Early efforts to treat cancer had assumed that cancer was cancer. But we now know that there are over two hundred different types of cancer. That means what works for one form of cancer may not work for others. But don’t let that fact discourage you. One of the most exciting features of immunotherapy is that, because it works in conjunction with the body’s natural immune system, it has the potential to treat many types of cancer, and hopefully, as new drugs are developed, maybe all cancers. Different cancers may have their specific immune weaknesses, and those are being rapidly sorted out with current immunotherapy research. Unfortunately, I often hear from patients who have been told by their doctor that immunotherapy does not work for their cancer type. I think if you look at the research, however, and the swift pace at which immunotherapy is gaining approval, you will agree that it is probably not true. I do admit that the current CTLA-4/PD-1/PD-L1 drugs may still be lacking. While it is true that some cancers are more immunogenic and respond better than others to immunotherapy, there is the potential for all cancers to respond to immunotherapy—particularly when used in combinations, directly injected into the tumor, or together with ablation procedures in a specific manner.
I have many patients with lung cancer, bladder cancer and kidney cancer who were told that immunotherapy drugs would not work for their cancer, but now these same drugs have been approved for those cancer types. Because it takes years of research before the FDA will approve a specific drug for a specific form of cancer, the FDA approval process is a slow one. While drugs cannot be prescribed in the U.S. without having been approved by the FDA, once approved for use for one condition, FDA approval is not necessary for a physician to prescribe that drug for a condition for which it has not been approved. This is known as off-label use and is quite common. That means that while Yervoy was first approved for the treatment of melanoma, physicians can still prescribe it to treat other cancers.
Reference: Jason R. Williams, 15 Oct 2019, The Immunotherapy Revolution: The Best New Hope For Saving Cancer Patients’ Lives, https://williamscancerinstitute.com/the-immunotherapy-revolution