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Therapeutic drug monitoring (TDM) involves measuring and interpreting drug concentrations in biological fluids to adjust drug dosages. In onco-hematology, TDM guidelines for oral molecular targeted therapies (oMTTs) are varied. This study evaluates a quantitative approach with a score to predict the clinical usefulness of TDM for oMTTs. We identified key parameters for an oMTT's suitability for TDM from standard TDM recommendations. We gathered oMTT pharmacological data, which covered exposure variability (considering pharmacokinetic (PK) impact of food and proton pump inhibitors), technical intricacy (PK linearity and active metabolites), efficacy (exposure-response relationship), and safety (maximum tolerated dose, and exposure-safety relationship). To assess the validity and the relevance of the score and define relevant thresholds, we evaluated molecules with prospective validation or strong recommendations for TDM, both in oncology and in other fields. By September 1, 2021, the US Food and Drug Administration (FDA) approved 67 oMTTs for onco-hematological indications. Scores ranged from 15 (acalabrutinib) to 80 (sunitinib) with an average of 48.3 and a standard deviation of 15.6. Top scorers included sunitinib, sorafenib, cabozantinib, nilotinib, and abemaciclib. Based on scores, drugs were categorized into low (< 40), intermediate (≥ 40 and < 60), and high (≥ 60) relevance for TDM. Notably, negative controls generally scored around or under 40, whereas positive controls had a high score across different indications. In this work, we propose a quantitative and reproducible score to compare the potential usefulness of TDM for oMTTs. Future guidelines should prioritize the TDM for molecules with the highest score., (© 2024 The Authors. Clinical Pharmacology & Therapeutics © 2024 American Society for Clinical Pharmacology and Therapeutics.)

Objective: Previous studies have provided evidence that the discontinuation of hydroxychloroquine (HCQ), and chloroquine (CQ), in patients with systemic lupus erythematosus (SLE) is associated with an increased risk of disease flares, with limited information on the level of disease activity at the time of HCQ/CQ discontinuation. Here we aimed to describe the risk of SLE flare after withdrawal of HCQ or CQ in patients with SLE in remission., Methods: Case-control study (1:2) comparing the evolution of patients with SLE after HCQ/CQ withdrawal for antimalarial retinopathy (cases) with patients with SLE matched for sex, antimalarial treatment duration and age at SLE diagnosis, whose antimalarial treatment was continued throughout the entire follow-up period (controls). To be included in the study, patients had to be in remission for at least one year according to the DORIS classification. The primary endpoint was the proportion of patient experiencing a flare according to the SELENA-SLEDAI Flare Index after a 36-month follow-up., Results: We studied 48 cases and 96 controls. The proportion of patients experiencing a flare was significantly higher in the HCQ/CQ withdrawal group as compared to the maintenance group (15 [31.3%] patients versus 12 [12.5%]; OR 3.1 [95%CI 1.2-8.2], P=0.01). Withdrawal of HCQ/CQ was inferior with respect to occurrence of severe SLE flare (12 [25.0%] vs 11 [11.5%]; OR 2.5 [95%CI 0.9-6.9], P=0.053) and time to first flare (HR 6.3 [2.0-19.9], P<0.005). Elevated serum levels of anti-dsDNA antibodies were identified as a risk factor for SLE flare following HCQ/CQ discontinuation (HR 5.4 [1.5-18.7], P<0.01)., Conclusion: Withdrawal of HCQ or CQ in patients with SLE in remission is associated with a 3-fold increased risk of relapse., (Copyright © 2024 Société française de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: The number of cancer patients receiving long-term hemodialysis (HD) is increasing, and HD could jeopardize treatments' safety and efficacy. Therefore, managing anticancer drugs is critical in this frail population. In addition, evidence of HD safety or risk is regularly released both for cytotoxic chemotherapy (CT) or hormone therapy (HT) as well as new therapies with molecularly targeted therapies (MTT), immune checkpoint inhibitors (ICI), and a summary of current knowledge is needed., Methods: We aimed to synthesize available data on cancer treatments in HD patients using PubMed database, FDA labels, summary of product characteristics (SmPC), FDA and EMA approval documents, guidelines and finally case reports for which relevant pharmacokinetic (PK) data is available., Results: For CT, recently proposed guidelines were balanced by the publication of particular toxic reports following them. SmPC was helpful in some cases, but no data was found for most CTs. MTT, both oral and monoclonal antibodies, were rarely modified by HD. However, HD patients have particular frailty that could require dose adaptation despite no substantial PK modification. Similarly, exposure to ICIs is unlikely to be modified by HD since immunoglobulins are not dialyzable. For HT, PK characteristics and HD impact were more heterogeneous and were reviewed molecule by molecule., Conclusions: We summarized current knowledge on HD and cancer treatments. Data remains scarce, and the latest guidelines rely on few clinical data. There is a need to collect both retrospective and prospective data to better characterize the safety and relevant dose and schedule adaptations whenever needed in this situation to reinforce future guidelines., (Copyright © 2023 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Background: Long-term hydroxychloroquine (HCQ) or chloroquine (CQ) intake causes retinal toxicity in 0.3-8 % of patients with rheumatic diseases. Numerous risk factors have been described, eg, daily dose by weight, treatment duration, chronic kidney disease, concurrent tamoxifen therapy and pre-existing retinal or macular disease. However, those factors cannot explain the entire risk of developing antimalarial retinopathy., Objective: This study was undertaken to identify new risk factors associated with HCQ or CQ retinopathy (QRNP) in systemic lupus erythematosus (SLE) patients., Methods: This case-control (1:2) study compared SLE patients with QRNP (cases) to those without (controls). Controls were matched for sex and known QRNP risk factors: HCQ and/or CQ treatment duration (±1 year) and age (±5 year) at SLE diagnosis., Results: Forty-eight cases were compared to 96 SLE controls. Multivariable logistic-regression analysis retained the following as independent determinants significantly associated with QRNP: concomitant selective serotonin-reuptake inhibitor (SSRI) or serotonin- and norepinephrine-reuptake inhibitor (SNRI) intake (OR [95 % confidence interval] 6.6 [1.2 to 40.9]; p < 0.01); antiphospholipid syndrome (OR=8.9 [2.2 to 41.4] p < 0.01); blood hydroxychloroquine/desethylchloroquine concentration ([HCQ]/[DCQ]) ratio <7.2 (OR 8.4 [2.7 to 30.8]; p < 0.01) or skin phototype ≥4 (OR 5.5 [1.4 to 26.5]; p = 0.02), but not daily HCQ dose, blood [HCQ] or body mass index., Conclusion: The results of this case-control study identified blood [HCQ]/[DCQ] ratio, concurrent SSRI/SNRI therapy, skin phototype ≥4 and antiphospholipid syndrome as new risk factors for QRNP., Competing Interests: Declaration of competing interest AM has received grant/research support from Sobi; participated in advisory board related to lupus for AstraZeneca; received payment for expert testimony for GSK; received support for attending meetings and/or travel from AstraZeneca, GSK, Novartis and Otsuka; received consulting fees, speaking fees and honoraria from AstraZeneca, GSK, Novartis and Otsuka. FC has received grant/research support from AstraZeneca; participated in advisory board related to lupus for AstraZeneca, GSK, Celgene and Principabio; received speaking fees and honoraria from AstraZeneca and GSK. ZA has received grant/research support from GSK, AstraZeneca, Roche, Novartis, Amgen; participated in advisory board related to lupus for GSK, AstraZeneca, Kezar, Amgen, Otsuka; Novartis received consulting fees, speaking fees and honoraria from AstraZeneca and GSK. The remaining authors declare no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Aromatase inhibitors such as anastrozole, letrozole, exemestane and selective estrogen down-regulator (SERD) fulvestrant are used mostly to treat breast cancer estrogen receptor positive in post-menopausal women. These drugs are given either through the oral route or by intramuscular injection. They have shown great inter-individual variability with a risk of cardiometabolic disorders. Hence the importance of their therapeutic drug monitoring not only for exposure-efficacy but also exposure-toxicity. We describe here a LC-MS/MS method for the simultaneous quantification of anastrozole, letrozole, exemestane and fulvestrant in human plasma., Material and Methods: Plasma samples were prepared by a single-step protein precipitation. The liquid chromatography system was paired with a triple quadrupole mass spectrometer. Quantification were achieved in Multiple Reactions Monitoring mode and the electrospray ionization was in positive mode., Results: The method demonstrated consistent analytical performance across various parameters, including linearity, specificity, sensitivity, matrix effect, upper and lower limits of quantification, extraction recovery, precision, accuracy, hemolysis effect, dilution integrity, and stability under different storage conditions, in accordance with established guidelines. The analysis time for each run was 4 min. Calibration curves exhibited linearity within the 1-100 ng/mL range, with correlation coefficients > 0.99 for the four analytes. Plasma concentrations from 42 patients were integrated into the selected calibration. Stability assessments indicated that the four drugs remained stable at - 20 °C for three months, 15 days under refrigeration, up to 7 days at room temperature, and after three freeze-thaw cycles., Conclusion: We have developed and validated this quantitative method for therapeutic drug monitoring of those four hormone therapy drugs:anastrozole, letrozole, fulvestrant and exemestane. This method can be also used for future clinical pharmacokinetics /pharmacodynamics studies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)