Synribo (omacetaxine mepesuccinate)

Synribo can cause serious side effects including:

• Low blood counts. Low blood counts are common when using Synribo, including low red blood cells, white blood cells, and platelets, and can be severe. If your white blood cell count becomes very low, you are at increased risk for infection which can lead to death. Your healthcare provider will check your blood counts regularly during treatment with Synribo. Tell your healthcare provider right away if you get any of the following symptoms:
  • fever
  • chills
  • body aches
  • feeling very tired
  • shortness of breath
  • bleeding (see below)
• Bleeding. Synribo causes severe low platelet counts that may increase your risk of severe bleeding. Severe low platelet counts can cause you to have bleeding in your brain that can lead to death, or severe stomach bleeding. Your healthcare provider will check your platelet counts regularly during treatment with Synribo. Tell your healthcare provider right away if you get any of the following symptoms:
  • unusual bleeding
  • easy bruising
  • blood in urine or stool
  • confusion
  • slurred speech
  • vision changes

The most common side effects of Synribo include:

• infections,
• diarrhea,
• nausea,
• tiredness,
• weakness,
• redness, swelling, or pain at injection site; and
• fever.

Tell your healthcare provider or get medical help right away if you get nausea, diarrhea, stomach (abdominal) pain, severe or worsening skin rash, or itching that does not go away.

You may have hair loss during treatment with Synribo. Synribo may cause fertility problems in males, which may affect your ability to have children. Talk to your healthcare provider if this is a concern for you.

These are not all of the side effects of Synribo.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Induction Schedule

• The recommended starting schedule for induction is 1.25 mg/m² administered subcutaneously twice daily at approximately 12 hour intervals for 14 consecutive days every 28 days, over a 28-day cycle.
• Cycles should be repeated every 28 days until patients achieve a hematologic response.

Maintenance Dosing

• The recommended maintenance schedule is 1.25 mg/m² administered subcutaneously twice daily at approximately 12 hour intervals for 7 consecutive days every 28 days, over a 28-day cycle.
• Treatment should continue as long as patients are clinically benefiting from therapy.

Dose Adjustments And Modifications

Hematologic Toxicity

• Synribo treatment cycles may be delayed and/or the number of days of dosing during the cycle reduced for hematologic toxicities (e.g. neutropenia, thrombocytopenia).
• Perform complete blood counts (CBCs) weekly during induction and initial maintenance cycles.
• After initial maintenance cycles, monitor CBCs every two weeks or as clinically indicated.
•  If a patient experiences Grade 4 neutropenia (absolute neutrophil count (ANC) less than 0.5 x 10⁹/L) or Grade 3 thrombocytopenia (platelet counts less than 50 x 10⁹/L) during a cycle, delay starting the next cycle until ANC is greater than or equal to 1.0 x 10⁹/L and platelet count is greater than or equal to 50 x 10⁹/L. Also, for the next cycle, reduce the number of dosing days by 2 days (e.g. to 12 or 5 days).

Non-Hematologic Toxicity

• Manage other clinically significant non-hematologic toxicity symptomatically. Interrupt and/or delay Synribo until toxicity is resolved.

• Based on its mechanism of action and findings from animal studies, Synribo can cause fetal harm when administered to pregnant women.
• There are no available data on Synribo use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes.
• There are no data on the presence of omacetaxine mepesuccinate in either human or animal milk, the effects on the breastfed child, or the effects on milk production.
• Because of the potential for serious adverse reactions in the breastfed child, advise patients that breastfeeding is not recommended during treatment with Synribo, and for 2 weeks after the final dose.