Rutgers Cancer Institute of New Jersey
195 Little Albany Street
New Brunswick, NJ 08903-2681
For Carrie Best, and others, immunotherapy is a lifesaver. However, it doesn't work for everyone and researchers do not yet know why. It's often used when the standard treatment regimens have failed but is becoming the standard for some types of cancer. Howard L. Kaufman, MD, FACS, is a physician-researcher with expertise in the treatment of melanoma and other skin cancers and a pioneer in the immunotherapy field. He answers questions about the topic.
Q. What is immunotherapy?
A. It is an approach to treating cancer that works by activating an individual's immune system to fight the cancer--rather than directly killing the cancer cells, as occurs with radiation and/or chemotherapy.
Q. What is PD-L1 and what is its role in the spread of cancer?
A. One of our current clinical trial evaluates a new drug that targets a protein called programmed-death ligand one, or PD-L1 for short. PD-L1 is a cell receptor that has been found on the surface of many cancer cells where it functions to shut off T cells. Cancer cells can be killed by T cells, which make up part of the white blood cells that normally circulate through the body. T cells can be turned on and off as a way to regulate their function. The normal function of T cells can be turned off by a receptor found on the surface of the T cell called programmed death one (or PD-1). The normal function of PD-L1 is to bind to PD-1 on the T cell and turn it off. Antibodies that block this interaction have been shown to keep T cells active and result in cancer cell death. This approach has been very useful against a large number of cancers in clinical trials.
Q. How is the immunotherapy described above different from what has been available before to treat Merkel cell carcinoma?
A. In general, we have treated primary Merkel cell carcinoma with surgery and radiation therapy. Once the cancer spreads, the standard has been chemotherapy. Initially, the response is usually good, but few patients have responses that last longer than six months. This is the first study to evaluate an immunotherapy using PD-L1 as an alternative approach. About 80 percent of Merkel cell cancers are associated with a virus called Merkel cell polyoma virus. So, it is logical that a treatment that boosts immune response might be especially useful in managing this disease.
Q. Was Rutgers Cancer Institute of New Jersey the first site worldwide to offer this clinical trial? Why?
A. Yes. We were able to lead this clinical trial because my laboratory had contributed to the identification of PD-L1 expression in Merkel cell cancer samples. The Cancer Institute is the ideal place for such a study because we have a large patient population with skin cancer; we have a comprehensive team of physicians, nurses and pharmacists with an interest in advanced skin cancer treatment; and we have the research infrastructure to support important clinical trials, such as this one.
Q. How many people are enrolled in this clinical trial? Is the trial still recruiting participants?
A. We have enrolled six subjects at Rutgers and the trial is still open to recruitment. The total goal is 84 patients and the study will be open internationally throughout the U.S., Europe, Japan and Australia.
Q. What data exist supporting the effectiveness of the therapy? What do you think about this approach?
A. There have been major advances in the use of immunotherapy to treat cancer. This is an exciting area of research because immunotherapy appears to induce durable, long-lasting responses in patients when it works. Interleukin-2, another immunotherapy that has been used since 1992 to treat patients with metastatic melanoma and kidney cancer, has been highly successful in treating metastatic disease in some patients. Whether the newer agents, such as anti-PD-1 and anti-PD-L1, will have similar types of responses remains to be seen. The melanoma trials, however, are suggesting that a similar long-term benefit may be possible. This represents a very important new type of treatment for patients with cancer.
Q. Are there other drugs in the pipeline for Merkel cell and other skin cancers? When will they be available in clinical trials?
A. Yes. Based on the exciting initial data, another study using an anti-PD-1 antibody is being planned. If we continue to see positive results, I hope that other immunotherapy drugs, alone or in combination, may be considered high priority for evaluation in patients with advanced Merkel cell carcinoma.