Video: Immunotherapies + Other Treatments | Ask a Prostate Expert, Mark Scholz, MD

Ask a Prostate Expert | Transcription

Alex: So, can you combine immunotherapies with other medications in order to have a greater effect for the prostate cancer? 

Dr. Scholz: Treatment combinations in treating all illnesses have oftentimes been the pathway to real success. In the treatment of AIDS, when they developed the first antibiotics, they could get some benefit, but it wasn't until they gave two or three antibiotics in combination that they really were able to control AIDS. So, the same thing happened with chemotherapy for breast cancer. They found one agent and later they added a second or a third, and it's a logical progression because these different medicines attack the cancer from different angles—independent mechanisms of action—and so the cancer may be able to fight off one type, but if it's being attacked form two or three directions, it will succumb to the additional intense treatment. With immune therapy, we've been talking recently about Provenge and how it works by sensitizing the person's immune system to the presence of the cancer so that the immune system can then start to attack the cancer. And we also mentioned that with Keytruda that there's just a global ramping up—turning up the intensity of the whole immune system. So those are two independent approaches and it's logical that in combination they may work better because they have different mechanisms of action. So, studies are ongoing to look at giving Keytruda with Provenge and to try and determine if there's a better response and longer survival. 

Another type of immune approach is simply to radiate a metastatic site. This is called the abscopal effect and when a tumor is destroyed, say in the bone or in a lymph node, those dead cells still retain their molecular character, but now the immune defenses that cancer has had have been destroyed by the radiation. So those molecular substances can be detected by our immune systems; the white cells come in and they pick up the debris and then they learn the chemical structure of the cancer, and then they can talk to the rest of the immune system and enhance the immune attack on other sites of cancer that may be located in other parts of the body. That abscopal effect has been shown to reduce PSA and cause regression of tumors in other parts of the body when people get a single site radiated. We're talking about site in a different location that responds in someone who never had radiation in that different site—only to a single site, say, in the leg and a second site in the rib area can also shrink. It's not a uniform response, but it's a non-toxic intervention and so studies are being done to look and see if giving Provenge with spot radiation or Keytruda or all three can give a better anti-cancer effect than any one of them by themselves.