Herceptin (Trastuzumab)

What it is and what it treats

Herceptin is the brand name for trastuzumab, a humanised monoclonal antibody that binds the HER2 (human epidermal growth factor receptor 2) protein overexpressed on some tumour cells. By blocking HER2 signalling, it slows proliferation of HER2-positive cancer cells and can be combined with chemotherapy or used as monotherapy following prior treatment.

Regulatory approvals cover HER2-positive early breast cancer (as adjuvant therapy following surgery, chemotherapy and, where applicable, radiotherapy), HER2-positive metastatic breast cancer, and HER2-positive metastatic gastric or gastro-oesophageal junction adenocarcinoma in patients who have not received prior HER2-targeted treatment for metastatic disease. HER2 status must be confirmed by validated laboratory testing before treatment is considered.

Herceptin is often used together with other targeted agents, such as pertuzumab, or with chemotherapy regimens, depending on disease stage and treatment line. Because it does not treat HER2-negative disease, testing and specialist oncology oversight are integral parts of appropriate use.

Presentations and dosage forms

• Powder for concentrate for solution for infusion, 150 mg per vial, for intravenous administration
• Powder for concentrate for solution for infusion, 440 mg multidose vial, for intravenous administration
• Subcutaneous injection formulation (trastuzumab with hyaluronidase), fixed-dose vial for administration under the skin
• Reconstitution requires bacteriostatic water for injection (where supplied) followed by dilution in sodium chloride solution for intravenous use

How it is administered

The EU SmPC describes two main intravenous schedules: a three-weekly regimen (8 mg/kg loading dose followed by 6 mg/kg maintenance doses) and a weekly regimen (4 mg/kg loading dose followed by 2 mg/kg weekly). The initial infusion is administered over 90 minutes with close observation for infusion-related reactions; if well tolerated, subsequent infusions may be shortened to 30 minutes under medical supervision.

The subcutaneous formulation is described in its label as a fixed dose given by injection under the skin over approximately 2–5 minutes, avoiding the need for infusion-related dose calculations based on body weight, and is typically administered every three weeks by trained healthcare staff.

Because trastuzumab can affect left ventricular function, the label describes baseline and periodic cardiac assessment (echocardiogram or MUGA scan) before treatment starts and at intervals during therapy, with guidance on withholding or discontinuing treatment if significant declines in cardiac function are observed. Duration of adjuvant treatment described in regulatory labelling is one year (or until disease recurrence or unacceptable toxicity, whichever occurs first).

Storage and handling

• Store vials at 2–8 °C in a refrigerator; do not freeze
• Keep the vial in the outer carton to protect from light
• Reconstituted or diluted solutions have defined in-use stability periods described in the SmPC and should be used within the stated timeframe
• Do not shake the vial during reconstitution; gently swirl to avoid foaming
• Unused reconstituted solution should be discarded according to local pharmaceutical waste procedures

Side effects

The following effects are described in the approved EU SmPC and FDA prescribing information for trastuzumab. Frequencies and management approaches should be discussed with the treating oncology team.

Commonly reported

Serious effects requiring medical attention

Patients should seek prompt medical attention for shortness of breath, swelling of the legs, palpitations, fever with signs of infection, or symptoms occurring during or shortly after an infusion. Suspected adverse reactions should be reported to national pharmacovigilance systems.

Trastuzumab biosimilars and intravenous vs subcutaneous presentations

Since the expiry of Roche's original patents, several trastuzumab biosimilars (such as those marketed under different brand names in various regions) have received regulatory approval on the basis of demonstrated similarity to the reference product in quality, efficacy and safety. Biosimilars are approved through dedicated regulatory pathways and are considered clinically interchangeable with the originator by the approving authority, though switching decisions are typically made by the prescribing physician in line with local guidance.

Herceptin is available in both intravenous and subcutaneous presentations. The intravenous form is dosed by body weight with a loading dose followed by maintenance dosing, whereas the subcutaneous form is a fixed dose independent of body weight, administered over a few minutes rather than by infusion. Both routes are supported by clinical data demonstrating comparable efficacy and pharmacokinetic exposure; the choice between them is generally guided by patient preference, venous access, and infusion-chair capacity at the treating centre.

Neither presentation nor biosimilar status changes the underlying cardiac monitoring requirements or the HER2-testing prerequisites described in product labelling.

Availability and supply route

Herceptin's regulatory status varies by country: it holds marketing authorisation in the EU (via EMA), the United States (via FDA) and numerous other jurisdictions, but specific presentations, biosimilar availability and reimbursement pathways differ between national health systems. Clinicians and procurement teams should verify current local authorisation status before planning treatment.

As a prescription-only oncology biologic, Herceptin is dispensed and administered only against a valid prescription issued by an appropriately qualified physician, generally within a hospital or specialist oncology infusion setting due to its cold-chain requirements and the need for infusion monitoring. In some jurisdictions, named-patient supply frameworks allow access to a specific patient's prescribed treatment where the product is not locally registered, subject to national import and pharmacovigilance rules.

Pharmacy Remedy is a licensed Turkish pharmaceutical wholesaler operating within the regulated depot and distribution channel; it supplies healthcare institutions and licensed pharmacies against valid documentation and does not sell prescription medicines directly to members of the public.

Frequently asked questions

Primary sources

• EMA — Herceptin product information
• EMA — Herceptin (subcutaneous) product information
• FDA — Herceptin prescribing information

Further reading and regulatory routes

• How to verify a medicine is genuine
• Why medicines cost less in Türkiye
• WHO falsified medicine alerts
• Named patient supply
• UAE import guide
• For healthcare professionals
• All medicine monographs

Related medicines

• Keytruda (pembrolizumab)
• Opdivo (nivolumab)
• Kyprolis (carfilzomib)