On March 8, 2019, the U.S. Food and Drug Administration (FDA) approved the immunotherapy Tecentriq (chemical name: atezolizumab) in combination with the chemotherapy medicine Abraxane (chemical name: albumin-bound or nab-paclitaxel) as a first treatment for unresectable locally advanced or metastatic triple-negative, PD-L1-positive breast cancer.
Tecentriq is the first immunotherapy medicine approved to treat breast cancer.
The approval is based on results from the Impassion130 trial, which showed that Tecentriq and Abraxane offered better progression-free survival and overall survival compared to Abraxane alone for people diagnosed with locally advanced or metastatic triple-negative breast cancer who had not been treated yet for advanced-stage disease.
Progression-free survival is how long the people lived without the cancer growing. Overall survival is how long the people lived whether or not the cancer grew.
It is important to know that the follow-up time for the IMpassion130 study was only about a year. The FDA approval of Tecentriq for breast cancer is an accelerated approval based on progression-free survival results. Continued approval may be contingent on results from other studies that confirm this benefit.
Tecentriq is approved to treat a very specific type of breast cancer
Tecentriq is approved to treat a specific type of triple-negative breast cancer.
Triple-negative breast cancer is breast cancer that is:
Triple-negative breast cancers are usually more aggressive, harder to treat, and more likely to come back (recur) than cancers that are hormone-receptor-positive or HER2-positive. Triple-negative breast cancers don't usually respond to hormonal therapy medicines or the medicines that target the HER2 protein, such as Herceptin (chemical name: trastuzumab), Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine), Nerlynx (chemical name: neratinib), Tykerb (chemical name: lapatinib), or Perjeta (chemical name: pertuzumab).
Unresectable locally advanced breast cancer is breast cancer that has spread outside the breast to other tissues in the breast area. Unresectable means that it can’t be removed with surgery.
Metastatic breast cancer is cancer that has spread to other parts of the body away from the breast, such as the bones or liver.
PD-L1 is a protein that helps your body’s immune system work.
“The FDA approval of this Tecentriq combination is an important treatment advance for people with PD-L1–positive, metastatic triple-negative breast cancer, a disease with high unmet medical need,” Sandra Horning, M.D., chief medical officer and head of global product development at Genentech (Roche), the company that makes Tecentriq, said in a statement. “This Tecentriq combination is the first cancer immunotherapy regimen to be approved in breast cancer, representing a meaningful step forward in the understanding of this disease.”
How do immunotherapy medicines work?
Immunotherapy medicines work by helping your immune system work harder or smarter to attack cancer cells. Immunotherapy medicines use substances — either made naturally by your body or man-made in a lab — to boost the immune system to:
- stop or slow cancer cell growth
- stop cancer cells from spreading to other parts of the body
- be better at killing cancer cells
There are several types of immunotherapy medicines. Tecentriq is an immune checkpoint inhibitor immunotherapy medicine.
To start an immune system response to a foreign invader, the immune system has to be able to tell the difference between cells or substances that are “self” (part of you) versus “non-self” (not part of you and possibly harmful). Your body’s cells have proteins on their surfaces or inside them that help the immune system recognize them as “self.”
Some of these proteins that help your immune system recognize “self” cells are called “immune checkpoints.” Cancer cells sometimes find ways to use these immune checkpoint proteins as a shield to avoid being identified and attacked by the immune system’s T cells.
Immune checkpoint inhibitors target these immune checkpoint proteins and help the immune system recognize and attack cancer cells. Immune checkpoint inhibitors essentially take the brakes off the immune system by blocking checkpoint inhibitor proteins on cancer cells or on the T cells that respond to them.
Tecentriq is a PD-L1 checkpoint inhibitor.
PD-1 is a checkpoint protein on T cells. PD-L1 is another checkpoint protein found on many healthy cells in the body. When PD-1 binds to PD-L1, it stops T cells from killing a cell. Some cancer cells have a lot of PD-L1 on their surface, which stops T cells from killing these cancer cells. These cancers are called PD-L1-positive. An immune checkpoint inhibitor medicine such as Tecentriq that stops PD-1 from binding to PD-L1 allows T cells to attack the cancer cells.
Tecentriq side effects
As with most cancer medicines, Tecentriq and Abraxane may cause side effects, some of them severe.
In the IMpassion130 study:
- 99.3% of people treated with Tecentriq and Abraxane had side effects
- 97.9% of the people treated with Abraxane had side effects
The most common side effects in both treatment groups were:
- hair loss: 56.4% in the Tecentriq-Abraxane group and 57.5% in the Abraxane-alone group
- nausea: 46% in the Tecentriq-Abraxane group and 38.1% in the Abraxane-alone group
- cough: 24.8% in the Tecentriq-Abraxane group and 18.9% in the Abraxane-alone group
- peripheral neuropathy: 21.7% in the Tecentriq-Abraxane group and 22.1% in the Abraxane-alone group
- neutropenia (low white blood cell counts): 20.8% in the Tecentriq-Abraxane group and 15.3% in the Abraxane-alone group
- fever: 18.8% in the Tecentriq-Abraxane group and 10.7% in the Abraxane-alone group
- hypothyroidism (underactive thyroid): 13.7% in the Tecentriq-Abraxane group and 3.4% in the Abraxane-alone group
Severe side effects happened in:
- 48.7% of people treated with Tecentriq and Abraxane
- 42.2% of people treated with Abraxane alone
The most common severe side effects were low white blood cell counts, peripheral neuropathy, fatigue, and anemia. Rates of severe peripheral neuropathy were about twice as high in the Tecentriq-Abraxane group (5.5%) compared to the Abraxane-alone group (2.7%).
Because immunotherapy medicines are relatively new, the researchers also noted side effects of special interest that potentially may have an immunity-related cause. Serious side effects of special interest happened almost twice as often in people treated with Tecentriq and Abraxane (7.5%) compared to people treated with Abraxane alone (4.3%). The researchers pointed out that hypothyroidism was more than four times more common in people treated with Tecentriq and Abraxane compared to people treated with Abraxane alone.
Overall, 15.9% of people in Tecentriq-Abraxane group stopped treatment because of side effects and 8.2% of people in the Abraxane-alone group stopped treatment because of side effects.
The researchers attributed three of six deaths in the Tecentriq-Abraxane group to the treatment regimen and one of three deaths in the Abraxane-alone group to the treatment regimen.
What this means for you
If you’ve been diagnosed with locally advanced or metastatic triple-negative breast cancer and are deciding on treatments for the advanced-stage disease, you may want to talk to your doctor about PD-L1 testing on the cancer and whether Tecentriq is right for your unique situation.
For more information on immunotherapy medicines, including how they work and their possible side effects, visit the Breastcancer.org Immunotherapy page.
To discuss Tecentriq and other immunotherapy medicines with others, join the Breastcancer.org Discussion Board forum Immunotherapy - Before, During, and After.
Written by: Jamie DePolo, senior editor