Immunotherapy takes cancer treatment into a new era

The history of immunotherapy goes back decades, but in recent years a host of new drugs and therapies have seen some treatment labels usher in a new era in cancer care. “Immunotherapy is not new to the field of cancer treatment,” says Eugene Ahn, MD, a hematologist/oncologist at The Hospital of Chicago. “But what has generated a lot of excitement in recent years are the success stories of patients with metastatic melanoma and lung cancer who have been able to achieve positive long-term results with a new class of immunotherapy drugs.”

Former President Jimmy Carter is one of the most prominent examples. In August 2015, Carter announced that he had been diagnosed with metastatic melanoma that had spread to the liver and brain. Four months later, after undergoing immunotherapy, Carter announced that his latest brain scan revealed no signs of cancer.

“President Carter’s case has certainly brought to the fore the discussion of immunotherapy,” says Dr. Glenn Weiss, director of clinical research and an oncologist at Phoenix Hospital. “Patients come to counseling appointments with a certain degree of knowledge and ask the right questions: Am I a candidate for immunotherapy? Do you have an immunotherapy clinical trial that I can participate in?”

Fuss over checkpoint inhibitors

Pembrolizumab (Keytruda® ⁾ , used to treat former President Jimmy Carter’s metastatic melanoma, nivolumab (Opdivo® ⁾ and ipilimumab (Yervoy® ⁾ , are among the drugs called “checkpoint inhibitors” that have added to the hype around immunotherapy. Designed to stimulate the immune system to target certain cancer cells, these drugs have been approved to treat skin cancer, kidney cancer, and/or lung cancer. Trials are underway on a variety of other cancers.

Checkpoint inhibitors work by rewiring specific receptors of T cells in the immune system. The receptors normally act as brakes and accelerators, slowing or accelerating the T cells as they travel through the body in search of invaders. The immunotherapy drugs now on the market aim to interrupt the signal from a specific receptor and prevent it from putting pressure on the brakes. This allows T cells to speed through checkpoints and attack cancer cells.

Although checkpoint inhibitor immunotherapy drugs make the medical and scientific communities hope for the future, many questions remain about this still developing field of cancer treatment. To help solve these and other mysteries, clinicians and researchers are testing theories and assumptions in clinical trials. “Clinical trials are evaluating the safest doses, schedules, duration and combination of these treatments to improve outcomes for already approved drugs and to increase the percentage of patients who will not only have a response to immunotherapy but hopefully have a long-term response measured in years, not weeks or months.” Dr. Weiss says.

What’s on the horizon

A series of trials, for example, is exploring the efficacy of immunotherapy in patients with different types of cancer, while outlining how to combine treatments to achieve positive results. “Currently, we don’t have a great way to select patients who are most likely to benefit, but there are teams of researchers working on this,” Dr. Weiss says. “Currently, these drugs are given to patients with advanced metastases who may also be considered suitable candidates for other systemic therapy, such as chemotherapy.”

In January, our Phoenix Hospital launched a new clinical trial that tests the effectiveness of combining the immunotherapy drug nivolumab with some chemotherapy. Medicines to treat certain types of colorectal and pancreatic cancer. The study will look at how combinations of immunotherapy and chemotherapy work in other advanced cancers. In another clinical trial that began in December 2014, Dr. Weiss and his fellow researchers found that combining pembrolizumab with conventional chemotherapy produced better outcomes for some patients with advanced small cell lung cancer and non-small cell lung cancer than chemotherapy alone. Since then, the study has expanded to include research on the group’s performance in treating patients with sarcoma and other advanced cancers.