On March 8th, The Food and Drug Administration (FDA) granted accelerated approval to an immunotherapy regimen for breast cancer. The regimen includes a combination of the immunotherapy drug Tecentriq and the chemotherapy Abraxane. The regimen is for a specific type of breast cancer known as triple negative breast cancer which means that it has the following three conditions:
- It is locally advanced or metastatic
- It cannot be surgically removed
- The cells contain a protein called PD-L1
The FDA’s decision is based on a groundbreaking study done by Genetech Inc and published in the New England Journal of Medicine. The study found that people who took the immunotherapy drug in conjunction with chemotherapy versus those who took just the placebo with chemotherapy had a higher progression-free survival (the amount of time in which a patient’s cancer does not get worse). For those on the drug, their progression-free survival averaged around 7.4 months versus those on chemo alone whose progression-free survival averaged 4.8 months.
While the study has shown that it prevents cancer from getting worse but it doesn’t treat cancer. The FDA only grants accelerated approval on drugs that “treat serious conditions that fill an unmet medical need.” Genetech, the manufacturers of Tecentriq are required to do more clinical trials to show that the drug is still beneficial. Otherwise, the FDA has the right to pull the drug.
About 15% of all breast cancers reported are triple negative. It is usually found in women who between the ages of 40 and 50 and are of Hispanic and African descent but can also be found with women who have the BRCA1 gene mutation.
The drug is not meant to be used on its own yet, as the chemotherapy helps the drug be effective. Cancer cells are hard to treat because the body’s immune system does not recognize them as a foreign object (i.e. like bacteria or virus). The PD-L1 protein fools the immune system into thinking it is part of the body. Tecentriq attaches to the cancer cell and deactivates the PD-L1 protein, allowing the body’s immune system to naturally fight the cell. However, without chemotherapy, the Tecentriq cannot get to the protein inside the cancer cell.