Question: Hi, How would you know if you had found a medicine that you were going to test on someone who had pancreatic cancer, wouldn't just make it worse? thanks xx pandance10

Natasha Aley answered on 26 Jun 2020:

Hi Pandance,
Great question!
Drug testing is a very rigorous procedure and that’s why it can take in some cases more than 10 years before it reaches humans. This is all done so that as little problems can occur as possible.
First a drug is tested on just the cancer cells in a laboratory. If it kills those cells, it is then tested to see if it also kills healthy cells and if so, would this just cause side effects or if it could be lethal to a human. If the drug then passes these tests then it can be tested on cancerous mice to see what effect it has on their tumours.
Then, if it shows that the cancer slows down or dies with the drug and has limited side effects then it gets tested in other animals to see if it also works on them.
If by this point, if the drug is still showing signs that it kills or slows down cancer in animals then it goes into phase 1 clinical trials, where it is tested on consenting humans with cancer that have run out of any other options. Again, if it shows to be beneficial in those humans, then it can go forward to phase 2 (which involves slightly more people) and then phase 3 (which involves people from all around the world).
If, it passes phase 3 with some good effects on people with cancer and side effects that the patient can manage, then the results are sent to drug accreditation authorities to see if it can be accepted to use in anyone with that cancer.
As you can see there are many “if”s. Most drugs that work on just cancer cells don’t reach phase 3 human trials because of many reasons such as harsh side effects or it just doesn’t slow down or kill the cancer when put into humans.
I hope that all makes sense.
Tasha