Provincial
The Science and Key Facts About Bioequivalence
Each year approximately 317 million prescriptions are filled in Canada using generic versions of brand-name pharmaceuticals. This compares to approximately 210 million brand-name prescriptions dispensed annually in Canada. With more than 60% of all prescriptions being filled with generics, patients, pharmacists and physicians all recognize the tremendous value of generic medicines.
WHAT IS BIOEQUIVALENCE?
The science of bioequivalency is a recognized methodology that is used by both brand-name and generic drug companies to ensure patient safety and efficacy of prescription drugs. Bioequi-valence for generic drugs means that the active ingredient in a generic medicine is absorbed into the body at the same rate and amount as in the brand-name product. This ensures that the generic delivers the same therapeutic effect as the brand counterpart and can be safely substituted with the brand product. Bioequivalence gives consumers, patients, physicians and pharmacists the assurance that generic medicines provide the same medicine and the same clinical effects, with the same safety profile, as their brand counterparts.
Health Canada requires that generic drugs contain the same active ingre-dient as the brand-name counterpart, be the same strength and dosage form (tablet, capsule, etc.) and have the same route of administration (oral, topical, injectable, etc.). It is important to know that bioequivalent drugs, whether brand-to-brand or generic-to-brand, work in the body in the same way and provide the same safety and efficacy profile. In short, generics provide the same medicines, but at a more affordable cost.
UNDERSTANDING THE SCIENCE
There is a common misstatement regarding the bioequivalence of generic drugs, which asserts that blood levels of the active ingredient in generic drugs may differ from those of the brand-name version by a margin ranging from minus 20% to plus 25%. This simply is not true and any generic with a difference that dramatic would never be approved by Health Canada. The -20% to +25% margin is a criterion for one part of a complex statistical calculation used to help measure the bioequivalence. In no way does it represent the actual difference in the amount of active ingredient in patient’s bloodstream. There will always be a slight, but not clinically important, level of natural variability – just as there is between one batch of brand-name drug and another batch of the same brand-name drug.
HEALTH CANADA
STANDARDS - WORLD LEADERS
Health Canada is a world leader in bioequivalence standards. Health Canada’s approval process for generic drugs is equally as stringent as the process followed to approve brand-name drugs. The rigorous chemistry, manufacturing and quality controls are applicable to both new brand-name
drugs and generic drugs. Labeling and testing requirements also are the same for both brand-name and generic drugs. The same Health Canada inspectors evaluate the manufacturing facilities for generics and for brand products, using the same standards, to ensure compliance with all good manufacturing practices. The only meaningful difference between the generic and brand approval process is that human and animal clinical studies to show safety and efficacy are conducted for new brand-name drugs, whereas bioequivalence studies are used in place of clinical studies in approving generics. It should be noted, however, that brand-name companies use bioequivalence studies during the approval process of the new drug or after it is commercially available when the companies make significant changes to the manufacture of the drug product.
All provincial governments and hospitals in Canada accept Health Canada’s declaration of bioequivalence and utilize generic prescription medicines whenever possible.
ALL INGREDIENTS
ARE APPROVED
All ingredients – active and inactive – used in generic drugs are approved by Health Canada in the same manner they are approved for the brand companies. Companies that make generic drugs often obtain these active and inactive ingredients from the very same suppliers as the brand companies.
Generic drugs are less expensive than brands in large part because generic manufacturers do not have to conduct costly animal and clinical trials to test the safety and effectiveness of a generic version of a drug that has been safely and effectively used for several years. Rather, generic pharmaceutical companies perform smaller studies to confirm bioequivalence to the brand product. Moreover, generics do not spend hundreds of millions of dollars in advertising and promotion.
PATIENT SAFETY:
BRAND-NAME AND GENERIC
Claims that generic drugs are not as safe
and effective as brand-name drugs are
simply not true. In fact, the high-profile
patient safety issues involving prescription
medicines that have occurred
recently all involve brand-name drugs
such as Vioxx®, Rezulin®, Prepulsid® and
Baycol .
In fact, because the generic versions
do not come to market until several years
after their brand-name equivalents, the
safety profile of these products is often
better understood by prescribers, regulators
and patients. There has never
been a product recall in Canada due to
bioequivalence issues.
Brand-name drug companies use
this standard of bioequivalency testing
when comparing trial batches of a new
drug to full production batches of the
new drug especially if significant manufacturing
changes have occurred. The
generic manufacturers replicate the exact
same test when creating a generic
version of the brand-name drug.
Study groups commonly include between 32 and 72 individuals. In the first
step group one is given a generic drug and group two a brand-name drug.
Their absorption into patient’s bloodstream is measured and compared. In
the second step group one is given a brand-name drug and group two a
generic drug. Their absorption is again measured and compared.
In the bioequivalency test the total amount of drug absorbed (AUC) and
the maximum concentration of a drug (Cmax) as well as the length of time
it takes to achieve Cmax (Tmax) are all measured. Each participant’s results
in terms of AUC, Cmax and Tmax are analyzed by the statistical method
required by Health Canada for the determination of bioequivalence of the
generic and brand-name drugs.
