MadSci Network: Medicine

Re: Why does it take so long to approve a drug for use...

Date: Fri Feb 11 15:40:30 2000
Posted By: Josh Rodefer, Fellow & Lecturer, Harvard Medical School
Area of science: Medicine
ID: 949297209.Me

Hi Chuck,

Good question.  Yes, it does usually take a long time for a drug to be 
approved in the USA.  I will try to walk you through the process that a 
drug goes through before it can be marketed.

First, you need to realize that the discovery of new drugs often occurs in 
one of three ways:
a. the rediscovery of old folk remedies
b. the accidental observation of a new drug effect (could be from an old or 
new drug)
c. the synthesis of a compound (again, could be an old drug or a new one).

A new drug is one that: has never been synthesized before; or one that is 
made up of a new recipe of older ingredients; or even a new use for an old 
drug.  In each case, the drug has to go through the Food and Drug 
Administration (FDA) guidelines so that it can be taken to market and sold 
to people like you and me.

Here is a rough outline of the stages of testing and marketing:

1. Start with a belief or hypothesis that a particular drug or compound has 
some clinical therapeutic value

2. Pre-clinical (animal) studies to determine safety, toxicity and whether 
it does what you think it should.
This takes anywhere from 1-3 years.  Often the animal work is conducted 
first in mice, then in rats, then in monkeys (or some other large mammal or 
primate).  Another key piece of information that is sought out at this 
stage is whether the drug has any abuse liability.  Usually this type of 
question is answered by seeing if primates will self-administer the 
proposed drug (primates self-administer most of the same drugs that humans 
abuse - like cocaine and heroin - so it is a good bet that if a monkey will 
press a lever to get a drug injection, then a human might become addicted 
to that drug).  If this stage is successful then the drug developer applies 
for designation of an Investigational New Drug (IND).  This application 
needs to be approved before the drug can go into clinical (human) trials.

3. Experimental studies with healthy volunteers - this is called Phase I.  
Up to 50 "normal, healthy" volunteers are studied (usually these are also 
young, white men, although there has been an effort of late to also include 
more persons of color and women (who are not pregnant and not trying to get 
pregnant)). The purpose of this stage is to determine whether the drug is 
safe for humans and whether it has any unpleasant side effects.

4. Phase II Clinical trials come next.  These are controlled studies in 
patients with a "target" disease, usually the disease that the drug is 
being developed to treat.  In this stage, 50-200 people are studied to see 
if the drug works against the disease they way everyone thought it should. 
 If successful, then the drug proceeds onward to:

5. Phase III Clinical trials.  These are the large open clinical trials 
across the country.  Often, more than 1000 people will participate in these 
studies.  The patients are monitored for drug effectiveness and drug side 
effects (adverse reactions). The data from this set of experiments is used 
to determine appropriate doses and what information needs to appear on the 
drug label.    The total time that a drug spends in Phases I, II, and III 
ranges from 2-10+ years.  If this stage is successful, then….

6. The drug developer files a new drug application with the FDA.  The FDA 
has 6 months to review the application and take action on it.  If the drug 
is approved, then the developer may market and sell the drug in the USA and 
export it for sale outside of the USA.  If there are any concerns about the 
drug, the FDA may require more testing or information before approval is 

7. If a drug has made it successfully through all of these stages, it is 
still monitored once physicians begin prescribing it to patients.  
Sometimes, new side effects are noticed at this stage and the dosage and 
labeling information must be changed.  

So, I hope you can see that marketing of a new drug is a very time 
consuming process that can take as short as 3 years or so….or last as long 
as 13 or so years !!!

One thing to keep in mind is that this long process has become 
controversial.  There are a number of diseases (most notably HIV/AIDS) that 
are very serious and debilitating.  Advocates for AIDS patients argue that 
the approval process needs to be quicker so that persons may actually 
benefit from the new drugs before they die.  Others also point out that by 
pushing drugs to market faster, we may overlook (or drug companies may not 
adequately report) all the side effects or toxicity issues - and as a 
result kill people who otherwise were only sick.

Here are some links that might interest you:

The New Drug Development Process:

FDA Drug Approvals List<

National Institute on Drug Abuse (NIDA)

The Issues Surrounding The Drug Approval Process With The Food And Drug 

Report: FBI investigating approval of diet drug Redux

Hope this helps answer what, on the surface is a simple question, but once 
you delve deeper you realize it is quite complicated.


Joshua Rodefer, Ph.D.
Harvard Medical School

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