Titan Pharmaceuticals’ (TTNP) implantable device for the treatment of opioid addiction performed as well as standard sublingual buprenorphine tablets in a phase 3 study, the company reported on Monday. They’re headed to the FDA later this year.
The study was designed to demonstrate the equivalence of Titan’s implantable buprenorphine device, called Probuphine, to daily sublingual buprenorphine/naloxone tablets at keeping opioid addicts from using illicit drugs. The two were compared for six months in the study. Patients in the Probuphine arm of the trial still received placebo tablets, and patients in the buprenorphine/naloxone arm also received dummy implants – a double-dummy protocol. The primary efficacy analysis was a non-inferiority comparison of the proportions of treatment responders in each group, a responder being defined as having at least four out of six months free of illicit opioids based on urine testing and self-reporting.
The study demonstrated response rates of 96.4% for the Probuphine arm and 87.6% for the sublingual buprenorphine/naloxone arm. The two-sided 95% confidence interval (0.009, 0.167) of the treatment difference was within the margin for non-inferiority. Titan added that the number of patients with all six months testing negative for illicit opioid use was significantly higher in the Probuphine arm (88%) compared to the sublingual buprenorphine/naloxone arm (72%), (p=0.008).
Probuphine delivers buprenorphine continuously for 6 months, which the company expects will improve compliance among patients (opioid addicts) who otherwise take a daily tablet. The implant insertion and removal procedures were generally well tolerated.
Titan and partner Braeburn Pharmaceuticals plan to resubmit a NDA for Probuphine in the second half of the year. The drug was rejected in 2013 when the FDA requested another clinical trial.
Titan ended the first quarter with $13.4 million in cash, which they believe will be sufficient to fund operations into the fourth quarter of 2016. The company will receive a $15 million payment from Braeburn upon FDA approval of Probuphine, and the company is eligible to up to $165 million in sales milestones and $35 million in regulatory milestones if the device is approved in other indications.
