Imetelstat

Imetelstat is a prescription medication indicated for the treatment of adults with low- to intermediate-1 risk myelodysplastic syndromes (MDS) with transfusion-dependent anemia requiring 4 or more red blood cell units over 8 weeks who have not responded to, have lost response to, or are ineligible for erythropoiesis-stimulating agents (ESA).

• Imetelstat is available under the following different brand names: Rytelo.

Common side effects of Imetelstat include:

• decreased platelet counts
• decreased white blood cell counts
• decreased neutrophil counts
• increased liver enzymes (AST, alkaline phosphatase, and ALT)
• tiredness
• longer than usual blood clotting times
• joint, bone, and muscle pain
• Covid-19 infections
• headache

Serious side effects of Imetelstat include:

• Low platelet counts (thrombocytopenia) symptoms include unusual bleeding or bruising, bleeding that lasts a long time, nosebleeds, vomiting blood, blood in the stools, or black tarry stools
• Low neutrophil counts (neutropenia) symptoms include fever, shortness of breath or trouble breathing, cough, chills, pain or burning when urinating
• Infusion-related reactions include stomach pain, joint pain, weakness and tiredness, back and bone pain, diarrhea, redness, headache, high blood pressure, not feeling well, chest pain that is not related to the heart, itching, hives

Rare side effects of Imetelstat include:

• none 

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, coordination loss, unsteady, very stiff muscles, high fever, profuse sweating, or tremors.
• Serious eye symptoms include sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult dosage

Injection, lyophilized powder for reconstitution

• 47 mg/single-dose vial
• 188 mg/single-dose vial

Myelodysplastic syndromes

Adult dosage

• 7.1 mg/kg IV every 4 weeks; infuse over 2 hours
• Discontinue if RBC transfusion burden does not decrease after 24 weeks of treatment (6 doses) or if unacceptable toxicity occurs at any time
• Premedication
  • Administer more than 30 minutes before dosing to prevent or reduce potential infusion-related reactions
  • Diphenhydramine (or equivalent): 25-50 mg IV/orally
  • Hydrocortisone (or equivalent): 100-200 mg IV/orally
  • Monitor for adverse reactions for at least 1 hour after infusion completed

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Imetelstat has no noted severe interactions with any other drugs
• Imetelstat has no noted serious interactions with any other drugs
• Imetelstat has no noted moderate interactions with any other drugs
• Imetelstat has no noted minor interactions with any other drugs

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, health questions, or concerns.

Contraindications

• None

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Imetelstat?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Imetelstat?”

Cautions

• Thrombocytopenia
  • Can cause thrombocytopenia based on laboratory values
  • Median time to onset of the first occurrence of Grade 3 or 4 decreased platelets was 6 weeks and the median time to recovery from each occurrence was 1.3 weeks
  • Monitor patients with thrombocytopenia for bleeding
  • Monitor CBC counts before initiation, weekly for the first 2 cycles, and then before each cycle after that and as clinically indicated
  • Administer platelet transfusions as appropriate
  • Delay the next cycle and resume at the same or reduced dose, or discontinue as recommended
• Neutropenia
  • Can cause neutropenia based on laboratory values
  • The median time to onset of the first occurrence of Grade 3 or 4 decreased platelets was 4.6 weeks and the median time to recovery from each occurrence was 1.9 weeks
  • Monitor patients with Grade 3 or 4 neutropenia for infections, including sepsis
  • Monitor CBC counts before initiation, weekly for the first 2 cycles, and then before each cycle after that and as clinically indicated
  • Administer growth factors and anti-infective therapies for treatment or prevention as appropriate
  • Delay the next cycle and resume at the same or reduced dose, or discontinue as recommended
• Infusion-related reactions
  • May cause infusion reactions with symptoms, including those resulting in a hypertensive crisis
  • The most common symptom included headache
  • Premedicate at least 30 minutes before infusion with diphenhydramine and hydrocortisone as recommended
  • Monitor for at least 1 hour after infusion
  • Manage symptoms with supportive care and infusion interruptions, decrease infusion rate, or permanently discontinue as recommended
• Embryo-fetal toxicity
  • Based on findings in animals, can cause embryo-fetal harm when administered to pregnant women
  • Advise females of reproductive potential to use effective contraception during treatment and for 1 week after the last dose

Pregnancy and Lactation

• Based on findings in animals, can cause embryo-fetal harm when administered to pregnant women
• Verify pregnancy status of women of reproductive potential before initiating
• Advise females of reproductive potential to use effective contraception during treatment and for 1 week after the last dose
• Contraception
  • Advise women of reproductive potential to use effective contraception during treatment and for 1 week after the last dose
• Infertility
  • Based on findings in animals, may impair fertility in women of reproductive potential
  • Effect on fertility is reversible
• Lactation
  • Data are not available regarding the presence of Imetelstat in human milk, its effects on breastfed children, or on milk production
  • Owing to the potential for adverse reactions in breastfed children, advise women not to breastfeed during treatment and for 1 week after the last dose