INTRON A (high-dose interferon alfa-2b)
Purpose: High-dose interferon is given to rev up the immune system in order to kill melanoma cells. Interferon is given to prevent the cancer from coming back after initial therapy, such as surgery.
How it works: Interferon is a naturally occurring protein that fights viral infections and other diseases. While the drug's main function is to alert the immune system to kill the melanoma cells, its mechanism is not completely understood. It is possible that it also chokes the blood supply to the tumor (antiangiogenesis) and directly fights the tumor growth.
Which patients: Intron A is given in the adjuvant setting after surgery to Stage III patients who are free of disease but are at a high risk of the disease returning. It is also given to certain late Stage IIB or Stage IIC patients (those with lesions of Breslow thickness > 4 mm).
How it is given: Intron A can be given intravenously, intramuscularly, subcutaneously, or intralesionally.
In the United States, Intron A is usually given in a 2-phase process over a 1-year period. In the induction phase, Intron A is given intravenously in a hospital or an office setting at the maximum tolerated dose, which is 5 days a week for 4 weeks. Each injection takes about 20-30 minutes. During the maintenance phase, Intron A is given subcutaneously 3 times a week for the remainder of the year. Most often, patients can do these injections themselves.
There have also been studies using low-dose Intron A. In these studies, there was a subcutaneous induction phase for 1-3 weeks followed by a maintenance phase for 3 times a week for a period of 1-3 years.
Effectiveness: When compared with patients who had no adjuvant treatment (treatment following surgery), Intron A was effective at preventing melanoma relapse. It extended the relapse free period from 0.98 years to 1.72 years. Five year-survival was 46% for those who took the drug compared to 37% for those who did not.
Side effects: Interferon is associated with a variety of side effects:
- Acute flu-like symptoms occur typically within 4-8 hours of injection (fever, chills, muscle pain, headache, nausea, vomiting). These are often worst at the beginning of treatment but then improve with time.
Important: Stay hydrated during the acute phase, and you may want to take a fever-lowering drug to relieve some of the flu symptoms, if your doctor advises. Keep warm with plenty of warm blankets.
- Fatigue is also very common. It typically starts during week 2 or week 3 and increases throughout the therapy. See "Managing Side Effects" for a discussion of how to manage fatigue.
Important: Some techniques to fight fatigue include:
- Try to be active. Balance your activity with rest, and plan activity for times when you feel well
- Get as much sleep as you can
- Eat a balanced diet with lots of fruits and vegetables
- Drink plenty of water
Other side effects include:
- Low white blood cell and red blood cell counts (as recorded before, during, and at the completion of treatment)
- Liver damage (depending on severity, a potential signal to discontinue treatment)
- Depression is common, occurring in about 40% of patients in the main trial. A small percentage of patients, approximately 2%, attempt suicide or develop suicidal ideas.
Important: Be aware of the potential seriousness of depression and call 911 if you think you may harm yourself or anyone else. Your physician may screen you for depression at the beginning and throughout your treatment to determine if you need a dose reduction or need to be taken off treatment. If you have any history of depression or any psychiatric history, tell your physician.
- Loss of appetite (resulting in weight loss). This may result from nausea and vomiting or altered taste.
- Eat smaller portions and have healthy snacks in between
- Avoid greasy and spicy foods
- If cooking smells make you sick, try eating foods cold.
- If you have a metallic taste in your mouth, get some tart liquids such as lemonade or orange juice. Use plastic rather than metallic utensils. Eat fresh foods rather than canned foods.
- Lessened attention/memory. This may interfere with your ability to take the drug and perform certain tasks.
Other points about side effects:
As with any treatment, the side effects of interferon therapy depend on the prescribed dose. Low-dose therapy is often well tolerated, while high-dose therapy tends to produce more severe and consistent side effects. Often, the most severe side effects occur during the first few weeks of therapy and then taper off significantly.
If the symptoms or signs are significantly abnormal, the treatment may be interrupted for a time and then resumed at a lower dose. Throughout the course of the therapy, treatment may be stopped and restarted at different dosages as needed.
If you are having severe side effects, talk to your doctor. Treatments are available to relieve symptoms such as nausea and fatigue. You will also receive careful and continuous monitoring for life-threatening side effects, including bone marrow suppression and liver damage. Many side effects are generally reversible when therapy is stopped.
Patient assistance: ACT program. 1-866-363-6379 (http://www.merck.com/merckhelps/act-program/home.html)
- Patient assistance: ACT program. 1-866-363-6379 (http://www.merck.com/ merckhelps/act-program/ home.html)