ADEPT (antibody-directed enzyme pro-drug therapy)

Developing a new drug Back to top

When a drug is being developed, it has to go through various stages of research called clinical trials| or studies. The aim of these is to establish a safe dosage, the side effects that the drug may cause and which cancers it may be used to treat. The trials also find out how effective the drug is, whether it is better than the existing treatments, or whether it has extra benefits when given with existing drugs.

Many drugs that are thought to be promising may be found not to be as good as existing treatments, or to have side effects that outweigh any benefits. For this reason, doctors and other medical staff carry out frequent and careful checks on the progress of everyone who is taking one of these developmental drugs. If you are having a developmental drug, your doctor will explain all about the drug, the procedures being used, and how you will be looked after while you are taking it. If you have concerns at any time, you should ask your doctor or nurse for information and advice.

ADEPT Back to top

ADEPT is a new type of cancer treatment that uses drugs called monoclonal antibodies. At the moment, ADEPT is being used only in clinical trials. The trials aim to find out whether ADEPT may be useful as a new type of treatment for bowel cancer .

Monoclonal antibodies Back to top

Monoclonal antibodies|  recognise certain proteins that are found on the surface of some cancer cells. They are used to try to destroy the cancer cells, while causing little harm to normal cells. The monoclonal antibody recognises the protein on the surface of the cancer cell and locks onto it. Some monoclonal antibodies can then trigger the body’s immune system to attack the cancer cells and can also cause the cells to destroy themselves. Sometimes (when used in cancer treatment) monoclonal antibodies have a cancer drug or radioactive substance attached to them. They can be used in this way to deliver treatment directly to the cancer cell. This is known as targeted therapy.

How ADEPT works Back to top

ADEPT is a type of targeted therapy. It uses a monoclonal antibody to carry an enzyme directly to the cancer cells. Enzymes are proteins that control chemical reactions in the body. First, the monoclonal antibody is given (with the enzyme attached). A few hours later, a second drug (the pro-drug) is given. When the pro-drug comes into contact with the enzyme, a reaction takes place. This reaction activates the pro-drug and it's then able to destroy the cancer cells. As the enzyme does not attach to normal cells, this treatment does not affect them.

What it looks like Back to top

ADEPT is a colourless fluid.

How it is given Back to top

ADEPT is given by a drip (infusion) through a small tube (cannula) inserted into a vein. The monoclonal antibody and the pro-drug are usually given in two separate doses on the same day.

Possible side effects Back to top

Trials are looking at the side effects that may occur. As ADEPT is still a relatively new treatment, it's too early to know all of the possible side effects. However, the following appear to be the most common:

• Flu-like symptoms These may include a high temperature and chills, headaches, itching, and joint and muscle aches.These may occur a few hours after the treatment is given, but don't last for more than a day or two.
• Allergic reaction Signs of an allergic reaction include skin rashes and itching, high temperatures, shivering, redness of the face, dizziness, a headache, breathlessness , anxiety and a need to pass urine. You'll be monitored for any sign of an allergic reaction during your treatment. Tell your doctor or nurse if you have any of these signs. Before you have your treatment you'll be given medication to reduce the chances of an allergic reaction.
• Increased risk of infection . A temporary reduction in your white blood cells can occur a few days after the treatment is given. If this happens, you are more likely to get an infection during this period. Your doctor or nurse will advise you about this and any precautions that you should take. Your white blood cells usually recover in 3–4 weeks.
• Nausea (feeling sick) and being sick (vomiting) If you feel sick , it may begin a few hours after ADEPT has been given and may last for a few days. Your doctor can prescribe anti-sickness (anti-emetic) drugs to prevent or greatly reduce nausea and vomiting. If the sickness is not controlled, or if it continues, tell your doctor. They can prescribe other anti-sickness drugs which may be more effective.

If you have any questions about these or any other side effects, talk to your doctor or nurse. It is also important to let them know if you have any symptoms or side effects that you think may be related to the treatment.

References Back to top

This information has been compiled using information from a number of reliable sources including:

• Souhami and Tobias. Cancer and its Management. 5th edition. 2005. WileyBlackwell.

• DeVita,V et al. Cancer - Principles & Practice of Oncology. 8th Edition. 2008. Lippincott, Williams & Wilkins.

For further references, please see the general bibliography| .