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Introduction: Osilodrostat is a new 11β-hydroxylase inhibitor with a mode of action analogous to Metyrapone. The objective of this study was to compare steroidogenic profiles in patients treated with either Osilodrostat or Metyrapone for adrenocorticotrophic hormone (ACTH)-dependent Cushing's syndrome (CS). Methods: Patients followed up at Cochin hospital Endocrinology department between March 2019 and December 2021 for an ACTH-dependent CS, controlled by either Osilodrostat or Metyrapone, were included. A serum profile of five steroids (cortisol, 11-deoxycortisol, 17-hydroxyprogesterone, androstenedione and testosterone) was determined using UPLC- tandem mass spectrometry (UPLC-MS/MS). Results: Nineteen patients treated with Osilodrostat, eight patients treated with Metyrapone and six patients treated with consecutive Metyrapone then Osilodrostat were included. Hypocortisolism (basal cortisol <100 nmol/L) was found in 48% of patients treated with Osilodrostat and 7% of patients treated with Metyrapone. 11-deoxycortisol and androstenedione levels were higher in patients treated with Metyrapone (80.9 (2.2-688.4) and 14.9 (2.5-54.3) nmol/L, respectively) than in patients treated with Osilodrostat (10.3 (0.5-71.9) and 4.0 (0.3-13.3) nmol/L) (P = 0.0009 and P = 0.0005). Testosterone level in women was also higher in Metyrapone group (3.3 (0.93-4.82) nmol/L vs 1.31 (0.13-5.09) nmol/L, P = 0.0146). CYP11B1 activity (11-deoxycortisol/cortisol) was not significantly different between the two groups. CYP21A2 activity (17OH proge stero ne/11 -deox ycort isol) and CYP17A1 activity (17OH proge stero ne/an drost enedi one) were significantly decreased in Osilodrostat group (P < 0.0001). Conclusion: In patients with ACTH-dependent CS, the use of CYP11B1 inhibitors in routine care suggests that Osilodrostat has a less specific effect on the inhibition of steroidogenic enzymes than Metyrapone. This might explain a smaller increase in 11-deoxycortisol and androgen levels in patients treated with Osilodrostat. [ABSTRACT FROM AUTHOR]

A new method for the quantitative analysis by liquid chromatography-tandem mass spectrometry (LC–MS/MS) of five tyrosine kinase inhibitors (afatinib, crizotinib, osimertinib, erlotinib and nintedanib) used in the treatment of non-small cell lung cancer (NSCLC) was developed and validated in human plasma. Separation was performed on an Accucore ® C18 (2.1 × 50 mm; 2.6 μm) column using a gradient elution of water acidified with 0.1% (v/v) formic acid (A) and acetonitrile containing 0.1% (v/v) formic acid (B) at a flow rate of 500 μL/min. The analytes were detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer after positive ionization with heated electrospray interface. After addition of three isotopically labeled internal standards, plasma pretreatment consisted in a simple protein precipitation. This method presented satisfactory results in terms of sensitivity, specificity, precision (intra- and inter-assay coefficient of variation from 2.6% to 10.6%), accuracy (from 96.1% to 108.5%), recovery and matrix effects. The lower limit of quantification and the linearity of these five tyrosine kinases inhibitors are suitable with the expected concentrations in clinical practice. This new bioanalytical method can be used in daily clinical practice for therapeutic drug monitoring of these tyrosine kinase inhibitors in NSCLC patients. [ABSTRACT FROM AUTHOR]