A look at IL-15 and IL-2
April 25th, 2012 by Chris Battle, survivor
Crossposted from the Kidney Cancer Chronicles.
Building 10 is the heart of the National Institutes of Health – the Old Main of this little research university where the clinical trials are performed. It’s a nicely designed building with a lot of light and plenty of sitting areas near windows if you are able to venture out of your room. From the seventh floor you can look across Wisconsin Avenue and see the tower of the Bethesda Naval Hospital looming over the city.
The building is apparently so vast, it circumvents the globe — as evidenced by my room which is in 3 SEN — which stands for South, East, North. That’s right, we’re so far South, we’re North. I think the toilets flush backwards and it might be winter here. Either that, or it’s just part of the clinical trial mentality — a way to frustrate lab mice as they wander the maze. This could explain whey I get an electric shock every time I make a wrong turn.
Actually, the only shock I’ve received so far, if you can call it that, was Monday night when I tried to put a movie into the computer/DVD system and was denied access. The nurse had to reboot the system, she informed me, because the previous patient was doing “inappropriate things” with it and they had to cut him off.
“What, was the guy watching porn?” I asked.
“Really, you have porn here?” My interest was peaked.
“He brought his own,” she said.
Evidently he didn’t even try to hide it. Nurses, doctors, whomever would walk into the room to the sounds of 70s porno soundtracks and lord knows what else. Nor would he turn it off when they came in. I can only imagine the conversations that occurred. Sir, I’m going to need that wrist for a minute to take your blood pressure. One of the nurses told me that he’d ask for a blanket and she’d hand it to him at arm’s length and then make good use of the liquid sanitary soap on the wall near the door. On three different occasions this occurred, and finally they just had to shut down access to the computer. That or install mirrors wall-to-wall in the ward.
Other than their newfound fears of sexual deviants (they were clearly wary of me when I first arrived), the oncology nurses here are excellent – skilled, compassionate and good-humored. I see more of the trial oncologist, Dr. Kevin Conlon, than I have been able to see previous physicians during treatments. He’s happy to sit down and talk about his research, and as a living part of that research I’m interested in what he has to say.
Here’s an simplistic overview of the research surrounding IL-15:
IL-15 is a cousin of IL-2, but it is believed to be more targeted than the latter. Both drugs are immunotherapeutic, attempting to kickstart the body’s natural immune system into fighting the cancer naturally. Each tries to increase and activate lymphocyites which house Natural Kill Cells. I’m not making this up; Natural Killer Cellsis actually what they are called. And although they sound like murderous psychotics, and to some degree they are, they are on our side. Like the body’s own mob hit men. They recognize the alien and threatening viruses and attack them with a chemical called Perforin. This chemical “perforates” the threatening cells, causing the cellular matter to leak out, thereby killing it. It’s cellular gangland warfare and, gutshot by our assassins, the viral cells bleed out on the street.
The promise of IL-15 is that it targets the lymphocytes with the Natural Killer Cells better than IL-2. IL-2 is a blunter instrument, attacking a more diverse range of cells and causing more damage to the body. Which is why the side effects of IL-2 are so much more severe. The researchers know that the IL-15 works with better precision than IL-2 with regard to attacking viral cells, but they don’t really know how well it will work on cancerous cells. Cancer cells are mutations of normal cells. They aren’t foreign in the way viral cells are, which is why cancer is so hard to combat. The body’s immune system doesn’t really recognize cancer cells as being abnormal and therefore doesn’t attack. So the purpose of the research is to see if IL-15, by focusing more narrowly on activating Natural Killer Cells, will be more effective at prompting the immune system to recognize and attack the cancer.
Which is why I am here. (Well, technically I am here to see what level of toxicity human beings can withstand from the drug. That is the purpose of any Phase I trial: Does this hurt? Does this hurt? How about this?) All day long yesterday nurses withdrew copious amounts of blood – at least twenty vials. I’m so wired up with cables running through my veins I look like a cyborg. I’ve got an IV in one arm and in the other a PICC line with multiple lumens. (A PICC line is a peripherally inserted central catheter with thicker, heavier tubing than an IV and that is inserted in the arm and coiled through the vein around the shoulder and collarbone and dropped down, more or less, into the heart for better intravenous distribution. You can find a more detailed description of a PICC line and how it works here.)
The result, so far, is a drop in my Lymphocyte count. Which is good news. It means the lymphocytes have woken up and are groggily scrambling about the body looking for something to do. Like a bunch of hung-over frat boys waking up and scrambling to find classes. Dr. Conlon said he expects to see further drops and then eventual increases in the lymphocytes.
This means that the drug is having an effect. The lymphocytes, and the Natural Killer Cells, are gearing up for war. The question is whether they can recognize the enemy.