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Treatment Name: Omacetaxine (Synribo®)

Omacetaxine (Synribo®) is a Treatment Regimen for Chronic Myeloid Leukemia (CML)

How does omacetaxine (Synribo®) work?

Omacetaxine is designed to stop specific cancerous white blood cells from growing and dividing. It may also permit non-cancerous blood cells in the bone marrow to grow normally.

Goals of therapy:

Omacetaxine is taken to reduce symptoms from Chronic Myeloid Leukemia (CML) or prevent symptoms from ever occurring. Omacetaxine is not commonly taken with the goal of cure, but may be taken for many years to prevent CML from progressing to more aggressive phases.


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How is omacetaxine (Synribo®) therapy for CML taken?


  • Omacetaxine subcutaneous (SubQ) injection twice daily (12 hours apart) on Days 1 through 14, then no drug on Days 15 through 28
    • For example, two doses per day continuing for two weeks, followed by a break for two weeks


  • Subcutaneous injection twice daily (12 hours apart) on Days 1 through 7, then no drug on Days 8 through 28
    • For example, two doses per day continuing for 1 week, followed by a break for 3 weeks

Omacetaxine may be given in an outpatient infusion center, allowing the person to go home afterwards, or it can be taken at home.

Omacetaxine is repeated every 28 days. This is known as one Cycle. The induction phase is repeated up to a maximum of 6 cycles. Patients that respond to induction treatment may then move on to the maintenance phase that is continued until the drug no longer works or until unacceptable side effects occur.

Click here for the common omacetaxine starting doses.

Important Note: Once reconstituted (made into liquid), omacetaxine (Synribo®) may be stored in a refrigerator at 36°F to 46°F (2°C to 8°C) for up to 6 days (144 hours) and must be used during this time frame. Your healthcare provider or pharmacy may reconstitute several doses of drug for you to take at home to decrease the number of clinic visits you need to receive this medication. 

Once reconstituted (made into liquid), omacetaxine (Synribo®) may be stored at room temperature for up to 12 hours and must be used during this time frame. Because refrigeration extends the life of this product by about 5 days, we recommend refrigeration whenever possible. Please ask your healthcare provider for a cooler and ice packs to transport omacetaxine prior to starting treatment.

Side Effects

What are the most common side effects from omacetaxine (Synribo®) for CML?

In clinical studies, the most commonly reported side effects of omacetaxine are shown here. Side effects sometimes have percentage ranges [example: 54 – 79%] because they differed between clinical studies:

  • Low platelets [thrombocytopenia] (67-79%)
  • Low red blood cells [Anemia] (54-66%)
  • Low white blood cells [neutropenia] (50%)
  • Infection (42-59%)
  • Diarrhea (40-44%)
  • Nausea (30-34%)
  • Fatigue (24-29%)
  • Joint pain (23%)
  • Fever (20-29%)
  • Weakness (20-27%)
  • Headache (18-20%)
  • Hair loss (18%)
  • Constipation (18%)
  • Cough (18%)
  • Injection site redness (17-21%)
  • Nosebleeds (17%)
  • Stomach pain (16%)
  • Vomiting (15%)
  • Swelling in arms or legs (13-15%)
  • Trouble sleeping (13%)
  • Pain in arms or legs (11-17%)
  • Back pain (11%)
  • Skin rash (11%)
  • Muscle pain (11%)

On average, 10% of patients discontinue treatment due to unacceptable side effects.

Importantly, not all people who experience a side effect from omacetaxine (Synribo®) will experience it in the same way. It may be mild in some or severe in others, depending upon the individual. Everybody is different. Additionally, side effects may vary over time. For some, side effects may be a reason to delay or switch treatment, reduce the dose, or avoid treatment with a certain medication altogether.

Side effects may be treatable when they occur or preventable by taking certain medications before they happen. When medications are taken to prevent a problem, this is known as prophylaxis, or "prophy" for short.

After starting treatment with omacetaxine (Synribo®), be sure to come back and watch all of the side effect videos shown below. Each of these videos contain valuable information about side effect management that will hopefully help you to both feel better and stay out of the hospital.

Watch videos on common omacetaxine (Synribo®) therapy side effects below

Side effect videos Side Effect Videos
AnemiaAnemiaDiarrheaDiarrheaNausea and VomitingNausea and VomitingFatigue Fatigue PainPainHair LossHair LossConstipationConstipationBleedingBleeding


How often is monitoring needed with omacetaxine (Synribo®)?

Labs (blood tests) may be checked before treatment, then weekly during the induction phase and while beginning the maintenance phase, then every 2 to 4 weeks thereafter. Labs often include: Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), plus any others your doctor may order.

Importantly, your doctor will order a test known as BCR/ABL. Your doctor uses the BCR/ABL% to monitor your response to omacetaxine (Synribo®).

How do I know if I am responding to omacetaxine (Synribo®)?

It is important for you to know what your BCR/ABL% is. This way, if the BCR/ABL% begins to increase, you will know and can look for reasons why.

How often is imaging needed with omacetaxine (Synribo®)?

Imaging may be checked if there are concerns for certain side effects. Imaging may include: X-rays, magnetic resonance imaging (MRI), or computerized tomography (CT) scans.

How might blood test results/imaging affect treatment?

Depending upon the results, your doctor may advise to continue omacetaxine as planned, reduce the number of treatments per cycle, delay treatment until the side effect goes away, or switch to an alternative therapy.

Questions to Ask Your...

A better understanding of your treatments will allow you to ask more questions of your healthcare team. We then hope that with the answers, you will get better results and have greater satisfaction with your care. Because we know it's not always easy to know what questions to ask, we've tried to make it easy for you!

Choose any healthcare provider below to see common questions that you may want to ask of this person. Then, either print each list to bring to your clinic visits, or copy the questions and send them as a message to your healthcare team through your electronic medical record.

ChemoExperts Tips

What are the most important things to know about omacetaxine (Synribo®) while receiving therapy?

  • Omacetaxine (Synribo®) is a subcutaneous injection that may be given by a nurse or other trained health professional. You may also be taught how to give this medicine to yourself at home or with the help of a caregiver. In order to give this at home, the patient or caregiver must be trained on proper handling, storage, administration, disposal, and clean-up of accidental spills. Some of the necessary items to have at home include protective eyewear, gloves, a biohazard container, absorbent pads, alcohol swabs, gauze pads, and ice packs or a cooler
  • Omacetaxine (Synribo®) can lower the number of white cells in your blood, increasing your risk of infection. It is important to wash your hands often and avoid sick contacts when possible
  • Omacetaxine (Synribo®) can lower blood platelet counts, increasing the risk of bleeding. Report any unusual bleeding or bruising to your doctor immediately. Medications such as aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), and anticoagulants should be avoided when your platelets are low
  • Your doctor may prescribe other medications along with omacetaxine (Synribo®), such as ondansetron (Zofran®) or dexamethasone (Decadron®), in order to prevent nausea and vomiting
  • Rarely, omacetaxine (Synribo®) may affect blood sugar levels. Patients with diabetes may need more frequent monitoring of blood sugar and adjustment of their medications to treat their diabetes
  • A pharmacist should ALWAYS review your medication list to ensure that drug interactions are prevented or managed appropriately
  • Clinical trials may exist for CML. Ask your doctor if any studies are currently enrolling in your area. If not, go to clinicaltrials.gov to search for other centers offering study medications.

Patient Assistance & Co-payment Coverage

Patients under the age of 65 years, or those with private insurance plans:
If you have insurance and are looking for patient assistance or copay assistance for Omacetaxine (Synribo®), we have provided links that may help.

Visit our Patient Assistance page and click the links to various patient assistance programs for help paying for Omacetaxine (Synribo®). Depending upon your income, they may be able to help cover the cost of:

  • Omacetaxine

For Branded medications (may be available for generic medications too), check with the manufacturer to determine if a co-pay card is offered and if it could reduce your monthly copay.

  • If you are uninsured, check with the manufacturer to determine if you are eligible to receive medication at no cost.

Medicare and Medicaid patients (Patients 65 years or older):
The clinic providing treatment will likely pre-authorize medications and immune therapies such as Omacetaxine (Synribo®) and are the best source to help you understand drug cost.

  • Ask to speak with a patient assistance technician or financial counselor at the clinic or hospital administering this therapy.

Emotional Wellness

What is Emotional Wellness?
Emotional wellness is having a positive outlook balanced with a realistic understanding of current life events. This requires both an awareness and acceptance of your emotions. It is with this knowledge that you can develop a plan to take the necessary actions to positively impact your life.

Emotional wellness uses an ongoing process to continually reflect on the stressors of life in a constructive manner to move forward and create happiness.

Because emotional wellness is deeply connected with physical, social, and spiritual wellness, pursuing it often becomes particularly difficult in times of major illness. Despite this difficulty, working toward emotional wellness has been connected to improved treatment outcomes and a higher likelihood of achieving goals of therapy.

Learn more about pursuing emotional wellness while receiving treatment with Omacetaxine (Synribo®)

Individual Drug Label Information

Omacetaxine (Synribo®)

  • ​Is a subcutaneous (SubQ) injection 
  • If you miss a dose, skip the missed dose and give the next scheduled injection at the next scheduled time. DO NOT give two injections to make up for a missed injection.
  • Once reconstituted (made into liquid), may be stored in a refrigerator at 36°F to 46°F (2°C to 8°C) for up to 6 days (144 hours) and must be used during this timeframe
  • Once reconstituted (made into liquid), may be stored at room temperature for up to 12 hours and must be used during this timeframe
  • Omacetaxine causes low white blood cells, which increases your risk of infection
  • May cause low blood platelet counts, which increases your risk of bleeding. 
  • Dosage adjustments may be required for low white blood cells, low platelets, or other serious side effects
  • Omacetaxine may cause fetal harm if given to pregnant females. Females should use effective contraception during treatment and for 6 months after completing treatment. Males should use effective contraception during treatment and for 3 months after completing treatment. Women should not breast feed while receiving treatment with omacetaxine.
General side effects from omacetaxine 
  • Low blood platelets, red blood cells, and white blood cells
  • Infections
  • Diarrhea 
  • Nausea and vomiting
  • Fever 
  • Fatigue and weakness 
  • Injection site redness 
  • Headache 
  • Hair loss 
  • Nosebleeds 
  • Pain and swelling in arms and legs 
  • Click on the omacetaxine (Synribo®) package insert below for reported side effects, possible drug interactions, and other omacetaxine prescribing information

Side Effect Videos
Nausea and VomitingNausea and VomitingDiarrheaDiarrheaHair LossHair LossFatigue Fatigue BleedingBleedingConstipationConstipationPainPainAnemiaAnemia

See DailyMed package insert.

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1) Cortes J, Lipton JH, Rea D, et al. Phase 2 study of subcutaneous omacetaxine mepesuccinate after TKI failure in patients with chronic-phase CML with T315I mutation. Blood 2012;120(13):2573-2580.

2) Cortes J, Digumarti R, Parikh PM, et al. Phase 2 study of subcutaneous omacetaxine mepesuccinate for chronic-phase chronic myeloid leukemia patients resistant to or intolerant of tyrosine kinase inhibitors. Am J Hematol. 2013;88:350-354.

Created: November 6, 2020 Updated: November 6, 2020

What is Chronic Myeloid Leukemia (CML)?

A disease of the white blood cells found in the bone marrow that results when 2 chromosomes trade small sections of their DNA forming what is known as the “Philadelphia Chromosome.” When this happens within a white blood cell, it may grow and divide without being able to stop.

CML is a relatively rare condition and represents about 10% of diagnosed leukemias. CML is not thought to be an inherited disorder and most of the time, the cause is unknown. The average age at diagnosis is about 65 years old.

CML can present in one of three phases: Chronic Phase, Accelerated Phase, or Blast Crisis

Without treatment, CML may evolve over time causing aggressive disease. This may lead to symptoms such as weight loss, abdominal discomfort, decreased appetite, fever, bruising or bleeding, among others. The stage of CML can vary at diagnosis and throughout treatment. The effectiveness of the treatment may depend upon the phase of CML at diagnosis.

NOTE: Treatment Options listed below are not all-inclusive. Other treatments may be available. ChemoExperts provides drug information and does not recommend any one treatment over another. Only your Doctor can choose which therapy is appropriate for you.

What does Cure mean?

The word “cure” means there are no cancer cells left in the body and cancer will never come back. Depending on the cancer type and stage, this may be the true goal of therapy. However, it is very difficult to prove all cancer cells are gone. Even though images, like X-rays and MRI’s, and blood tests may not show any signs of cancer, there can be a small amount of cancer cells still left in the body. Because of this, the word “remission” is used more often. This means there are no signs or symptoms of cancer. Patients in remission are followed closely for any signs of cancer returning. Sometimes, more chemotherapy may be given while in remission to prevent the cancer from coming back.

Doctors usually do not consider a patient “cured” until the chance of cancer returning is extremely low. If cancer does return, it usually happens within 5 years of having a remission. Because of this, doctors do not consider a patient cured unless the cancer has not come back within 5 years of remission. The five-year cutoff does not apply to all cancers.

Common Starting Doses


  • 1.25 mg/m2 subcutaneous injection twice daily on days 1 through 14


  • 1.25 mg/m2 subcutaneous injection twice daily on days 1 through 7

Each vial provides 3.5 mg of omacetaxine (Synribo®). In most cases, one vial will be sufficient to make an entire dose.

Note: Individual doses may vary based upon your Doctor's recommendation, or drug availability.

What is a CBC?

A Complete Blood Count (CBC) is a frequently ordered blood test that tells clinicians the status of your: 1) White blood cell count, 2) Hemoglobin, and 3) Platelet count at the time the test was taken.

Common uses:
1) White blood cell count (WBC): is used to determine infection risk, or response to chemotherapy. Certain chemotherapy agents may harm our good infection-fighting cells. Sometimes chemotherapy may need to be delayed to allow these cells to recover.

2) Hemoglobin: is used to determine if someone is anemic. Anytime the hemoglobin is below 12 g/dL, the person is said to be anemic. Red blood cell transfusions, and sometimes iron can be given to restore the hemoglobin level, but anemia treatment should always aim at treating the underlying cause or condition.

3) Platelet count: is used to determine if the risk of bleeding is increased or if a platelet transfusion is required to prevent bleeding. Certain medications that increase bleeding risk, such as: aspirin, certain chemotherapy agents, and blood thinners, may need to be stopped temporarily until the platelet count is within a safe range.

What is a CMP?

A Comprehensive Metabolic Panel (CMP) is a frequently ordered blood test that tells clinicians the status of your: 1) Electrolytes & Acid/Base status2) Kidney function, 3) Liver function, 4) Blood sugar, and 5) Calcium at the time the test was taken. It is commonly used to monitor liver and kidney function when beginning new medications such as chemotherapy. A total of 14 tests are run simultaneously and are shown below.

Electrolytes & Acid/Base status:
1) Sodium, 2) Potassium, 3) Carbon dioxide, 4) Chloride

Kidney Function:
5) BUN (blood urea nitrogen), 6) Serum creatinine (Scr)

Liver Function:
7) AST, 8) ALT, 9) Total bilirubin, 10) Alk Phos, 11) Albumin, 12) Total protein

Blood sugar:
13) Serum glucose

14) Serum calcium

What is BCR/ABL?

BCR/ABL is a gene mutation within CML cells. The percent of cells that have the BCR/ABL mutation goes down by taking Omacetaxine (Synribo®) therapy. The goal is that the percentage will become undetectable.

This happens in many patients and is known as a complete molecular response, or 0.000%. At diagnosis, the BCR/ABL % is often very high, sometimes exceeding 100%. This is because the test is based upon the average BCR/ABL% from patients in one of the earliest clinical studies with Omacetaxine (Synribo®). Having a BCR/ABL% greater than 100% at diagnosis does not usually affect the response to Omacetaxine (Synribo®).

Responding to omacetaxine?

The optimal response to omacetaxine depends upon how long you have been taking it. Ultimately, the goal is an undetectable BCR/ABL%, or 0.0000%, but a level less than 1% usually predicts long-term survival as well.

Patients who have a BCR/ABL of 10% or more after 6 months of omacetaxine (without missing doses) may need to switch therapy to another medication that treats CML.

Goal BCR/ABL% (International Scale, IS) while taking omacetaxine therapy:

  • Complete Hematologic Response (CHR): Less than 10%
  • Complete Cytogenetic Response (CCyR): Less than 1%
  • Major Molecular Response (MMR): Less than 0.1%
  • Complete Molecular Response (CMR): 0.0000%