Rytelo
Rytelo (imetelstat) is used to treat a blood condition called myelodysplastic syndrome (MDS). It's for adults with lower-risk MDS who also have anemia and need regular red blood cell (RBC) transfusions. Rytelo (imetelstat) is typically used after erythropoiesis‑stimulating agents (ESAs) stop working, don’t work, or can’t be used. It's given as an intravenous (IV) infusion at a clinic once every 4 weeks. Each infusion takes about 2 hours, and you’ll get medications right before to lower the chance of infusion reactions. Common side effects include low platelets, low white blood cells, and feeling tired.
What is Rytelo (imetelstat)?
What is Rytelo (imetelstat) used for?
- Lower-risk myelodysplastic syndromes (MDS) with transfusion-dependent anemia
How Rytelo (imetelstat) works
Rytelo (imetelstat) is a telomerase inhibitor. It blocks a protein called telomerase that helps cells grow and divide. In MDS, abnormal blood cells often have high telomerase activity.
By blocking telomerase, Rytelo (imetelstat) slows or stops these abnormal cells from growing. This can help your body make healthy blood cells again and raise your hemoglobin levels. So, you might need fewer blood transfusions.
Drug facts
| Common Brands | Rytelo |
|---|---|
| Drug Class | Telomerase inhibitor |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | No lower-cost generic available |
| Availability | Prescription only |
Side effects of Rytelo (imetelstat)
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Drop in platelet count (97%)
- Drop in white blood cell count (94%)
- Higher liver enzyme levels (up to 55%)
- Feeling tired (29%)
- Joint or muscle aches (25%)
Less Common Side Effects
- Headache
- Fainting
- Nosebleed
- Bruising
- Itching
- Abnormal heart rhythm
- Infusion‑related reactions
- Broken bone
- COVID-19 infection
- Urinary tract infection (UTI)
Rytelo (imetelstat) serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Bleeding (from having low platelets): easy bruising, frequent nosebleeds, bleeding from the gums, blood in urine or stool, tiny red spots on the skin, severe headache, dizziness
- Infection (from having low white blood cells): fever, chills, sore throat, cough that won’t go away, shortness of breath, burning with urination, confusion, weakness
- Infusion reactions: headache, flushing, chest tightness, trouble breathing, rash, hives, blood pressure changes
The following Rytelo (imetelstat) side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- Infection—fever, chills, cough, sore throat, wounds that don't heal, pain or trouble when passing urine, general feeling of discomfort or being unwell
- Infusion reactions—chest pain, shortness of breath or trouble breathing, feeling faint or lightheaded
- Liver injury—right upper belly pain, loss of appetite, nausea, light-colored stool, dark yellow or brown urine, yellowing skin or eyes, unusual weakness or fatigue
- Unusual bruising or bleeding
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
- Bone, joint, or muscle pain
- Fatigue
- Headache
Pros and cons of Rytelo (imetelstat)
Pros
- Shown to reduce or stop the need for RBC transfusions for many people with lower‑risk MDS
- An option for people who already tried erythropoiesis‑stimulating agents (ESAs) or can't use them
- Given once every 4 weeks at a clinic, so no at‑home mixing or injections
Cons
- Can raise your risk of easy bleeding and infection
- Requires frequent blood tests to check for safety, especially early in treatment
- Must stay at the clinic for at least 1 hour after the infusion ends so your care team can check for infusion reactions
Pharmacist tips for Rytelo (imetelstat)
- Write the dates of your Rytelo (imetelstat) infusions in your calendar and set up reminders. They're given once every 4 weeks. Staying on track with your treatment plan helps the medication work best.
- If you miss a Rytelo (imetelstat) infusion visit, call the clinic as soon as you can. Your care team can help you reschedule it.
- Give yourself plenty of time for your Rytelo (imetelstat) appointment. Before the infusion, your nurse will help get you settled. Then, the infusion itself takes about 2 hours. It can take even longer if your care team needs to slow it down to help with side effects. After, you'll need to stay for at least another hour so your care team can watch for infusion reactions. Bring a book or something to do to pass the time.
- Before your Rytelo (imetelstat) infusion, your nurse will give you medications to lower your risk of infusion reactions. These usually include an antihistamine and a steroid. They're often given at least 30 minutes before your infusion.
- During and right after your Rytelo (imetelstat) infusion, tell your nurse right away if you feel dizzy, have chest tightness, trouble breathing, or a headache. These can be signs of an infusion reaction. Your care team can slow or stop the infusion and treat your symptoms.
- Be sure to get your blood work done on schedule. Rytelo (imetelstat) can cause low platelets and low blood cells. It might also raise your liver enzymes. Your care team will check your blood work weekly for the first 2 cycles, before each cycle after that, and then as needed. This helps catch problems early and keep you safe.
- Rytelo (imetelstat) can raise your risk of easy bleeding and bruising. Use a soft toothbrush and brush your teeth gently. Also, avoid activities that could make you get hurt. Tell your care team if you notice unusual bruising or frequent nosebleeds. Get medical help right away if you have black stools or blood in your urine; these can be signs of serious bleeding.
- Watch for signs of infection every day while taking Rytelo (imetelstat). This medication can make it easier for you to get sick. Call your care team if you have a fever, chills, new cough, shortness of breath, or burning with urination. Quick care can prevent a serious infection.
- If you can become pregnant: Use reliable birth control while taking Rytelo (imetelstat) and for 1 week after your last dose. This medication might harm an unborn baby. If you get pregnant during treatment, tell your oncologist or hematologist right away.
- If you're thinking about breastfeeding: It's not recommended to breastfeed while taking Rytelo (imetelstat) and for 1 week after your last infusion. We don't know if this medication can pass into breast milk and how it could affect your baby. Talk to a healthcare professional about safer ways to feed your baby.
Risks and warnings for Rytelo (imetelstat)
Rytelo (imetelstat) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Low platelets
Rytelo (imetelstat) often lowers your platelet count. Platelets help your blood clot, so low levels can make it easier to bleed or bruise.
Some people have had a severe drop in platelet levels while taking Rytelo (imetelstat). This has happened early in treatment (within about 6 weeks) and has taken a few weeks to improve. It can also happen again later during treatment.
Your care team will check your platelet count with blood work before you start treatment. Then, they'll check weekly for the first 2 cycles, before each cycle after that, and as needed. If your levels get too low, your oncologist or hematologist might delay your dose, lower it, or stop treatment. They might also give platelet transfusions. This depends on how low your platelet count is.
Watch for easy bruising, bleeding that's hard to stop, nosebleeds, gum bleeding, blood in your urine or stool, or severe headaches. These can be signs of bleeding. Call your care team right away if these happen while taking Rytelo (imetelstat).
Low white blood cells
Rytelo (imetelstat) can lower your white blood cell (WBC) count. Low white blood cells can put you at risk of infections, which can become very serious.
Some people have had a severe drop in WBCs while taking Rytelo (imetelstat). This sometimes happened within weeks after you begin treatment, even as early as 1 week. Then, it can take a few weeks to get better. Very low WBCs can happen again during later cycles.
Your care team will check your WBCs with a blood test before you start treatment. Then, they'll check every week for the first 2 cycles, before each cycle after that, and then as needed. If your levels get too low, your oncologist or hematologist might delay your next infusion, lower your dose, or stop treatment. If needed, they might give you medication called growth factors to help raise your WBCs.
Call your care team right away for any fever that's 100.4°F or higher. Also call if you have chills, sore throat, shortness of breath, a cough that won’t go away, or burning with urination. These can be signs of an infection. Your care team might give you antibiotics or other anti-infectives to help treat or prevent infections.
Infusion-related reactions
Headache, flushing, chest pain, and joint aches can sometimes happen during or shortly after the Rytelo (imetelstat) infusion. This is called an infusion-related reaction. Serious reactions aren't common but can include very high blood pressure.
To lower your risk, your care team will give you medications before each Rytelo (imetelstat) infusion. These can be diphenhydramine (Benadryl) and hydrocortisone. You'll also need to stay for at least 1 hour after each infusion so your care team can watch for reactions.
Tell your care team right away if you feel dizzy, have chest tightness, trouble breathing, or a headache. These can be signs of an infusion reaction. Your care team can slow or stop the Rytelo (imetelstat) infusion and treat your symptoms. If the reaction is severe, you might need to stop treatment.
Harm to an unborn baby
- Risk factors: Pregnancy
Based on animal data, Rytelo (imetelstat) might harm an unborn baby. If pregnancy is possible, you’ll typically need to take a pregnancy test before starting.
If you can become pregnant, use effective birth control during treatment and for 1 week after your last dose. If you get pregnant or think you are, tell your care team right away to discuss next steps.
Rytelo (imetelstat) dosage
Typical dosage for Rytelo (imetelstat)
Rytelo (imetelstat) is given as an infusion through a vein, or an intravenous (IV) infusion. It's given by a healthcare professional at a clinic.
The typical dose is 7.1 mg/kg of body weight given IV once every 4 weeks.
Your dose might be lowered if you have certain side effects during treatment.
