I've been following the Science Based Medicine blog for a while now (even though I'm not a doctor) and one of the things I realized is that medical research is a whole lot more complicated than, say, chemistry. In the sort of trials I might do, if you put the same ingredients in a jar, you'll get the same results every time. In medical trials, this isn't the case, because human bodies are a whole lot more complicated than even a jar full of a hundred different chemicals. I sort of already knew this, but some of the articles on SBM have really made this clear to me.
Another thing I realized is that there is a lot of vocabulary around these trials which I only partially understood. So, here is my attempt at explaining this stuff more completely to myself. And, as it says in my sidebar, "I thought I'd share."
(If a medical doctor happens to read this and notices that I have something wrong, I would be thrilled to get a correction. I'm not a doctor and I'm writing this for other not-doctors; while I'm ok with simplification I don't want to be wrong.)
The first one I'm going to cover is clinical trials.
Last year, and a few years prior to that, email forwards (and facebook, and other venues) quickly spread messages about this new drug called "DCA" that cured cancer but the eeeevul pharmaceutical companies were suppressing it because it couldn't be patented, the news organizations were ignoring it, and other conspiracy theories. (Yes, this is relevant.)
DCA (dichloroacetate) is being studied for its effects on cancer, it is non-patentable with the associated difficulty in getting a pharmaceutical company to pay for its development—and contrary to the claims, it has been in the news. In 2007, because tests with cancerous cells in petrie dishes were promising; and in 2010, for promising results on a few patients with a specific type of brain cancer.
Once the lab has shown promise, a drug has to go through clinical trials before it can be used as a treatment on patients; that it wasn't available to cancer patients immediately after the university's press release doesn't mean the pharmaceutical industry is suppressing it. I'm sure they'd be happy to make it once it's approved; there's good money in out-of-patent generics if you didn't pay for the research. Aspirin/ASA anyone?
Clinical trials have many stages. Once the lab has shown an effect, in this case shrinking samples of tumour tissue, it has to go on to humans. The DCA news articles from 2007 were talking about lab results only.
First, however, it has to be shown safe. Stage 1 Clinical Trials do this, by taking healthy people and putting doses of the drug into them until they start showing side effects: this establishes the common side effects and tells the researchers what the maximum dose should be. In the case of DCA, it has been used to treat other things in humans, so the side effects and toxicity levels were fairly well known already.
Only then can Stage 2 Clinical Trials begin, where the researchers take sick people and try to figure out how well the new drug works, sometimes compared to a placebo (non-medicinal treatment that is known to have no effect). The news articles from 2010 sound like the results of a stage 2 trial: 5 people with brain tumours treated with DCA.
After that, the drug still can't go on the market: Stage 3 Clinical Trials still have to be done. This is where lots of people are treated through multiple hospitals and universities, with the drug compared against existing treatments or placebo. These studies take a long time and a lot of money, and they continue to watch for side effects (started in stage 1) and refine and answer definitively how well it works (started in stage 2). At a guess and based on the timing and content of the previous DCA press releases, they're either fundraising for their stage 3 trials or doing further stage 2 trials as I write this. They might have started their stage 3 trials already, however, I don't know.
Only after a drug has passed the stage 3 trials may it be sold as a treatment. And even then, there's Stage 4: while in use as a treatment, what other drugs does it not mix well with? Does it have any special dangers to specific groups of people? (children, pregnant women, people with other conditions as well as the one this drug treats)
The second thing is the placebo. I mentioned it above in the stage 2 and 3 trials, because it's remarkably important to determining what medicine works.
People, being much more complicated than my jars of chemicals, also have a nifty thing called an immune system, which makes them get better from a lot of diseases all on their own, and a brain, which is easily fooled. For a given disease, if you give the patient a sugar pill and tell them it's medicine, a certain percentage will get better. Sometimes they are actually better, and sometimes they just think they're feeling better even if tests show no change in their condition.
So if you give a medicine to a group of people as you would in a clinical trial, and 10% of them get better, was it actually the medicine? If, instead, you have two groups of people, and in the group with the medicine 10% got better and in the group with the placebo 10% got better, then the medicine works no better than placebo and it isn't worth pursuing because it doesn't do anything.
This is still very simplified; for example a medicine might reduce the severity of symptoms, or reduce the duration of the disease, for something like a cold where most everybody who catches it survives and gets better with or without treatment. Or in the case of cancer, the tumour might stop growing, or shrink, instead of going away entirely—not a cure, but helpful.
I think I'll stop here for today. I have a long list of terms and this post is already pretty long.