The emerging science of immunotherapy is helping in the fight against cancer. Science writer for the blog Biotech Strategy, Pieter Droppert, and medical oncologist and immunotherapy scientist Dr. Daniel Chen discuss this new field. Read on for a excerpt or click above to listen to the whole interview. Want to learn more? Watch an animated video from Dr. Chen.
On why immunotherapy is so important:
Droppert: “It touches the lives of so many people. It’s a fascinating topic especially in light of the scientific developments that are taking place. What’s really exciting me is the ability to harness the body’s immune system in the fight against cancer and that’s what we know as cancer immunotherapy, immuno-oncology. It’s the hottest area in drug development and where the most progress is being made."
On what doctors are most excited about:
Droppert: “One of the really promising areas is called checkpoint inhibition. So if you imagine that the T cells, which are the foot soldiers that kill cancer cells, they are sometimes what’s called inhabited fare, actions that are stunted by the cancer cells. What is taking place is that you now have new drugs in development that can release the break on T cells so they can fight the cancer. What is really exciting is that we are seeing progress being made in what’s called PD1 and PDL1 inhibition. If you imagine two coaches in a train whistling together, that’s what happens between PDL1 on a cancer cell and PD1 on a T-cell. It basically stops the T cell from being as effective as it would do. If you target the receptor PD1 or you target PDL1, you put a block on either end of that. Then you can stop the two from coupling. What that means is especially you can make the T cells more effective in their fighting against cancer. And that’s one of the exciting areas taking place. There are several drugs in development. Several drugs have received breakthrough therapy designation from the FDA and it’s providing some stunning results."
On how immunotherapy works:
Chen: “Our immune system, we are born with it, it protects us from viruses, bacteria, and as it turns out, our immune system can also help fight things like cancer. The reason for that is that cancer, much like a virus, can look different than normal cells in your body. When your immune system can detect that, they can then specifically seek out those cancer cells and kill them. What cancer immunotherapy does is it allows your immune system to do a better job fighting against cancer, because cancer has its own ways of shutting down the immune system. With these new therapies, what we’re seeing is you can take away the things that cancer does to fight off the immune system. And in some cases, the immune system then really becomes very active and can go out and kill those cancer cells. One of the things that makes us excited is that when that happens, patients, who otherwise may have terminal cancer, not only do their cancers start to shrink, they can go away for a long time. In the best cases, we hope that the cancer never comes back."
On the immune system as a security checkpoint:
Chen: "One of the ways we’ve looked at it is that your immune system is a lot like the security checkpoint at the airport. And at that security checkpoint, it’s scanning your body looking at normal cells and looking for the presence of abnormal cells. Cancer falls into that abnormal cell type that your security checkpoint is looking for and that’s what your immune system is doing. So when it sees it, it can pull that cancer cell out, or pull that virus-infected cell, and get rid of it. Cancer has a way of essentially donning a disguise. It has a way to hide from that security checkpoint. Molecules like PDL1 seem to do this. One of the ways we’ve gone about trying to cheat patients now is to recognize that cancer cells may have this disguise and essentially take away this disguise. When you do that, you can see just some very dramatic responses where it’s just that “Aha” moment when the immune system suddenly sees that there was a disguised cancer cell sitting in front of it. When that disguise disappears, it will go and get that cancer cell and kill it."