Wednesday, September 23, 2009

Clinical Trials

I attended an information session last night about new and emerging trends in MS research. Wow. Lots of information and I took two pages of notes. I'll get to the medications being developed in the next couple of days, but I felt a review of the process of drug development is warranted. It's a good reminder of why it takes so long to get drugs into people.

From the time a compound is discovered it takes 10-12 years for that drug to get on the market. After a compound is deemed to be of interest, it is tested on animals. Then it enters the Phase 1 trial. The first stage is to test the drug on 20-80 healthy subjects to determine if it is safe. Once it has been determined that it is safe and the side effects are manageable, then it goes to a Phase 2 trial where it is tested on 100-300 "sick" subjects, those who are affected by the disease the drug is supposed to treat. These studies are often two years duration. It is at this stage where, if a drug fails to work, the trial will be halted. If the drug shows some benefit, then it proceeds to the Phase 3 stage.

The Phase 3 stage involves 500-1000 subjects and it is at this stage that there are randomized multi-centre trials. Again, this stage may take a couple of years, as not all subjects are enrolled at the same time (not all subjects are diagnosed with a specific disease at the same time). In my case, I was enrolled in the CHAMPS Avonex study one year after the enrollment began. The CHAMPS study was supposed to be 3 years duration but was halted after two because of outstanding positive results; subjects were automatically given the drug at that point as it would have been unethical to continue giving some patients the placebo.

During the Phase 3 stage, drug makers will apply to the appropriate health authority (FDA, Health Canada) for approval to market the drug. Data analysis continues through all stages of course and at this point the drug enters Phase 4, post market surveillance or observational study. It involves safety surveillance and ongoing support of the drug. It is at this point that long term adverse effects may be detected or drug interactions reported.

According to Wikipedia, about 1000 drugs are developed before one makes it to the clinical trial stage. And finding people to take part in the trials is equally as daunting. Strict criteria must be met for most trials. Again, in the CHAMPS study I took part in, it was required that subjects have had only one symptomatic demyelinating event and an MRI that showed at least 3 lesions.

So there's your lesson on clinical trials. Next post I'll get into what is actually being developed these days.



Have Myelin? said...

Look forward to reading about the next developments!

Lisa Jo Rudy said...

This clinical trial may be of interest to your readers:
This is great news from sanofi-aventis about their investigational oral medicine for MS, teriflunomide. There is currently a worldwide clinical research study that is evaluating teriflunomide for relapsing forms of MS. Click here for more information:


Shauna said...

Have Myelin: read on!

Thanks for the link. This one looks good, but even better in combination with one of the interferons!