Drug plan cost increases have levelled in recent years due to a large number of high-volume medications becoming available in a generic form and provincial drug reform driving down the price of generic drugs. At the same time, some insurance carriers have automatically implemented mandatory generic substitution policies on the majority of their plans (giving plan sponsors the option to opt out if they choose).
Generic substitution can help to control drug plan costs, but at the Drug Plan Substitutions Forum (held February 8 in Toronto), presenters explored situations where drug substitution might not result in therapeutic equivalence in individual patients and could lead to decreased efficacy or increased safety concerns.
Approval and authority
“Brand name medications are required to complete clinical trials to demonstrate safety and efficacy to Health Canada to gain approval,” explained George Dranitsaris, independent consultant in health economics and biostatistics. “Whereas generic medications are only required to demonstrate bioequivalency to the brand drug.”
Bioequivalency is determined by comparing bioavailability, which measures how much and how fast the active ingredient of the drug becomes available in the bloodstream. Once Health Canada confirms that the generic drug is within an acceptable range to the brand drug, it approves the generic based on this bioequivalence.
Pharmacists are given the authority to interchange a generic for a brand name drug without consulting the physician by provincial regulatory bodies and based on Health Canada’s declaration of bioequivalency.
In certain cases, generic drugs can achieve the same health outcome as the brand name drug. In other cases, patients may not receive the same therapeutic effects. When people aren’t receiving the best treatment for them, it can hinder their day-to-day activities, including how quickly they return to work if they are off or how they function at work.
Here are a few examples that are cause for concern among some medical professionals.
Concerta for ADHD
In the treatment of ADHD, Dr. Kenny Handelman, child, adolescent and adult psychiatrist with the Oakville Trafalgar Hospital, cautioned substituting Concerta—a popular drug used for treating ADHD—with a generic alternative. “[This] may result in therapeutic challenges and changes in patient outcomes,” he said. “This may be due to the fact that current Canadian bioequivalence measures do not necessarily imply therapeutic equivalence for more complex delivery systems, such as Concerta.”
“Medical professionals in the transplant community are concerned about uncontrolled switching between multiple interchangeable generics,” explained Jennifer Harrison, pharmacy clinical site leader with the Toronto General Hospital, University Health Network. The body sees the transplanted organ as foreign, and the immune system will attack or reject it without immunosuppressive drugs.
“While many other diseases have clinical tests to monitor patient health, in transplantation, there is no test to tell how immunosuppressed the patient is,” said Harrison. “Blood level and clinical monitoring are essential with a change in medication.” Although Health Canada requires generic drugs to be bioequivalent to the brand name drug, there are no requirements for interchangeable generic drugs to be bioequivalent to each other. If a transplant patient is switched from one generic to another generic, there can be a wide variability in blood levels and poor outcomes, which are difficult to manage if the prescriber is not aware of the switch.
Biologic drugs are derived from living cells, and the manufacturing process is complex. Even small changes in the process can affect the final product, how it reacts in the human body and how it impacts patients. Health Canada approval for biologics differs from traditional drugs because biologics must provide more detailed chemistry and manufacturing information.
“When approving subsequent entry biologics, Health Canada states that they are not considered ‘generic’ biologics and should not be interchangeable with the reference brand product,” explained John Holland, director, government affairs, with Amgen Canada.
“We anticipate that provinces will follow this guidance, and, as a result, pharmacists will likely not be able to make substitution decisions without the consent of the prescribing physician,” Holland continued.
Plan sponsors need to keep in mind what’s best for their plan and for their plan members. When implementing these cost-containing strategies, sponsors should ensure that their mandatory generic substitution plans have processes in place to make sure appropriate treatments are maintained when automatic substitution is required.
Suzanne Lepage is a private health plan strategist based in Kitchener, Ont. firstname.lastname@example.org