Drug Studies’ Results Make Case for Access to All Opioid Dependence Medications

To the medical director at Caron Treatment Centers, giving physicians and patients multiple options in treatment stands as a primary goal. That is why Joseph Garbely, DO, FASAM, is reassured by results of two recent studies, including one published this week, that showed comparable efficacy and safety between sublingual buprenorphine and injectable naltrexone for opioid dependence.

“We as physicians need choices,” Garbely tells Addiction Professional. And one factor remains unmistakable to him when it comes to treating patients with opioid addiction: “They have to be on medication-assisted treatment. We have to get them on medication-assisted treatment.”

Garbely says Caron definitely leans toward the monthly injectable Vivitrol as its preferred medication treatment for opioid dependence. As an extended treatment program, Caron is able to negotiate the factor that the most recently published of the two studies identifies as the main impediment to success with injectable naltrexone: the challenge of successful induction to the antagonist drug due to the patient needing to be opioid-free before receiving the initial dose.

This open-label U.S. study, published online this week in The Lancet, involved 570 adult patients with an opioid use disorder who were randomized to monthly injections of Vivitrol or daily self-administered doses of sublingual Suboxone film for 24 weeks. When looking only at patients who were successfully initiated on a medication, the researchers found similar rates of opioid-negative urine screens and patient relapse, as well as comparable adverse effect results. But the researchers reported that while the initiation rate was 94% in the buprenorphine group, it was only 72% in the injectable naltrexone group.

Lead author Joshua D. Lee, MD, of the New York University School of Medicine’s Department of Population Health, tells Addiction Professional that while the study results confirmed practical issues that already were well-known, such as the initiation challenge with injectable naltrexone, the main emphasis was to examine the trajectory of treatment with each of the medications over six months. “The heartening finding was that outcomes were comparably quite good for those initiating either treatment,” Lee says.

The other recently released study, a Norwegian study involving 159 patients that was published last month, found comparable efficacy and safety profiles between buprenorphine and injectable naltrexone over a three-month period. Garbely says that study bypassed the issue of induction.

“We needed to look at these two modalities head to head to see if both work, and are they safe,” says Garbely. Once patients were successfully initiated, patients on the medications had largely equivalent results, in both studies, he says.

Lee explains that in the study published this week, the comparative risk of relapse between the two medications appeared to favor buprenorphine at the early stages of the study, then evened out between the two drugs, and then appeared to skew more in favor of use of injectable naltrexone.

He hopes the findings will add to evidence that could convince more substance use treatment programs to offer their patients access to all of the available medications for opioid dependence, including methadone as well. Lee also says these findings should counteract the effect of some recent unflattering media portrayals of Vivitrol and the marketing efforts behind it—coverage that he believes has inaccurately portrayed the drug to some as “snake oil.”