Two other opioids faced greater opposition
The other two agents that the committee considered received much less support and sharper skepticism. The application for Aximris XR, an extended release form of oxycodone with a purported abuse-deterrent formulation (ADF) that relies on being difficult to extract for intravenous use as well as possibly having effective deterrence mechanisms for other forms of abuse. But FDA staffers reported that the only effective deterrence they could document was against manipulation for intravenous use, making Aximris XR the first opioid seeking ADF labeling based on deterrence to a single delivery route. This led several committee members, as well as the FDA, to comment on the clinical meaningfulness of ADF for one route. So far, the FDA approved ADF labeling for seven opioids, most notably OxyContin, an extended-release oxycodone with the biggest share of the U.S. market for opioids with ADF labeling.
“For ADF, we label based on what we expect from the premarket data. We don’t really know how that translates into what happens once the drug is on the market. Every company with an ADF in their label is required to do postmarketing studies on the abuse routes that are supposed to be deterred. We see shifts to other routes. Assessment of ADF is incredibly challenging, both scientifically and logistically, because there has not been a lot of uptake of these products, for a variety of reasons,” said Judy Staffa, PhD, associate director for Public Health Initiatives in the Office of Surveillance & Epidemiology in the FDA’s Center for Drug Evaluation and Research. The company that markets OxyContin has been the first to submit to the FDA all of its required postmarketing data on ADF efficacy, and the agency is now reviewing this filing, Dr. Staffa said.
The data presented for Aximris XR appeared to generally fail to convince committee members that it provided a meaningful addition to the range of opioids with ADF designations already available, which meant that their decision mostly came down to whether they felt it made sense to bring a me-too opioid to the U.S. market. Their answer was mostly no.
“In the end, it’s another opioid, and I’m not sure we need another opioid,” said committee member Lonnie K. Zeltzer, MD, professor of pediatrics, anesthesiology, psychiatry, and biobehavioral sciences and director of pediatric pain at the University of California, Los Angeles “There are so many options for patients and for people who abuse these drug. I don’t see this formulation as having a profound impact, but I’m very concerned about adding more prescription opioids,” said Martin Garcia-Bunuel, MD, deputy chief of staff for the VA Maryland Health Care System in Baltimore. Another concern of some committee members was that ADF remains a designation with an uncertain meaning, pending the FDA’s analysis of the OxyContin data.
“At the end of the day, we don’t know whether any of the [ADF] stuff makes a difference,” noted Steve B. Meisel, PharmD, system director of medication safety for M Health Fairview in Minneapolis and a committee member,
The third agent, oxycodegol, a molecule designed to pass more slowly across the blood-brain barrier because of an attached polyethylene glycol chain that’s supposed to prevent a rapid high after ingestion and hence cut abuse potential. It received unanimous committee rejection, primarily because its safety and efficacy evidence had so many holes, but the shadow of opioid abuse permeated the committee’s discussion.
“One dogma in the abuse world is that slowing entry into the brain reduces abuse potential, but the opioid crisis showed that this is not the only factor. Some people have become addicted to slow-acting drugs. The abuse potential of this drug, oxycodegol, needs to be considered given where we’ve been with the opioid crisis,” said Jane B. Acri, PhD, chief of the Medications Discovery and Toxicology Branch of the National Institute on Drug Abuse.
“During the opioid epidemic, do we want to approve more opioids? If the [pain] efficacy is about the same as oxycodone, is better safety or abuse potential a reason to approve it? We need guidance [from the FDA] about what is ‘better enough.’ No opioid will ever be perfect; there will always be abuse and misuse. But what is good enough to justify bringing another opioid onto the market? What is a good enough improvement? I don’t have an answer,” Dr. Hernandez-Diaz said.
Adviser comments showed that the continued threat of widespread opioid addiction has cooled prospects for new opioid approvals by making FDA advisers skittish over how to properly score the incremental value of a new opioid.
“Do we need to go back to the drawing board on how we make decisions on exposing the American public to these kinds of agents?” Dr. Garcia-Bunuel asked. “I don’t think we have the tools to make these decisions.”