Table 5.

Recommended approach for hyperphosphatemia management.

Serum phosphate level	Supportive care	Guidance for interruption/discontinuation of pemigatinib	Guidance for restarting pemigatinib
>5.5 mg/dl and ⩽7 mg/dl	Initiate a low-phosphate diet	No action	Not applicable
>7 mg/dl and ⩽10 mg/dl	Initiate/continue a low-phosphate diet and initiate phosphate binding. Monitor serum phosphate at least twice a week and adjust the dose of binders as needed; continue to monitor serum phosphate at least twice a week until return to normal range	If serum phosphate level continues to be >7 mg/dl and ⩽10 mg/dl with concomitant phosphate-binding therapy for 2 weeks, or if there is recurrence of serum phosphate level in this range, interrupt pemigatinib for up to 2 weeks	Restart at the same dose when serum phosphate is <7 mg/dl. If serum phosphate level recurs at >7 mg/dl, restart study drug with dose reduction
>10 mg/dl	Continue to maintain a low-phosphate diet, adjust phosphate-binding therapy, and start/continue phosphaturic agent. Continue to monitor serum phosphate at least twice a week until return to normal range	If serum phosphate level is >10 mg/dl for 1 week following phosphate-binding therapy and low-phosphate diet, interrupt study drug. If there is recurrence of serum phosphate level in this range following two dose reductions, permanently discontinue pemigatinib	Restart study drug at reduced dose with phosphate binders when serum phosphate is <7 mg/dl.