Drug regulators in the United States have granted the immunotherapy drug Tecentriq (atezolizumab) accelerated approval to treat the most common type of bladder cancer - urothelial carcinoma. The drug is the first PD-1/PD-L1 inhibitor approved to treat this type of cancer. It works by helping to stop cancer cells evade the immune system.
In their announcement on May 18th, the Food and Drug Administration (FDA) say the
Tecentriq is the first new drug approved in the U.S. for 30 years for treating patients with the most common form of bladder cancer.
The FDA have given Tecentriq accelerated approval based on tumor response rate and duration of response. This type of approval can be given to a medicine that fills an unmet medical need for a serious condition, based on early evidence suggesting clinical benefit. However, it is conditional on the evidence being confirmed in later trials.
Dr. Richard Pazdur - of the FDA's Center for Drug Evaluation and Research - says, "Tecentriq provides these patients with a new therapy targeting the PD-L1 pathway."
Tecentriq targets a cellular pathway called PD-1/PD-L1. PD-1 is a receptor (a protein that sits on the surface of the cell membrane) and PD-L1 is one of the molecules that binds to it. The pathway is an example of what is called an immune checkpoint - molecules or immune cells that need to be activated or stopped to start an immune response.
By blocking the pathway, Tecentriq may help the body's immune system fight cancer cells.
FDA also approve PD-L1 expression test
The FDA's approval is based on evidence from a clinical trial involving 310 patients with locally advanced or metastatic urothelial carcinoma. Nearly 15 percent of patients experienced at least a partial shrinkage of tumors, which lasted from about 2 months to nearly 14 months at the time the results were analyzed.
- An estimated 76,960 new cases of bladder cancer are expected to be diagnosed in the U.S. in 2016
- Men are about 3 to 4 times more likely to develop it during their lifetime than women
- Bladder cancer occurs mainly in older people.
In patients whose cancer cells tested "positive" for PD-L1 expression, 26 percent showed a tumor response. In contrast, of patients who were classed as "negative" for PD-L1 expression, only 9.5 percent showed a tumor response. The FDA also note in their announcement that:
"While patients who received Tecentriq experienced a tumor response across the study, the greater effect in those who were classified as "positive" for PD-L1 expression suggests that the level of PD-L1 expression in tumor-infiltrating immune cells may help identify patients who are more likely to respond to treatment with Tecentriq."
Therefore, the FDA have also approved a test for detecting PD-L1 protein expression levels in patients' tumor cells. The test - called the "Ventana PD-L1 (SP142) assay" - should help doctors decide which patients are most likely to benefit from treatment with Tecentriq.
The drug may also give rise to infection and serious side effects - known as "immune-mediated side effects" - due to interaction with the immune system. These can affect healthy organs, including the lungs, colon and endocrine system.
Tecentriq is marketed by Genentech of San Francisco, CA, who provide prescribing information.
The drug is the first FDA-approved PD-L1 inhibitor and the latest in the broader class of PD-1/PD-L1 targeting products approved by the FDA in the last 2 years.
"Products that block PD-1/PD-L1 interactions are part of an evolving story about the relationship between the body's immune system and its interaction with cancer cells."
Dr. Richard Pazdur