By Pat Anson, Editor
The U.S. Food and Drug Administration is expected to finally make a decision next month on a new drug delivery system to treat opioid addiction – an implant that could also be used someday to treat pain and other chronic illnesses that require steady doses of medication.
The latest results from a Phase 3 double blind study of a buprenorphine implant called Probuphine would appear to boost its chances of winning FDA approval. Titan Pharmaceuticals (NASDAQ: TTNP) said over 85% of the patients who had the implant for six months abstained from using illicit opioids, compared to about 72% of patients who used oral buprenorphine film strips that were taken daily.
The study findings were recently presented at the annual meeting of the American Society of Addiction Medicine in San Francisco.
"This was the first head-to-head comparison study of Probuphine and sublingual buprenorphine, demonstrating the efficacy of a long-acting six month buprenorphine implant," said lead investigator Richard Rosenthal, MD, Professor of Psychiatry and Medical Director of Addiction Psychiatry at the Icahn School of Medicine at Mount Sinai. “If approved, Probuphine could help expand access to medication to treat opioid use disorders, providing people with a new option."
Probuphine is about the size of a matchstick and is implanted under the skin. For six months it delivers a steady dose of buprenorphine, a weaker acting opioid that’s long been used as an addiction treatment drug sold under the brand name Suboxone.
There are many advantages to an implant. The dosage is controlled and there’s little risk of abuse, diversion or overdose. Users also never have to remember to take a pill.
Probuphine’s path to the marketplace has been rocky at times. Titan and its partner, Braeburn Pharmaceuticals, were stunned in 2013 when the FDA denied approval of the implant and asked for a new clinical study proving Probuphine’s effectiveness.
Positive results from a Phase 3 trial were submitted in 2015 and in January of this year an FDA advisory committee voted 12 to 5 in favor of approving the implant. But then the agency added another delay by extending its decision date to May 27.
The time may be ripe for approval this time around, as the FDA is under intense political pressure to do more to address the nation's opioid abuse epidemic. The Obama administration has proposed a rule change that would double the number of patients that a doctor can treat with buprenophine from 100 to 200. And Congress is considering funding proposals that would allocate another $1 billion to the war on drugs, with most of the money spent on addiction treatment.
Probuphine was developed using a patented implant technology called ProNeura, which is designed to provide continuous levels of medication in the blood. Titan is also developing implants to treat Parkinson’s disease and hypothyroidism, and its CEO told Pain News Network in a recent interview that ProNeura could also potentially be used to deliver pain medication.
“Clinical studies will need to be done to establish the ability, but the drug levels can certainly be delivered that are going to be beneficial for treating chronic pain,” said Titan CEO and President Sunil Bhonsle. “There are many applications for this technology and I think the medical community is now more in tune with looking at long-term delivery technology in the chronic disease setting.”