CPT: Pharmacometrics & Systems Pharmacology (Aug 2022)

Altered intravenous drug disposition in people living with cystic fibrosis: A meta‐analysis integrating top‐down and bottom‐up data

  • Pieter‐Jan De Sutter,
  • Maxime Van Haeverbeke,
  • Eva Van Braeckel,
  • Stephanie Van Biervliet,
  • Jan Van Bocxlaer,
  • An Vermeulen,
  • Elke Gasthuys

DOI
https://doi.org/10.1002/psp4.12832
Journal volume & issue
Vol. 11, no. 8
pp. 951 – 966

Abstract

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Abstract Cystic fibrosis (CF) has been linked to altered drug disposition in various studies. However, the magnitude of these changes, influencing factors, and underlying mechanisms remain a matter of debate. The primary aim of this work was therefore to quantify changes in drug disposition (top‐down) and the pathophysiological parameters known to affect pharmacokinetics (PKs; bottom‐up). This was done through meta‐analyses and meta‐regressions in addition to theoretical PK simulations. Volumes of distribution and clearances were found to be elevated in people living with CF. These increases were larger in studies which included patients with pulmonary exacerbations. Differences in clearance were smaller in more recent studies and when results were normalized to body surface area or lean body mass instead of body weight. For the physiological parameters investigated, measured glomerular filtration rate and serum cytokine concentrations were found to be elevated in people living with CF, whereas serum albumin and creatinine levels were decreased. Possible pathophysiological mechanisms for these alterations relate to renal hyperfiltration, increases in free fraction, and inflammation. No differences were detected for cardiac output, body fat, fat free mass, hematocrit, creatinine clearance, and the activity of drug metabolizing enzymes. These findings imply that, in general, lower total plasma concentrations of drugs can be expected in people living with CF, especially when pulmonary exacerbations are present. Given the potential effect of CF on plasma protein binding and the variability in outcome observed between studies, the clinical relevance of adapting existing dosage regimens should be evaluated on a case‐by‐case basis.