Iberdomide (Zenbexus™)
Pronounce: eye-BER-doh-mide
Classification: Cereblon-modulating protein degrader
About Iberdomide (Zenbexus™)
This medication is a cereblon-modulating protein degrader. It works by attaching to a protein called cereblon and changing how it functions, causing it to target two proteins (Ikaros and Aiolos) that cancer cells rely on to survive and grow. Once targeted, these proteins are broken down and removed by the cell's own disposal system. This weakens and kills the cancer cells while also stimulating the immune system to attack them.
How to Take This Medication
This medication comes in a capsule. Your dosing schedule will be determined by your provider. It can be taken with or without food around the same time every day. Swallow the capsules whole. Do not open, break, or chew the capsules. If you touch a broken capsule, wash the area exposed to the medication right away with soap and water.
If you miss a dose, and it has been less than 12 hours since your last scheduled dose, take it as soon as you remember. If more than 12 hours have passed, skip that dose and take the next dose at your usual scheduled time. Do not take 2 doses at once to make up for a missed dose.
It is important to take the correct amount of medication. Before each dose, check that the medication and the amount match what your provider prescribed.
The blood levels of this medication can be affected by certain foods and medications, so they should be avoided. These can include grapefruit juice, itraconazole, fluconazole, diltiazem, ketoconazole, clarithromycin, ritonavir, rifampin, carbamazepine and phenytoin, and others. Be sure to tell your healthcare provider about all medications and supplements you take.
Iberdomide (Zenbexus™) REMS Program
In order to receive this medication, you will need to participate in a program called REMS (Risk Evaluation and Mitigation Strategy). This program educates healthcare professionals and patients about the dangers of the medication exposure to a fetus. This exposure can cause serious birth defects, and patients who can get pregnant while taking the medication will need to use two reliable forms of birth control. The REMS program limits who can prescribe and dispense the medication. Patients will also need to complete a survey and safety agreement before starting the drug, and every month they are taking it.
If you can become pregnant, you should not have sex, or you should use two different forms of birth control for at least 4 weeks before starting treatment, during treatment, during any breaks in treatment and for 4 weeks after your last dose. You will have 2 pregnancy tests before starting treatment with this medication, a pregnancy test every week for the first four weeks of treatment, and then every 2-4 weeks depending on your menstrual cycles.
Treatment must be stopped immediately if you become pregnant, miss a period, or have unusual bleeding. Do not donate eggs during treatment and for 4 weeks after treatment.
If you can get someone pregnant, you should use a latex or synthetic condom during treatment and for 1 month after your last dose of this medication, even if you have had a vasectomy. Do not donate blood or sperm during therapy and for at least 1 month after stopping therapy.
Storage and Handling
Store your medication in the original container with the label. If you want to use a pillbox, talk to your pharmacist. Keep it in a dry place at room temperature unless your provider or pharmacist tells you otherwise. Keep containers out of reach of children and pets.
If a caregiver prepares your dose for you, they should consider wearing gloves or pour the pills directly from their container into the cap, a small cup, or directly into your hand. They should avoid touching the pills. They should always wash their hands before and after giving you the medication. Pregnant or nursing people should not prepare the dose for you. Ask your provider where to return any unused medication for disposal. Do not flush down the toilet or throw in the trash.
Where Do I Get This Medication?
Some cancer medications are only available through specialty pharmacies. Your provider or pharmacist will start this process. Your insurance plan may also affect where you can get your medication. Call your prescription plan provider to find out which specialty pharmacies are in-network.
Insurance Information
This medication may be covered by your prescription plan. If you qualify, you may be able to get financial help through patient assistance programs (PAP). Co-pay cards may also be available to lower your out-of-pocket cost if you have commercial (not Medicare/Medicaid/Tricare) insurance. Your pharmacist, social worker, or navigator can help find resources for financial support.
Possible Side Effects
These are some of the most common or most serious side effects of this medication. Talk with your provider about the side effects you are having and how they can be managed.
Infection and Low White Blood Cell Count (Leukopenia or Neutropenia)
This medication can cause serious infections, with or without a decrease in white blood cell counts.
White blood cells (WBC) help your body fight infection. While you are having cancer treatment, your WBC count can drop, putting you at a higher risk of an infection. Tell your provider right away if you have a fever (a temperature greater than 100.4°F or 38°C), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.
Tips for preventing infection:
- Hand washing, both yours and your visitors, is the best way to prevent the spread of infection.
- Avoid large crowds and people who are sick (those who have a cold, fever, or cough, or if someone you live with has these symptoms).
- When working outside, wear clothes that protect you, like long pants and gloves.
- Do not handle pet waste.
- Keep all cuts and scratches clean.
- Shower or bathe daily.
- Brush your teeth at least twice a day.
- Do not cut cuticles or ingrown nails. You may wear nail polish, but not fake nails.
- Ask your providers before scheduling dental appointments or procedures.
Ask your providers before you or someone you live with has any vaccines.
Low Platelet Count (Thrombocytopenia)
Platelets are blood cells that help your blood clot. Thrombocytopenia is when your platelet count is lower than normal, and you are at a higher risk of bleeding. Tell your providers if you have any bruising or bleeding, including nose bleeds, bleeding gums, or blood in your urine or stool. If your count gets too low, you may receive platelets from a donor.
- Do not use a razor (an electric razor is fine).
- Do not do activities that can cause injury or bleeding.
- Talk to your provider before taking any non-steroidal, anti-inflammatory medications (NSAIDs) like Motrin/Advil (ibuprofen), Aleve (naproxen), Celebrex (celecoxib), and others. These can raise the risk of bleeding.
- Use a soft-bristle toothbrush to brush your teeth. Ask your provider about flossing or using toothpicks.
Low Red Blood Cell Count (Anemia)
Anemia is when your red blood cell count is lower than normal. Red blood cells carry oxygen to the tissues in your body. When your red cell count is low, you may feel tired or weak. Tell your providers if you have shortness of breath, trouble breathing, or pain in your chest. If your count gets too low, you may receive a blood transfusion.
Upper Respiratory Infection (URI)
An upper respiratory infection causes swelling or irritation in your upper airways. It can cause a runny nose, cough, and sore throat. Call your provider if you have any of these symptoms and for ways to manage a URI.
Hypocalcemia
Hypocalcemia is an electrolyte imbalance that is characterized by a low level of calcium in the blood. Your provider will periodically check your blood calcium levels while receiving this medication.
Fatigue
Fatigue can cause exhaustion, feeling worn out and that your body is "heavy" and hard to move, or being unable to focus. It is common when you have cancer, and it is not the same as feeling tired. You may need to adjust your schedule to manage fatigue. Plan times to rest during the day and save your energy for more important activities. Exercise can help lessen fatigue. Talk to your providers about ways to deal with this side effect.
Muscle or Joint Pain/Aches and Headache
You may have joint or muscle pain/aches and headaches while taking this medication. Your provider can recommend medications and other ways to help relieve your pain.
Pneumonia
This medication can increase your risk of pneumonia. Symptoms can include cough, fever, chills, chest pain, and shortness of breath. Be sure to tell your provider right away if you have any of these symptoms.
Diarrhea
Diarrhea is when you pass three or more stools in a day. Your providers can suggest medications to relieve diarrhea. Do not take any medications to manage your diarrhea without talking to your provider first, as your stool may need to be tested. To manage it, try eating foods that are low in fiber and bland, like white rice and boiled or baked chicken. Try not to eat raw fruits, vegetables, whole grain breads, cereals, and seeds. Soluble fiber is a type of fiber found in some foods that helps absorb (soak up) fluid. Foods high in soluble fiber are applesauce, bananas (ripe), canned fruit, oranges, boiled potatoes, white rice, foods made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Stay hydrated by drinking 8 to 10 glasses of non-alcoholic, non-caffeinated fluid each day.
Rash
Some people may get a rash, scaly skin, or red, itchy bumps from this medication. Tell your provider if you notice any of these changes in your skin, since it could be a reaction. Your provider may suggest:
- Using an alcohol-free moisturizer on your skin and lips, and do not use moisturizers with perfumes or scents.
- Keep the area clean to avoid infection, especially if it cracks or bleeds.
- Using a topical medication (applied to the skin) if the itching bothers you.
Be sure to talk with your provider about how to care for your skin.
Liver Toxicity
This medication can cause liver toxicity, or liver problems, which your provider may monitor for with blood tests called liver function tests. Symptoms may be:
- Yellowing of your skin or eyes.
- Dark or brown urine.
- Pain in your abdomen (belly).
Tell your provider if you have any of these symptoms.
Sleep Problems (Insomnia and Restless Leg Syndrome)
Insomnia is when there is a change in your sleep habits. This medication can cause new or worsening insomnia. Symptoms may be:
- Having a hard time falling asleep.
- Having a hard time staying asleep.
- Waking often through the night.
- Feeling unrested the next day.
Restless leg syndrome is an urge to move your legs when you are sitting or lying still, especially at night. You may feel tingling or aching in your legs and muscles that can get better by moving your legs, stretching, or shaking them out. Because this happens at night, it can make it hard to fall asleep or stay asleep. Talk with your provider if changes to sleep are affecting your daily life.
Movement (Motor) Problems
This medication can cause problems with how your body moves or controls the muscle including
- Trouble with balance or coordination (ataxia).
- Feeling unsteady on your feet.
- Changes in the way you walk (gait disturbance).
- Tight, stiff, or weak muscles.
- Muscle cramps.
- Inability to move a body part.
- Nerve damage that affects the signals telling your muscles to move.
Tell your provider about any new weakness, changes in movement or balance.
Hypogammaglobulinemia
Hypogammaglobulinemia is low levels of immunoglobulin. This medication can cause low levels of immunoglobulin. Immunoglobulins are antibodies made by your immune system to help you fight infections. Your levels will be checked while on treatment and you may get immunoglobulin if needed. While your levels are low, you are at a higher risk of getting an infection. Talk with your provider before you get any vaccines and about ways you can decrease your chance of an infection.
Constipation
Constipation is when you have less bowel movements than usual or are having trouble passing stool. To relieve constipation, you can include fiber in your diet (fruits like prunes, apples, peaches, and pear nectars/juices), drink 8 to 10 glasses of non-alcoholic fluids a day, and stay active. Taking a stool softener once or twice a day can prevent constipation. If you do not have a bowel movement for 2 to 3 days, call your provider.
Fertility
This medication may affect your fertility. It can cause changes to your menstrual cycle or sperm. You may want to consider sperm banking or egg harvesting if you might wish to have a child in the future. Talk about your options with your provider before treatment.
Reproductive Concerns
There is a higher risk of health problems for your baby if you are pregnant, become pregnant, or get someone pregnant while on this medication. To lower the risk of birth defects, you should use birth control (contraception) to avoid pregnancy. Talk with your provider about what kind of birth control is safest for you and your partner.
Exposure of an unborn child to this medication could cause birth defects. You should not become pregnant or get someone pregnant while on this medication. Effective birth control is necessary for four weeks before treatment, during treatment, and for four weeks after treatment is completed, even if your menstrual cycle stops or you believe you are not producing sperm. You should not breastfeed while taking this medication. Do not donate eggs, blood, or sperm during therapy and for at least 1 month after stopping therapy.
Important but Less Common Side Effects
Blood Clots, Heart Attack, and Stroke
This medication increases your risk for blood clots, stroke, and heart attack. Symptoms may be:
- Swelling, redness, or pain in an arm or leg.
- Chest pain or pressure.
- Pain in your back, neck, or jaw.
- Shortness of breath.
- Numbness or tingling.
Tell your provider right away if you have any of these symptoms.
Secondary Cancers
A secondary cancer happens as a result of cancer treatment for another cancer. This is rare, but you should know your risk. Secondary cancers can be related to chemotherapy and other anti-cancer medications. Often, a secondary cancer is a blood cancer. This can happen years after treatment and is often related to repeated treatments or high doses. Your provider will watch your labs closely. They may suggest you have a blood test called a complete blood count with differential. This is often done each year if you had high risk therapies.