24 November 2009 59 views No Comment protect ur eyes
Interleukin-2 is the only drug approved in the US for the treatment of metastatic RCC . It is also approved in many other countries. But IL-2 isn’t just a drug. IL-2 is a natural part of your immune system, a messenger protein called a cytokine which activates parts of your immune system. IL-2 does not kill tumor cells directly like classical chemotherapy. Instead, IL-2 activates and stimulates the growth of immune cells, most importantly T-Cells, but also Natural Killer Cells (NK Cells), both of which are capable of destroying cancer cells directly.
There are several types of T-Cells but, without going into detail, certain T-Cells are capable of killing tumor cells if they recognize a specific antigen on the surface of the tumor cell. Antigens are normally proteins. Each T-Cell is specific for only one antigen but you have many different T-Cells. NK Cells have the ability to kill tumor cells without needing to recognize a specific antigen (I’m not sure how!). While this sounds good, NK cells are weaker cancer killers than T-Cells. The so called LAK cells which were used in some of the early immunotherapy experiments are actually NK cells.
Back in 1989 my goal was a cure or at least a long remission and it is probably your goal now. In my view, the proven chance of getting such a result is the reason to try IL-2. At this time the only other therapy I know of that has this kind of long term result is surgery in some cases. I explore the documentation for and odds of getting that kind of result from IL-2 in detail in my pages on specific IL-2 therapies.
Although the therapy rarely causes serious permanent damage, it’s more or less miserable while you’re getting it, and often more rather than less. Most importantly, only a small minority of patients get the kind of long term relief that is the reason to try it. In the end whether it’s worth it to endure the side-effects of IL-2 for a small (but the best known unless surgery is also an option) chance at a great result is strictly a personal decision. In my case, I was 33 years old and quality of life wasn’t an issue since the disease had already taken that from me. I had nothing to lose. You might feel differently.
IL-2 eligibility always a matter of clinical judgment – it’s not like eligibility for a clinical trial which is mainly determined by rigidly specified criteria and it’s not a legal thing either. Requirements to take IL-2 vary somewhat according to which IL-2 therapy it is and I do discuss additional requirements for specific IL-2 therapies in articles on each therapy, particularly high dose IL-2, which is more rigorous than other IL-2 therapies.
There is a bewildering variety of different IL-2 regimens. Many different dose levels, methods of administration, and as well as schedules and combinations with other drugs have been tried and more than a few are in current use. While I don’t cover them all in CancerGuide, I do cover the most commonly used and of course anything I find that looks especially promising.
It’s very helpful to understand IL-2 dosing when comparing the details of different IL-2 protocols. You may not be interested in these minutiae now, but as you get further into the details you may want to come back and give this section a closer look.
It will be helpful to read my general article on Understanding Cancer Drug Dosing first.
Because IL-2 is a protein it can’t be given by mouth because you’d simply digest it, so it’s normally given by injection (it has also been given by inhalation on an experimental basis). Outpatient IL-2 is given by injection under the skin (subcutaneous), much like the way diabetics inject insulin. Most patients learn to self inject. Inpatient IL-2 is normally given by injection into the vein (Intravenous Infusion). IV dosing can either be a continuous infusion (CIV) or more usually, a dose is given over a short period every few hours. This is called bolus dosing. The Classic High Dose IL-2 Protocol uses bolus dosing.
This isn’t essential reading but it is pretty interesting!
Proteins like IL-2 are huge molecules made of dozens of amino acids linked together. A single amino acid is a relatively small molecule. A protein is very unlike typical small molecule drugs like aspirin, most chemotherapy drugs, and in fact most drugs you’ve ever heard of. Small molecules can be synthesized in a chemical plant but it isn’t practical to make proteins by ordinary chemical synthesis.
But every cell of every living thing knows how to make proteins which, among other things, catalyze most of the chemical reactions necessary for life. The instructions for making a particular protein are encoded in the gene for that protein. To make IL-2, scientists transferred the gene for human IL-2 into bacteria (nice trick!). The bacteria then make the IL-2 protein in large quantities, which can then be purified as a drug (another nice trick!)
Excerpt from Steve Dunn ’s Cancer Guide