Breaking Down The Brixadi Clinical Trials


One of the most recent opioid addiction drugs to pass clinical trials and hit the market is Brixadi, an injectable form of extended-release buprenorphine for treating moderate to severe opioid addiction.

Let’s examine how Brixadi performed during clinical trials and how effective it is for treating opioid use disorder, as well as how it fares in comparison to other opioid addiction medications.  

What Is Bridaxi?

Brixadi is an injectable medication used to treat opioid use disorder (OUD). It contains the active ingredient buprenorphine in liquid form, packed in a prefilled syringe. Bridaxi can be taken weekly or monthly.

As the first and only long-acting buprenorphine injection, Braxadi underwent rigorous testing and clinical trials before getting FDA approval in May of 2023.

Trial One: Brixadi Vs. Vivitrol

One study was designed to compare the effects of Brixadi to Vivitrol, another popular drug for opioid use disorder. Vivitrol is an extended-release injection of naltrexone.  

The study was a randomized controlled trial, which means participants were divided into two groups and randomly assigned one of the two drugs. They were then monitored for several months to see how they responded to treatment.

The individuals were all incarcerated inmates who suffered from severe opioid use disorder and needed substance abuse treatment.

Where the Study Took Place

The randomized clinical trial included 240 inmates from seven counties in Maryland, USA. The counties were geographically diverse so that the results could represent a more varied sample of the general population.

The seven counties were :

  • Three from the Baltimore area
  • Two from the Eastern Shore of Maryland
  • One from the Southern Region
  • One from the DC Region

The jails in these counties were chosen because most of them already offered FDA-approved medication, and many inmates fit the selection criteria for the study.  

Selection Criteria: Who Participated In the Study?

In addition to being an inmate suffering from opioid dependence, participants had to fulfill specific criteria to join the study, such as:

  • Being scheduled for release from jail within 120 days
  • Falling under DSM-5 criteria for opioid use disorder
  • Willingness to take either Braxadi or Vivitrol without knowing which of the two they’ve been given
  • Planning to live in Maryland after release, especially in or around one of the seven counties (this was important for monitoring purposes)

Exclusion Criteria

Some inmates were not eligible for the clinical study because they had one or more of the following exclusion criteria:

  • Liver function test results came back at least four times higher than the normal range
  • Currently taking certain antibiotics such as azithromycin, clarithromycin, and erythromycin
  • Low potassium levels
  • Previous allergic reactions to one of the two active ingredients (buprenorphine and naltrexone)
  • Pregnant or breast-feeding mothers
  • Obese individuals with a BMI (body mass index) of over 40
  • Any active medical illnesses that could affect the study results
  • Untreated mental disorders
  • Being currently enrolled in any opioid treatment programs
  • Going through detox or withdrawal  

The Purpose of The Clinical Trial

The clinical trial was designed to see how effective Bridaxi and Vivitrol were in helping the inmates lead opioid-free lives.

The study gauged this by measuring a few factors that can be summarized into three main questions:

  • How consistent are the participants with taking their monthly injections?
  • Do the participants relapse and take opioids? If so, do they report it?
  • How’s their quality of life several months post-treatment?

The 18-month clinical trial was established to answer these questions.  

What Happened During The Clinical Trial?

The 240 inmates were divided into two groups of 120 individuals each. The first group took Bridaxi, which was given the code “XR-B,” while the second group took Vivitrol, which was named “XR-NTX.”

The “XR” was short for extended-release since both drugs had extended-release versions of their active ingredients.

Each participant took their respective injections each month for the remaining 120 days of their incarceration.

After they’d been released from jail, they continued to take their monthly injections for another six months as part of a community treatment program.

The scientists who conducted the clinical trial monitored the inmates monthly during the first six months and checked on them at the 12th and 18th months post-release.

Here’s what they measured:

  • Adherence to injections
  • Illicit opioid use
  • Physical and mental health
  • Criminal activity

Study Outcomes

The primary outcome of these first six months was to see how well the inmates stuck to their treatment schedules. This was easily gauged by the number of injections each inmate had taken by month six.

The inmates were also subjected to urine drug tests to see if they’d remained sober during this period. The purpose was to identify those who had relapsed and to see if these individuals had reported their drug use or had kept it a secret.

In addition to opioid use, the scientists monitored their quality of life and criminal activity. The participants who had been re-arrested during the first 12 months were likely to have relapsed.

In the end, both drugs proved to be nearly as effective in treating opioid use disorder. However, the study concluded that to choose one over the other definitively, they would need a larger sample size and more than 18 months.  

Trial Two: Brixadi Vs. Sublingual Buprenorphine/Naloxone

Another randomized controlled trial compared the effectiveness of the Brixadi injection to a sublingual combination of buprenorphine and naloxone.  

The idea was to see which of the two dosage forms, injectable or oral transmucosal, was more effective in treating opioid use disorder.

This study included 428 participants split into two equal groups, each given one of the two options.

The group taking Brixadi started with weekly injections for 12 weeks and then moved to monthly injections for the remaining 12 weeks. The other group took daily sublingual buprenorphine/naloxone for all 24 weeks.

At the end of each phase, the participants were required to take a urine drug test to see if they had relapsed during treatment.

Those who got negative opioid assessments, meaning their urine tests were opioid-free, were considered “responders.” In other words, they’d remained sober the entire time, meaning their treatment had succeeded.

The trial concluded that 16.9% of the Brixadi group were responders, compared to 14% of the sublingual buprenorphine group.

While the difference isn’t significant, it proves that Brixadi is just as effective, if not slightly more, than sublingual buprenorphine/naloxone.


This study proved that Brixadi was relatively safe, showing few side effects except mild injection-site irritation.

Another clinical trial that compared the safety of Braxadi to sublingual buprenorphine also concluded that the injection is just as safe as the sublingual form.

These results and those of other clinical trials proved that Braxadi had met all of the FDA’s quality, safety, and efficiency requirements.

Medication-Assisted Addiction Treatment is Safe and Effective…

There’s always some controversy when a new drug hits the market. However, Brixadi’s successful track record in clinical trials proves its potential to help those struggling with opioid use disorder.

If you or a loved one you know are struggling with opioid use disorder, book an appointment with Curednation and get started on your recovery journey today.


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