Trastuzumab deruxetecan was first approved by the United States Food and Drug Administration (FDA) on December 20, 2019.

In a 2021 study, researchers assessed the safety and activity of trastuzumab deruxtecan (T-DXd) in patients with various HER2-expressing or HER2-mutant solid tumours. They reported a confirmed objective response rate (ORR) of 28.3% and a median progression-free survival (PFS) of 7.2 months. 

The study highlighted promising activity in HER2-mutant non-small cell lung cancer (NSCLC) and other solid tumours.

Trastuzumab deruxetecan is used in the treatment of the following:

• HER2-positive metastatic breast cancer: Treat adult patients with inoperable or metastatic HER2-positive breast cancer who have already received a prior anti-HER2-based treatment.
• HER2-low metastatic breast cancer: Treat adult patients with inoperable or metastatic HER2-low breast cancer who have undergone prior chemotherapy in the metastatic setting or experienced cancer recurrence during or within six months of completing adjuvant chemotherapy.
• Locally advanced or metastatic gastric cancer: Treat adult patients with locally advanced or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma who have already received a prior trastuzumab-based treatment.

Trastuzumab deruxtecan is available as an injection and administered intravenously (into a vein) by the healthcare provider on scheduled appointments. Your healthcare provider will decide the suitable dosage for your condition according to your age and physical circumstances.

Common side effects of Trastuzumab deruxtecan include:

• Cough
• Trouble breathing or shortness of breath
• Fever
• New or worsening breathing symptoms (e.g., chest tightness, wheezing)
• Low white blood cell count (neutropenia)

Serious side effects of Trastuzumab deruxtecan are:

• Severe lung problems (which may be life-threatening or lead to death)
• Heart problems affecting the heart's ability to pump blood
• Signs of infection or fever and chills
• Irregular heartbeat
• Sudden weight gain
• Swelling of the ankles or legs

• Trastuzumab deruxtecan has severe and life-threatening threatening lung issues. It is important for patients to be closely monitored for symptoms like cough, difficulty breathing, or fever during treatment.
• Trastuzumab deruxtecan can also lead to decreased white blood cells (neutropenia), which can increase the risk of serious infections. Routine blood check-ups are important to monitor neutropenia during treatment. Any signs of infection, fever, or chills should be reported immediately.
• Trastuzumab deruxtecan also has a risk of heart problems that can affect the heart's ability to pump blood effectively. Patients should be observed for symptoms like shortness of breath, irregular heartbeat, sudden weight gain, or swelling of the legs, and these symptoms should be addressed promptly.

• Infections: Assess patients for infection risks before starting Trastuzumab deruxtecan and regularly monitor for signs of infection throughout treatment.
• Lung Function: Regularly assess lung function and monitor for any breathing issues during treatment.
• Heart Function: Check heart function before and during treatment with Trastuzumab deruxtecan.
• Pregnancy and Contraception: Confirm pregnancy status before beginning treatment. Advise patients to use effective contraception during and after treatment to avoid potential harm to a developing fetus.

If you are taking trastuzumab deruxtecan, it is crucial to regularly monitor your lung and liver functions with your doctor due to potential side effects. Both women and men should use effective contraception during treatment. Women should continue using birth control for at least seven months after the final dose of trastuzumab deruxtecan, while men should do so for four months after completing treatment to avoid risks to their partners who may become pregnant. It's essential to consult with your doctor about the best contraceptive methods and inform them before you decide to stop using contraception. 

Additionally, male patients should be aware that trastuzumab deruxtecan may impact fertility, so it is advisable to avoid fathering a child for four months after treatment and discuss sperm preservation options with your doctor before starting the medication.

1. Daiichi Sankyo UK Ltd, Electronic Medical Compendium (EMC),[Revised on July 2023][Accessed on Jan 2024] https://www.medicines.org.uk/emc/files/pil.12135.pdf 

2. Daiichi Sankyo, Inc, Food and Drug Safety Administration (FDA), [Revised on Jan 2021] [Accessed on Jan 2024] https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/761139s011lbl.pdf 

3. https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/761139s021lbl.pdf

The drug information on this page is not a substitute for medical advice, it is meant for educational purposes only. For further details consult your doctor about your medical condition to know if you are eligible to receive this treatment.