The story of a medication before it gets to
the shelf of a chemist is a long one.
Less than 10% of drugs designed by pharmaceutical
companies
actually end up making it onto the market.
That’s because most don’t pass all the
hurdles on the way to being approved for sale.
Before a drug even comes near being tested
on humans, it’s tested on animals.
This first step helps scientists test the
effects of the drug on vital organs and how
toxic the drug is at different doses.
Once this hurdle has been cleared, the drug
must go through three phases of human trials
– known as clinical trials –
before it
is approved for sale.
Phase one is the first time the effects of
a new drug are studied in humans.
At this stage it’s all about safety.
A small sample of up to around 80 healthy
volunteers trial the drug to establish its
toxicity over a range of doses, based on the
results of the animal studies.
If the drug is found to be safe, it enters
the next phase of testing.
Phase two of the trial process focuses on
the benefits of the drug:
whether the drug treats the target condition, or minimises its effects.
Several hundred patients with the condition
are included in the trial sample, and if there
is evidence of a benefit to patients (with
an acceptable level of side effects),
the drug progresses to the third phase.
Phase three is the most important phase of
drug testing, and the last stage before drug
developers seek approval from regulatory agencies
– like the Therapeutic Goods Administration in Australia
or the Food and Drug Administration
in the US – before it goes to market.
Phase three is where researchers seek the
definitive answers on a drug’s efficacy
and safety.
The number of participants involved, and the
duration of the studies vary depending on
the product and target condition, but hundreds
or even thousands of participants are often
involved.
And the best way of proving a drug’s efficacy
against the current standard of care is through
a randomised controlled trial.
Randomised controlled trials generally divide
study participants randomly into two separate groups
- one group of participants receives
the new drug,
while the other is a “control” group –
they receive either no treatment
at all,
a placebo (which appears to be the treatment but has no active ingredient)
or the standard treatment available at the time of the trial.
The two groups are randomly allocated to make
sure that effects shown in a trial are the
result of the drug itself rather than factors
like age, lifestyle choices (like whether
the participants are smokers or live in a
specific environment) or gender.
And to make sure that the effects aren’t
boosted or hampered by the patient knowing
which treatment they’re getting, trials
are generally what’s called “blind”.
Where possible, the researchers and treating
doctors are also blinded, so no-one knows
what treatment a participant is receiving
until the results are in.
Once the drug clears phase three, it generally
gets approved for sale and hits the market.
But testing doesn’t stop there; that’s
when phase four kicks in.
It’s the final safety measure on a drug
and focuses on its long-term effects and potential
use for treatment in other conditions or new
populations, like children.
These studies generally involve a wide population
receiving the drug (sometimes thousands) and
are often a condition of the drug receiving
approval.
So when you take medication, you can be safe
in knowing that it’s gone through a process
of testing that can take up to a decade.
