Futibatinib (Specialist drug)

PATIENT SELECTION: confirm the presence of an FGFR2 gene fusion or other rearrangement before initiating treatment (indication: unresectable, locally advanced or metastatic intrahepatic cholangiocarcinoma). The label notes that an FDA-approved test for detecting FGFR2 gene fusions or other rearrangements for this purpose is not available. MISSED DOSE OR VOMITING: if a dose is missed for more than 12 hours, or if vomiting occurs, resume dosing with the next scheduled dose. DOSE REDUCTIONS: first dose reduction 16 mg once daily (four 4 mg tablets or one 16 mg tablet); second dose reduction 12 mg once daily (three 4 mg tablets); permanently discontinue if unable to tolerate 12 mg orally once daily. HYPERPHOSPHATAEMIA MODIFICATIONS: serum phosphate 5.5 to 7 mg/dl — continue at the current dose, start phosphate-lowering therapy and monitor serum phosphate weekly. Serum phosphate above 7 and up to 10 mg/dl — start or adjust phosphate-lowering therapy, monitor weekly, and reduce to the next lower dose; if phosphate resolves to 7 mg/dl or less within 2 weeks continue at the reduced dose, otherwise reduce again, and if still not 7 mg/dl or less within 2 weeks after the second reduction, withhold until phosphate is 7 mg/dl or less then resume at the dose prior to suspending. Serum phosphate above 10 mg/dl — start or adjust phosphate-lowering therapy, monitor weekly, and withhold until phosphate is 7 mg/dl or less then resume at the next lower dose; permanently discontinue if phosphate is not 7 mg/dl or less within 2 weeks following 2 dose interruptions and reductions. RETINAL PIGMENT EPITHELIAL DETACHMENT (RPED): continue at the current dose with periodic ophthalmic evaluation; if resolving within 14 days continue at the current dose, and if not resolving within 14 days withhold until resolving then resume at the previous or a lower dose. OTHER ADVERSE REACTIONS: Grade 3 — withhold until the toxicity resolves to Grade 1 or baseline, then resume at the dose prior to suspending for haematological toxicities resolving within 1 week, or at the next lower dose for other reactions; Grade 4 — permanently discontinue. MONITORING: perform a comprehensive ophthalmological examination including optical coherence tomography before starting, every 2 months for the first 6 months, every 3 months thereafter, and urgently at any time for visual symptoms; monitor for hyperphosphataemia. PAEDIATRIC: the safety and effectiveness of futibatinib have not been established in paediatric patients; repeat-dose animal studies showed increased plasma phosphorus and calcium, ectopic mineralisation and bone/cartilage lesions at exposures below the human exposure at the 20 mg clinical dose. SOURCE: no UK SPC was fetched in this bundle; this draft is distilled from the US LYTGOBI prescribing information and must be verified against the UK SPC. Fetched sections were truncated at the source-fetch limit.