Enhertu 100 mg contains trastuzumab deruxtecan, a targeted cancer therapy designed for patients with HER2-positive or HER2-low cancers. It is a combination drug, made up of a HER2-targeting monoclonal antibody (trastuzumab) linked to a potent chemotherapy agent (deruxtecan). This innovative design allows Enhertu to specifically seek out cancer cells that express the HER2 protein and deliver chemotherapy directly to them. Enhertu is used in advanced stages of cancer when other treatments have not worked or are no longer effective.

Mechanism of Action

Trastuzumab deruxtecan works in a two-part process:

• First, trastuzumab attaches to the HER2 receptors found on the surface of certain cancer cells. HER2 is a growth-promoting protein, and its overexpression is linked to aggressive forms of cancer. By binding to these receptors, trastuzumab helps to block growth signals and flags the cancer cell for immune attack.

• Second, once inside the cancer cell, the deruxtecan component is released. This is a topoisomerase I inhibitor, a type of chemotherapy that damages the DNA of the cancer cell, stopping its ability to multiply and survive.

This dual approach increases precision and potency while limiting exposure to healthy cells.

Uses

Enhertu is used for the treatment of certain types of HER2-positive and HER2-low cancers that are unresectable or have metastasized (spread to other parts of the body), particularly when other treatments have failed.

Primary approved indications include:

• HER2-positive breast cancer after prior anti-HER2 therapies

• HER2-low breast cancer, a newly recognised subset where traditional HER2 therapies may not have worked

• HER2-positive gastric or gastroesophageal junction cancer

• Being studied for non-small cell lung cancer and other solid tumors expressing HER2

  Adverse Effects

  Enhertu offers targeted treatment, but it is still a powerful therapy that can cause side effects. These can range from mild to serious and require close monitoring.

  Common Side Effects

  • Nausea and vomiting

  • Fatigue or weakness

  • Hair thinning or loss

  • Low blood counts, such as white cells or platelets

  • Loss of appetite

  • Diarrhea or constipation

  • Cough or mild breathing discomfort