Care During Chemotherapy and Beyond


Generic name: Denileukin Diftitox uses generic names in all descriptions of drugs. Ontak is the trade name for Denileukin Diftitox. In some cases, health care professionals may use the trade name Ontak when referring to the generic drug name Denileukin Diftitox.

Drug type:  Ontak is a targeted therapy.  This medication is classified as a "biologic response modifier agent."  (For more detail, see "How this drug works" section below).

What This Drug Is Used For:

  • Denileukin diftitox is used to treat patients with persistent or recurrent cutaneous T-cell lymphoma.  The patient's lymphoma cells need to be a specific type -- they must have the high affinity component of the IL-2 receptor -- to be treated with this drug.  This is generally confirmed by testing the lymphoma tissue before the drug is given.

Note:  If a drug has been approved for one use, physicians may elect to use this same drug for other problems if they believe it may be helpful.  

How This Drug Is Given:

  • This medication is given by intravenous injection (IV), through a vein.  The infusion will take 15 minutes or longer.
  • The amount of denileukin diftitox that you will receive depends on many factors, including your height and weight, your general health or other health problems, and the type of cancer or condition being treated.  Your doctor will determine your dose and schedule.

Side Effects:

Important things to remember about the side effects of denileukin diftitox:

  • Most people do not experience all of the side effects listed.
  • Side effects are often predictable in terms of their onset and duration.
  • Side effects are almost always reversible and will go away after treatment is complete.
  • There are many options to help minimize or prevent side effects.
  • There is no relationship between the presence or severity of side effects and the effectiveness of the medication

The following side effects are common (occurring in greater than 30%) for patients taking denileukin diftitox:

  • Hypersensitivity reaction during the infusion with symptoms such as low blood pressure, back pain, shortness of breath (see allergic reactions).
  • Fever/Chills (usually occurs during or soon after the infusion).
  • Nausea and vomiting.
  • Blood test abnormalities (low albumin level, hypoalbuminemia).
  • Liver problems (elevated liver enzymes; transaminase).
  • Weakness.
  • Swelling (usually of hands and feet).
  • Infection.
  • Pain.
  • Low blood pressure (hypotension).
  • Poor appetite.
  • Rash.

These side effects are less common side effects (occurring in about 10-29%) of patients receiving denileukin diftitox:

  • Diarrhea
  • Shortness of breath
  • Headache
  • Chest pain
  • Cough
  • Dizziness
  • Itching
  • Pharyngitis or Rhinitis (inflammation of the throat or nose) (see cold symptoms).
  • Low Red blood cell count. Your red blood cells may temporarily decrease.  This can put you at increased risk for anemia.
  • Numbness and tingling of hands and feet.
  • Blood test abnormalities (low calcium level, low albumin level).
  • Muscle pain
  • Weight loss
  • Rapid heart rate (see heart problems)
  • Anxiety or nervousness
  • Sweating (see skin problems)
  • Blood in the urine (see bladder problems)
  • Cloudy urine (see kidney problems)
  • A serious side effect of denileukin diftitox  is "capillary leak syndrome" or "vascular leak syndrome."  Capillary leak syndrome is a potentially serious disease in which fluids within the vascular system (veins and capillaries) leaks into the tissue outside the bloodstream.  This results in low blood pressure and poor blood flow to the internal organs.  Capillary leak syndrome is characterized by the presence of 2 or more of the following 3 symptoms; low blood pressure, swelling, and low levels of protein in the blood.  Your doctor will monitor these things carefully while you are taking denileukin diftitox.   You should notify your doctor immediately if you notice dizziness (especially when changing position), sudden swelling or rapid weight gain, little or no urine output (for 8-12 hours), shortness of breath, difficulty breathing, irregular heartbeats, or chest pain.  If this syndrome occurs, it will likely be delayed, within about 2 weeks of treatment.

Not all side effects are listed above. Some that are rare (occurring in less than 10% of patients) are not listed here.  However, you should always inform your health care provider if you experience any unusual symptoms.

When to contact your doctor or health care provider:

Contact your health care provider immediately, day or night, if you should experience any of the following symptoms:

  • Dizziness (especially when changing position), sudden swelling or rapid weight gain, little or no urine output (for 8-12 hours), shortness of breath, difficulty breathing, irregular heartbeats, or chest pain.

The following symptoms require medical attention, but are not an emergency.  Contact your health care provider within 24 hours of noticing any of the following:

  • Fever of 100.4° F (38° C) or higher, chills occurring 1-2 days after infusion or later (possible signs of infection).
  • Nausea (interferes with ability to eat and unrelieved with prescribed medication)
  • Vomiting (vomiting more than 4-5 times in a 24 hour period)
  • Diarrhea (4-6 episodes in a 24-hour period)
  • Unusual bleeding or bruising
  • Blood in the urine
  • Cloudy urine
  • Pain or burning with urination
  • Extreme fatigue or weakness (unable to carry on self-care activities)
  • Anxiety or nervousness that interferes with your ability to function
  • Yellowing of the skin or eyes

Note:  Notify your health care provider of any symptoms that get worse or do not go away.

Always inform your health care provider if you experience any unusual symptoms.


  • Before starting denileukin diftitox treatment, make sure you tell your doctor about any other medications you are taking (including prescription, over-the-counter, vitamins, herbal remedies, etc.).   Do not take aspirin, products containing aspirin unless your doctor specifically permits this.
  • Denileukin diftitox may be inadvisable if you have had a hypersensitivity (allergic) reaction to denileukin diftitox, diphtheria toxin or interleukin-2.
  • Do not receive any kind of immunization or vaccination without your doctor's approval while taking denileukin diftitox.
  • Inform your health care professional if you are pregnant or may be pregnant prior to starting this treatment.  Pregnancy category C (use in pregnancy only if benefit to mother outweighs risk to fetus).
  • For both men and women: It is not recommended to conceive a child (get pregnant) while taking denileukin diftitox. Barrier methods of contraception, such as condoms, are recommended. Discuss with your doctor when you may safely become pregnant or conceive a child after therapy.
  • Do not breast feed while taking this medication.

Self-Care Tips:

  • Drink at least two to three quarts of fluid every 24 hours, unless you are instructed otherwise.
  • Wash your hands often.
  • Avoid contact sports or activities that could cause injury.
  • To reduce nausea, take anti-nausea medications as prescribed by your doctor, and eat small, frequent meals.  
  • Avoid sun exposure.  Wear SPF 15 (or higher) sunblock and protective clothing.
  • In general, drinking alcoholic beverages should be kept to a minimum or avoided completely.  You should discuss this with your doctor
  • Get plenty of rest
  • Maintain good nutrition
  • If you experience symptoms or side effects, be sure to discuss them with your health care team.  They can prescribe medications and/or offer other suggestions that are effective in managing such problems.

Monitoring and Testing:

You will be checked regularly by your health care professional while you are taking denileukin diftitox, to monitor side effects and check your response to therapy.  Periodic blood work to monitor your complete blood count (CBC) as well as the function of other organs (such as your kidneys and liver) will also be ordered by your doctor.   

How This Drug Works:

Targeted therapy:
Targeted therapy is the result of about 100 years of research dedicated to understanding the differences between cancer cells and normal cells.  To date, cancer treatment has focused primarily on killing rapidly dividing cells because one feature of cancer cells is that divide rapidly.  Unfortunately, some of our normal cells divide rapidly too, causing multiple side effects. 

Targeted therapy is about identifying other features of cancer cells.  Scientists look for specific differences in the cancer cells and the normal cells.  This information is used to create a targeted therapy to attack the cancer cells without damaging the normal cells, thus leading to fewer side effects.  Each type of targeted therapy works a little bit differently but all interfere with the ability of the cancer cell to grow, divide, repair and/or communicate with other cells. 

There are different types of targeted therapies, defined in three broad categories.  Some targeted therapies focus on the internal components and function of the cancer cell.  The targeted therapies use small molecules that can get into the cell and disrupt the function of the cells, causing them to die.  There are several types of targeted therapy that focus on the inner parts of the cells.   Other targeted therapies target receptors that are on the outside of the cell.   Therapies that target receptors are also known as monoclonal antibodies.  Antiangiogenesis inhibitors target the blood vessels that supply oxygen to the cells, ultimately causing the cells to starve.

Researchers agree that targeted therapies are not a replacement for traditional therapies.  They may best be used in combination with traditional therapies.  More research is needed to identify which cancers may be best treated with targeted therapies and to identify additional targets for more types of cancer.

Denileukin Diftitox. Denileukin diftitox is a fusion protein (a combination of diphtheria toxin and interleukin-2) which selectively delivers the cell-killing activity of the diphtheria toxin to targeted cells.  The lymphoma cells need to be a specific type -- they must express the high affinity IL-2 receptor on the surface of the cancer cell which then permits the IL-2 part of the fusion protein to attach/bind to the cell, halt protein synthesis and lead to cell death because of the diptheria toxin.

Research continues to identify which cancers may be best treated with targeted therapies and to identify additional targets for more types of cancer. 

Note:  We strongly encourage you to talk with your health care professional about your specific medical condition and treatments. The information contained in this website is meant to be helpful and educational, but is not a substitute for medical advice. is designed to provide the latest information about chemotherapy to patients and their families, caregivers and friends. For information about the 4th Angel Mentoring Program visit