Triple-negative breast cancer is an aggressive cancer that does not express the common hormone receptors, including the estrogen receptor (ER) and the progesterone receptor (PR). Hormone receptors (ER or PR) allow many patients to receive endocrine (hormone-based) therapies instead of chemotherapy. It also doesn’t express the HER2 protein that enables the use of the HER2-targeted medication Herceptin (trastuzumab), a common drug used for breast cancer.
Patients with cancer that involves ER, PR, or HER2 can receive treatment with targeted drugs and not just chemotherapy. Until recently, this was not the case for patients with triple-negative breast cancer. Oncologists and cancer researchers have been working for a long time to find targeted therapies that would allow them to offer women with triple-negative breast cancer a targeted therapy.
Tecentriq First Immunotherapy for Triple-Negative Breast Cancer
In March 2019, the FDA approved Tecentriq (atezolizumab), a PD-L1 antibody, for use as the first (or first-line) treatment of patients with metastatic (spreading) triple-negative breast cancer, in combination with the chemotherapy Abraxane (nabpaclitaxel). This was a groundbreaking development for many reasons. First, it is the first immunotherapy to be approved for use in breast cancer. Second, it is the first-ever targeted therapy to be approved for patients with metastatic triple-negative breast cancer. Third, Tecentriq extends survival in patients with this type of cancer, meaning that women who received this drug lived longer than those who did not receive this immunotherapy.
The FDA approved Tecentriq for this type of breast cancer based on the results of a clinical trial called IMpassion130 that I supervised at Sarah Cannon Research Institute in Nashville, Tennessee. In this trial, 902 patients untreated metastatic triple-negative breast cancer from 41 countries received either Abraxane, a standard chemotherapy for this type of cancer, or immunotherapy with Tecentriq in combination with Abraxane chemotherapy.
Tecentriq is known as a PD-L1 inhibitor, meaning that it enables the immune system to recognize cancer cells as “bad cells” and destroy them. For the women who received only chemotherapy with Abraxane, the time without disease progression was on average 5.5 months. But the women who received chemotherapy plus immunotherapy with Tecentriq, the time without disease progression was improved to an average of 7.2 months.
More important, in terms of the duration of actual survival, for the 41% of women in the study whose cancer had high levels of PD-L1, the average duration of survival increased from 15.5 months to 25 months. Finding a group of women for whom we can improve life expectancy from only a little over 1 year to more than 2 years is very exciting.
The Power of Clinical Trials
I was fortunate to be able to offer Tecentriq to my patients at Sarah Cannon as part of the IMpassion130 clinical trial beginning in 2015. In January 2016, I met a lovely young woman named Samantha, who had just found out that her cancer, which was initially diagnosed in 2012, had returned. In addition to offering Samantha the opportunity to start standard chemotherapy, I offered her the option of participating in this clinical trial, in which she had a 50% chance of receiving Tecentriq immunotherapy plus standard chemotherapy.
Samantha enrolled in the trial and luckily was in the group that received immunotherapy plus chemotherapy, and within the first several months the tumors in her chest and abdomen disappeared. Samantha’s cancer ultimately had a complete response to the treatment, meaning we could no longer see tumors on her CT scans.
About 2 years after entering the study, Samantha still had no evidence of cancer. Because of its cumulative side effects, the chemotherapy was stopped. Now, more than 3.5 years after we met, Samantha receives Tecentriq alone without chemotherapy. She continues to work full time and have a great quality of life.
Not every patient will be as lucky as Samantha, but her story highlights the power of clinical trials and the advances we make in cancer treatment every day. Thanks to courageous women like Samantha, who took the chance to try a new medication and participate in a clinical trial, thousands of women with metastatic triple-negative breast cancer will now be able to use immunotherapy in addition to chemotherapy, which may significantly extend their life.
Although research has shown that most (70%) Americans indicate that they would be inclined or very willing to participate in a cancer clinical trial,1 only about 3% to 5% of patients with cancer in America participate in clinical trials.2,3 A survey on clinical trial participation showed that 50% of survey respondents were not even aware of the existence of clinical trials.3
This disconnect is complex and is caused by multiple reasons, such as access to clinical trials, strict enrollment criteria, and misconceptions about research. Although some of these issues are tough to tackle, educating family, friends, and patients about clinical trials may increase participation. All patients diagnosed with cancer should ask their doctors if a clinical trial is a good option for them.
Many more new drugs are currently in clinical trials that have the potential to bring new and improved treatments to many patients with cancer.
Because no 2 cancers are alike, we need to tailor treatment for cancer to each person individually. We are now able to understand tumors by their molecular profile and to look at the genes in the cancer cells to see what makes them grow.
We call this approach “personalized medicine,” which refers to looking for biomarkers in the individual’s cancer to select the therapy that would work best for that patient. Although personalized medicine has been around for decades in testing for hormone receptors (ER or PR) and HER2 status, other tests, such as tests for PD-L1 expression, are much newer.
We now also perform broad molecular testing of tumors in which the DNA in a person’s cancer cells is examined for genetic errors (or mutations) and extra copies specific to that person that can be very important for selecting the best treatment.
- Comis RL, Miller JD, Aldigé CR, et al. Public attitudes toward participation in cancer clinical trials. Journal of Clinical Oncology. 2003;21:830-835.
- SubjectWell. Survey of Clinical Trial Awareness and Attitudes. 2016. http://subjectwell.com/wp-content/uploads/2016/03/Clinical-Trial-Awareness-Survey.pdf.
- Lewis JH, Kilgore ML, Goldman DP, et al. Participation of patients 65 years of age or older in cancer clinical trials. Journal of Clinical Oncology. 2003;21:1383-1389.