trastuzumab emtansine: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
trastuzumab emtansine: clinical details
Prescribing considerations
- Confirm HER2-positive tumour status using a validated test.
- Prescribing and administration require an oncology service equipped to manage infusion reactions and anaphylaxis.
- Record the product name and batch number for biological traceability.
- Check carefully that trastuzumab emtansine is not confused with trastuzumab or trastuzumab deruxtecan.
- Use caution in hepatic impairment, severe renal impairment, low baseline platelets, pre-existing neuropathy, reduced cardiac function or significant pulmonary risk.
Contraindications and cautions
- Contraindicated in hypersensitivity to trastuzumab emtansine or any excipient.
- Treatment is not recommended where trastuzumab was permanently stopped because of an infusion-related or hypersensitivity reaction.
Monitoring
- Platelet count before each administration and closer assessment when anticoagulants or antiplatelets are used.
- Liver function before treatment and before each administration.
- Left ventricular function before treatment and at regular intervals.
- Ongoing assessment for peripheral neuropathy, bleeding, pulmonary toxicity, infusion reactions and extravasation.
Clinical pharmacology
Trastuzumab emtansine is a humanised anti-HER2 IgG1 antibody linked through a stable MCC linker to the maytansinoid microtubule inhibitor DM1. Following HER2 binding and internalisation, lysosomal degradation releases DM1-containing catabolites. DM1 is eliminated mainly through hepatic pathways and is metabolised principally by CYP3A4.
Formulation and product differences
- Supplied as a white to off-white powder for concentrate in two single-vial presentations.
- Both presentations are reconstituted to the same concentration and require further dilution for intravenous infusion.
- The vial presentations have different cap colours to assist identification; labels must still be checked carefully.
- Glucose solution must not be used for reconstitution or dilution because it causes protein aggregation.
trastuzumab emtansine preparations and strengths
Solution for infusion
Route: Intravenous
Strengths: 100 mg, 160 mg
trastuzumab emtansine interactions
Provide the cancer team with a complete list of prescribed, over-the-counter and complementary products.
Strong CYP3A4 inhibitors, including itraconazole, ketoconazole, voriconazole, clarithromycin and ritonavir
These may increase exposure to DM1 and toxicity, so concurrent use should generally be avoided or managed with specialist monitoring.
Anticoagulants, such as warfarin, heparin or low-molecular-weight heparins
Bleeding risk may be increased, particularly if platelet counts fall; closer monitoring may be required.
Antiplatelet medicines, including aspirin
Concurrent use may add to bleeding risk and should be reviewed by the treating team.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.