Immunotherapy questions
OMRF’s Stephen Prescott helps provide understanding on new cancer therapies.
Afriend has undergone a variety of treatments for his cancer, but the disease has continued to progress. Now, his doctors are recommending something called immune therapy. What is this treatment and how does it work?
Dr. Prescott Prescribes
Immunotherapy is a new type of cancer drug that harnesses the body’s own immune system to kill malignant cells. The Food and Drug Administration has approved four of these drugs, called checkpoint inhibitors, to fight various forms of cancer.
You may have heard of some these drugs, which are frequently advertised on television. The bestknown ones are Opdivo and Keytruda, which have been approved for use in treating several cancers.
The idea behind immunotherapy is to deactivate a molecular shield used by certain cancers to hide from the body’s disease-fighting white blood cells. Checkpoint inhibitors pierce the shield, enabling the immune system to target and destroy tumor cells.
The drugs seem to work best against cancers that carry large numbers of genetic mutations — changes in the tumors’ DNA sequences. Lung cancer and melanoma are both characterized by many genetic mutations, and checkpoint inhibitors have made inroads in treating them.
For example, in patients with advanced stages of the most common type of lung cancer, those who received chemotherapy alone had a 12-month survival rate of just under 50 percent. But when immunotherapy was combined with chemotherapy, that number climbed to nearly 70 percent.
As you can see, this is not a silver bullet. But when you’re talking about deadly cancers, extending life by even a matter of months can be a big win.
Still, these are powerful drugs, and they often are accompanied by side effects. Most commonly, this means fatigue, cough, nausea, appetite loss, itching and skin rash. They also can cause the immune system to launch unwanted attacks against the body, resulting in serious damage to the kidneys and other organs.
Checkpoint inhibitors also come at a cost of more than $100,000 a year. But with treatment options so limited for many cancers, neither this price tag nor potential side effects seem to be dampening the enthusiasm for these new weapons in the fight against a deadly foe. As a result, they’re now being studied as potential therapies against a host of other cancers.
Unfortunately, cancers that carry few mutations — prostate, breast and ovarian cancers typically fit this mold — rarely respond to checkpoint inhibitors. Nevertheless, there have been exceptions. The drugs have shown positive results in treating a handful cancers that carry few mutations, such as mesothelioma, an unusual form of skin cancer called Merkel cell carcinoma and certain forms of kidney cancer.
While it doesn’t work for all cancers or all patients, immunotherapy represents a big step forward in cancer treatment. I hope it proves effective for your friend.
Prescott, a physician and medical researcher, is president of the Oklahoma Medical Research Foundation. Cohen is a marathoner and OMRF’s senior vice president and general counsel.