Clinical Trial Design: Part 2

Page 2, almost done. Promise.

Types of Variables

Good experiments have independent and dependent variables. The independent variable is the treatment. The dependent variable is the result or what they are measuring.

Again, the idea is to keep as much as possible the same between our two or more groups. The groups are generally treatment(s) and control. Control groups get the sham ‘treatment’. The only things that ideally should be different among the groups are the independent variables, treatments.

In reading a study you can tell what your chances are of getting a treatment by checking how many different treatments they are looking at. For example, if there are three, different quantities of stem cells they are inserting and only one control group, you have a 75% chance of getting a treatment.

The Statistics

After the experiment is done, the researchers do statistical magic and find out if there was a real effect of the treatment. They want to see if what happened could have happened by chance. If there is little chance that it did happen by chance, they are that much closer to finding an effective treatment. At least in the studies I am interested in, people in the control group are offered the effective treatments when the experiments are done. They are not out of luck.

Remember, the medical research we may volunteer for has been done many times on laboratory animals. Unless you are very brave and sign up for a phase 1 clinical trial, other people have had the procedure before you. Real research is published in reputable journals. Ask where their initial findings were published. If you don’t get a decent answer, be very cautious. If you do get a journal reference and cannot interpret it, send it along. I don’t guarantee we will get it right, but we will give it the old, college try.

Size of the study

Also, in research there is such a thing as a cohort. A cohort is a group of subjects going through the same treatment pretty much at the same time. Phase 1 cohorts are small, maybe 7 or 8 people, but phase 2 cohorts may be a couple of dozen people. There are more people in the higher phases. If you are told you are the only one or one of just a few, be suspicious.

Those are some of the things that legitimate research have as well as a couple of extra tips on making sure you are looking at a legitimate study. The information is pretty dry but having access to it is better than falling for a bogus offer and being rendered blind. That is, after all, what we are all trying to avoid!

Just remember, caveat emptor. Check things out very well first. Continue reading “Clinical Trial Design: Part 2”

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Clinical Trial Design: Part 1

The Hypothesis

All good experiments start with a hypothesis. A hypothesis is an educated guess about what should happen under a certain set of conditions. For example, “stem cells can grow in the eye and replace worn out RPEs”.

The way I was taught, this statement is then ‘turned around’ to be the negative. “Stem cells cannot grow and replace worn out RPEs”. This ‘turned around’ statement is called the null hypothesis. This is what will or will not be disproven with our experiment. The idea is to see if we can generate a result that will be significantly different from the starting point. The null hypothesis predicts no change. We want to see if we can affect a change that is big enough to matter. Good so far?

The Plan

After deciding what we want to figure out, we need a plan. Our plan is our experimental design. We want to design our experiment so we are reasonably sure there are no stray influences that may have caused the results.

 

The groups

If we are comparing treatments or treatment versus no treatment, we need to make sure our groups are as similar as possible. If we want to see if our new exercise program is better than another training program we really would (ethically) not want 20 year olds in one group and 80 year olds in another.

This is part of the reason good experiments on clinicaltrials.gov list exclusions which means reasons why a person couldn’t be in the trial. They are looking for similar subjects. Another reason for exclusions may be related to the treatments they are using and people’s sensitivities to them. You don’t want a subject who has an allergic reaction to your treatment!

The Sample

Once we have our sample (all possible examples or cases of something is called the population), we should be reasonably sure we have controlled for most of the important variables. Variables are factors that can affect the outcome of our study. However, there are other variables we have to control for in our experimental design.

The Treatments

One of these is the Hawthorne Effect. Anyone who has ever taken intro to psych or industrial/organizational should remember the Hawthorne Effect. In a plant they were trying to increase productivity. The problem became, no matter what they did, production improved! These people could have been working in the dark with the heat turned up to 90F but they were going great guns.

The researchers discovered just the fact that they were noticing the workers and trying to do something for them was enough to increase productivity. It did not matter that working conditions worsened. The workers felt noticed. They wanted to please the researchers.

Placebo effect happens when subjects believe the ‘treatment’ is effective even though it is not. They may show improvement as a result of their belief.

You will see attempted control for the Hawthorne and Placebo Effects in studies that list themselves as ‘double blind’ or ‘double mask’. They will perform fake (sham) procedures on people in the control so they feel noticed and loved, too.

Double blind? The double is because doctors and nurses treat people getting the actual treatment differently. They may not realize it but they may be more encouraging to those actually getting the treatment than they are towards the people who are the controls. When a study is double blind neither the patients nor the people caring for them actually know.

That is my 500+ words for this one. One or two more pages and I should be done. Hang in there!


For more information, click here for Designing Experiments Using the Scientific Method from dummies.com.

Continue reading “Clinical Trial Design: Part 1”

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News: August 23-24, 2016

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News: July 20-21, 2016

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Super Lab Rat

So now I am reasonably sure I have a shot at becoming a test subject. Never really believed one of my greatest ambitions in life was going to be to become a lab rat. However, I can assure you I had ambitions to be the best damn lab rat Wills Eye has ever seen. My visual gains will be extraordinary! I will become spokes-rat for the program and travel around the area doing the ‘rubber chicken’ circuit. I will be brilliant. (Did I happen to mention I have no problems generally with my self-esteem? Perhaps…can you spell megalomania?) I even designed my t-shirt. It includes a drawing of a cute little mascot that will, of course, represent the hospital for decades to come.

I will be the best damn lab rat Wills eye has ever seen! I’ll become spokes-rat for the program and travel around the area doing the ‘rubber chicken’ circuit.

I did continue my research. I wanted to know what exactly I was getting into. I’m not one for invasive procedures or even for a lot of ‘doctoring.’ However, assuring vision for myself in the future tended to trump all other considerations.

Although Regillo tended to gloss over some of the more gory and unpleasant details, I wanted to know. My source was the 2015 Lancet article on the Phase 1 experiment.

Let me go off on a tangent here for a moment. Until I got into this, I had no clue what happens in clinical trials. Short tutorial if I may: clinical trials are made up of four phases. The first phase is a safety and tolerability phase. Essentially, the researchers are looking to make sure that nothing serious goes wrong. They want to make sure that no one has an allergic reaction or grows stray body parts where they should not be growing.

In Phase 1 they want to make sure no one has an allergic reaction or grows stray body arts where they should not be growing.

After Phase 1, the efficacy experiment starts. They want to see how their treatment actually works. Does it do what they claim it will do ? They also start messing around with different independent variables to see what works best. In the study I am trying to get into, for example, they are comparing different immunosuppressant drugs to see which one works best. In other Phase 2 experiments they compare slightly different operation procedures or any more of the dozen of different treatment variables. All Phase 1 studies use only a very small number of people, Phase 2 studies use many more.

In Phase 2 they want to see how their treatment actually works.

As I understand it, Phase 3 studies are essentially larger variations on Phase 2 studies. Techniques and procedures are refined and the subject pool is made up of hundreds or even thousands of people.

In Phase 3 they perfect the techniques and procedures on more people.

Phase 4 is sort of like an off-Broadway show or traveling company. Instead of just being administered by people at the experimental sites, the procedures are now made available to other professionals to try. Reports are made back to the original team. By this time, the subjects can number in the thousands. Once a procedure gets through Phase 4, it is ready for prime time. If good enough, it can become standard procedure around the globe.

In Phase 4 they make their procedures available to other professionals to try at other locations.

Continue reading “Super Lab Rat”

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