PK and pharmacodynamic analysis
BLOOD
Blood samples for pemigatinib PK assessments were collected during both ID and CD regimens before dosing on Days 1, 2, 8, 14, 15, and 16 of Cycle 1. Postdose samples were collected at 0.5, 1, 2, 4, 6, and 8 h on Day 1, and at 1 h on Day 14 of Cycle 1. For patients in the CD regimen, a postdose sample at 6 h on Day 14 was also collected. Pemigatinib plasma concentrations were determined using bioanalytical methods previously described by Ji et al.Plasma samples for pharmacodynamic assessments were collected predose on Days 1, 14, and 15 of Cycle 1 and any time on Day 1 (±3 days) of the subsequent cycles. Blood samples for evaluating comprehensive serum chemistry including serum phosphate concentrations after treatment of pemigatinib were collected on Days 1, 8, and 15 of Cycle 1, and Day 1 of each cycle thereafter. Baseline FGF23 concentrations were assessed in plasma samples collected on Days 1 and 15 of Cycle 1 using a commercially available assay (Meso Scale Discovery). The pharmacodynamic effects of pemigatinib were determined in plasma from samples collected predose and at Cycle 1 Day 15 (0 h) before pemigatinib administration. Inhibition of FGFR2 was assessed using an ex vivo assay that measured phosphorylated 