An immunotherapy treatment often used to treat urinary and lung cancers has now been approved by the US Food and Drug Administration (FDA) to treat an aggressive form of breast cancer known as triple-negative. Nearly 15% of all breast cancers are considered triple-negative, and the disease has a high death rate because of its tendency to spread throughout the body. This immunotherapy treatment, which also involves chemotherapy, has been shown to stop cancer growth in several patients.
The treatment is approved for patients with triple negative breast cancer, a type of breast cancer that tests negative for estrogen, progesterone, and human human epidermal growth factor 2 (HER2). Patients with this cancer, either local or metastatic, who are not able to have their tumor removed in surgery are eligible to try the treatment regiment. It consists of two drugs, Tecentriq, an immunotherapy drug, and Abraxane, a chemotherapy drug. The immunotherapy works to by binding to a particular protein called PD-L1, so its also necessary that patients using this drug have that protein in their cancer cells. After binding to the protein, the drug allows the immune system to recognize the cancer and begin to fight it. Once the immune system has been activated, the chemotherapy comes in and damages the cells further.
The protocol was approved by the FDA after clinical study results were published in the New England Journal of Medicine. The trial showed that of the patients with the PD-L1 protein who received the regimen, there was a median “progression-free survival” of 7.4 months compared to 4.8 months in patients who only received chemotherapy and a placebo drug. Progression-free survival refers to the time during which a cancer patient’s disease does not worsen.
The study’s lead author is Dr. Peter Schmid of Queen Mary University of London, and he has been very enthusiastic about the results. “This is the first time immunotherapy has worked in such a difficult to treat cancer.” Unfortunately, triple-negative breast cancer oftentimes becomes resistant to chemotherapy, allowing the disease to spread. It’s also ineligible for any available hormonal treatments. That’s why this new protocol is what Schmid calls “a huge step forward for these breast cancer patients.”
The FDA granted the treatment its “accelerated approval.” This designation is for treatments that have shown promise in preliminary clinical trials but whose long-term success is still relatively unknown. Because there is a great need for a new way to treat triple-negative breast cancer, the FDA sped up its approval for now. The drug protocol will continue to undergo trials so that researchers can determine it’s long-term efficacy. The drug will either receive full FDA approval or be pulled depending on the trial’s future results.
Overall, this approval has left many people optimistic. The field of immunotherapy is rapidly expanding and offering many patients with renewed hope for treating their disease. According to Dr. Larry Norton, director of the Evelyn H. Lauder Breast Center at Memorial Sloan Kettering Cancer Center, researchers are really focused on figuring out “other ways to stimulate the immune system.” He believes that there will be “an explosion of well-designed studies that push the agenda forward.”