FDA Issues Complete Response Letter for Opioid Use Disorder Treatment

The FDA has replied with a complete response letter (CRL) for CAM2038 (Braeburn Pharmaceuticals), a long-acting subcutaneous injection of buprenorphine for the treatment of opioid use disorder (OUD).

The FDA requested that more data be compiled for the therapy. Its decision was made based on the results of 7 phase 1—3 trials that tested CAM2038 in weekly doses of 8, 16, 24, and 32 mg, and monthly doses of 64, 96, 128, and 160 mg.

The therapy was tested in both weekly and monthly doses. Had it been approved, CAM2038 would have been the first and only injectable for OUD that can be administered by health care professionals from day 1 of a patient's OUD treatment.

"Braeburn will continue to work closely with the FDA with the goal of bringing CAM2038 to market as quickly as possible," Mike Derkacz, the president and CEO of Braeburn, said in a statement. "Opioid addiction is one of the worst public health crises in our nation's history. We are committed to introducing this innovative treatment to better meet the overwhelming needs of patients."

Study 421 included 428 patients to compare CAM2038 (n = 213) with sublingual buprenorphine/naloxone (SL BPN; n = 215) in 2 phases: weekly and monthly. The weekly phase compared 8—24 mg/day SL BPN and placebo in the SL BN arm, and 16–32 mg/week CAM2038 with an SL placebo. The monthly phase did the same with 8–32 mg/day SL BPN and 64–160 mg/month CAM2038.

Response rates for the CAM2038 arm were 17.8% compared to 14.4% with SL BPN (95% CI, —3.5%-10.4%; P <.001). Utilizing urine tests and patient reporting to determine the cumulative distribution function (CDF) of the percent of participants with negative assessments, data revealed that the CAM2038 arm performed 20% better (95% CI, 6.7%-33.3%; P = .004).

Another of the phase 3 trials, Study 499, which tested the 32- and 160- mg doses, consisted of long-term safety data over a 48-week period, which showed a safety profile consistent with already approved buprenorphine therapies, as well as high retention rates at weeks 24 (81%) and 48 (69%).

Adverse events (AEs) through 12 or more weeks were consistent with approved therapies as well. The 32-mg weekly CAM2038 arm (n = 175) had 98 patients with at least 1 AE (56%) and the 160-mg monthly arm (n = 48) had 25 (52%), compared with 52 patients (58%) in the SL BPN arm (n = 52).

The Braeburn product was previously recommended by the FDA’s Psychopharmacologic Drugs Advisory Committee in early November 2017, 17-3, in favor of approval.

While the United States faces an opioid epidemic that impacts millions, more than 10 million Americans reportedly misused opioids in 2016, with only an estimated 1.1 million receiving medication-assisted aid, per the Substance Abuse and Mental Health Services Administration. According to a White House Commission report, opioid overdose is the leading cause of death among those under 50 years of age, highlighting a critical need for OUD therapies.

Braeburn recently announced the completion of $110 million financing round in preparation for the market release of CAM2038.

This article was originally published by MD Magazine.