Drugs in development
When a drug is being developed it has to go through various stages of research called clinical trials or studies. These are intended 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, and whether it is better than the existing treatments, or has extra benefit when given with these 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 each patient 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 at any time you have concerns, you should ask your doctor or nurse for information and advice.
ADEPT (Antibody-Directed Enzyme Pro-drug Therapy) is a new type of cancer treatment that involves a group of 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 in the future.
What is a monoclonal antibody?
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 on to it (like a key in a lock). 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 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 which is known as targeted therapy.
How does ADEPT work?
ADEPT is a type of targeted therapy. It uses a monoclonal antibody to carry an enzyme directly to the cancer cells. A few hours after the monoclonal antibody is given (with the enzyme attached) a pro-drug is given. The pro-drug is an inactive anti-cancer drug. When this pro-drug comes into contact with the enzyme, which is now attached to the cancer cell, a reaction takes place which activates the anticancer drug. The anti-cancer drug is then able to destroy the cancer cells. As normal cells do not have the antibody with the enzyme the treatment does not affect them.
What it looks like
ADEPT is a clear fluid.
How it is given
ADEPT is given by a drip (infusion) into the vein through a small tube (cannula) inserted into the vein. It is usually given in two separate doses on the same day.
Possible side effects
Trials are looking at the side effects that may occur. As ADEPT is still a relatively new treatment it is 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 fever and chills, headaches, itching and joint and muscle aches. These may occur a few hours after the drug is given, but do not 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 will 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 receive your treatment you will 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 cells usually recover in three to four weeks.
Nausea (feeling sick) and vomiting There are now very effective anti-sickness drugs to prevent or greatly reduce nausea and vomiting. If it does happen it may begin a few hours after the drug has been given, and may last for a few days. If the sickness is not controlled, or continues, tell your doctor. He or she can prescribe other anti-sickness drugs which may be more effective.
If you have any questions about these or any other side effects do talk to your doctor or nurse. It is also important to let them know if you have any symptoms or side effects that may be related to the treatment.
This section has been compiled using information from a number of reliable sources including:
- Martindale: The Complete Drug Reference (33rd edition). Sweetman et al. Pharmaceutical Press, 2002.
- British National Formulary (46th edition). British Medical Association and Royal Pharmaceutical Society of Great Britain, September 2003.
For further references, please see the general bibliography.