vemurafenib: clinical use

Prescribing considerations

• Confirm BRAF V600-positive tumour status using a validated test; do not use for BRAF wild-type melanoma.
• Evidence for rare BRAF V600 variants other than V600E and V600K is not convincingly established.
• Review QT risk, electrolytes, interacting medicines, radiotherapy and concurrent or previous RAS-mutated malignancy.
• Use caution and monitor closely in severe renal impairment or moderate-to-severe hepatic impairment.
• Review pregnancy intentions and contraception, recognising that hormonal contraceptive effectiveness may be reduced.

Contraindications and cautions

• Hypersensitivity to vemurafenib or any listed excipient.

Monitoring

• ECG and electrolytes, including magnesium, before treatment, after one month and after treatment modification; monitor more closely with hepatic impairment or other QT risks.
• Liver enzymes, alkaline phosphatase and bilirubin before treatment and regularly during therapy.
• Serum creatinine before treatment and subsequently as clinically indicated.
• Baseline and regular dermatological assessment, continuing surveillance after treatment.
• Routine assessment for ophthalmic inflammation or retinal vascular events.
• Appropriate surveillance for non-cutaneous squamous-cell carcinoma and prompt investigation of unexplained abdominal pain.

Clinical pharmacology

Vemurafenib selectively inhibits activated BRAF serine-threonine kinases, particularly those with codon 600 mutations. It also inhibits CYP1A2 and P-glycoprotein and induces CYP3A4, creating substantial interaction potential.

Formulation and product differences

• The selected product is an oral film-coated tablet containing vemurafenib as a co-precipitate with hypromellose acetate succinate.
• Tablets must be swallowed whole.
• Store in the original aluminium blister packaging to protect from moisture.

Tablet

Route: Oral

Strengths: 240 mg