Product Introduction:
Trasturel is a biosimilar of Trastuzumab, developed by Reliance Life Sciences. It is used in patients with HER2-positive malignancies, particularly breast and gastric cancers, either alone or in combination with chemotherapy. It is provided as a lyophilized powder that is reconstituted for intravenous infusion.
Uses (Indications):
Trasturel is used in the treatment of:
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HER2-positive metastatic breast cancer (MBC) – in combination with paclitaxel or as monotherapy
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Adjuvant treatment of HER2-positive early breast cancer – following surgery, chemotherapy, and/or radiotherapy
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HER2-positive metastatic gastric cancer – in combination with cisplatin and capecitabine or 5-FU
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Locally advanced or inflammatory HER2-positive breast cancer
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Neoadjuvant therapy in early HER2-positive breast cancer
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Maintenance therapy following initial chemotherapy response in HER2-positive cancers
Storage Instructions:
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Store the lyophilized powder at 2–8°C (refrigerated)
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Do not freeze the vial or the reconstituted solution
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Reconstituted solution should be used within 24 hours if stored under refrigeration
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Protect from light and contamination
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Store out of reach of children
How It Works (Mechanism of Action):
Trastuzumab is a humanized monoclonal antibody that selectively binds to the extracellular domain of the HER2 receptor, a transmembrane tyrosine kinase receptor that is overexpressed in 20–30% of breast cancers and some gastric cancers.
Mechanisms include:
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Inhibition of HER2 signaling → prevents proliferation of cancer cells
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Antibody-dependent cellular cytotoxicity (ADCC) → enhances immune-mediated destruction of tumor cells
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Receptor downregulation and apoptosis induction
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Inhibits angiogenesis and tumor metastasis
Side Effects:
Common Side Effects:
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Fever and chills (infusion-related reactions)
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Nausea and vomiting
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Diarrhea
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Headache
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Weakness and fatigue
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Skin rash
Serious Side Effects:
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Cardiotoxicity – including congestive heart failure, especially in combination with anthracyclines
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Infusion reactions – can include hypotension, dyspnea, bronchospasm
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Pulmonary toxicity – interstitial pneumonitis or pulmonary fibrosis
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Hematologic toxicity – neutropenia, anemia
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Hepatotoxicity – elevated liver enzymes
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Fetal harm – contraindicated in pregnancy due to potential embryo-fetal toxicity
Dosage (Typical Recommended Dose):
For Breast Cancer:
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Loading dose: 8 mg/kg IV infusion over 90 minutes
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Maintenance dose: 6 mg/kg IV every 3 weeks over 30–90 minutes
For Gastric Cancer:
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Loading dose: 8 mg/kg IV infusion over 90 minutes
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Maintenance dose: 6 mg/kg IV every 3 weeks
Doses are adjusted based on weight and clinical response, and cardiac function must be assessed regularly.
Method of Administration:
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IV infusion only, not for IV push or bolus
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Reconstitute lyophilized powder with sterile water as per instructions
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Administer through infusion pump under close monitoring
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First infusion should be given over 90 minutes; subsequent doses may be shortened if tolerated
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Pre-medication (antipyretics, antihistamines) may be given to reduce infusion reactions
Precautions:
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Cardiac monitoring before and during therapy is mandatory (e.g., LVEF assessments every 3 months)
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Use with caution in patients with pre-existing heart disease or prior anthracycline therapy
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Pregnancy must be avoided – contraception required during and 7 months after treatment
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Discontinue in case of severe infusion reactions or pulmonary toxicity
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Monitor CBC, liver enzymes, and renal function regularly
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Do not substitute biosimilars interchangeably without oncologist approval
Drug Interactions:
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Anthracyclines (e.g., Doxorubicin) – increased risk of cardiac toxicity
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Cyclophosphamide – may potentiate myelosuppression
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Radiotherapy – increased pulmonary and cardiac risks
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Paclitaxel/Docetaxel – commonly co-administered but may enhance neutropenia
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No significant CYP450 interactions; however, caution advised in polypharmacy scenarios
Allergies (Warnings for Allergic Reactions):
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Contraindicated in patients with known hypersensitivity to Trastuzumab or any excipients
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Infusion-related reactions may involve urticaria, angioedema, and bronchospasm
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Anaphylaxis has been reported – resuscitation equipment should be readily available during administration
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Premedicate high-risk patients with antihistamines and corticosteroids
Overdose Information:
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Limited data available on Trastuzumab overdose
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Symptoms may include severe infusion reaction, cardiac dysfunction, and respiratory distress
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Provide symptomatic and supportive care
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Monitor vitals and cardiac function intensively
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No specific antidote available
Missed Dose Instructions:
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If a scheduled dose is missed by less than 1 week, administer as soon as possible
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If delayed by more than 1 week, re-administer the loading dose (8 mg/kg)
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Resume the regular schedule afterward
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Doses should always be administered under supervision of an oncology professional
Additional Notes:
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HER2 testing (IHC or FISH) must confirm HER2 positivity before initiating Trastuzumab
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Not interchangeable with subcutaneous formulations without dosage adjustment
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Patients should be educated about early symptoms of heart failure or allergic reactions
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Periodic echocardiography or MUGA scan is standard during treatment
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Combination with chemotherapy should follow established oncological protocols
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Trasturel is a cost-effective biosimilar option compared to the innovator (Herceptin) in many countries
