Lyrfigtu (lirafugratinib) for Pretreated FGFR2 Cholangiocarcinoma: 70mg Daily, REFOCUS Efficacy, Ocular and Phosphate Monitoring

　　1.Disease and FGFR2 Testing

　　Cholangiocarcinoma includes intrahepatic,perihilar,and extrahepatic subtypes;most cases present locally advanced or metastatic.FGFR2 fusions/rearrangements cluster in intrahepatic disease,with published estimates around 10%–15%in some intrahepatic cohorts.The alteration causes constitutive FGFR2 signaling through RAS-MAPK,PI3K-AKT,and related pathways.

　　Testing must report gene,variant class(fusion/rearrangement),partner gene,and method;NGS is preferred,with FISH/IHC as adjuncts when indicated.Isolated FGFR2 overexpression,point mutation,amplification,or unspecified positive results usually do not meet the approved targeted population;variants of uncertain significance require molecular tumor board review.

　　2.Drug and Sponsor

　　Lyrfigtu(lirafugratinib,development code RLY-4008)is developed/commercialized by Elevar Therapeutics as an oral,highly selective FGFR2 kinase inhibitor;some sources describe it as irreversible or FGFR2-biased to reduce FGFR1/3/4 off-target effects.FDA review used priority review,breakthrough therapy,orphan-drug designation,and RTOR;these expedite review but do not imply approval elsewhere or change single-arm evidence limits.

　　3.Indication and Dosing

　　Adults with previously treated,unresectable locally advanced or metastatic cholangiocarcinoma and documented FGFR2 fusion or other rearrangement.REFOCUS enrolled patients with prior chemotherapy or chemoimmunotherapy and no prior FGFR inhibitor.

　　Dose:70mg orally once daily,swallow whole,with or without food per labeling,continue until disease progression or unacceptable toxicity.Do not self-stop,double,or switch based on news reports.Missed-dose rules,CYP3A/P-gp/transporter interactions,and hepatic/renal adjustments follow the full prescribing information.

　　4.REFOCUS Key Data

　　REFOCUS(NCT04526106)was multicenter,open-label,single-arm phase I/II;the key cholangiocarcinoma cohort included 116 patients on lirafugratinib 70mg once daily,independently reviewed by RECIST v1.1:

　　Objective response rate 46%(95%CI 36–55),mostly partial responses;complete-response proportion follows the formal label.

　　Median duration of response 11.8 months(95%CI 7.5–13.0).

　　Supplementary reports show median PFS around 11.3 months and 12-month PFS rate around 49%,but single-arm data cannot prove superiority over randomized chemotherapy.

　　Eligibility required prior chemo/chemo-immuno and FGFR-inhibitor-naive,so results generalize mainly to that population.

　　ORR indicates tumor shrinkage meeting partial/complete response,not cure;DOR is the median maintenance among responders and is not guaranteed for every patient.

　　5.Safety and Monitoring

　　FDA labeling highlights ocular toxicity,hyperphosphatemia/soft-tissue mineralization,and embryo-fetal toxicity.

　　Ocular:dry eye,blurred vision,retinal pigment epithelial detachment(RPED),keratitis/corneal toxicity,floaters,photopsia.Obtain baseline visual acuity,fundus,and OCT;repeat per schedule;for vision loss,flashes,new floaters,color/vision/field changes,stop driving/high-risk tasks and arrange urgent ophthalmology.In some safety summaries RPED was about 31%,dry eye about 38%,blurred vision about 18%,but manage by the product label.

　　Phosphate and mineralization:FGFR affects phosphate handling;monitor phosphate,calcium,creatinine,renal function.Mild elevation:low-phosphate diet and retesting;moderate/severe:phosphate binders,hold,or dose reduction per label.Prolonged hyperphosphatemia risks skin,soft-tissue,and vascular calcification;hypophosphatemia requires corrective management.Do not self-prescribe long-term calcium or phosphate supplements.

　　Other common events:nail toxicity,palmar-plantar erythrodysesthesia/hand-foot syndrome,stomatitis,alopecia,dry mouth,dysgeusia,rash,dry skin,fatigue,constipation,abdominal pain,diarrhea,musculoskeletal pain,nausea,decreased appetite,infection,hemorrhage;labs may show transaminases,bilirubin,creatinine,hemoglobin/leukocyte/platelet/lymphocyte/neutrophil changes,sodium/glucose/alkaline phosphatase/albumin/bicarbonate abnormalities.

　　Urgent signals:pneumonia,serious infection,significant bleeding,jaundice,persistent vomiting/diarrhea with dehydration,acute vision loss,severe phosphate/calcium disturbance,altered mental status or respiratory distress—return to the biliary oncology team with ophthalmology,infectious disease,or hepatology as needed.

　　6.Fertility,Pregnancy,Special Populations

　　Animal/mechanism data suggest embryo-fetal harm.Confirm negative pregnancy before starting in people of childbearing potential;use effective contraception per label for patients and male partners with childbearing-potential partners,including the post-treatment period specified in prescribing information.Avoid breastfeeding unless the label permits;duration of lactation cessation follows the product label.Severe hepatic impairment,significant renal dysfunction,uncontrolled active eye disease,or mandatory strong interacting drugs requires individualized benefit-risk review by a biliary tumor team.