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Casgevy

exagamglogene autotemcel
Used for Sickle Cell Disease, Thalassemia

Casgevy is a gene therapy that treats certain inherited blood conditions. It's used in people 12 years and older who have sickle cell disease (SCD) with frequent painful episodes or beta-thalassemia (β-thal) needing regular blood transfusions. The medication is made from your own blood stem cells, which are changed in a lab using a special technology. Even though it's given as a one-time infusion, the whole treatment process can take up to a year. Common side effects include mouth sores, fever related to low white blood cell counts, and reduced appetite.

Reviewed by:Last reviewed on December 11, 2025
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What is Casgevy?

What is Casgevy used for?

Treatment for people 12 years and older who have:

How Casgevy works

Casgevy is a gene therapy that's designed specifically for you. It works by changing some of your own blood stem cells so they can make healthier red blood cells. Your care team collects these stem cells from your blood and sends them to a lab. There, a special gene-editing technology called CRISPR-Cas9 changes them to produce more fetal hemoglobin. This type of hemoglobin helps keep your red blood cells from becoming sickled or breaking down too fast.

After the edited cells are ready, you receive them back through a one-time infusion. Over time, this can help reduce painful episodes in SCD or lower how often you need blood transfusions in β-thal.

Drug facts

Common BrandsCasgevy
Drug ClassGene therapy
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
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Side effects of Casgevy

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

SCD:

  • Lower blood cell counts (up to 100%)
  • Mouth sores (86%)
  • Fever related to low blood cell counts (48%)
  • Reduced appetite (41%)

β-thal:

  • Lower blood cell counts (up to 100%)
  • Mouth sores (71%)
  • Fever related to low blood cell counts (54%)

Less Common Side Effects

SCD:

  • Muscle pain
  • Stomach pain
  • Gallstones
  • Itching
  • High bilirubin

β-thal:

  • Reduced appetite
  • Nosebleed
  • Rise in liver enzymes
  • Liver problems

Casgevy serious side effects

Contact your healthcare provider immediately if you experience any of the following.

  • Severe allergic reaction: hives, swelling of the face or throat, trouble breathing

Source: DailyMed

The following Casgevy 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
  • Bleeding—bloody or black, tar-like stools, vomiting blood or brown material that looks like coffee grounds, red or dark brown urine, small red or purple spots on skin, unusual bruising or bleeding
  • Infection—fever, chills, cough, or sore throat

Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):

  • Back pain
  • Loss of appetite
  • Pain, redness, or swelling with sores inside the mouth or throat
  • Stomach pain
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Pros and cons of Casgevy

Pros

  • One of the first gene therapies for SCD
  • Is a one-time treatment
  • FDA approved for people 12 years and older

Cons

  • Risk of serious infections and bleeds
  • Treatment process can up to 1 year
  • Must be done in a specialized treatment center
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Pharmacist tips for Casgevy

pharmacist

Tips for before starting Casgevy treatment:

  • Talk to your hematologist about all the stages of Casgevy treatment (including cell collection, conditioning, and recovery) so you know what to expect.
  • Let your hematologist know about all the medications you're taking before starting Casgevy. Some medications can lower your stem-cell count, so medications like hydroxyurea and Adakveo (crizanlizumab) need to be stopped 8 weeks before cell collection. Iron chelators must also be stopped at least 7 days before cell collection.
  • Before receiving Casgevy, your hematologist will give you medications to help prevent fever, like acetaminophen, and medications to prevent allergic reactions, like diphenhydramine.

Tips for after Casgevy treatment:

  • After you've received the Casgevy infusion, you will stay in the hospital for 4 to 6 weeks. This allows your care team to monitor your recovery closely.
  • It might take time for your platelet counts to return to normal after receiving Casgevy. Low platelets can make bleeding harder to stop, so tell your care team right away if you notice abnormal bruising, severe headache, blood in your urine, black tarry stools, or vomit that looks like coffee grounds.
  • Talk to your care team if you get a fever, cough, chills, sore throat, runny or stuffy nose, or body aches after treatment with Casgevy. This medication can affect your immune system and raise your risk for serious infections.
  • After receiving Casgevy, don't donate blood, organs, tissues, or cells in the future. This is to protect your health and the safety of others.
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Risks and warnings for Casgevy

Casgevy 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 blood cell counts

Casgevy can cause your blood cell counts to drop, including your platelets and neutrophils (a type of white blood cell). This can raise your risk for bleeding and infections. There is also a chance that your blood cells might not grow back as expected.

Let your care team know right away if you have symptoms of low blood cell counts, such as:

  • Low neutrophils: fever, headache, cough, sore throat, tiredness, or body aches
  • Low platelets: blood in the urine, black tarry stool, coffee ground vomit, unexplained bruising, or severe headache

Your hematologist will check your blood tests often after treatment until your levels return to normal. In some cases, you might need rescue treatment with extra stem cells.

Serious allergic reaction

  • Risk factor: Allergy to DMSO or dextran 40

Serious allergic reactions to Casgevy, including anaphylaxis, can happen because the solution contains dimethyl sulfoxide (DMSO) or dextran 40. Your care team will watch you closely during and after the infusion for any signs of an allergic reaction. Let them know right away if you feel symptoms like trouble breathing, swelling, itching, or dizziness.

Risk of wrong DNA edits

Casgevy is a medication that works by changing the genes of a person's cells. This helps to treat SCD or β-thal. There's a small risk that this medication can make changes to DNA in the wrong place, since everyone's genes are slightly different. Your care team will monitor you over time to help watch for any issues.

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Casgevy dosage

Typical dosage for Casgevy

Casgevy is usually given at a qualified treatment center or in a hospital. Your hematologist will choose your dose based on your weight. The treatment process takes several stages:

  • Cell collection and manufacturing: Your stem cells are collected and sent to a lab where they're made into Casgevy that's specific for you. This part of the process can take up to 6 months.
  • Conditioning: You'll receive chemotherapy to prepare your body to receive Casgevy.
  • Infusion: Your care team will infuse Casgevy through a vein as a one-time infusion.

After treatment, you'll stay in the hospital for about 4 to 6 weeks so your care team can monitor your recovery and watch for side effects.

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What are alternatives to Casgevy?

There are a number of medications that your doctor can prescribe in place of Casgevy. Compare a few possible alternatives below.
Casgevy
Used for:

Treatment for people 12 years and older who have:

Used for:
  • Beta-thalassemia in adults and children who need regular RBC transfusions
Used for:
  • Lessen the number of vaso-occlusive crises (pain crises) in people aged 16 years and older with sickle cell disease (SCD)
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News about Casgevy

References

Best studies we found

Capriotti, K., et al. (2012). Dimethyl sulfoxide: History, chemistry, and clinical utility in dermatology. The Journal of Clinical and Aesthetic Dermatology.

Frangoul, H., et al. (2024). Exagamglogene autotemcel for severe sickle cell disease. The New England Journal of Medicine.

Kaufman, D. P., et al. (2023). Physiology, fetal hemoglobin. StatPearls.

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