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5. Intervention Development
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Intervention Development
This learning activity discusses the typical pathway of development of a new medical
intervention. We will base our discussion on the typical development of new drugs.
We will discuss the five stages in the development pathway and where the clinical trials
fit into the picture.
Medical interventions come in different forms and from a wide variety of sources.
Sometimes it could be a new class or category of drugs, or a new way of using existing
drug treatments, or they maybe behavioural such as new approaches to increasing
peoples’ physical activity levels. Medical research can pick interventions up at different
stages of their development. Interventions may develop from clinical observations or
from basic or lab science that is then tested in clinical settings.
In this section we will discuss the drug development pathway because it has driven the
research structures and processes that we follow today.
Development Pathway
The drug development process typically takes ten to twenty years. It is timeconsuming, expensive and risky. Of the 5,000 to 10,000 potentially therapeutic
chemicals discovered in the lab, only one or two may end up being developed into a
new treatment, and only twenty percent of these may make a profit for the company
who develops it.
This diagram shows a typical pharmaceutical treatment development pathway and
where clinical trials usually fit into this pathway. Non-pharmaceutical interventions
follow similar pathways and although the stages may differ, their development can be
equally as expensive and time-consuming.
As you can see, the longest part of this process is the clinical development phase. This
is when the research known as clinical trials occurs. Click on the shapes to find out
more about each stage.
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Discovery (basic research)
Discovery phase is referring to the process of basic or lab research where
researchers try to understand the properties of different biological agents,
how they work and how they might be directed against different
diseases. Most commonly, researchers are following a particular
molecular pathway in cell development, maintenance or death, and trying
to understand how this works, or why it goes wrong and how specific
treatments might interrupt the pathway or the mechanism that is out of
control. This stage of research will usually involve invitro or test tube
research where biological agents are mixed with different cancer cell
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lines to see whether they affect cell development. If the cells stop
growing or die, it is a signal that the treatment is doing something and
therefore is worth investigating further. The headlines of new cures for
cancer are often based on results from this stage.
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Pre-Clinical (animal testing)
In the pre-clinical phase treatments that have shown some activity in the
discovery phase are tested further, both invitro and invivo; that is in
living organisms. It is usual to test treatments on animals. In most cases
this will include mice, sometimes rats, rabbits and dogs. Rats are more
commonly used when investigating behavioural effects of treatments.
The aims of research at this stage are to understand better how the
intervention works, what maybe its side effects and whether these side
effects are desirable or undesirable. This is termed non clinical safety.
Researchers can only move onto clinical investigations after satisfactory
information has been gathered on the quality of the non clinical safety of
treatments.
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Clinical Development (trials)
Clinical development is the stage of research in which interventions are
tested in people in clinical trials. Research in this phase investigates the
safety and efficacy, or effectiveness, of these interventions. There are
three phases of trials in the drug development process; phase one, phase
two and phase three. Briefly, phase one trials aim to work out the safe
dose range of a treatment, that is how much drug can be taken before it
makes people sick with side effects. Phase two trials aim to see whether
treatments work against the target disease and whether further testing is
warranted. Phase three trials compare new treatments with the best
currently available treatment, also to standard care or standard treatment,
to work out if new treatment works better or has less side effects. For a
more detailed discussion of the different phases of clinical trials, please
refer to the Learning Activity titled “Why Clinical Trials”.
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Phase 1 Trials
Phase one trials aim to work out the safe dose range of a
treatment, that is how much drug can be taken before it makes
people sick with side effects.
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Phase 2 Trials
Phase two trials aim to see whether treatments work against the
target disease and whether further testing is warranted.
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Phase 3 Trials
Phase three trials compare new treatments with the best currently
available treatment, also to standard care or standard treatment, to
work out if new treatment works better or has less side effects.
For a more detailed discussion of the different phases of clinical
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trials, please refer to the Learning Activity titled “Why Clinical
Trials”.
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Registration Review and Marketing Approval
Registration review and marketing approval is the stage where results
generated in the pre-clinical and clinical development phases are
submitted to regulatory bodies, such as the Therapeutic Goods Authority,
or TGA. They are evaluated to determine whether or not a particular
drug should be registered and available for doctors to prescribe as part of
clinical practise. In Australia, this is not the same as when a treatment
becomes Government funded through the Pharmaceutical Benefit
Scheme.
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Post Marketing
Once a treatment is commercially available, there maybe other studies
done. Pharmaceutical companies might use these as opportunities to
have people use their drug. However, often public good clinical trials
are considered to be post-marketing studies. Their aim is to understand
how best to use the approved drug in the most cost-effective way for the
patients and for the broader community. Examples of this might include
trial of the duration of Herceptin as treatment for early breast cancer, or
whether a laparoscopic colectomy is an acceptable treatment for people
with bowel cancer.
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