mL (range 3922-12531) compared to 23 ng × h/mL (range 18-75) after IV infusion. Thus, topotecan exposure in the orbit was 218-fold (range 75-540) higher after OAC than after IV infusion despite comparable systemic exposure (AUCpl) between routes (AUCpl, OAC: 141 ng × h/mL [127-191] versus AUCpl, IV: 139 ng × h/mL [126-186]). OAC was more selective to target the orbit because the median (range) orbital-to-plasma exposure ratio was 44 (28-65) after OAC compared to 0.18 (0.13-0.40) after IV infusion. Conclusions: OAC of topotecan resulted in higher orbital exposure than after IV infusion and was a more selective route for local drug delivery. Patients with orbital retinoblastoma may benefit from a multimodal treatment strategy including OAC therapy.

Real-World Evidence of Factors Affecting Cannabidiol Exposure in Children with Drug-Resistant Developmental and Epileptic Encephalopathies.

The identification of factors that affect cannabidiol (CBD) systemic exposure may aid in optimizing treatment efficacy and safety in clinical practice. In this study, we aimed to correlate CBD plasma concentrations at a steady state to demographic, clinical, and pharmacological characteristics as well as seizure frequency after the administration of a purified CBD oil solution in a real-world setting of children with drug-resistant developmental and epileptic encephalopathies (DEEs). Patients receiving oral CBD pharmaceutical products at maintenance were enrolled. Venous blood samples were drawn before the CBD morning dose, 12 h apart from the last evening dose (C0 or CBD trough concentration). A linear mixed-effect analysis was implemented to assess the correlation between C0 and clinical, laboratory, pharmacological, and lifestyle factors. Fifteen females and seven males with a median age of 12.8 years (ranging between 4.7 and 17.2) were included. The median CBD dose was 8.8 mg/kg/day (ranging between 2.6 and 22.5), and the CBD C0 median (range) was 48.2 ng/mL (3.5-366.3). The multivariate model showed a 109.6% increase in CBD C0 in patients with concomitant levothyroxine (ß = 0.74 ± 0.1649, p < 0.001), 56.8% with food (ß = 0.45 ± 0.1550, p < 0.01), and 116.0% after intake of a ketogenic diet (ß = 0.77 ± 0.3141, p < 0.05). All patients included were responders without evidence of an association between C0 and response status. In children with DEEs, systemic concentrations of CBD may be significantly increased when co-administered with levothyroxine, food, or a ketogenic diet.

A Systematic Review of High-Dose Methotrexate for Adults with Primary Central Nervous System Lymphoma.

Primary central nervous system lymphoma (PCNSL) is a highly aggressive non-Hodgkin lymphoma that is confined within the CNS. Due to its ability to cross the blood-brain barrier, high-dose methotrexate (HDMTX) is the backbone for induction chemotherapy. This systematic review was conducted to observe outcomes among different HDMTX doses (low, <3 g/m2; intermediate, 3-4.9 g/m2; high, ≥5 g/m2) and regimens used in the treatment of PCNSL. A PubMed search resulted in 26 articles reporting clinical trials using HDMTX for PCNSL, from which 35 treatment cohorts were identified for analysis. The median dose of HDMTX used for induction was 3.5 g/m2 (interquartile range IQR, 3-3.5); the intermediate dose was most frequently used in the studies examined (24 cohorts, 69%). Five cohorts used HDMTX monotherapy, 19 cohorts used HDMTX + polychemotherapy, and 11 cohorts used HDMTX + rituximab ± polychemotherapy. Pooled overall response rate (ORR) estimates for low, intermediate, and high dose HDMTX cohorts were 71%, 76%, and 76%, respectively. Pooled 2-year progression-free survival (PFS) estimates for low, intermediate, and high HDMTX dose cohorts were 50%, 51%, and 55%, respectively. Regimens that included rituximab showed a tendency to have higher ORR and 2-year PFS than those that did not include rituximab. These findings indicate that current protocols utilizing 3-4 g/m2 of HDMTX in combination with rituximab provide therapeutic efficacy in PCNSL.

Retinoblastoma seeds: impact on American Joint Committee on Cancer clinical staging.

AIM: To investigate whether the American Joint Committee on Cancer (AJCC) clinical category cT2b needs to be subclassified by the type and distribution of retinoblastoma (RB) seeding. METHODS: Multicentre, international registry-based data were collected from RB centres enrolled between January 2001 and December 2013. 1054 RB eyes with vitreous or subretinal seeds from 18 ophthalmic oncology centres, in 13 countries within six continents were analysed. Local treatment failure was defined as the use of secondary enucleation or external beam radiation therapy (EBRT) and was estimated with the Kaplan-Meier method. RESULTS: Clinical category cT2b included 1054 eyes. Median age at presentation was 16.0 months. Of these, 428 (40.6%) eyes were salvaged, and 430 (40.8%) were treated with primary and 196 (18.6%) with secondary enucleation. Of the 592 eyes that had complete data for globe salvage analysis, the distribution of seeds was focal in 143 (24.2%) and diffuse in 449 (75.8%). The 5-year Kaplan-Meier cumulative globe-salvage (without EBRT) was 78% and 49% for eyes with focal and diffuse RB seeding, respectively. Cox proportional hazards regression analysis confirmed a higher local treatment failure risk with diffuse seeds as compared with focal seeds (hazard rate: 2.8; p<0.001). There was insufficient evidence to prove or disprove an association between vitreous seed type and local treatment failure risk(p=0.06). CONCLUSION: This international, multicentre, registry-based analysis of RB eyes affirmed that eyes with diffuse intraocular distribution of RB seeds at diagnosis had a higher risk of local treatment failure when compared with focal seeds. Subclassification of AJCC RB category cT2b into focal vs diffuse seeds will improve prognostication for eye salvage.

Population pharmacokinetics of sublingually administered tacrolimus in infants and young children with liver transplantation.

AIMS: Pharmacokinetics of tacrolimus after sublingual administration is not characterized in paediatric liver transplant patients. Therefore, we aimed to develop a population pharmacokinetic model of sublingually administered tacrolimus in patients who cannot swallow the capsules due to their age, sedation status and/or mechanical ventilation during the first weeks post-transplantation. METHODS: Demographic, clinical and pharmacological variables, including tacrolimus whole blood concentrations obtained from therapeutic drug monitoring and data from dense-sampling pharmacokinetic profiles, were recorded in 26 paediatric patients with biliary atresia who underwent liver transplantation between 2016 and 2021. Population pharmacokinetic analysis was performed with NONMEM v7.4. RESULTS: Disposition of tacrolimus was best characterized by a 2-compartment model with clearance achieving half of the maximum elimination capacity (CLMAX  = 4.1 L/h) at 4.6 days post-transplantation (T50 ). Compared to sedated patients, nonsedated status showed an increased first-order absorption rate constant (1.1 vs. 0.1 h-1 ) and a 24% reduction in bioavailability (FNS ) at 14 days post-transplant. The model was able to explain the oral absorption pattern in nonsedated patients as the result of gut bioavailability (0.9) and hepatic extraction ratio, with the latter being responsible for first-pass effects. Estimates of interindividual variability remained moderate (25.9% for the gut bioavailability) to high (79.8% for the apparent volume of distribution of the central compartment, and 101% for T50 ). CONCLUSION: A population pharmacokinetic model of sublingually administered tacrolimus in paediatric patients was developed to characterize different absorption mechanisms. Once the model is externally validated, the effect of post-transplant time on clearance and the sedation status may be considered in routine dosing management.

A pharmacometrics model to define docetaxel target in early breast cancer.

AIMS: We aimed to study the relation between pharmacokinetics (PK) and pharmacodynamics (PD) of docetaxel in early breast cancer and recommend a target exposure. METHODS: A PK/PD study was performed in 27 early breast cancer patients treated with doxorubicin and cyclophosphamide for 4 cycles followed by 4 cycles of docetaxel 75-100 mg/m2 infused every 21 days. Individual Bayesian estimates of docetaxel PK parameters were obtained using a nonparametric population PK model developed with data from patients with metastatic breast cancer who received dose-intensified docetaxel (300-350 mg/m2 ). Docetaxel area under the curve (AUC) and maximum concentration (Cmax) in each cycle and total cumulative AUC (AUCcum) were calculated and related to the incidence of adverse effects and tumour recurrence. RESULTS: Docetaxel clearance showed no change over the 4 treatment cycles, but a gradual increase in the volume of distribution was observed. One third of the patients had at least 1 dose reduction of docetaxel due to toxicity. The mean AUC, AUCcum and Cmax in patients showing docetaxel-associated adverse events were significantly higher than in patients free of toxicity (P < .05). Fatigue and decrease in haemoglobin and haematocrit levels were related to docetaxel AUC and Cmax and pain to AUC. AUC and Cmax >4.5 mg*h/L and 3.5 mg/L, respectively, were risk factors for docetaxel toxicity, while an AUC <4.5 mg*h/L was associated with tumour recurrence. CONCLUSION: We report for the first time a relation between docetaxel exposure and toxicity and recommend specific targets of drug exposure with implications for the clinical management of early breast cancer patients.

Follow-up of intraocular retinoblastoma through the quantitative analysis of conserved nuclear DNA sequences in aqueous humor from patients.

Fundoscopy is the standard method for diagnosis and follow-up of intraocular retinoblastoma, but it is sometimes insufficient to discern whether tumors are inactivated following treatments. In this work, we hypothesized that the amount of conserved nuclear DNA sequences in the cell-free DNA (cfDNA) fraction of the aqueous humor (AH) might complement fundoscopy for retinoblastoma follow-up. To address our hypothesis, we developed highly sensitive droplet digital polymerase chain reaction (ddPCR) methods to quantify highly conserved DNA sequences of nucleus-encoded genes (GAPDH and B4GALNT1) and of a mitochondrial gene, MT-ATP6. We obtained AH samples during intravitreal treatments. We analyzed 42 AH samples from 25 patients with intraocular retinoblastoma and 11 AH from controls (non-cancer patients). According to clinical criteria, we grouped patients as having progression-free or progressive retinoblastoma. cfDNA concentration in the AH was similar in both retinoblastoma groups. Copy counts for nucleus-derived sequences of GAPDH and B4GALNT1 were significantly higher in the AH from patients with progressive disease, compared to the AH from progression-free patients and control non-cancer patients. The presence of mitochondrial DNA in the AH explained that both retinoblastoma groups had similar cfDNA concentration in AH. The optimal cut-off point for discriminating between progressive and progression-free retinoblastomas was 108 GAPDH copies per reaction. Among patients having serial AH samples analyzed during their intravitreal chemotherapy, GAPDH copies were high and decreased below the cut-off point in those patients responding to chemotherapy. In contrast, one non-responder patient remained with values above the cut-off during follow-up, until enucleation. We conclude that the measurement of conserved nuclear gene sequences in AH allows follow-up of intraocular retinoblastoma during intravitreal treatment. The method is applicable to all patients and could be relevant for those in which fundoscopy evaluation is inconclusive.

Insights from a pharmacometric analysis of HDMTX in adults with cancer: Clinically relevant covariates for application in precision dosing.

AIMS: High-dose methotrexate (HDMTX) is an essential part of the treatment of several adult and paediatric malignancies. Despite meticulous supportive care during HDMTX administration, severe toxicities, including acute kidney injury (AKI), may occur contributing to patient morbidity. Population pharmacokinetics provide a powerful tool to predict time to clear HDMTX and adjust subsequent doses. We sought to develop and validate pharmacokinetic models for HDMTX in adults with diverse malignancies and to relate systemic exposure with the occurrence of severe toxicity. METHODS: Anonymized, de-identified data were provided from 101 US oncology practices that participate in the Guardian Research Network, a non-profit clinical research consortium. Modelled variables included clinical, laboratory, demographic and pharmacological data. Population pharmacokinetic analysis was performed by means of nonlinear mixed effects modelling using MonolixSuite. RESULTS: A total of 693 HDMTX courses from 243 adults were analysed, of which 62 courses (8.8%) were associated with stage 2/3 acute kidney injury (43 stage 2, 19 stage 3). A three-compartment model adequately fitted the data. Time-dependent serum creatinine, baseline serum albumin and allometrically scaled bodyweight were clinically significant covariates related to methotrexate clearance. External evaluation confirmed a satisfactory predictive performance of the model in adults receiving HDMTX. Dose-normalized methotrexate concentration at 24 and 48 hours correlated with AKI incidence. CONCLUSION: We developed a population pharmacometric model that considers weight, albumin and time-dependent creatinine that can be used to guide supportive care in adult patients with delayed HDMTX elimination.

[Performance evaluation of a precision dosing service for vancomycin in a tertiary level pediatric hospital]. / Una evaluación de desempeño del servicio de dosificación de precisión para vancomicina en un hospital pediátrico de nivel terciario.

Background: Plasma level-based therapeutic drug monitoring of vancomycin is recommended in the treatment of complex pediatric infections in order to increase the probability of achieving safe and effective pharmacotherapy. Objective: To retrospectively evaluate the activities and performance of pharmacotherapeutic optimization based on vancomycin levels at a tertiary pediatric hospital between 2007 and 2020. Métodos: Vancomycin levels of pediatric patients were analyzed, assessing care quality indicators and analytical verifications, as well as aspects related to teaching and research. The predictive performance of vancomycin levels was evaluated after adjustment of the therapeutic regimen using a population pharmacokinetic optimization program (BestDose v1.126) considering the coefficient of determination (R2), the mean absolute percentage error (MAPE), and the root mean square error (RMSE). Results: 13269 vancomycin level determinations were analyzed; 70% were trough levels and 81% belonged to patients in the intensive care units. Forty percent of the trough levels were within the therapeutic range when adjusted without software. Three hundred seventy-four pharmacotherapeutic interventions, of which 97% were accepted by the treating physician; 75% of the post-adjustment trough levels were within the therapeutic range, compared to 40% when the approach was empirical, a difference that was statistically significant (p=0.03). The values associated with predictive performance (n subgroup of patients = 91) were: R2=0.61, MAPE=28.16%, and RMSE=3.3, which all showed to be adequate. Conclusion: The performance of therapeutic vancomycin monitoring and related pharmacokinetic clinical activities showed to be good.

Introducción: La dosificación de precisión a través del monitoreo de vancomicina basado en sus concentraciones plasmáticas (vancocinemia) es una práctica recomendada en el tratamiento de infecciones pediátricas de alta complejidad para aumentar la probabilidad de lograr una farmacoterapia segura y eficaz. Objetivo: Evaluar retrospectivamente las actividades y el desempeño relacionado a la optimización farmacoterapéutica basada en las vancocinemias (período 2007-2020) de un hospital pediátrico terciario. Métodos: Se analizaron las vancocinemias de pacientes pediátricos, estimándose indicadores de calidad asistencial y verificaciones analíticas, así como también aspectos relacionados a docencia e investigación. Se evaluó el desempeño predictivo de las concentraciones de vancomicina cuando se ajustaron los regímenes terapéuticos con un programa de optimización farmacocinética (BestDose v1.126) considerando el coeficiente de determinación (R2), el error porcentual absoluto medio (MAPE) y la raíz del error cuadrático medio (RMSE). Resultados: Se analizaron 13269 vancocinemias. El 70% fueron valles y el 81% pertenecieron a pacientes de Unidades de Cuidados Intensivos. El 40% de los valles se encontró dentro del margen terapéutico al ajustarse sin programa informático. Se realizaron 347 intervenciones farmacoterapéuticas, el 97% de las cuales fueron aceptadas por el médico tratante; el 75% de los valles posteriores al ajuste entraron en el margen terapéutico, valor significativamente mayor respecto al 40% de cuando el abordaje fue empírico (p=0.03). Los valores asociados al desempeño predictivo, (n subgrupo de pacientes = 91) fueron: R2=0.61, MAPE=28.16% y RMSE=3.3, mostrándose todos adecuados. Conclusión: Las actividades de monitoreo y farmacocinética clínica de vancomicina mostraron un buen rendimiento clínico. Resultados: Se analizaron 13269 vancocinemias. El 70% fueron valles y el 81% pertenecieron a pacientes de Unidades de Cuidados Intensivos. El 40% de los valles se encontró dentro del margen terapéutico al ajustarse sin programa informático. Se realizaron 347 intervenciones farmacoterapéuticas, el 97% de las cuales fueron aceptadas por el médico tratante; el 75% de los valles posteriores al ajuste entraron en el margen terapéutico, valor significativamente mayor respecto al 40% de cuando el abordaje fue empírico (p=0.03). Los valores asociados al desempeño predictivo, (n subgrupo de pacientes = 91) fueron: R2=0.61, MAPE=28.16% y RMSE=3.3, mostrándose todos adecuados. Conclusión: Las actividades de monitoreo y farmacocinética clínica de vancomicina mostraron un buen rendimiento clínico.

Metastatic Death Based on Presenting Features and Treatment for Advanced Intraocular Retinoblastoma: A Multicenter Registry-Based Study.

PURPOSE: To evaluate presenting features, tumor size, and treatment methods for risk of metastatic death due to advanced intraocular retinoblastoma (RB). DESIGN: International, multicenter, registry-based retrospective case series. PARTICIPANTS: A total of 1841 patients with advanced RB. METHODS: Advanced RB was defined by 8th edition American Joint Committee on Cancer (AJCC) categories cT2 and cT3 and new AJCC-Ophthalmic Oncology Task Force (OOTF) Size Groups (1: < 50% of globe volume, 2: > 50% but < 2/3, 3: > 2/3, and 4: diffuse infiltrating RB). Treatments were primary enucleation, systemic chemotherapy with secondary enucleation, and systemic chemotherapy with eye salvage. MAIN OUTCOME MEASURES: Metastatic death. RESULTS: The 5-year Kaplan-Meier cumulative survival estimates by patient-level AJCC clinical subcategories were 98% for cT2a, 96% for cT2b, 88% for cT3a, 95% for cT3b, 92% for cT3c, 84% for cT3d, and 75% for cT3e RB. Survival estimates by treatment modality were 96% for primary enucleation, 89% for systemic chemotherapy and secondary enucleation, and 90% for systemic chemotherapy with eye salvage. Risk of metastatic mortality increased with increasing cT subcategory (P < 0.001). Cox proportional hazards regression analysis confirmed a higher risk of metastatic mortality in categories cT3c (glaucoma, hazard ratio [HR], 4.9; P = 0.011), cT3d (intraocular hemorrhage, HR, 14.0; P < 0.001), and cT3e (orbital cellulitis, HR, 19.6; P < 0.001) than in category cT2a and with systemic chemotherapy with secondary enucleation (HR, 3.3; P < 0.001) and eye salvage (HR, 4.9; P < 0.001) than with primary enucleation. The 5-year Kaplan-Meier cumulative survival estimates by AJCC-OOTF Size Groups 1 to 4 were 99%, 96%, 94%, and 83%, respectively. Mortality from metastatic RB increased with increasing Size Group (P < 0.001). Cox proportional hazards regression analysis revealed that patients with Size Group 3 (HR, 10.0; P = 0.002) and 4 (HR, 41.1; P < 0.001) had a greater risk of metastatic mortality than Size Group 1. CONCLUSIONS: The AJCC-RB cT2 and cT3 subcategories and size-based AJCC-OOTF Groups 3 (> 2/3 globe volume) and 4 (diffuse infiltrating RB) provided a robust stratification of clinical risk for metastatic death in advanced intraocular RB. Primary enucleation offered the highest survival rates for patients with advanced intraocular RB.

Subsequent malignant neoplasms in the pediatric age in retinoblastoma survivors in Argentina.

BACKGROUND: Retinoblastoma survivors in low- and middle-income countries are exposed to high-intensity treatments that potentially place them at higher risk of early subsequent malignant neoplasms (SMNs). METHODS: We followed 714 (403 [56.4%] nonhereditary and 311 [43.5%] hereditary) retinoblastoma survivors diagnosed from August 1987 to December 2016, up to the age of 16 years. We quantified risk of SMNs with cumulative incidence (CI) and standardized incidence ratios (SIR) analysis. Multivariate regression Cox model was used to determine the association of treatments and risk of SMNs. RESULTS: Median follow-up was of 9 years (range: 0.18-16.9) and 24 survivors (3.36%) developed 25 SMNs (n = 22 hereditary, n = 2 nonhereditary). SMNs included sarcomas (osteosarcomas, Ewing sarcomas, rhabdomyosarcomas; n = 12), leukemias (n = 5), and central nervous system tumors (CNS; n = 3). All cases of acute myeloid leukemia (AML) and most of Ewing sarcomas occurred within 5 years of retinoblastoma diagnosis. The type of SMN was the main indicator of mortality (five of five patients with leukemias, six of 12 with sarcomas, and zero of three with CNS tumors died). Compared to the general population, radiation increased the risk of Ewing sarcoma in hereditary survivors by 700-fold (95% CI = 252-2422.6) and chemotherapy increased the risk of AML by 140-fold (95% CI = 45.3-436). The CI of SMNs for hereditary survivors was 13.7% (95% CI = 8.4-22.1) at 15 years. CONCLUSION: Retinoblastoma survivors from Argentina are at higher risk of developing SMNs early in life compared to the general Argentinean population, especially those treated with radiation plus chemotherapy. AML and Ewing sarcoma presented within 5 years of retinoblastoma diagnosis are associated with chemotherapy and radiation exposure.

Treatment of Retinoblastoma: What Is the Latest and What Is the Future.

The management of retinoblastoma, the most common intraocular malignancy in children, has changed drastically over the last decade. Landmark developments in local drug delivery, namely, safer techniques for intravitreal chemotherapy injection and ophthalmic artery chemosurgery, have resulted in eye globe salvages that were not previously attainable using systemic chemotherapy or external beam irradiation. Novel drugs, oncolytic viruses, and immunotherapy are promising approaches in the treatment of intraocular retinoblastoma. Importantly, emerging studies of the pattern of tumor dissemination and local drug delivery may provide the first steps toward new treatments for metastatic disease. Here, we review recent advances in retinoblastoma treatment, especially with regard to local drug delivery, that have enabled successful conservative management of intraocular retinoblastoma. We also review emerging data from preclinical and clinical studies on innovative approaches that promise to lead to further improvement in outcomes, namely, the mechanisms and potential uses of new and repurposed drugs and non-chemotherapy treatments, and discuss future directions for therapeutic development.

High-risk Pathologic Features Based on Presenting Findings in Advanced Intraocular Retinoblastoma: A Multicenter, International Data-Sharing American Joint Committee on Cancer Study.

PURPOSE: To determine the value of clinical features for advanced intraocular retinoblastoma as defined by the eighth edition of the American Joint Committee on Cancer (AJCC) cT3 category and AJCC Ophthalmic Oncology Task Force (OOTF) Size Groups to predict the high-risk pathologic features. DESIGN: International, multicenter, registry-based retrospective case series. PARTICIPANTS: Eighteen ophthalmic oncology centers from 13 countries over 6 continents shared evaluations of 942 eyes enucleated as primary treatment for AJCC cT3 and, for comparison, cT2 retinoblastoma. METHODS: International, multicenter, registry-based data were pooled from patients enrolled between 2001 and 2013. High-risk pathologic features were defined as AJCC categories pT3 and pT4. In addition, AJCC OOTF Size Groups were defined as follows: (1) less than half, (2) more than half but less than two thirds, (3) more than two thirds of globe volume involved, and (4) diffuse infiltrating retinoblastoma. MAIN OUTCOME MEASURES: Statistical risk of high-risk pathologic features corresponding to AJCC cT3 subcategories and AJCC OOTF Size Groups. RESULTS: Of 942 retinoblastoma eyes treated by primary enucleation, 282 (30%) showed high-risk pathologic features. Both cT subcategories and AJCC OOTF Size Groups (P < 0.001 for both) were associated with high-risk pathologic features. On logistic regression analysis, cT3c (iris neovascularization with glaucoma), cT3d (intraocular hemorrhage), and cT3e (aseptic orbital cellulitis) were predictive factors for high-risk pathologic features when compared with cT2a with an odds ratio of 2.3 (P = 0.002), 2.5 (P = 0.002), and 3.3 (P = 0.019), respectively. Size Group 3 (more than two-thirds globe volume) and 4 (diffuse infiltrative retinoblastoma) were the best predictive factors with an odds ratio of 3.3 and 4.1 (P < 0.001 for both), respectively, for high-risk pathologic features when compared with Size Groups 1 (i.e., < 50% of globe volume). CONCLUSIONS: The AJCC retinoblastoma staging clinical cT3c-e subcategories (glaucoma, intraocular hemorrhage, and aseptic orbital cellulitis, respectively) as well as the AJCC OOTF Size Groups 3 (tumor more than two thirds of globe volume) and 4 (diffuse infiltrative retinoblastoma) both allowed stratification of clinical risk factors that can be used to predict the presence of high-risk pathologic features and thus facilitate treatment decisions.