Reblozyl is a brand-name prescription medication. It’s used to treat anemia (low red blood cell count) in adults with certain blood disorders. Specifically, it’s used for adults with:

  • Beta thalassemia. This is an inherited condition (passed down through genetics) in which your red blood cells don’t make hemoglobin correctly. (Hemoglobin is the molecule in red blood cells that moves oxygen around your body.) For this use, Reblozyl is used in adults who need regular red blood cell transfusions.
  • Certain forms of myelodysplastic syndrome (MDS).* MDS is a group of cancers that affect your bone marrow and blood cells. With MDS, you have low numbers of one or more types of blood cells. For this use, Reblozyl is used in adults who need regular red blood cell transfusions. It’s used when other drugs called erythropoiesis stimulating agents haven’t worked to treat anemia.

Note: Reblozyl isn’t used instead of red blood cell transfusions in people who need their anemia corrected right away.

* For more details about the forms of MDS that Reblozyl is used in, see the “Reblozyl uses” section below.

Drug details

Reblozyl is a type of drug called an erythroid maturation agent. It helps raise the number of healthy, mature red blood cells in your blood. Reblozyl is a biologic (a drug made using living cells). It contains the active drug luspatercept-aamt.

Reblozyl is given by subcutaneous injection (an injection under the skin). It’s typically given once every 3 weeks. Your healthcare professional will give you the injection in their office or clinic.

Reblozyl comes as a powder in a single-dose vial. It’s available in two strengths: 25 milligrams (mg) and 75 mg. Your healthcare professional will mix the powder with sterile water before giving you the injection.

FDA approval

Reblozyl was first approved by the Food and Drug Administration (FDA) in 2019 to treat anemia in adults with beta thalassemia. In 2020, the FDA also approved Reblozyl to treat anemia in adults with certain forms of MDS.

Reblozyl is the first in a new class of medications called erythroid maturation agents.

Is Reblozyl a controlled substance?

No, Reblozyl isn’t a controlled substance. Controlled substances are drugs that have a high risk of misuse and dependence. Reblozyl doesn’t have these risks.

Although it’s not a controlled substance, Reblozyl is a drug that’s banned in competitive sports. This is because it has the potential to be misused to enhance someone’s performance.

Effectiveness

For information about the effectiveness of Reblozyl, see the “Reblozyl uses” section below.

Reblozyl is a biologic drug that’s available only as a brand-name medication. A biologic is a drug that’s made using living cells. Reblozyl isn’t currently available in generic or biosimilar form.

A generic drug is an exact copy of the active drug in a brand-name medication. A biosimilar drug is a drug that’s similar to the active drug in a brand-name biologic medication. (It’s not possible to produce exact copies of biologic medications.)

Generics and biosimilars are considered to be just as safe and effective as the brand-name drug they’re based on. They usually cost less than brand-name drugs.

The Food and Drug Administration (FDA) approves prescription drugs such as Reblozyl to treat certain conditions. Reblozyl may also be used off-label for other conditions. Off-label drug use means using a drug for a purpose other than what it’s been approved for by the FDA.

Reblozyl for anemia caused by beta thalassemia

Reblozyl is FDA-approved to treat anemia (low red blood cell count) in adults with beta thalassemia who need regular red blood cell transfusions.

Beta thalassemia is an inherited blood disorder (passed down through genetics) in which your red blood cells don’t make hemoglobin correctly. Hemoglobin is the molecule in red blood cells that moves oxygen around your body. With beta thalassemia, you have certain gene abnormalities that tell your red blood cells how to make hemoglobin. As a result, you may have low hemoglobin and red blood cell levels. This is called anemia.

Anemia can cause symptoms such as:

People with beta thalassemia may have mild or severe anemia. This depends on whether they inherit abnormal genes from one or both parents.

Having regular red blood cell transfusions adds more red blood cells to your blood. It increases your levels of red blood cells and treats anemia. But it can also lead to a buildup of iron in organs such as your liver, heart, or spleen. This is because red blood cells are rich in iron. Treatments called chelating agents are then needed to remove the excess iron.

Reblozyl increases your levels of red blood cells. Then, more healthy red blood cells are able to mature in your bone marrow. This treats anemia without increasing your iron levels.

Note: Reblozyl isn’t used instead of red blood cell transfusions in people who need their anemia corrected right away.

Effectiveness for anemia caused by beta thalassemia

Clinical studies have found Reblozyl to be an effective treatment for anemia in adults with beta thalassemia who need regular red blood cell transfusions. The drug has been shown to reduce the number of red blood cell transfusions needed by people with this condition.

To find out how Reblozyl performed in clinical studies, see the drug’s prescribing information.

Reblozyl for anemia caused by myelodysplastic syndrome

Reblozyl is also FDA-approved to treat anemia (low red blood cell count) in adults with certain types of myelodysplastic syndrome (MDS).

MDS is a group of cancers that affect your bone marrow and blood cells. Your blood cells usually develop from stem cells in your bone marrow (the spongy tissue inside your bones). But with MDS, your stem cells become abnormal and don’t develop into mature blood cells. Instead, they develop into immature blood cells, called blasts.

As a result, you have low levels of one or more types of blood cells in your blood, particularly red blood cells. This causes anemia. (For a list of anemia symptoms, see “Reblozyl for anemia caused by beta thalassemia” above.)

There are several types of MDS, and Reblozyl is approved to treat anemia in two types:

  • MDS with ring sideroblasts (MDS-RS)
  • myelodysplastic/myeloproliferative neoplasms with ring sideroblasts and thrombocytosis* (MDS/MPN-RS-T)

* With thrombocytosis, your body has too many platelets.

Reblozyl can be used when these forms of MDS have a very low to intermediate risk of developing into leukemia. Most people with MDS have a low risk for the condition progressing in this way. Your doctor will determine the risk level of your MDS.

Reblozyl is used when other drugs called erythropoiesis stimulating agents haven’t worked to treat anemia. It’s used in adults who need regular red blood cell transfusions.

Note: Reblozyl isn’t used instead of red blood cell transfusions in people who need their anemia corrected right away.

Effectiveness for anemia caused by MDS

Reblozyl is an effective treatment for anemia in adults with certain types of MDS who need regular red blood cell transfusions. The drug has been shown to help reduce the need for red blood cell transfusions in people with MDS. To find out how Reblozyl performed in clinical studies, see the drug’s prescribing information.

Guidelines from the National Comprehensive Cancer Network include Reblozyl as a treatment option for anemia caused by certain types of MDS.

Reblozyl and children

Reblozyl isn’t approved for use in children. It’s not known if Reblozyl is safe or effective in children.

If you have a child with MDS or beta thalassemia, talk with their doctor about their treatment options.

As with all medications, the price of Reblozyl can vary. To find current prices for Reblozyl in your area, check out GoodRx.com.


The cost you find on GoodRx.com is what you may pay without insurance. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

It’s important to note that Reblozyl can only be ordered by your doctor or healthcare professional. It’s only given at places like your doctor’s office, an infusion clinic, or a similar healthcare setting. You won’t pick up Reblozyl at the pharmacy.

Before approving coverage for Reblozyl, your insurance company may require you to get prior authorization. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the prior authorization request and decide if the drug will be covered.

If you’re not sure if you’ll need to get prior authorization for Reblozyl, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Reblozyl, or if you need help understanding your insurance coverage, help is available.

Acceleron Pharma Inc., the manufacturer of Reblozyl, offers a program called Celgene Patient Support. For more information and to find out if you’re eligible for support, call 800-931-8691 or visit the program website.

Generic or biosimilar version

Reblozyl isn’t available in generic or biosimilar form.

A generic drug is an exact copy of the active drug in a brand-name medication. A biosimilar drug is a drug that’s similar to the active drug in a brand-name biologic medication. Biologic drugs are made using living cells. It’s not possible to produce exact copies of biologic medications.

Generics and biosimilars are considered to be just as safe and effective as the brand-name drug they’re based on. They tend to cost less than brand-name drugs.

The Reblozyl dosage your doctor prescribes will depend on several factors. These include:

  • your body weight in kilograms (kg)
  • the level of hemoglobin in your blood
  • the number of red blood cell transfusions you need

Your doctor may adjust your dosage over time to reach the amount that’s right for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly used or recommended. But your doctor will determine the best dosage to fit your needs.

Drug forms and strengths

Reblozyl is given by subcutaneous injection (an injection under the skin). Your healthcare professional will give you the injection in their office or clinic.

Reblozyl comes as a powder in a single-dose vial. It’s available in two strengths: 25 milligrams (mg) and 75 mg. Your healthcare professional will mix the powder with sterile water, measure the correct dose, and give the injection.

Dosage for anemia caused by beta thalassemia or myelodysplastic syndrome

The usual starting dosage for adults with anemia caused by beta thalassemia or myelodysplastic syndrome (MDS) is 1 mg per kg (mg/kg) of body weight. This is usually given once every 3 weeks.

Your doctor will check your hemoglobin level before each dose and adjust your dose if needed. Reblozyl is meant to reduce the number of red blood cell (RBC) transfusions you need. If you don’t need fewer RBC transfusions after receiving two injections of Reblozyl at the starting dose, your doctor may increase your dose. They’ll decide the dosage that’s right for you at each appointment.

The maximum dosage for anemia caused by beta thalassemia is 1.25 mg/kg given once every 3 weeks.

The maximum dosage for anemia caused by MDS is 1.75 mg/kg given once every 3 weeks.

If you don’t need fewer RBC transfusions after receiving three injections of Reblozyl at the maximum dose, it’s likely that this drug doesn’t work for you. You’ll need to stop using Reblozyl. Your doctor will recommend alternative treatments to manage your anemia.

What if I miss a dose?

If you miss an appointment to have a dose of Reblozyl, call your doctor’s office right away to reschedule. You should get the missed dose as soon as possible. You should then continue with your usual dosing schedule, with at least 3 weeks between your doses.

To help make sure that you don’t miss an appointment for your Reblozyl dose, try setting a reminder on your phone.

Will I need to use this drug long term?

Reblozyl is meant to be used as a long-term treatment. If you and your doctor determine that Reblozyl is safe and effective for you, you’ll likely take it long term.

Reblozyl is used to treat anemia (low red blood cell count) in adults with certain blood disorders. Specifically, it’s used for adults with:

Reblozyl helps increase red blood cell count in adults with these conditions.

* An inherited condition is passed down through genetics.

What happens with beta thalassemia

With beta thalassemia, a genetic condition stops the immature red blood cells from making hemoglobin correctly. Healthy hemoglobin is usually made up of several different proteins. But with beta thalassemia, the immature red blood cells don’t make enough of one of these proteins, called beta globin. As a result, the body produces less hemoglobin.

This problem triggers certain signals that stop the immature red blood cells from becoming mature red blood cells.

The immature red blood cells build up in the bone marrow, leaving less space for healthy red blood cells to develop and mature. Because of this, people with beta thalassemia have low levels of red blood cells and hemoglobin in their blood.

What happens with myelodysplastic syndrome

With MDS, your stem cells develop an abnormality that stops them developing into mature blood cells. Instead, they develop into immature blood cells, called blasts.

The blasts build up in the bone marrow, leaving less space for healthy blood cells to develop and mature. Because of this, people with MDS have low levels of one or more types of blood cells, particularly red blood cells.

What Reblozyl does

Reblozyl’s mechanism of action (the way it works) is that it treats anemia in MDS by increasing your levels of red blood cells. It does this by helping more healthy red blood cells mature in your bone marrow. This reduces the number of red blood cell transfusions you may need to treat anemia.

How long does it take to work?

Reblozyl typically starts to work about a week after your first injection. But it may take a few weeks before you need fewer red blood cell transfusions. Your doctor will monitor how well the treatment is working for you by checking your hemoglobin and red blood cell levels.

If you have questions about when you should see results from Reblozyl, talk with your doctor.

Reblozyl is administered by subcutaneous injection (an injection under the skin). Your healthcare professional will give you the injection in their office or clinic.

The injection may be given in your upper arm, thigh, or abdomen (belly).

When it’s given

Reblozyl is usually given once every 3 weeks.

To help make sure that you don’t miss an appointment for your Reblozyl dose, try setting an alarm or timer on your phone or downloading a reminder app.

Reblozyl can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Reblozyl. These lists do not include all possible side effects.

For more information about the possible side effects of Reblozyl, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be concerning or bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to notify the FDA about a side effect you’ve had with Reblozyl, you can do so through MedWatch.

Mild side effects

Mild side effects* of Reblozyl can include:

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

* This is a partial list of mild side effects from Reblozyl. To learn about other mild side effects, talk with your doctor or pharmacist or view Reblozyl’s patient information.

Serious side effects

Serious side effects from Reblozyl aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 or your local emergency number if your symptoms feel life threatening or you think you’re having a medical emergency.

Serious side effects and their symptoms can include:

* For more information about this side effect, see “Side effect details” below.

Side effect details

Here’s some detail on certain side effects this drug may cause.

Blood clots

There may be a small risk of blood clots in the veins or arteries with Reblozyl treatment. This side effect wasn’t common in clinical studies of the drug, but it may be serious.

In studies, blood clots were reported in some people who took Reblozyl to treat anemia caused by beta thalassemia. The types of blood clots reported include:

To find out how often these side effects occurred in clinical studies, see Reblozyl’s prescribing information.

Symptoms of a blood clot may include:

  • pain or swelling in your leg
  • cold or pale arm or leg
  • chest pain
  • trouble breathing
  • pain or swelling in your abdomen (belly)
  • sudden weakness or numbness on one side of your body
  • sudden headache or confusion
  • sudden trouble talking, seeing, or walking

You may have a higher risk for blood clots with Reblozyl if you’ve had your spleen removed or had a blood clot in the past. You may also have a higher risk if you smoke or take certain medications. These include birth control pills and hormone replacement therapy.

If your doctor thinks you have a high risk for blood clots with Reblozyl, they may prescribe medication to help prevent this side effect.

If you have symptoms of a blood clot during your Reblozyl treatment, talk with your doctor right away. But if your symptoms feel life threatening or you think you’re having a medical emergency, call 911 or your local emergency number.

If you have a blood clot, you’ll typically need to stop taking Reblozyl until it’s been treated.

Hypertension

You may develop hypertension (high blood pressure) during your Reblozyl treatment. This side effect was commonly reported in clinical studies of the drug. To find out how often this side effect occurred in studies, see Reblozyl’s prescribing information.

High blood pressure doesn’t usually cause symptoms. But it can increase your risk for heart attack or stroke.

Your doctor will check your blood pressure before you receive each dose of Reblozyl. If your blood pressure is too high, your doctor may delay treatment until your blood pressure is managed. Your doctor may also prescribe medication to help lower your blood pressure. If you already take blood pressure medication, your doctor may increase your dose.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Reblozyl.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have an allergic reaction to Reblozyl, as the reaction could become severe. Call 911 or your local emergency number if your symptoms feel life threatening or you think you’re having a medical emergency.

Reblozyl isn’t known to interact with alcohol. But if you have certain side effects with Reblozyl, such as headache, dizziness, diarrhea, or nausea, drinking alcohol could make this worse.

If you drink alcohol, talk with your doctor about how much is safe for you to drink while you take Reblozyl.

Reblozyl can interact with several other medications.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Reblozyl and other medications

Below is a list of medications that can interact with Reblozyl. This list does not contain all drugs that may interact with Reblozyl.

Before taking Reblozyl, talk with your doctor or pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also, tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

Types of drugs that can interact with Reblozyl include:

  • Birth control pills. Reblozyl can sometimes cause blood clots. You may have a higher risk for this side effect if you take birth control pills with Reblozyl. Examples include:
    • ethinyl estradiol/desogestrel (Apri, Azurette, Kariva, Mircette, Reclipsen)
    • ethinyl estradiol/drospirenone (Gianvi, Loryna, Ocella, Syeda, Yasmin, Yaz, Zarah)
    • ethinyl estradiol/levonorgestrel (Aviane, Lessina, Levora, Lutera, Portia, Sronyx)
    • ethinyl estradiol/norethindrone (Balziva, Junel, Loestrin, Microgestin, Nortrel, Ortho-Novum)
    • ethinyl estradiol/norgestimate (Ortho-Cyclen, Previfem, Sprintec)
  • Hormone replacement therapy (HRT). Reblozyl can sometimes cause blood clots. You may have a higher risk for this side effect if you take HRT with Reblozyl. Examples of HRT medications include:
    • estradiol/drospirenone (Angeliq)
    • estradiol/levonorgestrel (Climara Pro)
    • estradiol/norethindrone (Activella, Amabelz, Lopreeza)
    • estradiol/norgestimate (Prefest)
    • estradiol/progesterone (Bijuva)
    • ethinyl estradiol/norethindrone (Femhrt, Jinteli)
    • estradiol patch (Alora, Climara, Minivelle, Vivelle-Dot)
    • oral estrogen (Menest, Premarin)
    • estrogen/methyltestosterone (Covaryx)
    • estrogen/bazedoxifene (Duavee)
    • estrogen/medroxyprogesterone (Prempro, Premphase)

Reblozyl and herbs and supplements

There aren’t any herbs or supplements that have been specifically reported to interact with Reblozyl. But you should still check with your doctor or pharmacist before using any of these products while taking Reblozyl.

Reblozyl and foods

There aren’t any foods that have been specifically reported to interact with Reblozyl. If you have any questions about eating certain foods with Reblozyl, talk with your doctor.

Reblozyl isn’t safe to take during pregnancy. The drug hasn’t been studied in pregnant humans. But it’s expected to cause fetal harm if used during pregnancy. This is based on the way the drug works and findings from animal studies.

If you can become pregnant, you’ll need to have a pregnancy test before you start Reblozyl. This is so your doctor can be sure you’re not pregnant before giving you the drug.

If you’re pregnant or planning to become pregnant, talk with your doctor about other treatment options. And if you think you could be pregnant while taking Reblozyl, tell your doctor right away.

Reblozyl and fertility

Reblozyl may affect your ability to become pregnant. The drug was found to temporarily reduce female* fertility in animal studies. In these studies, male* fertility wasn’t affected by the drug. But animal studies don’t always predict what will happen in humans.

If you’re concerned about the possible effect of Reblozyl on your fertility, talk with your doctor.

* Sex and gender exist on spectrums. Use of the terms “male” and “female” in this article refers to sex assigned at birth.

Reblozyl isn’t safe to take during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re taking Reblozyl.

For more information about taking Reblozyl during pregnancy, see the “Reblozyl and pregnancy” section above.

For females using Reblozyl

Females* should use effective birth control during treatment with Reblozyl and for 3 months after the last dose.

For males using Reblozyl

The manufacturer of Reblozyl hasn’t given birth control recommendations for males* using the drug. If you’re a male using Reblozyl and you have a partner who can become pregnant, talk with your doctor about your birth control needs during treatment.

* Sex and gender exist on spectrums. Use of the terms “male” and “female” in this article refers to sex assigned at birth.

You shouldn’t breastfeed during treatment with Reblozyl and for 3 months after your last dose.

It’s not known if Reblozyl passes into human breast milk. But if it does get into breast milk, it has the potential to cause serious side effects in a breastfed child.

If you’re breastfeeding or planning to breastfeed, talk with your doctor before using Reblozyl.

Here are answers to some frequently asked questions about Reblozyl.

Will Reblozyl cure my condition?

No, Reblozyl won’t cure the cause of your anemia. Reblozyl helps increase your red blood cell count. It can improve anemia that’s caused by beta thalassemia or myelodysplastic syndrome (MDS). But it can’t cure the conditions that cause anemia. And anemia that’s caused by beta thalassemia or MDS can come back after you stop Reblozyl.

How will I know if Reblozyl is working for me?

There are a few things that can show if Reblozyl is working for you.

  • You may notice that your anemia symptoms start to improve. For example, you may feel less tired or breathless.
  • You may need fewer red blood cell transfusions.
  • Blood tests may show that your hemoglobin level has increased.

If you don’t need fewer red blood cell transfusions after getting three maximum doses of Reblozyl, it’s likely that this drug doesn’t work for you. If that’s the case, you’ll need to stop using Reblozyl. Your doctor will recommend other treatment options to manage your anemia.

What can I do to help prevent a blood clot during my Reblozyl treatment?

There are a few ways to help prevent blood clots during your Reblozyl treatment. These include not smoking, keeping active, and reaching or maintaining a body weight that’s healthy for you.

Certain medications, such as birth control pills and hormone replacement therapy, can also increase your risk for blood clots. If you take one of these medications, talk with your doctor about possible alternatives.

If you have certain factors that raise your risk for blood clots with Reblozyl, your doctor may talk with you about taking blood thinners. These are medications that can help prevent blood clots.

In clinical studies, blood clots were reported in a few people with beta thalassemia who took Reblozyl. To read more about this side effect, see “Reblozyl side effects” above.

Before taking Reblozyl, talk with your doctor about your health history. Reblozyl may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Allergic reaction. If you’ve had an allergic reaction to Reblozyl or any of its ingredients, you shouldn’t take this drug. Ask your doctor what other medications are better options for you.
  • Risk for blood clots. Blood clots have been reported in some people with beta thalassemia who took Reblozyl. You may have a higher risk for blood clots with Reblozyl if you’ve had your spleen removed or had a blood clot in the past. You may also have a higher risk if you smoke or take certain medications. These include birth control pills and hormone replacement therapy. If your doctor thinks you have a high risk for blood clots with Reblozyl, they may prescribe medication to help prevent this side effect.
  • Hypertension. Reblozyl can sometimes cause hypertension (high blood pressure). If you already have high blood pressure, Reblozyl could make this worse. Talk with your doctor about whether Reblozyl is right for you. If you take Reblozyl, your doctor will regularly monitor your blood pressure. If it gets too high, your doctor may need to increase your dose of blood pressure medication. Or, they may need to prescribe extra medication.
  • Pregnancy. Reblozyl isn’t safe to take during pregnancy. For more information, see the “Reblozyl and pregnancy” section above.
  • Breastfeeding. You shouldn’t breastfeed while taking Reblozyl. For more information, see the “Reblozyl and breastfeeding” section above.

Note: For more information about the potential negative effects of Reblozyl, see the “Reblozyl side effects” section above.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.