cobimetinib hemifumarate: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
cobimetinib hemifumarate: clinical details
Prescribing considerations
- Initiation and supervision should be by a clinician experienced in anticancer treatment.
- Confirm BRAF V600 mutation-positive tumour status using a validated test.
- Licensed only in combination with vemurafenib.
- Consider sequencing carefully after progression on a previous BRAF inhibitor.
- Evidence is limited for brain metastases; intracranial activity is unknown.
- Safety and efficacy are not established in people younger than 18 years.
Contraindications and cautions
- Hypersensitivity to cobimetinib or any excipient.
- Use caution with bleeding risks, severe renal impairment, hepatic impairment and medicines affecting CYP3A.
- Patients with baseline left ventricular ejection fraction below the institutional normal limit or below 50% were not studied.
- Contains lactose and is unsuitable for certain rare hereditary disorders of galactose metabolism.
Monitoring
- Confirm tumour BRAF V600 status.
- Assess left ventricular ejection fraction before treatment, after the first month and at least every three months, or as clinically indicated.
- Check liver tests before and regularly during treatment.
- Measure creatine phosphokinase and creatinine at baseline and regularly; investigate elevations or muscle symptoms.
- Ask about visual symptoms and arrange ophthalmological assessment when indicated.
- Monitor diarrhoea, dehydration, bleeding, blood pressure, skin toxicity, photosensitivity and respiratory symptoms.
- Review prescription, non-prescription and herbal products for interactions.
Clinical pharmacology
Cobimetinib is an oral, reversible, selective allosteric MEK1/2 inhibitor. It is extensively metabolised, principally through CYP3A oxidation and UGT2B7 glucuronidation, with minimal renal elimination.
Formulation and product differences
- The UK product is a white, round film-coated tablet marked “COB”; it contains lactose and is essentially sodium-free.
- No special storage conditions are required.
cobimetinib hemifumarate preparations and strengths
Tablet
Route: Oral
Strengths: 20 mg
cobimetinib hemifumarate interactions
A full medicines and supplements review is needed before and during treatment.
Strong CYP3A inhibitors, including clarithromycin, itraconazole, voriconazole, posaconazole, ritonavir and cobicistat
Can substantially increase cobimetinib exposure and should generally be avoided.
Moderate CYP3A inhibitors, including erythromycin, fluconazole, diltiazem, verapamil and amiodarone
May increase exposure, requiring caution and closer toxicity monitoring.
CYP3A inducers, including rifampicin, carbamazepine, phenytoin and St John’s wort
May reduce exposure and compromise effectiveness, so concurrent use should be avoided.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.