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Treatment Name: Pegfilgrastim (Neulasta®, Neulasta OnPro®, Udenyca®, Fulphila®, Ziextenzo®, Nyvepria®, Fylnetra®)

Pegfilgrastim (Neulasta®, Neulasta OnPro®, Udenyca®, Fulphila®, Ziextenzo®, Nyvepria®, Fylnetra®) is a Supportive Care Therapy to prevent Neutropenic Fever

How does pegfilgrastim work?
Pegfilgrastim is designed to lower the risk of infection after chemotherapy. It is part of a family of medicines called “granulocyte colony-stimulating factor” (G-CSF), or growth factor. Pegfilgrastim binds to bone marrow stem cells to speed up production of certain white blood cells known as neutrophils. Neutrophil white blood cells are part of your immune system. Chemotherapy kills fast growing cells such as cancer cells, but sometimes kills good cells such as neutrophils too. When this happens, it is called neutropenia, a sign that your immune system is weakened and low in neutrophils.

When neutrophils become low and you have a fever, it is called neutropenic fever. Neutropenic fever is a medical emergency. Fevers after chemotherapy should be reported to a doctor immediately or patients should report to a hospital emergency department.

Goals of therapy:
Pegfilgrastim is used to keep the neutrophil count from declining to unsafe levels after certain chemotherapy regimens are given, specifically those having a high risk of neutropenic fever. Pegfilgrastim also shortens the time that neutrophils are low after chemotherapy. This greatly lowers the risk of neutropenic fever, but does not prevent it all of the time. When a medicine is taken to prevent neutropenic fever, it is known as prophylaxis, or prophylactic therapy.


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  • Pegfilgrastim is usually injected under the skin (subcutaneous injection) at home, in the clinic, or by an on-body injector (Neulasta OnPro®) placed on your abdomen or upper arm by a nurse in the infusion room
  • Pegfilgrastim is supplied as a clear, colorless, preservative-free solution in a prefilled single use syringe. If injecting this yourself at home, pegfilgrastim should be stored in the refrigerator between 2° to 8° C (36° to 46° F)
  • Pegfilgrastim is usually given in the outpatient setting 24 hours after each chemotherapy cycle and no sooner than 14 days before the next chemotherapy treatment
  • If you are using the on-body injector, sometimes referred to as the “O.B.I.,” or Neulasta OnPro®, the actual injection will take place on the last day of chemotherapy in each cycle, but the medicine will not be injected by the OBI device until about 27 hours after placement on your body.

Pegfilgrastim is usually used for patients with curable cancers whose chemotherapy carries more than a 1 in 5 (20%) chance of neutropenic fever. It may also be used for lower risk chemotherapy in patients who have weak immune systems, poor organ function, a history of low neutrophil count, or neutropenic fever. When initially prescribed, pegfilgrastim is usually repeated at the end of every chemotherapy cycle.

Pegfilgrastim usual adult starting dose:

  • Pegfilgrastim 6 mg subcutaneous injection once, delivered 24 hours after the end of the last dose of myelosuppressive chemotherapy. Not all chemotherapy agents are “myelosuppressive,” or decrease your neutrophils. Ask your doctor or pharmacist which agents cause neutropenia

Side Effects

In the pegfilgrastim prescribing label information (package insert), the most commonly reported side effects from pegfilgrastim are shown here. The exact percentages of patients that will experience pegfilgrastim side effects is unknown because it has been used under widely varying patient populations in a variety of clinical trials:

Rare (less than 1%):

  • Rupture of the spleen
  • Sickle cell crisis
  • Acute respiratory distress syndrome (ARDS), consisting of fever with difficulty breathing
  • Serious allergic reactions
  • It is unknown if pegfilgrastim will harm a developing baby. Pegfilgrastim should be used in pregnant women only if the potential benefits to the mother outweighs the potential risks to the unborn baby

Side effect videos Side Effect Videos
Neutropenic FeverNeutropenic FeverPainPain


How often is monitoring needed?
Labs (blood tests) will usually be checked on the day of chemotherapy, or shortly before a new cycle. If you develop fevers, labs will need to be drawn again to see if your “absolute neutrophil count” (ANC) is low. If your ANC is low, you may need to have blood cultures or other labs done to look for infection. Labs often include: Complete Blood Count, plus any others your doctor may order.

How might blood test results/imaging affect treatment?
Depending upon the results, your doctor may advise to continue your chemotherapy as planned, reduce the dose of future treatments, delay the next dose until your ANC improves, 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

  • Pegfilgrastim is usually used to shorten the time neutrophils are low after chemotherapy with a high risk (at least 1 in 5 chance) of causing neutropenic fever. It has only been approved by FDA for prevention (not treatment) of neutropenic fever
  • If you develop neutropenic fever, you may need to be given “broad spectrum” antibiotics until your ANC rises to a safe level. Antibiotics are most often intravenous, given in a hospital setting
  • When using the on-body injector (Neulasta OnPro®), the dose should inject 27 hours after the device is applied to your body. When this happens, the green light on the device will stop flashing or turn off. The fill indicator should also read as “EMPTY.” Be sure to watch for any sign of a leak as this may mean the injector has failed. Call your oncology provider if the light flashes red or you notice any sign of a leak
  • Avoid bumping or sleeping on the on-body injector (Neulasta OnPro®) if you use this product
  • Neutropenic fever most commonly happens 1 to 2 weeks after receiving chemotherapy. Make sure to have a thermometer at home so you can check your temperature
  • After chemotherapy, it is important to watch for fevers. Call your oncology clinic immediately or go to the nearest emergency department if you have any temperature of 101° F (38.3° C) or above, or any temperature of 100.4° F (38° C) or above that stays elevated for over one hour
  • Although no drug interactions with pegfilgrastim are currently known, a pharmacist should ALWAYS review your medication list to ensure that drug interactions are prevented or managed appropriately

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 Pegfilgrastim (Neulasta®, Neulasta OnPro®, Udenyca®, Fulphila®, Ziextenzo®, Nyvepria®, Fylnetra®), 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 Pegfilgrastim (Neulasta®, Neulasta OnPro®, Udenyca®, Fulphila®, Ziextenzo®, Nyvepria®, Fylnetra®). Depending upon your income, they may be able to help cover the cost of:

  • Pegfilgrastim (Neulasta®, Neulasta OnPro®, Udenyca®, Fulphila®, Ziextenzo®, Nyvepria®, Fylnetra®)

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 Pegfilgrastim (Neulasta®, Neulasta OnPro®, Udenyca®, Fulphila®, Ziextenzo®, Nyvepria®, Fylnetra®) 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.

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Pegfilgrastim prescribing label information (package insert)

Created: May 3, 2017 Updated: October 24, 2018

What is Neutropenic Fever?

Neutropenia is when you have a low number of infection fighting cells in your blood called neutrophils.

A fever is when someone has a single temperature of 101°F or higher or a temperature of at least 100.4°F that does not go away after one hour. When someone develops a fever at the same time they have low neutrophils, they are considered to have a "neutropenic fever." This is also sometimes called "febrile neutropenia."

Unless told otherwise by their doctor, someone with neutropenic fever should get to the emergency room IMMEDIATELY! Do NOT wait! Without proper treatment, neutropenic fever can cause life-threatening symptoms within a matter of hours. Fever may be one of the only signs of infection, therefore it is very important that you have a thermometer if you are receiving chemotherapy.

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 is neutropenia?

This occurs when there is an abnormally low amount of a certain type of white blood cells, called neutrophils, in the blood. These neutrophils help the body fight infections caused by bacteria and viruses.

Many chemotherapy drugs temporarily damage bone marrow where white blood cells are created, resulting in neutropenia. Please watch our video on neutropenic fever to learn more.

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.