Study treatment
hyperphosphatemia
HYPERPHOSPHATEMIA
In Part 1, patients self‐administered oral pemigatinib starting with 9 mg once daily (QD) on a 2‐weeks‐on/1 week‐off intermittent dosing (ID) regimen. The safety and tolerability of each dose regimen was observed for 21 days (1 cycle) before escalation to the next dose. Dose increases were limited to ≤50% in successive cohorts. MTD was defined as the maximum dose at which one‐third or fewer of patients reported a DLT. The pharmacologically active dose was defined as the one at which at least 80% of participants developed hyperphosphatemia (defined as serum phosphorus ≥5.5 mg/dL). In Part 2, patients started at the RP2D determined in Part 1.A protocol amendment (November 6, 2018) introduced a continuous dosing (CD) regimen of pemigatinib 13.5 mg and the possibility of up‐titration for patients receiving 13.5 mg (ID or CD) to 18 mg beginning at Cycle 2 Day 1. At the time of protocol development for this study, the FIGHT‐101 study of pemigatinib at doses ranging from 1 to 20 mg QD was ongoing in the United States and Denmark. Interim safety data from FIGHT‐101 accrued at that time of protocol development for FIGHT‐102 supported an ID regimen starting at 9 mg QD and introduction of CD with a starting dose of 13.5 mg.