Imfinzi (durvalumab) is a type of cancer treatment called an immunotherapy, developed by AstraZeneca and approved to treat certain cancers of the bladder, urinary tract and lungs. Immunotherapy drugs use the body’s own immune system to fight cancer.

How does Imfinzi work?

A type of white blood cell called T-cells that play an important role in the normal function of the immune system are activated and can attack and destroy cancer cells.

However, some tumors can evade destruction by the immune system by using a strategy called the “PD-1/PD-L1 pathway.” PD-L1 is a protein frequently found on the surface of cancer cells. When it binds to its receptors (called PD-1) found on T-cells, the normal function of T-cells is altered, and they fail to kill cancer cells.

Imfinzi binds to the PD-L1 protein found on cancer cells, preventing it from binding to its receptors (PD-1) on T-cells, thereby restoring normal T-cell activity and stimulating the immune system to attack and kill cancer cells.

Because Imfinzi works by stimulating the immune system, it can also attack healthy organs and tissues in the body such as the lungs, liver, pancreas, kidneys, intestines, thyroid, and adrenal glands, causing serious side effects.

Imfinzi in clinical trials

Bladder cancer

Imfinzi received accelerated approval from the U.S. Food and Drug Administration (FDA) in May 2017 for the treatment of patients with cancer of the bladder or urinary tract that stopped responding to standard treatments, such as chemotherapy.

This approval was based on the rapid and durable responses observed with Imfinzi in a Phase 1/2 study (NCT01693562). This study completed in February 2020.

This was the first approval for Imfinzi, but the use of the drug continues to be investigated in bladder cancer.

One Phase 3 trial (NCT02516241) called DANUBE is investigating Imfinzi as a first treatment for bladder cancer, both alone and in combination with another immunotherapy drug called tremelimumab compared to standard of care (SOC, cisplatin + gemcitabine or carboplatin + gemcitabine, based on cisplatin eligibility). DANUBE is a global trial that started in November 2015 and recruited participants at 220 locations in various countries. The study enrolled a total of 1126 participants with Stage IV, unresectable (cannot be surgically removed) bladder cancer who had not received treatment yet. Results of the trial did not show a statistically significant difference between either of the treatment groups and the standard of care group. The safety and tolerability of the treatments were similar to previous trials of Imfinzi and tremelimumab.

Several more clinical trials are currently recruiting for different forms of bladder cancer, as well.

Lung cancer

The FDA expanded its approval of Imfinzi to include certain types of stage 3 non-small cell lung cancer in February 2018. Imfinzi is also being investigated for the treatment of patients with other types of lung cancer in several clinical trials.

The FDA in July 2017 granted Imfinzi breakthrough therapy designation based on the results from a Phase 3 trial (NCT02125461) called PACIFIC. This trial is taking place in 235 centers across 26 countries, including the U.S., Canada, Europe, South America, Japan, Korea, Taiwan, South Africa, and Australia. Breakthrough therapy designation is designed to accelerate the development of new medicines which have shown encouraging results in early clinical trials for the treatment of serious conditions.

Based on early results from the Phase 3 (NCT03043872) CASPIAN trial, Imfinzi — along with standard of care chemotherapy (SOC, including etoposide and either carboplatin or cisplatin chemotherapy) — was given priority approval by the FDA in March 2020 as a first-line treatment of people with extensive-stage small cell lung cancer (SCLC). CASPIAN, which is continuing, is evaluating Imfinzi plus tremelimumab and SOC versus SOC alone in 988 adults with advanced SCLC.

Updated results — released in May 2020 after a median follow-up of more than two years — showed sustained efficacy with Imfinzi plus chemotherapy, with a 25% reduction in the risk of death (overall survival) seen in the Imfinzi arm versus chemotherapy alone.

Imfinzi is under review by regulatory agencies elsewhere, including the EU and Japan, based on the CASPIAN trial interim results.

Other information

Imfinzi continues to be investigated in other types of cancer, as well, both alone and in combination with other drugs. The U.S. National Library of Medicine’s Clinical Trials website lists over 300 active and recruiting studies of Imfinzi.


Last updated: June 22, 2020


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