Belzutifan

FDA label, Merck Sharp & Dohme LLC, oral, effective 2026-06-12. Full label on DailyMed

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From MedlinePlus, U.S. National Library of Medicine

Specialty pharmacy: therapy management checklist, storage and cold chain, dosing calendar, Medicare Part D coverage.

Quoted from the FDA label. Product labels differ by manufacturer and change over time; confirm against the label for the product you are using.

Boxed warning

WARNING: EMBRYO-FETAL TOXICITY Exposure to WELIREG during pregnancy can cause embryo-fetal harm. Verify pregnancy status prior to the initiation of WELIREG. Advise patients of these risks and the need for effective non-hormonal contraception. WELIREG can render some hormonal contraceptives ineffective [see Warnings and Precautions (5.3) , Drug Interactions (7.2) , Use in Specific Populations (8.1 , 8.3) ]. WARNING: EMBRYO-FETAL TOXICITY See full prescribing information for complete boxed warning. Exposure to WELIREG during pregnancy can cause embryo-fetal harm. Verify pregnancy status prior to the initiation of WELIREG.

Advise patients of these risks and the need for effective non-hormonal contraception. WELIREG can render some hormonal contraceptives ineffective. ( 5.3 , 7.2 , 8.1 , 8.3 )

Hypoxia-inducible Factor Inhibitor

Dosing in kidney impairment

Renal Impairment No dosage modification of WELIREG is recommended in patients with renal impairment including end-stage renal disease. For patients with severe renal impairment (eGFR 15-29 mL/min estimated by MDRD) monitor for increased adverse reactions and modify the dosage as recommended [see Dosage and Administration , Clinical Pharmacology ].

Dosing in liver impairment

Hepatic Impairment No dosage modification of WELIREG is recommended in patients with mild [total bilirubin ≤ upper limit of normal (ULN) and aspartate aminotransferase (AST) > ULN or total bilirubin >1 to 1.5 x ULN and any AST] or moderate (total bilirubin within range of >1.5 x ULN and ≤ 3 x ULN and any AST or Child-Pugh B) hepatic impairment.

WELIREG has not been studied in patients with severe hepatic impairment (total bilirubin >3 x ULN and any AST). For patients with moderate and severe hepatic impairment, monitor for increased adverse reactions and modify the dosage as recommended [see Dosage and Administration , Clinical Pharmacology ] .

Drug interactions

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  • Belzutifan
Label text (4 paragraphs)

7 DRUG INTERACTIONS UGT2B17 or CYP2C19 Inhibitors: Monitor for signs and symptoms of anemia and hypoxia and reduce the dosage of WELIREG as recommended. ( 2.2 , 7.1 ) Sensitive CYP3A4 Substrates : Avoid coadministration with WELIREG for which minimal decrease in concentration may lead to reduced efficacy of the substrate. ( 7.2 )

7.1 Effects of Other Drugs on WELIREG UGT2B17 or CYP2C19 Inhibitors Monitor for anemia and hypoxia and reduce the dosage of WELIREG as recommended [see Dosage and Administration (2.2) , Warnings and Precautions (5.1 , 5.2) , Adverse Reactions (6) ] . Coadministration of WELIREG with inhibitors of UGT2B17 or CYP2C19 increases belzutifan exposure [see Clinical Pharmacology (12.3 , 12.5) ] , which may increase the risk of adverse reactions of WELIREG.

7.2 Effect of WELIREG on Other Drugs CYP3A4 Substrates Avoid coadministration of WELIREG with sensitive CYP3A4 substrates, for which minimal decrease in concentration may lead to therapeutic failures of the substrate. If coadministration cannot be avoided, increase the sensitive CYP3A4 substrate dosage in accordance with its Prescribing Information. Coadministration of WELIREG with CYP3A4 substrates decreases concentrations of CYP3A substrates [see Clinical Pharmacology (12.3) ] , which may reduce the efficacy of these substrates. The magnitude of this decrease may be more pronounced in patients who are dual UGT2B17 and CYP2C19 poor metabolizers [see Clinical Pharmacology (12.3) ].

Hormonal Contraceptives Coadministration of WELIREG with hormonal contraceptives may lead to contraceptive failure or an increase in breakthrough bleeding [see Clinical Pharmacology (12.3) , Use in Specific Populations (8.3) ] .

Contraindications

None. None. ( 4 )

Safety data

Reported adverse events (FAERS)

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Source: FDA Adverse Event Reporting System via openFDA

Liver injury (LiverTox)

E

Likelihood score E: Unlikely cause of clinically apparent liver injury.

Belzutifan is a small molecule inhibitor of hypoxia-inducible factor 2 alpha used to treat solid tumors in patients with von Hippel-Lindau disease. Belzutifan is associated with a low rate of minor serum enzyme elevations during therapy, but has not been linked to cases of clinically apparent liver injury.

ABCDEA: well known cause; E: unlikely cause. [HD]: high doses only.

Source: LiverTox: Belzutifan (NIDDK, public domain)Chapter updated Jul 20, 2023

Pregnancy and lactation

Pregnancy

8.1 Pregnancy Risk Summary Based on findings in animal studies, WELIREG can cause fetal harm when administered to a pregnant woman. There are no available data on the use of WELIREG in pregnant women to inform the drug-associated risk. In an animal reproduction study, oral administration of belzutifan to pregnant rats during the period of organogenesis caused embryo-fetal lethality, reduced fetal body weight, and fetal skeletal malformations at maternal exposures ≥0.2 times the human exposure (AUC) at the recommended dose of 120 mg daily ( see Data ). Advise pregnant women and females of reproductive potential of the potential risk to a fetus.

The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2–4% and 15–20%, respectively. Data Animal Data In a pilot embryo-fetal development study, pregnant rats received oral doses of 6, 60, or 200 mg/kg/day of belzutifan during the period of organogenesis. Belzutifan caused embryo-fetal lethality at doses ≥60 mg/kg/day (approximately 1 time the human exposure at the recommended dose based on AUC).

Reduced fetal body weights, fetal rib malformations, and reduced skeletal ossification occurred at doses of 6 and 60 mg/kg/day (approximately ≥0.2 times the human exposure at the recommended dose based on AUC).

For breastfeeding, also see LactMed (National Library of Medicine), which summarizes milk levels and infant effects.

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