As basic scientists in disease biology, we always
strive towards an invention or discovery that can make a positive change in
existing clinical scenario. We aim to make the life of at least one patient
better. From the molecules appearing before us as signals and bands in our
basic science experiments to a practical application in clinics is an immensely
long journey.
Drug trials are
long tedious and meticulous procedures that ensure efficacy and efficiency of
drug formulations before they reach market for public use. The odds of a
molecule to reach market as a consumable pharmaceutical preparation are
approximately calculated to be one in 5000. It takes an estimated average of
twelve years for a molecule to travel the long distance between laboratories to
market. Here’s a quick peek into the rigorous grilling a molecule undergoes
before it “graduates” to be a marketable medication of clinical acceptance.
Preclinical Evaluation: Once
a potential therapeutic molecule is identified by in vitro studies in laboratories,
it has to undergo preclinical testing in animals to prove its efficacy as well
as to document potential side effects. Such a molecule will be considered for
further development only if benefits outweigh risks.
Once the
preclinical studies are published in effect and not disproved by peers, the
patent holders or their collaborating parties can file an Investigation New Drug
Application (INDA) to Food and Drug Administration (FDA). Thirty days are given
for FDA to consider the implications of developing the molecule concerned to
consumable medication. If FDA does not disapprove or reject the application in
thirty days, the applicants can proceed with clinical trials of the drug formulation.
The application should specify exactly how the formulation will be prepared,
number and inclusion/exclusion criteria of study subjects, expected therapeutic
and adverse effects and details of the study design and execution.
Phase 0 Study: Before clinical
trials begin, a Phase 0 study is carried out to study the pharmacological
properties of drug formulation. 10-15 healthy volunteers are given
subtherapeutic doses of the formulation to titrate optimum dosage depending on
absorption, distribution, metabolism and clearance of the chemical in human
body.
Phase I Trials: Once the
IND is approved by FDA, applicant parties by themselves or in collaboration
with pharmaceutical industry and clinicians can start using the drug
formulation on less than eighty healthy volunteers to document in detail
potential adverse effects. This is called the Phase I trial, when drug dosage,
safe therapeutic window, effective route of administration etc are fine tuned.
Moreover, this period is also utilized to study the pharmacokinetics and
dynamics including distribution, storage, metabolism, clearance, duration of
effect, half life etc. The execution of study and analysis of results may take up
to twelve months usually.
Phase II Trials: Once
Phase I trials provide favorable results; the formulation can be used in
patients with disease for which the drug is intended. This study requires data
analytics from about one to three hundred patients. Lasting for about eighteen
to twenty four months, these studies look into the dosing of drug formulation
in detail. Precise values of minimum and maximum dosages are determined, thus
validating a strict therapeutic window of safety. The efficacy of the drug in
humans is studied for the first time at this point. An expert team of molecular
biologists, biochemists, biostatisticians, pharmacologists and clinicians are
directly involved at this stage of the trial. The study is carried out under
extremely controlled settings to contain unforeseen adverse effect.
Phase III Trials: Another
thirty six to forty eight months are spent to determine therapeutic benefits
and potential side effects of the formulation. A randomized controlled study
involving multiple hospitals, clinicians, Institutional Ethical Bodies and
medical lawyers is carried out to collect data from nearly 3000 patients as
test and control subjects to document effects of the drug. Efficiency of the
drug formulation to manage targeted pathology is studied at a community level
at this point. Equal or perhaps, more attention is given to find out any
potential side effects previously undocumented during Phase II trials. The
study results should be published in peer-reviewed journals with no conflict of
interests of involved parties as well as no dispute from experts in relevant
fields. These results also serve as a basis for FDA to analyze risk versus
benefits of the drug formulation.
Once Phase III
trials show promising results, the involved parties, usually drug manufacturing
pharmaceutical giants at this point, file a New Drug Application (NDA) to FDA
with data regarding the drug formulation available till date. A typical NDA may
easily go from 100,000 to 150,000 pages. Expert committee formed by FDA will
then analyze the application unbiased. An estimated time of thirty months is
needed for FDA to meticulously analyze all the aspects of the new drug
formulation as this goes into market for widespread use across multiple
communities once approved at this point.
Unlike clinical trials under controlled settings, the usage of a drug at
community level cannot be steered or supervised. Needless to say, extreme
caution is therefore taken before formally approving the drug to be produced in
large scale for clinical use.
Phase IV Trials; Even
after reaching market, a drug is not dispensed completely uncontrolled.
Post-marketing Surveillance, also called Phase IV trials are carried out
strictly for up to twenty four months and leniently during the entire lifetime
of the drug’s medical use to document therapeutic and adverse consequences of
the drug formulation at a community level. At this point, the drug is available
only as its original formulation, manufactured and marketed only by the party
holding patent and FDA approval. One can easily understand why non-generic
drugs are expensive as the patent holding drug manufacturer is trying to win
back all its expenses of research and development of the formulation as well as
the exuberant expenses of conducting multiple phases of drug trials. Drug
developers are given patent protection of an original formulation for twenty
years in most of the countries. Under special circumstances, a patent term
restoration can be given for an additional five years if manufacturers convince
FDA for an extended period for clinical data evaluation. This is the period during
which manufacturers market the drugs as a brand and earn their invested capital
back. This period is also infamously regarded as the period of huge profits for
the manufacturer due to their monopoly in markets.
After the patent
protected period, other pharmaceutical companies can file an Abbreviated New
Drug Application (ANDA) to FDA demonstrating therapeutic equivalence of their
formulation to the original brand product. If approved by FDA, the new
formulation will be added to Approved Drug Products with Therapeutics Equivalence
Evaluations list. This is endearingly called The Orange Book. This is the
official approval for the applicant to manufacture and market its formulation
as generic drugs. As the capital investment involved in such drug development
is much less, generic drugs bring down the price of drugs by about thirty to
eighty percent of that of original brand. Moreover, as more manufacturers get
bioequivalence approval for their formulation, competition in markets will get
stronger, thus forcing companies to slash their prices to sustain demand. This
is one noble reason why good quality medications are available even to countries
with poor economy without having to sweat much on pharmaceutical research and
development.