From the Journals

‘Overwhelming evidence’ FDA’s opioid approval process is shoddy


Despite the ongoing epidemic of misuse, overuse, and diversion of opioids, the Food and Drug Administration has set a low bar for approval of these medications over the past 20 years, new research suggests.

Results of a cross-sectional study reveal that between 1997 and 2018, the majority of approvals of opioids for the treatment of chronic pain were based on pivotal trials that lacked critical safety and efficacy data.

The study results also show that the FDA did not require manufacturers to collect safety data on tolerance, withdrawal, overdose, misuse, and diversion in any rigorous fashion.

In addition, during the study period, 17 of the 39 new drug applications (NDAs) (only one was an innovator product, known as a new molecular entity) for chronic pain were approved with an “enriched enrollment randomized withdrawal” (EERW) trial design. Such a design, in this case, allowed manufacturers to exclude 32%-43% of the initially enrolled patients from the double-blind treatment phase.

“The question for regulators, policy makers, and others is: How did we get to a point where these approvals took place based on trials that were by design unlikely to yield some of the most important information about safety and efficacy that patients and clinicians would care about?” study investigator G. Caleb Alexander, MD, Johns Hopkins University, Baltimore, said in an interview.

The study was published online Sept. 29 in the Annals of Internal Medicine.

‘Cooking the books’

Little is known about the evidence required by the FDA for new approvals of opioid analgesics.

To characterize the quality of safety and efficacy data in NDAs for opioid analgesics approved by the FDA between 1997 and 2018, the investigators conducted the cross-sectional analysis using data from, FDA reviews, and peer-reviewed publications regarding phase 3 pivotal trials.

The investigators examined the key characteristics of each NDA, including the number, size, and duration of pivotal trials, trial control groups, use of EERW, and systematically measured safety outcomes.

Results showed that most of the 48 NDAs evaluated were for new dosage forms (52.1%) or new formulations (18.8%). Only one (2.1%) was for a new molecular entity.

Of 39 NDAs approved for the treatment of chronic pain, only 21 products were supported by at least one pivotal trial. The mean duration of these 28 trials was 84 days, and they enrolled a median of 299 patients.

Results showed that, for 17 of the 39 opioids approved for chronic pain, pivotal trials had an EERW design. For the latest period – 2012-2018 – trials of all eight of the approved opioids used the EERW method.

This EERW design allows the manufacturer to assess efficacy “among a subset of patients most likely to respond and least likely to have adverse effects, reducing generalizability to real-world settings,” the investigators noted.

They called on the FDA to stop relying on this type of trial to assess opioid efficacy.

In an August 2020 article, Andrew Kolodny, MD, pointed out the pitfalls of the EERW approach. In such a study, all participants are made physiologically dependent on the opioid in a 4- to 6-week open-label phase. Only those who tolerate the drug and find it helpful are included in the randomized study. Dr. Kolodny is codirector of opioid policy research at Brandeis University, Waltham, Mass.

“Critics of EERW have correctly described this methodology as ‘cooking the books,’ ” Dr. Kolodny writes.

He noted that the agency’s decision to rely on EERW trials for opioids was “based on discussions at private meetings between FDA officials and pharmaceutical company executives hosted by an organization called Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials.” The 2013 meetings were reported in an article published in the Washington Post.


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