Comparison of 19 F NMR and 14 C Measurements for the Assessment of ADME of BYL719 (Alpelisib) in Humans.

The human mass balance study is the definitive study for the assessment of absorption, distribution, metabolism, and excretion (ADME) properties of a new chemical entity in humans. Traditionally this has been carried out by the administration of radiolabeled drug substances, typically 14 C or occasionally 3 H, as detection methods for these isotopes allow the absolute quantification of drug-related material (DRM) in blood, plasma, and excreta. Coupled with the use of analytical techniques such as liquid chromatography-mass spectrometry, a picture of the metabolic fate of a compound can be elucidated. In this study, we demonstrate the capabilities of 19 F nuclear magnetic resonance (NMR) spectroscopy, applied as an alternative to radiolabeling, for the determination of mass balance and for metabolite profiling of an orally administered fluorinated drug. To demonstrate the capabilities of NMR, the study was conducted on remaining samples from a 14 C human mass balance study conducted on Alpelisib (BYL719), a compound in late stage development at Novartis for the treatment of solid tumors. Quantitative 14 C data were used to cross-validate the data obtained by NMR. The data show that, using 19 F NMR, comparable data can be obtained for key human ADME endpoints including mass balance, total DRM determination in plasma and metabolite profiling and identification in plasma and excreta. Potential scenarios where NMR could be employed as an alternative to radiolabeling for the conduct of an early human ADME study are discussed.