BALVERSA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BALVERSA (BALVERSA).
FGFR kinase inhibitor; binds to and inhibits FGFR1-4, reducing phosphorylation and downstream signaling.
| Metabolism | Primarily metabolized by CYP2C9 and CYP3A4 |
| Excretion | Primarily metabolized, with 69% of dose recovered in feces (19% unchanged) and 19% in urine (1% unchanged). |
| Half-life | Terminal elimination half-life is approximately 17 hours, supporting once-daily dosing. |
| Protein binding | 99.7% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Mean apparent volume of distribution (Vd/F) is 126 L (approximately 1.8 L/kg), indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is approximately 30% (range 20-40% due to first-pass metabolism). |
| Onset of Action | Clinical effect (tumor response) observed within 4-8 weeks of starting oral therapy. |
| Duration of Action | Duration of clinical effect is variable; continuous daily dosing until disease progression or unacceptable toxicity. |
8 mg orally once daily, with or without food, for adults.
| Dosage form | TABLET |
| Renal impairment | eGFR 30–59 mL/min/1.73m²: 6 mg orally once daily. eGFR 15–29 mL/min/1.73m²: 4 mg orally once daily. eGFR <15 mL/min/1.73m²: not recommended. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: 6 mg orally once daily. Child-Pugh C: 4 mg orally once daily. |
| Pediatric use | Safety and efficacy not established; no weight-based guidelines available. |
| Geriatric use | No specific adjustment; monitor renal function due to age-related decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BALVERSA (BALVERSA).
| Breastfeeding | There are no data on the presence of erdafitinib in human milk, its effects on the breastfed infant, or on milk production. Because of the potential for serious adverse reactions in breastfed infants from BALVERSA, advise women not to breastfeed during treatment with BALVERSA and for 1 month after the last dose. M/P ratio: unknown. |
| Teratogenic Risk | Based on its mechanism of action as a pan-FGFR inhibitor and animal studies, BALVERSA (erdafitinib) is expected to cause fetal harm when administered to a pregnant woman. In animal reproduction studies, erdafitinib was embryotoxic and teratogenic at maternal exposures below the recommended human dose. There are no adequate and well-controlled studies in pregnant women. Advise pregnant women of the potential risk to the fetus. First trimester: highest risk of major malformations. Second and third trimesters: potential for fetal growth restriction and oligohydramnios. |
■ FDA Black Box Warning
None.
| Serious Effects |
None.
| Precautions | Ocular disorders including central serous retinopathy/retinal pigment epithelial detachment; hyperphosphatemia and soft tissue mineralization; embryo-fetal toxicity; increased risk of ventricular arrhythmia/torsade de pointes in patients with electrolyte abnormalities |
| Food/Dietary | Avoid grapefruit and grapefruit juice during treatment as they inhibit CYP3A4 and may increase erdafitinib levels. Avoid foods high in phosphate (e.g., dairy products, nuts, beans, organ meats, colas) if hyperphosphatemia occurs; follow dietary phosphate restriction as advised by your healthcare team. No other specific food interactions noted, but maintain adequate hydration. |
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| Fetal Monitoring | Confirm pregnancy status prior to initiation. Monitor pregnant women exposed to BALVERSA for fetal development with serial ultrasound assessments (e.g., fetal anatomy, growth, amniotic fluid volume). Monitor for maternal toxicities including hyperphosphatemia, ocular toxicities, and dermatologic reactions. No specific fetal monitoring required outside standard obstetric care. |
| Fertility Effects | Based on animal studies, BALVERSA may impair fertility in males and females. In female rats, erdafitinib caused disruption of estrous cycles and reduced fertility at exposures below the clinical exposure. In male rats, reduced sperm count and motility were observed. The reversibility of these effects is unknown. |
| Clinical Pearls | Balversa (erdafitinib) is a fibroblast growth factor receptor (FGFR) inhibitor indicated for locally advanced or metastatic urothelial carcinoma with susceptible FGFR3 or FGFR2 genetic alterations. Monitor serum phosphate levels closely as hyperphosphatemia is an on-target effect; initiate phosphate-lowering therapy if serum phosphate >5.5 mg/dL. Ophthalmic examinations are required at baseline and periodically due to risk of central serous retinopathy/retinal pigment epithelial detachment. Avoid coadministration with strong CYP3A4 inhibitors or inducers; adjust dose accordingly. Assess for potential drug interactions with acid-reducing agents (e.g., proton pump inhibitors) as erdafitinib solubility is pH-dependent. |
| Patient Advice | Take Balversa exactly as prescribed, once daily with or without food. Swallow tablets whole; do not crush or chew. · Avoid taking antacids, H2 blockers, or proton pump inhibitors while on Balversa; if needed, separate antacid by at least 2 hours before or after dose. · Report any vision changes (blurred vision, floaters, flashes) immediately; you will need regular eye exams. · Your doctor will monitor your blood phosphate levels; you may need a phosphate-lowering medication or dietary phosphate restriction. · Use effective contraception during treatment and for at least 1 month after the last dose. Do not breastfeed. · Common side effects include increased phosphate levels, nail disorders, mouth sores, fatigue, dry mouth, and changes in taste. Report severe or persistent symptoms. · Do not start any new medications, including over-the-counter drugs or herbal supplements, without consulting your doctor. |