What to Know About Imfinzi (Durvalumab)

One of a class of drugs called checkpoint inhibitors, Imfinzi (generically known as durvalumab) is used to treat certain forms of lung and biliary tract cancer.

Prescribed either as a standalone treatment or alongside other drugs, this drug works by binding and blocking the activity of programmed death ligand 1 (PD-L1) proteins, thereby helping the immune system attack cancer cells. It’s administered using intravenous (IV) injection in the hospital under the care of oncology staff.

Uses

Imfinzi is approved by the Food and Drug Administration (FDA) for treating several serious forms of cancer, including non-small cell lung cancer (NSCLC), extensive-state small cell lung cancer (ES-SCLC), and biliary tract cancer (BTC).

Non-Small Cell Lung Cancer

Non-small cell lung cancers (NSCLCs) include squamous cell carcinoma and adenocarcinoma, among others. In these cases, Imfinzi is usually administered only after disease progression has not been observed with chemotherapy or radiation treatment and is reserved for when this cancer is at stage III or higher.

Extensive-Stage Small Cell Lung Cancer

ES-SCLC refers to a stage of lung cancer in which cancerous cells have spread throughout the lungs, as in when it has moved from one lung to the other, to lymph nodes, or other parts of the body.

Imfinzi is considered a first-line treatment for ES-SCLC when taken alongside the chemotherapy drugs, such as Toposar or Etopophos (etoposide), Paraplatin (carboplatin), and Cisplatin.

Biliary Tract Cancer (BTC)

This drug is approved for treating locally advanced or metastatic BTC in combination with gemcitabine and cisplatin.

Before Taking

Proper diagnosis is essential prior to the administration of Imfinzi, and a number of other factors need to be considered prior to its use. 

The first step in diagnosis is a physical examination and a review of medical history. If the healthcare provider suspects a problem, the next step is usually an imaging test, such as an X-ray, magnetic resonance imaging (MRI), or computer tomography (CT).

A biopsy may be performed; this is when a sample of cells is taken and analyzed.

Throughout this process, be sure to communicate openly with your medical team and don’t hesitate to ask any questions or concerns.

Precautions and Contraindications

Some conditions may contraindicate use of Imfinzi:

• Pregnancy: Evidence from animal studies suggests that this drug may be passed from mother to fetus, potentially causing harm. As such, pregnancy may cause the healthcare provider to consider alternatives, and women undergoing treatment are advised not to get pregnant during this time and for three months afterward.
• Age: The safety of this drug has not been established for children. The safety for people above age 70 is currently being investigated in a clinical study.
• Breastfeeding: People who are breastfeeding will be advised not to do so during the course of treatment.
• Thyroid disorders: There’s significant evidence that taking Imfinzi can have a harmful effect on the thyroid. Before undergoing treatment, the health of this organ is assessed, and existing problems may cause the healthcare provider to reconsider going ahead.
• Type 1 diabetes: This therapy has also been linked with the development and progression of type 1 diabetes. Healthcare providers will test for this condition, monitoring it if treatment goes ahead. Some cases of this disease may call for the healthcare provider to reconsider their approach.
• Kidney problems: The safety of the drug in patients with kidney problems has not been studied. Before treatment begins, the healthcare provider will assess kidney health to determine whether patients are a good fit for therapy. Monitoring kidney health is an essential component throughout treatment. 
• Allergic reaction: As Imfinzi is administered via IV, the medical team will monitor for allergic responses, clinically referred to as “infusion-related reactions.” Some of these can be quite severe and even fatal, leading the healthcare provider to either modify or discontinue this therapy.
• Autoimmune diseases: These can be a relative contraindication.

Other Checkpoint Inhibitors

Imfinzi is in a class of drugs that work similarly called checkpoint inhibitors. Others of this type in current use include:

• Keytruda (pembrolizumab)
• Opdiyo (nivolumab)
• Libtayo (cemiplimab)
• Tecentriq (atezolizumab)
• Bavencio (avelumab)

Dosage

Imfinzi is administered via IV in the hospital and does not come in a pill form. This administration takes about 60 minutes per session, and these sessions occur every two to four weeks.

The specific amounts recommended vary based on the condition being treated as well as whether the drug is administered on its own or alongside chemotherapy.

Here’s a quick breakdown:

• NSCLC: 10 mg of active dose for every kg of weight administered once every two weeks until toxicity in the body is overwhelming or the cancer is observed to continue spreading for an absolute maximum of 12 months. 
• ES-SCLC: For this cancer, if Imfinzi is recommended as an adjunct, it will typically be administered prior to chemotherapy. In these cases, doses of 1,500 mg every three weeks for a maximum of four cycles are indicated. Following that, or if this drug is given as a standalone treatment, the same 1,500 mg dose is delivered every four weeks.
• BTC: Patients with a body weight of 30 kg and more: 1,500 mg in combination with chemotherapy every 3 weeks (21 days) up to 8 cycles followed by 1,500 mg every 4 weeks as a single agent.

Keep in mind that specific dosages for your case are up to your healthcare provider; these amounts are FDA recommendations, not prescriptions.

Side Effects

Like all cancer drugs, Imfinzi is associated with a wide range of side-effects due to its effect on the immune system. That said, these are usually reversible and will go away after treatment has stopped.

Whereas some are more common and expected during the course of treatment, others are much more dangerous and constitute medical emergencies. It’s essential that you keep track of how you’re feeling, and don’t hesitate to seek help if you’re feeling sick or off.

Common

The more frequently seen side-effects seen with Imfinzi, while largely manageable, can be signs of more dangerous conditions, so healthcare providers monitoring for them throughout. These include:

• Fatigue
• Infection
• Muscle and bone pain
• Constipation
• Decreased appetite
• Rash
• Nausea
• Swelling
• Urinary tract infection
• Abdominal infection
• Fever
• Colitis
• Diarrhea
• Decreased sodium level
• Lower white cell count 

Severe

Alongside the more common side-effects, some adverse reactions to Imfinzi occur when the body’s immune system starts targeting healthy cells. These are more problematic and often require immediate medical attention as well as immediate cessation of the therapy. Here’s a quick breakdown:

• Pneumonitis: Pneumonitis is an inflammation of the kidney that may arise during treatment. Symptoms include shortness of breath, cough (especially if it doesn’t improve and gets worse), and chest pains.
• Hepatitis: This liver disorder can cause yellowing of eyes or skin, severe nausea and/or vomiting, pain on the right side of the stomach, dark or brown-colored urine, as well as easier bleeding or bruising.
• Hypothyroidism: Underactive thyroid can also occur during Imfinzi treatment. Initiate thyroid replacement therapy as clinically indicated.If hypothyroidism worsens, Imfinzi treatment is paused until levels to return to normal.
• Moderate to severe colitis: These intestinal issues lead to diarrhea, blood in the stool, and severe stomach pain.
• Gland problems: Imfinzi can also affect the pancreas, thyroid, and adrenal glands. Signs and symptoms of these types of problems vary a great deal and include rapid or slow heartbeat, leg swelling, excessive sweating, fatigue, sudden weight fluctuation, increased thirst or appetite, high blood sugar, hair loss, irritability and cognitive effects, constipation, deepening of the voice, low or high blood pressure, frequent urination, and stomach pain.
• Kidney problems: Adverse effects of Imfinzi on the kidney lead to less frequent urination, blood in the urine, ankle swelling, and loss of appetite.
• Other severe effects: A range of other organ systems can be affected by this drug. These can lead to neurological symptoms, such as headache, confusion, and change in balance. Other troubling symptoms include severe muscle weakness and pain, chest pain and tightness, trouble breathing, skin rashes, irregular heartbeat, and flu-like symptoms.

Warnings and Interactions

As with any pharmaceutical drug, Imfinzi activity can also be affected by other drugs and substances you’re taking. In particular, the following are known to interact with this drug:

• Kepivance (palifermin): A drug prescribed to help with chemotherapy, Kepivance should not be administered within the 24 hours before or after Imfinzi treatment.
• Depen Titratabs/Cuprimine (penicillamine): Indicated to take on toxicity due to elevated copper levels in the blood, Depen Titratabs, also known as Cuprimine, should not be used throughout the course of treatment.
• Aplical/Mantoux/PPD (tuberculin purified protein derivative): Immunosuppressive drugs like Imfinzi may also be hampered by tuberculin purified protein derivatives, which are used to diagnose for tuberculosis. As such, use of these should wait until six weeks after treatment.

Keep in mind that other substances you’re consuming may also interact with Imfinzi. When meeting with your healthcare provider for evaluation, have a list handy of all the medications you’re taking as well as any other herbs or supplements you’re taking.