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Vemurafenib (Monograph)

Brand name: Zelboraf
Drug class: Antineoplastic Agents
Chemical name: N-{3-[5-(4-Chlorophenyl)-1H-pyrrolo[2,3-b]pyridin-3-carbonyl]-2,4-difluorophenyl}propane-1-sulfonamide
Molecular formula: C23H18ClF2N3O3S
CAS number: 918504-65-1

Medically reviewed by Drugs.com on Jun 13, 2024. Written by ASHP.

Introduction

Antineoplastic agent; an inhibitor of b-Raf serine-threonine kinase with V600E mutation (BRAF V600E).

Uses for Vemurafenib

Melanoma

Treatment of unresectable or metastatic melanoma with BRAF V600E mutation (designated an orphan drug by FDA for this use).

FDA-approved in vitro diagnostic test (e.g., cobas 4800 BRAF V600 Mutation Test) required to confirm presence of BRAF V600E mutation prior to initiation of therapy.

Not indicated for use in patients with wild-type BRAF melanoma; safety and efficacy not established.

American Society of Clinical Oncology (ASCO) states that ipilimumab plus nivolumab, nivolumab alone, pembrolizumab alone, or combination BRAF/MEK inhibitor therapy (e.g., dabrafenib-trametinib, encorafenib-binimetinib, vemurafenib-cobimetinib) may be offered to patients with BRAF V600 mutation-positive cutaneous melanoma. For patients who progress on first-line programmed-death receptor-1 (PD-1) inhibitor therapy, combination BRAF/MEK inhibitor therapy may be offered. For patients who progress on first-line combination BRAF/MEK inhibitor therapy, PD-1 inhibitor therapy may be offered. Patients with mucosal melanoma may be offered the same treatment regimens as those recommended for cutaneous melanoma.

Erdheim-Chester Disease

Treatment of Erdheim-Chester disease with BRAF V600 mutation (designated an orphan drug by FDA for this use).

BRAF or MEK inhibitors have been used in the first-line setting in patients with life-threatening cases (e.g., CNS or cardiac involvement) of Erdheim-Chester disease. The most frequent second-line systemic therapy or salvage therapy for Erdheim-Chester disease includes BRAF or MEK inhibitors.

Vemurafenib Dosage and Administration

General

Pretreatment Screening

Patient Monitoring

Other General Considerations

Administration

Oral Administration

Administer orally twice daily without regard to meals.

Do not crush or chew tablets.

If a dose is missed, it may be taken up to 4 hours prior to next dose. Do not take 2 doses at the same time.

If vomiting occurs following administration, do not take a replacement dose. Administer next dose at regularly scheduled time.

Dosage

Adults

Melanoma
Oral

960 mg twice daily. Continue therapy until disease progression or unacceptable toxicity occurs.

If concomitant use with potent inducers of CYP3A4 cannot be avoided, increase vemurafenib dosage.

If concomitant use with potent inhibitor of CYP3A4 cannot be avoided, consider reducing vemurafenib dosage, if clinically indicated.

Erdheim-Chester Disease
Oral

960 mg twice daily. Continue therapy until disease progression or unacceptable toxicity occurs.

In the principal efficacy study, dosage reductions to 480 or 720 mg twice daily required in 64 or 36% of patients, respectively.

If concomitant use with potent inducers of CYP3A4 cannot be avoided, increase vemurafenib dosage.

If concomitant use with potent inhibitor of CYP3A4 cannot be avoided, consider reducing vemurafenib dosage, if clinically indicated.

Dosage Modification for General Toxicity
Oral

If intolerable grade 2 or 3 toxicity occurs, temporarily interrupt vemurafenib therapy. When toxicity resolves or improves to grade 1 or less, resume therapy at a reduced dosage of 720 mg twice daily.

If toxicity recurs at a dosage of 720 mg twice daily, temporarily interrupt therapy again until toxicity resolves to grade 1 or less, and resume therapy at a reduced dosage of 480 mg twice daily.

If grade 4 toxicity occurs, permanently discontinue or temporarily interrupt therapy until toxicity resolves to grade 1 or less, and resume therapy at a reduced dosage of 480 mg twice daily if clinically appropriate.

If toxicity recurs at a reduced dosage of 480 mg twice daily, permanently discontinue vemurafenib. Dosages <480 mg twice daily not recommended.

Dosage Modification for Prolongation of QT Interval
Oral

If the corrected QT interval (QTc) is >500 msec, temporarily interrupt vemurafenib therapy.

When QTc interval returns to ≤500 msec, resume therapy at a reduced dosage.

If QTc interval >500 msec and increases >60 msec from baseline despite correction of electrolyte abnormalities and control of other risk factors (e.g., CHF, bradyarrhythmias), permanently discontinue vemurafenib.

Dosage Modification for Development of New Primary Cutaneous Malignancies
Oral

No dosage adjustment necessary.

Special Populations

Hepatic Impairment

Mild or moderate hepatic impairment: No initial dosage adjustment required.

Renal Impairment

Mild or moderate renal impairment: No initial dosage adjustment required.

Geriatric Patients

No specific dosage adjustment recommendations at this time.

Cautions for Vemurafenib

Contraindications

Warnings/Precautions

Sensitivity Reactions

Hypersensitivity Reactions

Serious hypersensitivity reactions (e.g., anaphylaxis, generalized rash, erythema, hypotension, drug reaction with eosinophilia and systemic symptoms [DRESS syndrome]) reported during and upon reinitiation of therapy. Permanently discontinue vemurafenib in patients who experience a severe hypersensitivity reaction.

Photosensitivity Reactions

Risk of photosensitivity reactions. Reduce dosage of vemurafenib in patients who experience intolerable grade 2 or greater reaction.

Other Warnings and Precautions

Development of New Primary Malignancies

Cutaneous squamous cell carcinoma, keratoacanthoma, and melanoma reported. First appearance of cutaneous squamous cell carcinoma occurred within 7–8 weeks after initiating vemurafenib in patients with unresectable or metastatic melanoma; patients with more than one occurrence reported time between occurrences of approximately 6 weeks. Median time to first appearance of cutaneous squamous cell carcinoma was 12.1 weeks after initiating vemurafenib in patients with Erdheim-Chester disease. Possible risk factors include advanced age (i.e., ≥65 years of age), history of skin cancer, and chronic sun exposure.

Non-cutaneous squamous cell carcinoma of the head and neck (e.g., oropharyngeal area) reported. Progression of a preexisting chronic myelomonocytic leukemia with NRAS mutation also reported during postmarketing experience.

Perform dermatologic evaluation at baseline and every 2 months during therapy. May consider monitoring for 6 months following discontinuance of vemurafenib. Initiate appropriate therapy and excise suspicious cutaneous lesions for pathologic evaluation. Closely monitor for signs and symptoms of development of new non-cutaneous squamous cell carcinoma or other primary malignancies.

Myeloid neoplasms reported in patients with Erdheim-Chester disease receiving vemurafenib therapy. Monitor CBC in patients with Erdheim-Chester disease and coexisting myeloid malignancies.

Tumor Promotion in BRAF Wild-Type Melanoma

In vitro, paradoxical activation of mitogen-activated protein kinase (MAPK) signaling and increased cell proliferation observed in wild-type BRAF cells exposed to BRAF inhibitors. Confirm presence of BRAF V600E mutation prior to initiation of therapy.

Dermatologic Effects

Severe skin reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis) reported. Permanently discontinue vemurafenib in patients who experience severe skin reactions.

Prolongation of QT Interval

QT prolongation reported.

Do not use in patients with congenital long QT syndrome, electrolyte disturbances unresponsive to corrective measures, or QTc intervals >500 msec.

Avoid concomitant use with drugs known to prolong QT interval (e.g., class Ia and III antiarrhythmic agents).

Obtain ECG and serum electrolytes at baseline or following dosage modification for QT prolongation; monitor at 15 days after initiating vemurafenib, then monthly for the first 3 months, and every 3 months thereafter or more often as clinically indicated.

Interruption or discontinuance of vemurafenib may be necessary if increases in the QTc interval occur.

Hepatic Effects

Hepatic injury may occur resulting in functional hepatic impairment, including coagulopathy or other organ dysfunction. Elevations in ALT, AST, bilirubin, and alkaline phosphatase concentrations of grade 3 or 4 severity reported in 0.9–2.9% of patients.

Monitor serum aminotransferase, bilirubin, and alkaline phosphatase concentrations at baseline and then monthly thereafter.

If laboratory abnormalities occur, reduce dosage, temporarily interrupt, or discontinue vemurafenib therapy.

Safety and efficacy of vemurafenib used concomitantly with ipilimumab not established; however, grade 3 elevations in aminotransferase and bilirubin concentrations reported in patients receiving vemurafenib (720 or 960 mg twice daily) concurrently with ipilimumab (3 mg/kg).

Ocular Effects

Uveitis (including iritis), blurry vision, and photophobia reported. Monitor patients for signs and symptoms of uveitis. If uveitis occurs, treatment with ophthalmic corticosteroid and mydriatic preparations may be required.

Retinal vein occlusion also reported.

Fetal/Neonatal Morbidity and Mortality

May cause fetal harm.

Vemurafenib crossed the placenta in animal studies.

Advise women of childbearing potential to use effective contraception during therapy and for 2 weeks after the last dose. If used during pregnancy or if patient becomes pregnant, apprise of potential fetal hazard.

Radiation Sensitization and Recall

Radiation sensitization and recall, sometimes severe or fatal, reported in patients receiving vemurafenib prior to, during, or subsequent to radiation therapy. May involve cutaneous and visceral organs; fatal cases reported in patients with radiation sensitization or recall involving visceral organs.

Closely monitor patients receiving vemurafenib concomitantly or sequentially with radiation therapy for signs and symptoms of radiation sensitization or recall.

Renal Effects

Renal failure, including acute interstitial nephritis and acute tubular necrosis, reported.

Evaluate Scr concentrations at baseline and periodically during therapy.

Dupuytren Contracture and Plantar Fascial Fibromatosis

Dupuytren contracture and plantar fascial fibromatosis reported. Severity is usually mild to moderate, but severe and disabling cases have occurred.

Specific Populations

Pregnancy

May cause fetal harm.

Lactation

Not known whether vemurafenib is distributed into human milk. Effects on breast-fed infants and milk production also unknown. Discontinue nursing during therapy and for 2 weeks after the last dose.

Pediatric Use

Safety and efficacy not established in pediatric patients.

Limited data indicate similar steady-state exposures of vemurafenib in pediatric patients (range: 15–17 years of age) and adults. Maximum tolerated dosage not established; however, no new adverse effects observed in pediatric patients receiving a vemurafenib dosage up to 960 mg twice daily.

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether they respond differently than younger adults.

Hepatic Impairment

Not studied in patients with severe hepatic impairment; use with caution.

Renal Impairment

Not studied in patients with severe renal impairment; use with caution.

Common Adverse Effects

Melanoma (≥10%): Arthralgia, rash, alopecia, fatigue, photosensitivity reaction, nausea, pruritus, cutaneous squamous cell carcinoma, skin papilloma.

Erdheim-Chester Disease (≥20%): Arthralgia, maculopapular rash, alopecia, fatigue, QT interval prolongation, skin papilloma, diarrhea, hyperkeratosis, dry skin, palmar-plantar erythrodysesthesia syndrome, photosensitivity reaction, seborrheic keratosis, cough, cutaneous squamous cell carcinoma, hypertension, pruritus, peripheral sensory neuropathy, actinic keratosis, keratosis pilaris, nausea, melanocytic nevus, sunburn, papular rash, vomiting.

Drug Interactions

Vemurafenib is a moderate inhibitor of CYP1A2, and a weak inhibitor of 2D6 in vivo. Vemurafenib inhibits CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, and 3A4/5 in vitro. The drug also is an inhibitor and substrate of CYP3A4.

Vemurafenib is a substrate and inhibitor of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP).

Drugs and Foods Affecting Hepatic Microsomal Enzymes

Potent CYP3A4 inhibitors: Possible pharmacokinetic interaction (increased plasma concentrations of vemurafenib and increased incidence of adverse effects). Avoid concomitant use. If coadministration of a potent CYP3A4 inhibitor cannot be avoided, consider reducing the dosage of vemurafenib, if clinically indicated.

Potent CYP3A4 inducers: Possible pharmacokinetic interaction (decreased plasma concentrations of vemurafenib and reduced vemurafenib efficacy). Avoid concomitant use; selection of alternative drug with no or minimal CYP3A4 induction potential recommended. If concomitant therapy cannot be avoided, increase vemurafenib dosage by 240 mg twice daily (e.g., from 960 mg twice daily to 1.2 g twice daily).

Drugs Metabolized by Hepatic Microsomal Enzymes

Substrates of CYP1A2: Possible pharmacokinetic interaction (increased plasma concentrations of CYP1A2 substrate and possible toxicity). Avoid concomitant use of vemurafenib and CYP1A2 substrates with a narrow therapeutic index. If concomitant use cannot be avoided, consider dosage reduction of the CYP1A2 substrate and closely monitor for adverse effects.

Substrates of CYP2D6: Possible pharmacokinetic interaction (increased plasma concentrations of CYP2D6 substrate and possible toxicity).

Substrates of CYP3A4: Possible pharmacokinetic interaction (decreased plasma concentrations of CYP3A4 substrate and possible decreased efficacy).

Substrates of CYP2C9: Possible pharmacokinetic interaction (increased plasma concentrations of CYP2C9 substrate and possible toxicity).

Substrates of CYP2C19: No clinically important interaction reported.

Drugs Affected by Efflux Transport Systems

Substrates of P-gp: Possible pharmacokinetic interaction (increased plasma concentrations of P-gp substrate). Avoid concomitant use of vemurafenib and P-gp substrates with a narrow therapeutic index. If concomitant use cannot be avoided, consider dosage reduction of the P-gp substrate.

Drugs that Prolong QT Interval

Potential pharmacologic interaction (additive effect on QT prolongation). Avoid concomitant use.

Specific Drugs

Drug

Interaction

Comments

Antiarrhythmics (class Ia and III; e.g., amiodarone, procainamide, quinidine, sotalol)

Increased risk of QT-interval prolongation

Avoid concomitant use

Antifungals, azoles (e.g., itraconazole, ketoconazole, voriconazole)

Potent CYP3A4 inhibitors: Possible increased vemurafenib concentrations and increased adverse effects

Itraconazole: Systemic exposure of vemurafenib increased by approximately 40% at steady state; magnitude of effect on peak plasma concentration was similar

Potent CYP3A4 inhibitors: Avoid concomitant use; if coadministration cannot be avoided, consider reducing the dosage of vemurafenib, if clinically indicated

Antimycobacterials, rifamycins (e.g., rifampin)

Potent CYP3A4 inducers: Possible decreased vemurafenib concentrations and reduced vemurafenib efficacy

Rifampin decreased AUC of vemurafenib by 40%; no effect on peak plasma concentrations

Potent CYP3A4 inducers: Avoid concomitant use; select alternative agent with no or minimal enzyme induction potential

If concomitant use with potent CYP3A4 inducer cannot be avoided, increase vemurafenib dosage by 240 mg twice daily (e.g., from 960 mg twice daily to 1.2 g twice daily)

Antipsychotic agents that prolong QT interval (e.g., asenapine, chlorpromazine, haloperidol, olanzapine, paliperidone, pimozide, quetiapine, thioridazine, ziprasidone)

Increased risk of QT-interval prolongation

Avoid concomitant use

Caffeine

Increased AUC of caffeine

CYP1A2 substrates with a narrow therapeutic index: Concomitant use not recommended; if concomitant use cannot be avoided, consider dosage reduction of CYP1A2 substrate and closely monitor patient for adverse effects

Carbamazepine

Possible decreased vemurafenib concentrations and reduced vemurafenib efficacy

Avoid concomitant use; select alternative agent with no or minimal enzyme induction potential

If concomitant use cannot be avoided, increase vemurafenib dosage by 240 mg twice daily (e.g., from 960 mg twice daily to 1.2 g twice daily)

Dextromethorphan

Increased AUC of dextromethorphan

Digoxin

Vemurafenib increased AUC and peak plasma concentrations of digoxin by 1.8- and 1.5-fold, respectively

Avoid concomitant use; if concomitant use cannot be avoided, consider dosage reduction of digoxin

Gatifloxacin

Increased risk of QT-interval prolongation

Avoid concomitant use

HIV protease inhibitors (e.g., indinavir, nelfinavir, ritonavir, saquinavir)

Potent CYP3A4 inhibitors: Possible increased vemurafenib concentrations and increased adverse effects

Potent CYP3A4 inhibitors: Avoid concomitant use; if coadministration cannot be avoided, consider reducing the dosage of vemurafenib, if clinically indicated

Ipilimumab

Increased aminotransferase and bilirubin concentrations

Macrolides (e.g., clarithromycin)

Potent CYP3A4 inhibitors: Possible increased vemurafenib concentrations and increased adverse effects

Potent CYP3A4 inhibitors: Avoid concomitant use; if coadministration cannot be avoided, consider reducing the dosage of vemurafenib, if clinically indicated

Midazolam

Decreased AUC of midazolam

Moxifloxacin

Increased risk of QT-interval prolongation

Avoid concomitant use

Omeprazole

No change in systemic exposure of omeprazole

Phenytoin

Possible decreased vemurafenib concentrations and reduced vemurafenib efficacy

Avoid concomitant use; select alternative agent with no or minimal enzyme induction potential

If concomitant use cannot be avoided, increase vemurafenib dosage by 240 mg twice daily (e.g., from 960 mg twice daily to 1.2 g twice daily)

Tetrabenazine

Increased risk of QT-interval prolongation

Avoid concomitant use

Tizanidine

Vemurafenib increased AUC and peak plasma concentrations of tizanidine by 4.7- and 2.2-fold, respectively

CYP1A2 substrates with a narrow therapeutic index: Avoid concomitant use; if concomitant use cannot be avoided, consider dosage reduction of CYP1A2 substrate and closely monitor for adverse effects

Warfarin

Increased AUC of S-warfarin

Vemurafenib Pharmacokinetics

Absorption

Bioavailability

64% at steady state.

Food

Food increases systemic exposure. Administration of a single dose of vemurafenib with a high-fat meal increases AUC by approximately fivefold and increases peak concentrations by approximately 2.5-fold.

Distribution

Extent

Fetal plasma concentrations of vemurafenib were 3–5% of maternal plasma concentrations in animals.

Not known whether vemurafenib is distributed into human milk.

Plasma Protein Binding

>99% (mainly albumin and α1-acid glycoprotein).

Elimination

Elimination Route

Excreted in feces (94%) and urine (1%).

Half-life

Approximately 57 hours.

Stability

Storage

Oral

Tablets

20–25°C (excursions permitted between 15–30°C).

Actions

Advice to Patients

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Vemurafenib is available only from a designated specialty pharmacies. The manufacturer should be contacted for additional information.

Vemurafenib

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Tablets, film-coated

240 mg

Zelboraf

Genentech

AHFS DI Essentials™. © Copyright 2024, Selected Revisions June 23, 2022. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

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