Imfinzi (durvalumab) is a prescription drug that’s used to treat certain lung and other cancers. It comes as a solution that a healthcare professional injects into a vein. You receive this infusion every 2 to 4 weeks.

Specifically, Imfinzi is given to adults to treat:

Imfinzi may be prescribed alone or together with other therapies that treat certain types of cancer. These therapies include chemotherapy, radiation therapy, and other medications.

The active ingredient in Imfinzi is durvalumab. (An active ingredient is what makes a drug work.)

Imfinzi belongs to a group of drugs called PD-L1 inhibitors.

This article describes the dosages of Imfinzi, as well as its strengths and how it’s given. To learn more about this drug, see this comprehensive article about Imfinzi.

This section describes the usual dosages of Imfinzi. Keep reading to learn more.

What is Imfinzi’s form?

Imfinzi is available as a liquid solution that a healthcare professional gives as an intravenous (IV) infusion. This is an injection given into your vein over a period of time.

What strengths does Imfinzi come in?

Imfinzi comes in two strengths:

  • 500 milligrams (mg) in 10 milliliters (mL) of sterile water for injection
  • 120 mg in 2.4 mL of sterile water for injection

What are the usual dosages of Imfinzi?

Your dosage of Imfinzi depends on several factors. These include the condition being treated, your body weight, and other factors.

You’ll receive Imfinzi every 2, 3, or 4 weeks by itself or with other medications. Your doctor will prescribe the recommended dosage that provides the desired effect.

The information below describes dosages that are commonly used or recommended. In some cases, doctors may adjust your dosage from those shown below. They’ll determine the best dosage to fit your needs.

Dosage for small cell lung cancer

The typical Imfinzi dosage for adults with extensive-stage small cell lung cancer (SCLC) is an IV infusion of 1,500 mg, along with two chemotherapy drugs, every 4 weeks. This will continue for four cycles,* or about 16 weeks. Then every 4 weeks, you’ll receive 1,500 mg of Imfinzi alone.

* A cycle is when medications are taken, followed by a period of rest.

Dosage for biliary tract cancer

For adults with biliary tract cancer, the typical dosage of Imfinzi is an infusion of 1,500 mg every three weeks, with a chemotherapy medication. This will continue for up to eight cycles, or up to about 24 weeks. Then, every 4 weeks, you’ll receive 1,500 mg of Imfinzi alone.

Dosage for liver cancer

For adults with hepatocellular carcinoma, the typical dosage of Imfinzi is as follows: On day 1 of the first cycle, you’ll receive 1,500 mg of Imfinzi with a single dose of another medication. Then, every 4 weeks, you’ll receive 1,500 mg of Imfinzi alone.

Dosage for endometrial cancer

The typical dosage for adults with certain types of endometrial cancer is an infusion of 1,120 mg of Imfinzi every 3 weeks in combination with chemotherapy. This will continue for six treatment cycles, or about 18 weeks. Then you’ll receive 1,500 mg of Imfinzi every 4 weeks as a stand-alone treatment.

For more specific details about the dosage protocol for endometrial cancer, talk with your doctor.

Dosage for non-small cell lung cancer (NSCLC)

Stage 3 NSCLC that cannot be removed with surgery

The typical Imfinzi dosages for adults with stage 3 NSCLC that cannot be removed with surgery are as follows. Imfinzi is given alone. Your doctor may prescribe one of two dosages:

  • Every 2 weeks, you’ll receive an infusion of 10 mg of Imfinzi per kilogram (kg) of your body weight, or
  • Every 4 weeks, you’ll receive an infusion of 1,500 mg of Imfinzi

NSCLC that has spread to other parts of the body (metastasized)

The typical Imfinzi dosages for adults with NSCLC that has metastasized are as follows. Imfinzi is given together with other cancer therapies. Every 3 weeks, you’ll receive an infusion of 1,500 mg of Imfinzi together with other cancer medications. This will continue for four treatment cycles. Then every 4 weeks, you’ll receive an infusion of 1,500 mg of Imfinzi alone.

Ask your doctor for more details about the Imfinzi dosage protocol for metastatic NSCLC.

Is Imfinzi prescribed long term?

It may be. The length of your treatment often depends on how your body responds to it. It also may depend on how manageable the side effects of Imfinzi are.

Your doctor will discuss your treatment plan and how long you’re likely to need Imfinzi.

Dosage adjustments

Imfinzi doesn’t have dosage adjustments for any conditions. But some people may have certain serious side effects from Imfinzi. In these cases, your doctor may stop Imfinzi treatment temporarily or permanently.

During treatment, your doctor will monitor you and adjust your infusion rate if needed. That means they’ll adjust how fast you receive your infusion of Imfinzi.

The dosage of Imfinzi you’re prescribed may depend on several factors. These include:

  • the type and severity of the condition you’re receiving the drug to treat
  • other medications you may be taking or receiving
  • your weight

Imfinzi comes as a liquid solution that you receive by IV infusion. This is an injection into your vein over a period of time, given by a healthcare professional. You’ll receive Imfinzi injections at a clinic or a hospital.

An Imfinzi infusion typically lasts 60 minutes.

If you miss an appointment to receive a dose of Imfinzi, call your doctor’s office as soon as possible to reschedule. They’ll reschedule your dose and adjust your future appointments if needed.

If you need help remembering your appointments, try setting an alarm or downloading a reminder app on your phone.

Below are answers to some commonly asked questions about Imfinzi’s dosage.

Are Imfinzi’s dosages similar to the dosages of Keytruda?

No, they’re not. But both Imfinzi and Keytruda (pembrolizumab) treat certain types of cancer. And both come as liquid solutions for IV infusion by a healthcare professional.

The doses and how often you receive infusions of the medicines differ. For example, Imfinzi infusions are generally given every 2, 3, or 4 weeks. Keytruda infusions are given every 3 weeks or every 6 weeks.

Your doctor will prescribe the drug and dosage that’s right for you. Learn more about Imfinzi vs. Keytruda.

How long does it take for Imfinzi to start working?

Imfinzi starts to work after your first dose. Your doctor will monitor you during treatment to check whether the drug is working to treat your condition. The length of treatment depends on individual factors. These include your body’s response to Imfinzi treatment, your type of cancer, and other medications you may be taking.

If you have other questions about what to expect from your Imfinzi treatment, talk with your doctor.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.