The Annual Meeting of the American Society of Clinical Oncology (ASCO) provides an opportunity for thousands of oncologists and healthcare professionals to receive research updates and exchange ideas surrounding trends in cancer treatments. More than 30,000 attend each year, making it one of the largest educational and scientific conferences dedicated to advancing cancer care. I recently joined my colleagues for the ASCO 2015 Annual Meeting, where a focus was on breakthroughs in immunotherapy.
What is Immunotherapy?
Immunotherapy refers to treatments that prompt the human body’s immune system to attack cancer cells. Cancer occurs when a genetic mutations occurs that causes a healthy cell to become cancerous. Can the immune system recognize these cancerous cells as harmful or are they too at home within the body?
Recently, we have determined that the immune system often does recognize cancerous cells. The immune system produces white blood cells called lymphocytes that target harmful substances, called antigens, within the body. In response to the development of some cancers, lymphocytes will gather around cancerous cells. However, they do not always infiltrate cancerous cells and cause them to die.
Some cancers produce certain proteins, such as programmed cell death 1 (PD1). These are similar to other naturally-occurring proteins that prevent the immune system from interrupting certain normal biological functions. For instance, these proteins prevent the body from rejecting a fetus during pregnancy. When a cancer cell produces PD1, it sends a message to lymphocytes to back off.
A relatively new class of drugs called PD1-inhibitors prevents cancer cells from disguising themselves as healthy cells. Several ASCO 2015 Annual Meeting presentations on PD1-inhibitors revealed that they were an effective treatment for several cancers.
- Pembrolizumab – More than one-half of patients with advanced head and neck cancer experienced noticeable decrease in size of tumors following treatment with pembrolizumab.
- Nivolumab – Tumors ceased growing in approximately one-half of patients with advanced liver cancer treated with nivolumab. Advanced lung cancer patients treated with nivolumab lived an average of three months longer than patients treated with docetaxel, a chemotherapy.
Immunotherapy in Breast Cancer Patients
Ongoing research is also investigating the use of PD1-inhibitors in breast cancer patients. In an early stage trial, 4 of 21 triple-negative breast cancer patients with the PD1 protein responded to a PD1-inhibitor currently under investigation. These results prompted the FDA to assign the drug, MPDL3280A, Breakthrough Therapy Designation, which is reserved for treatments that appear significantly more effective in clinical trials than existing treatments.
In an upcoming phase III trial sponsored by drug maker Hoffman-La Roche, researchers will investigate the use of MPDL3280A in combination with nab-paclitaxel, a type of chemotherapy, in patients with metastatic breast cancer. The phase III trial is currently recruiting patients. Eligible candidates include women with advanced triple-negative breast cancer with no prior chemotherapy or targeted systemic therapy for inoperable disease.
Breastlink will work with researchers as a clinical partner in ongoing MPDL3280A research. This means patients eligible to participate in the study can receive MPDL3280A at Breastlink locations in Orange County. At this time, Breastlink locations are the only sites in Orange County and Los Angeles County where patients can participate in this study. As part of our commitment to advancing innovative breast cancer therapies, Breastlink is excited to play a role in ongoing research and to offer patients an opportunity to participate.
One drug already approved by the FDA for breast cancer patients combines immunotherapy with conventional chemotherapy. Ado-trastuzumab emtansine (T-DM1) uses an antibody called trastuzumab to target receptors present on cancerous cells in women with HER2-positive breast cancer. Once T-DM1 has bound to HER2 receptors, a chemotherapy agent called DM1 is delivered to the interior of cancerous cells, destroying them from the inside.
There are several benefits to immunotherapy over conventional chemotherapy and other targeted treatments. Researchers are continuing to produce evidence that immunotherapy improves clinical outcomes compared with conventional chemotherapy. Additionally, patients generally experience fewer side effects when treated. Immunotherapy also allows the immune system to develop a lasting memory of the antigen – in this instance, a type of cancer cell. If this specific type of cancer recurs, the immune system will continue to respond.
Developments such as those presented provide hope for a cure. The scientific and medical communities recognize new immunotherapy agents as huge breakthroughs. With these drugs, we can avoid treating more women with chemotherapy while improving their outcomes. At Breastlink, we are excited by these advancements and will eagerly track updates as they occur.