Trastuzumab 440 mg: Uses, Dosage, and Side Effects Explained

What is Trastuzumab?

Trastuzumab is a targeted therapy that is specifically used to treat cancers that helps to overexpress the HER2 protein. This HER2 protein is involved in cell growth and cell division. When these proteins are overexpressed, these can lead to an uncontrollable cell growth, which is the key characteristic of some aggressive forms of cancer, especially breast cancer.

Trastuzumab drugs work by binding to the HER2 receptors on the surface of the cancer cells, which helps to block their ability to receive growth signals and thereby inhibiting the tumour growth. These drugs were first approved for the treatment of HER2 positive breast cancer and later found to be effective in treating HER2 positive gastric cancer as well.

Trastuzumab 440 mg Dosages

For Breast Cancer

Initial loading dose for breast cancer: The typical initial dose of trastuzumab drug is 8mg/kg of the body weight, given as an intravenous infusion. This dose is quite high because it helps to saturate the cancer cells and achieve quick therapeutic effects. 

Maintenance dosage: After the initial loading dosage, trastuzumab is often given as a maintenance dose of 6 mg/kg every three weeks. The 440 mg dosage is commonly used as a standard dose in the maintenance phase for patients who weigh around 70 kg.

Additionally, trastuzumab can also be administered every 21 days via intravenous infusion or every three weeks in combination with chemotherapy regimens, mainly depending on the specific treatment plans.

For Gastric Cancer

Trastuzumab is typically given in combination with chemotherapy (such as cisplatin and capecitabine or 5-fluorouracil) as an intravenous infusion. It's highly important to note that the exact dosage and frequency of trastuzumab infusions will majorly depend on the oncologist’s recommendation and the circumstances of your treatment.

Side effects of Trastuzumab 440 mg

Trastuzumab is highly effective, but it comes with some side effects as well. These side effects can range from mild to severe and should be closely monitored during the treatment.

Some of these common side effects may include:

• Fever and chills
• Fatigue and tiredness
• Nausea or vomiting
• Headache
• Rash or skin irritation
• Joint pain or muscle pain

Serious side effects

Heart issues (Cardiotoxicity): This is one of the most serious side effects associated with these drugs, which cause damage to the heart. These can often lead to heart failure, low ejection fraction, or other cardiac issues. Patients who are usually monitored closely for the signs of some heart issues, especially if they have a history of heart diseases.

Monitoring: Before the starting of the trastuzumab treatment, some patients need to undergo tests such as echocardiogram and MUGA scan to assess the heart function.  

Infusion reaction: Some patients might experience allergic or infusion reactions, which can include symptoms such as fever, chills, shortness of breath, chest pain, or rash. Some of these reactions are more common with the first dose, but they can occur during any infusion.

Lung problems: In some rare cases, trastuzumab might cause lung issues like interstitial lung disease or pneumonitis, which can often lead to difficulty in breathing and other respiratory issues. 

Infections: These drugs help to lower the body’s ability to fight against the infections, so it's important for patients to report any signs of infection, such as fever or chills, immediately. 

Low blood cell counts: In some cases, trastuzumab can cause low white blood cell counts, also known as leukopenia, leading to an increased risk of infection, or low red blood cell counts (anemia), often leading to fatigue.