Generic drug: melphalan flufenamide

Brand name: Pepaxto

What is Pepaxto (melphalan flufenamide), and how does it work?

Pepaxto is a prescription medicine used in combination with the medicine dexamethasone to treat adults with multiple myeloma who did not respond to or stopped responding to at least four prior medicines including at least one proteasome inhibitor, one immunomodulatory agent and one CD38-directed antibody.

Pepaxto is not for use to prepare for transplant.

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

What are the side effects of Pepaxto?

Pepaxto may cause serious side effects, including:

  • Low blood cell counts are common with Pepaxto and can be serious. Your healthcare provider will do blood tests as needed to check your blood cell counts during your treatment with Pepaxto.
    • Low platelet counts: Tell your healthcare provider right away if you have a bleeding or bruising under the skin.
    • Low red blood cell counts: Tell your healthcare provider if you are feeling weak, tired or you get tired easily, you look pale, or if you feel short of breath.
    • Low white blood cell counts: A low white blood cell count increases the risk of infections.
  • Infections. Pepaxto can cause infections that have led to death. Tell your healthcareprovider right away if you develop new or worsening signs or symptoms of infection such as fever, chills, cough, pain, or burning during urination during treatment with Pepaxto.
  • Secondary cancers. New cancers such as myelodysplastic syndromes or acute leukemia have happened in people with multiple myeloma who have received Pepaxto. Your healthcare provider will monitor you for new cancers.

Your healthcare provider may change your dose of Pepaxto, stop your treatment for a period of time, or completely stop your treatment if you have certain side effects.

Pepaxto may cause fertility problems in males and females, which may affect your ability to have children. Talk with your healthcare provider if you have concerns about fertility.

The most common side effects of Pepaxto include, low blood cell counts, fatigue, nausea, diarrhea, fever, and cold-like symptoms (respiratory tract infection).

These are not all of the possible side effects of Pepaxto.

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

What is the dosage for Pepaxto?

Recommended Dosage

  • The recommended dosage of Pepaxto is 40 mg administered intravenously over 30 minutes on Day 1 of each 28-day cycle until disease progression or until unacceptable toxicity. Administer dexamethasone 40 mg orally or intravenously on Days 1, 8, 15 and 22 of each cycle.
  • For patients 75 years of age or older, reduce the dose of dexamethasone to 20 mg.
  • Refer to the prescribing information for dexamethasone for additional dosing information.

Recommended Premedication And Concomitant Medications

  • Consider providing a serotonin-3 (5-HT3) receptor antagonist or other antiemetics prior to and during the treatment with Pepaxto.

Dosage Modifications For Adverse Reactions

  • Withold Pepaxto if the neutrophil count is less than 1 x 109/L or the platelet count is less than 50 x 109/L.
  • The recommended dose reductions and dosage modifications for adverse reactions for Pepaxto are presented in Table 1 and Table 2, respectively.

Table 1: Recommended Dose Reductions for Adverse Reactions of Pepaxto

Dose Reduction Dosage*
First 30 mg
Second 20 mg
Subsequent Permanently discontinue Pepaxto in patients who are unable to tolerate 20 mg.
* Administered intravenously on Day 1 of each 28-day cycle. For dosage modifications, see Table 2.

Table 2: Recommended Dosage Modifications for Adverse Reactions of Pepaxto

Adverse Reaction Severity Dosage Modification
Myelosuppression Platelet count less than 50 x 109/L on an intended Pepaxto dosing day
  • Withhold Pepaxto and monitor platelet count weekly until platelet count is 50 x 109/L or greater.
  • Resume Pepaxto
    • at same dose if delay is 2 weeks or less.
    • at 1 dose level lower if delay is more than 2 weeks.
Absolute neutrophil count less than 1 x 109/L on an intended Pepaxto dosing day
  • Withhold Pepaxto and monitor neutrophil count weekly until neutrophil count is 1 x 109/L or greater.
  • Resume Pepaxto
    • at same dose if delay is 2 weeks or less.
    • at 1 dose level lower if delay is more than 2 weeks.
Grade 4 hematological adverse reaction on an intended Pepaxto dosing day in 2 consecutive cycles
  • Resume Pepaxto at 1 dose level lower.
Non-Hematologic Adverse Reaction Grade 2
  • Consider withholding Pepaxto until resolved to at least Grade 1 or baseline.
  • Consider resuming Pepaxto at 1 dose level lower.
Grade 3 or 4
  • Withhold Pepaxto until resolved to at least Grade 1 or baseline.
  • Resume Pepaxto at 1 dose level lower as clinically appropriate.


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What drugs interact with Pepaxto?

No Information Provided

Is Pepaxto safe to use while pregnant or breastfeeding?

  • Based on its mechanism of action, Pepaxto can cause fetal harm when administered to a pregnant woman.
  • There are no available data on Pepaxto use in pregnant women to evaluate for a drug-associated risk. Pepaxto is a genotoxic drug. Advise pregnant women of the potential risk to a fetus.
  • There is no data on the presence of melphalan flufenamide or its metabolites in human breast milk, or the effects on the breastfed child or on milk production.
  • Because of the potential for serious adverse reactions in the breastfed child, advise women not to breastfeed during treatment with Pepaxto and for 1 week after the last dose.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 4/1/2021
All sections courtesy of the U.S. Food and Drug Administration