Bladder, kidney, and other urologic cancers:
Indications for: BALVERSA
Locally advanced or metastatic urothelial carcinoma that has susceptible FGFR3 or FGFR2 genetic alterations, and has progressed during or following at least 1 line of prior platinum-containing chemotherapy, including within 12 months of neoadjuvant or adjuvant platinum-containing chemotherapy.
Confirm presence of FGFR genetic alterations by an FDA-approved test. Swallow whole. Initially 8mg once daily; increase to 9mg once daily at 14–21 days if serum phosphate level <5.5mg/L with no ocular disorders or Grade ≥2 adverse reactions. Continue until disease progression or unacceptable toxicity occurs. Dose modifications for adverse reactions: see full labeling.
Perform ophthalmic exam (include visual acuity, slit lamp, fundoscopy, optical coherence tomography) monthly for the first 4 months then every 3 months thereafter, and as needed. Withhold if central serous retinopathy occurs; permanently discontinue if not resolved within 4 weeks or if Grade 4 severity. Monitor for hyperphosphatemia. Restrict phosphate intake to 600–800mg daily; if serum phosphate is >7.0mg/dL, consider adding oral phosphate binder until level returns to <5.5mg/dL. Withhold, reduce dose, or permanently discontinue based on duration and severity of hyperphosphatemia. Known or suspected CYP2C9*3/*3 genotype: monitor. Severe hepatic impairment: limited data. Severe renal impairment: not studied. Embryo-fetal toxicity. Advise females of reproductive potential and males (w. female partners) to use effective contraception during and for 1 month after the last dose. Pregnancy: exclude status prior to initiation. Nursing mothers: not recommended (during and for 1 month after the last dose).
Potentiated by strong CYP2C9 or CYP3A4 inhibitors: consider alternatives, if use unavoidable, monitor closely and adjust dose accordingly. May be antagonized by strong CYP2C9 or CYP3A4 inducers: avoid. May be antagonized by moderate CYP2C9 or CYP3A4 inducers: if use is necessary after initial dose increase period, increase to erdafitinib 9mg. Concomitant other serum phosphate level-altering agents may affect serum phosphate levels: avoid before initial dose increase period. Avoid concomitant sensitive CYP3A4 substrates with narrow therapeutic index. May potentiate OCT2 substrates; consider alternatives or reducing the dose of substrates. May potentiate P-gp substrates; if use unavoidable, separate dosing by ≥6hrs before or after substrates.
Phosphate increased, stomatitis, fatigue, creatinine increase, diarrhea, dry mouth, onycholysis, ALT/AST increased, alkaline phosphatase increased, sodium decreased, decreased appetite, albumin decreased, dysgeusia, hemoglobin decreased, dry skin, magnesium decrease, dry eye, alopecia, palmarplantar erythrodysesthesia syndrome, constipation, phosphate decreased, abdominal pain, calcium increased, nausea, musculoskeletal pain; ocular disorders (eg, central serous retinopathy/retinal pigment epithelial detachment).
Following a single oral dose of radiolabeled erdafitinib, ~69% of the dose was recovered in feces (19% as unchanged) and 19% in urine (13% as unchanged). The mean effective half-life of erdafitinib was 59 hours.
Generic Drug Availability:
Tabs 3mg—56, 84; 4mg—28, 56; 5mg—28