Phesgo 1200mg/600mg Injection is a targeted therapy containing the active constituents pertuzumab and trasrtuzumab. It is used to treat a type of breast cancer (human epidermal growth factor receptor 2 positive breast cancer) that has spread to other parts of the body (metastasized) or cancer that has come back after the treatment. 

It will also be given before or after the surgery if the cancer has not metastasized. Cancer occurs when cells begin to grow abnormally in an uncontrolled manner.

Before taking Phesgo 1200mg/600mg Injection, talk to the physician if you have heart problems, have had radiotherapy, or have allergic conditions. This medication is not recommended for adolescents and children under 18. 

In patients with early-stage HER2-positive breast cancer, adding pertuzumab or trastuzumab to standard chemotherapy can reduce the risk of recurrence and improve disease-free survival.

Phesgo 1200mg 600mg Injection is used to manage the following conditions:

• Early breast cancer
• Metastatic breast cancer

Phesgo (pertuzumab and trastuzumab) 1200mg/600mg injection is a fixed-dose combination therapy used for HER2-positive breast cancer, offering the therapeutic benefits of both monoclonal antibodies in a convenient subcutaneous formulation. Pertuzumab prevents HER2 receptor dimerization, while trastuzumab blocks HER2 signalling and triggers immune-mediated tumour cell destruction, collectively inhibiting cancer cell growth and proliferation. By targeting HER2-positive cells, Phesgo reduces tumour progression, improves survival rates, and enhances treatment convenience compared to intravenous administration.

Phesgo 1200mg 600mg has a long washout period, which can increase the risk of cardiac dysfunction when followed by anthracycline-based therapy. Patients who receive anthracyclines after stopping Phesgo may be at a higher risk of cardiotoxicity, necessitating careful monitoring of cardiac function. If possible, anthracycline-based treatments should be avoided for up to seven months after discontinuing Phesgo. Healthcare providers should assess cardiac function regularly when co-administering or sequencing these agents to minimize the risk of adverse cardiovascular effects.

• Store the Phesgo Injection in a refrigerator between 2°C and 8°C (36°F and 46°F).
• It should not be frozen.
• Keep it in its original packaging until it is ready to be used.
• Keep out of the reach of children and pets.

Phesgo 1200mg/600mg Injection is administered subcutaneously, not intravenously. The initial loading dose of 1,200 mg pertuzumab and 600 mg trastuzumab is given over approximately 8 minutes, followed every three weeks by a maintenance dose of 600 mg pertuzumab and 600 mg trastuzumab administered over approximately 5 minutes. Injections should alternate between the left and right thighs, ensuring each new injection is at least 2.5 cm away from the previous site and avoiding areas that are red, bruised, tender, or hard. Do not split the dose between multiple syringes or injection sites. After administering the loading dose, observe the patient for 30 minutes; for maintenance doses, a 15-minute observation period is recommended to monitor for injection-related reactions. If a serious hypersensitivity reaction occurs, discontinue the injection immediately and permanently. 

Side effects are unwanted symptoms caused by medicines. Even though all medicines cause side effects, not everyone gets them. The Phesgo Injection side effects are:

Common side effects of Phesgo 1200mg/600mg Injection are:

• Alopecia (hair loss)
• Nausea
• Diarrhea
• Anemia
• Asthenia (weakness)
• Fatigue
• Stomatitis (inflammation of the mouth)
• Myalgia (muscle pain)
• Arthralgia (joint pain)
• Constipation
• Neutropenia (low white blood cell count)
• Vomiting
• Radiation skin injury
• Dysgeusia (altered taste)
• Headache
• Decreased appetite
• Insomnia
• Peripheral sensory neuropathy
• Rash
• Dry skin
• Mucosal inflammation
• Injection site reactions (e.g., pain, redness)
• Cough

Serious Side Effects:

• Febrile neutropenia (fever with low white blood cell count)
• Neutropenic sepsis (a severe infection due to low white blood cell count)
• Decreased ejection fraction (a measure of heart function)
• Cardiac failure
• Pneumonitis/pulmonary fibrosis (lung inflammation or scarring)
• Hypersensitivity reactions, including anaphylaxis
• Severe injection-related reactions

If you have prescribed Phesgo 1200mg 600mg Injection, or any other medication, it is important to carefully read and understand the warnings and precautions associated with the medication. Patients should be monitored for signs of an allergic reaction, such as rash, itching, or swelling, and should seek immediate medical attention if these symptoms occur. It should be used with caution in patients with severe renal impairment. Talk to the physician if you have heart problems, have had radiotherapy, or have allergic conditions. Use effective birth control during the treatment and at least seven months after the last dose. Always maintain a healthy and balanced diet to support your overall health and well-being.

1. Roche products limited, Electronic medicines compendium (EMC), [Revised on Jan 2022] [ Accessed on 03/05/2023], https://www.medicines.org.uk/emc/files/pil.11989.pdf
2. zhu Chenjing et al.; Safety and efficacy evaluation of pertuzumab in patients with solid tumors; Medicine; [Published on May 2017]; [Accessed on 03/05/2023] https://journals.lww.com/md-journal/fulltext/2017/05190/safety_and_efficacy_evaluation_of_pertuzumab_in.19.aspx
3. Sandra M Swain et al; Pertuzumab, Trastuzumab, and docetaxel in HER2-positive metastatic breast cancer; The New England Journal of Medicine; [Published on Feb 2015]; [Accessed on 03/05/203]; https://pubmed.ncbi.nlm.nih.gov/25693012/
4. https://www.phesgo-hcp.com/dosing/dosing-administration.html 
5. chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.gene.com/download/pdf/phesgo_prescribing.pdf