What is RYTELO?

RYTELO (imetelstat) is a prescription medicine used to treat a condition called low- to intermediate-1 risk myelodysplastic syndromes (MDS) in adults: See more

  • with anemia (low red blood cell counts) who need blood transfusions of 4 or more red blood cell units over 8 weeks

and

  • who have not responded to, have stopped responding to, or cannot be treated with medicines called erythropoiesis-stimulating agents (ESAs).

It is not known if RYTELO is safe and effective in children.

Understanding the possible side effects of RYTELO

A smiling man wearing a blue shirt.

RYTELO works by slowing the spread of abnormal MDS cells in the bone marrow. As a result of receiving the medicine, levels of some healthy blood cells may also decrease. Low blood cell counts are the most common side effect seen with RYTELO.

While these side effects can be severe, your healthcare team knows what to look for and is experienced in monitoring and managing them. Certain low blood cell counts are expected with treatment and can be temporary.

Types of low blood cell counts that may occur

  • Thrombocytopenia

    Low platelet counts are called thrombocytopenia. This can be common during treatment with RYTELO and can also be severe. Low platelet counts can increase your risk for bleeding.

    Your healthcare provider may give you platelet transfusions to reduce the risk of bleeding if you develop a low platelet count during treatment with RYTELO.

  • Neutropenia

    Neutrophils are a type of white blood cell. Low neutrophil counts, called neutropenia, are common during treatment with RYTELO and can sometimes be severe. Neutropenia can increase your risk for infections, including serious infections and sepsis.

    Your healthcare provider may give you medicines before you start treatment to help prevent neutropenia and infections and may treat you with medicines if you develop these problems during treatment with RYTELO.

Infusion-related reactions

RYTELO can cause infusion-related reactions (IRRs) during or after your infusion, including a severe sudden increase in blood pressure called hypertensive crisis.

Your healthcare team can help prevent or treat reactions

Your healthcare provider will give you medicines before each RYTELO infusion to help prevent or lessen IRRs and will watch you for at least 1 hour after your infusion. If you develop IRRs, your healthcare provider may infuse RYTELO more slowly, temporarily stop, or permanently stop your treatment.

Healthcare provider holding a tablet

Tell your healthcare provider if you develop any signs or symptoms of IRRs, including:

  • 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 your heart
  • Itching
  • Hives

Most common side effects of RYTELO include:

  • Low platelet counts

  • Low white blood cell counts

  • Low neutrophil counts

  • Liver enzyme changes

  • Tiredness

  • Slower blood clotting

  • Joint/bone/muscle pain

  • COVID-19 infections

  • Headache

Man walking with a hat and backpack

These are not all of the possible side effects of RYTELO. Speak to your healthcare provider for more information and medical advice about side effects. Please see full Important Safety Information.

Remember, it is important to tell your healthcare provider how you are feeling during treatment and about any side effects you experience.

Your healthcare provider will continue to monitor you for side effects throughout treatment and will make any adjustments as needed.

Talk with your healthcare provider about RYTELO

The RYTELO Patient Brochure can help you discuss treatment as well as concerns over possible side effects.

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What is RYTELO?

RYTELO (imetelstat) is a prescription medicine used to treat a condition called low- to intermediate-1 risk myelodysplastic syndromes (MDS) in adults:

  • with anemia (low red blood cell counts) who need blood transfusions of 4 or more red blood cell units over 8 weeks

and

  • who have not responded to, have stopped responding to, or cannot be treated with medicines called erythropoiesis-stimulating agents (ESAs).

It is not known if RYTELO is safe and effective in children.

Please see RYTELO (imetelstat) full Prescribing Information, including Medication Guide.

Important Safety Information

Before you receive RYTELO, tell your healthcare provider about all of your medical conditions, including if you:

  • are pregnant or plan to become pregnant. RYTELO may harm your unborn baby and may cause loss of pregnancy (miscarriage). Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with RYTELO.

Females who are able to become pregnant:

  • Your healthcare provider will perform a pregnancy test before you are given RYTELO.
  • You should use effective birth control (contraception) during treatment with RYTELO and for 1 week after your last dose.
  • are breastfeeding or plan to breastfeed. It is not known if RYTELO passes into your breastmilk. Do not breastfeed during treatment with RYTELO and for 1 week after your last dose.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

What is the most important information I should know about RYTELO?

RYTELO may cause serious side effects, including:

  • Low platelet counts (thrombocytopenia). Low platelet counts are common during treatment with RYTELO and can also be severe. Low platelet counts can increase your risk for bleeding. Your healthcare provider may give you platelet transfusions to reduce the risk of bleeding if you develop a low platelet count during treatment with RYTELO. Tell your healthcare provider right away if you develop any signs or symptoms of bleeding, including:
    • unusual bleeding or bruising
    • bleeding that lasts a long time
    • nosebleeds
    • vomiting blood
    • blood in your stool or black tarry stool
  • Low neutrophil counts (neutropenia). Low counts of a type of white blood cell called neutrophils are common during treatment with RYTELO and can also be severe. Low neutrophil counts can increase your risk for infections, including serious infections and sepsis. Your healthcare provider may give you medicines before you start treatment to help prevent neutropenia and infections and may treat you with medicines if you develop these problems during treatment with RYTELO. Tell your healthcare provider right away if you develop any signs or symptoms of infection during treatment with RYTELO, including:
    • fever
    • shortness of breath or trouble breathing
    • cough
    • chills
    • pain or burning when you urinate

Your healthcare provider will do blood tests to check your platelet and neutrophil counts before starting treatment with RYTELO, weekly for the first 2 cycles of treatment, before you receive each additional cycle, and as needed during your treatment.

Your healthcare provider may delay your next treatment, decrease your dose, or stop treatment with RYTELO if you develop thrombocytopenia or neutropenia during treatment.

What are the possible side effects of RYTELO?

RYTELO may cause serious side effects, including:

  • See “What is the most important information I should know about RYTELO?”
  • Infusion-related reactions. RYTELO can cause infusion-related reactions during or after your infusion that can be severe, including a severe sudden increase in blood pressure called hypertensive crisis. Your healthcare provider will give you medicines before each RYTELO infusion to help prevent or lessen infusion-related reactions and will watch you for at least 1 hour after your infusion. If you develop infusion-related reactions, your healthcare provider may infuse RYTELO more slowly, temporarily stop, or permanently stop your treatment. Tell your healthcare provider if you develop any signs or symptoms of infusion-related reactions, including:
    • 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 your heart
    • itching
    • hives

The most common side effects of RYTELO 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

These are not all of the possible side effects of RYTELO. Call your doctor for more information and medical advice about side effects. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/MedWatch or call 1-800-FDA-1088.

Please see RYTELO (imetelstat) full Prescribing Information, including Medication Guide.

What is RYTELO?

RYTELO (imetelstat) is a prescription medicine used to treat a condition called low- to intermediate-1 risk myelodysplastic syndromes (MDS) in adults:

  • with anemia (low red blood cell counts) who need blood transfusions of 4 or more red blood cell units over 8 weeks

and

  • who have not responded to, have stopped responding to, or cannot be treated with medicines called erythropoiesis-stimulating agents (ESAs).

It is not known if RYTELO is safe and effective in children.

Please see RYTELO (imetelstat) full Prescribing Information, including Medication Guide.

Important Safety Information

Before you receive RYTELO, tell your healthcare provider about all of your medical conditions, including if you:

  • are pregnant or plan to become pregnant. RYTELO may harm your unborn baby and may cause loss of pregnancy (miscarriage). Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with RYTELO.

Females who are able to become pregnant:

  • Your healthcare provider will perform a pregnancy test before you are given RYTELO.
  • You should use effective birth control (contraception) during treatment with RYTELO and for 1 week after your last dose.
  • are breastfeeding or plan to breastfeed. It is not known if RYTELO passes into your breastmilk. Do not breastfeed during treatment with RYTELO and for 1 week after your last dose.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

What is the most important information I should know about RYTELO?

RYTELO may cause serious side effects, including:

  • Low platelet counts (thrombocytopenia). Low platelet counts are common during treatment with RYTELO and can also be severe. Low platelet counts can increase your risk for bleeding. Your healthcare provider may give you platelet transfusions to reduce the risk of bleeding if you develop a low platelet count during treatment with RYTELO. Tell your healthcare provider right away if you develop any signs or symptoms of bleeding, including:
    • unusual bleeding or bruising
    • bleeding that lasts a long time
    • nosebleeds
    • vomiting blood
    • blood in your stool or black tarry stool
  • Low neutrophil counts (neutropenia). Low counts of a type of white blood cell called neutrophils are common during treatment with RYTELO and can also be severe. Low neutrophil counts can increase your risk for infections, including serious infections and sepsis. Your healthcare provider may give you medicines before you start treatment to help prevent neutropenia and infections and may treat you with medicines if you develop these problems during treatment with RYTELO. Tell your healthcare provider right away if you develop any signs or symptoms of infection during treatment with RYTELO, including:
    • fever
    • shortness of breath or trouble breathing
    • cough
    • chills
    • pain or burning when you urinate

Your healthcare provider will do blood tests to check your platelet and neutrophil counts before starting treatment with RYTELO, weekly for the first 2 cycles of treatment, before you receive each additional cycle, and as needed during your treatment.

Your healthcare provider may delay your next treatment, decrease your dose, or stop treatment with RYTELO if you develop thrombocytopenia or neutropenia during treatment.

What are the possible side effects of RYTELO?

RYTELO may cause serious side effects, including:

  • See “What is the most important information I should know about RYTELO?”
  • Infusion-related reactions. RYTELO can cause infusion-related reactions during or after your infusion that can be severe, including a severe sudden increase in blood pressure called hypertensive crisis. Your healthcare provider will give you medicines before each RYTELO infusion to help prevent or lessen infusion-related reactions and will watch you for at least 1 hour after your infusion. If you develop infusion-related reactions, your healthcare provider may infuse RYTELO more slowly, temporarily stop, or permanently stop your treatment. Tell your healthcare provider if you develop any signs or symptoms of infusion-related reactions, including:
    • 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 your heart
    • itching
    • hives

The most common side effects of RYTELO 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

These are not all of the possible side effects of RYTELO. Call your doctor for more information and medical advice about side effects. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/MedWatch or call 1-800-FDA-1088.

Please see RYTELO (imetelstat) full Prescribing Information, including Medication Guide.

C-US-RYT-IM-0343 05/2026 © 2026 Geron Corp. All rights reserved. GERON, GERON logo, RYTELO, RYTELO logo, and REACH4RYTELO are registered trademarks of Geron Corporation.

This link will take you to a website that is outside the control of Geron. Links are provided as a courtesy for informational purposes only. We do not make or imply any endorsement of external websites.

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