Per Dr. Throckmorton, “Ongoing and planned activities reflect the commitment by FDA to integrate the use of all of our available tools to achieve our goals related to the safe use of prescription opioids.” Two crucial aspects of moving forward are smart policy initiatives and regulatory clarity. We are inching our way forward on both. We can and must do better.
A key part of the FDA’s Opioid Action Plan is “Expand access to abuse-deterrent formulations (ADFs) to discourage abuse.” In order to achieve this worthy goal, the agency has issued numerous guidance’s – but actions speak louder than words – and the FDA’s actions have been, at times, confusing. When it comes to the development of new therapies to prevent opioid abuse and addiction, predictability is power in pursuit of the public health.
One of the FDA’s stated goals is to “Incentivize the development of opioid medications with progressively better AD properties and support their widespread use.” Bravo. But the devil is in the details. One area of regulatory clarity that could be improved is the agency’s views on differentiation between extended-release and long-acting (ER-LA) and immediate release (IR) opioids and how new products are tested for abuse-deterrent properties. This is a critical concern as IR opioids, with over 240 million scripts annual, represent nearly 96% of the entire opioid market. They are the “gateway” drug of prescription opioid abuse and do not have a single approved ADF formulation.
Believe it or not, abuse deterrence is largely defined and determined by how admitted opioid abusers “like” the product. (Abuse of IR opioid drugs is attractive to abusers because bypassing intestinal absorption and metabolism can lead to a higher Cmax and faster Tmax resulting in a more intense and more immediate high.)
Not surprisingly, abusers prefer immediate release products because they get their highs faster. But, as far as regulatory review is concerned, that also means that IR products under review by the FDA are determined to be less abuse-deterrent.
It’s an apples-to-oranges comparison that is resulting in an uneven ER-LA/IR regulatory playing field. And the unfortunate result is that it’s harder for immediate release opioids to pass FDA muster. Since IR opioids are designed to release “immediately” and last for a short duration (3-4 hours), measurements of drug exposure and “liking” should be taken at earlier, more IR-relevant intervals (when measured against existing, non-abuse deterrent comparator drugs). Measuring IR products by ER-LA standards is not a real world proposition. (When ER-LA’s are compared to IR’s by abusers – of course they like the immediate “high” better). The “clinic” experience needs to be reflective of real-world abuse.
Regulatory ambiguity and common sense are not allies. In fact, the agency has identified one of its major challenges as assessing the impact of individual formulations. Admitting the problem is important. Addressing it is urgent.
It’s time for the FDA to reflect on a more nuanced approach in measuring and determining appropriate standards for demonstrating abuse-deterrent properties of immediate release opioid. Small differences can lead to big benefits in the real world of deterrence. The key question remains not unanswered, but unaddressed – are the endpoints suggested in FDA’s “Guidance for Industry: Abuse-Deterrent Opioids—Evaluation and Labeling” the most relevant for demonstrating abuse-deterrent properties of an IR opioid?
While the public health imperative must drive the regulatory agenda, another important issue is how agency actions impact continued robust research and development. Minus more up-to-date and predictable FDA review criteria for abuse deterrent opioids, investment in their development is already becoming less attractive. Can we really afford to leave these decisions in the hands of admitted drug addicts? Actions (or inactions) have consequences.
As Dr. Throckmorton said at the recent meeting of the Agency’s Science Board: “FDA will act within its authorities in support of our public health mission to help defeat the epidemic of opioid abuse through a science-based and continuously evolving approach by improving the use of opioids through careful and appropriate regulatory activities, improving the use of opioids through careful and appropriate policy development, improving the treatment of pain through improved science, and improving the safe use of opioids through communication, partnership and collaboration.”
The time to focus on this issue is now. Lives are at stake.