Late-phase opioid addiction success sparks surge in Indivior stock price

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Indivior (LON:INDV) has enjoyed another big day on the London Stock Exchange. Shares in the Reckitt Benckiser (LON:RB) spinout surged 15% after a Phase III trial of its opioid dependence drug met the primary endpoint and a key secondary outcome, setting the candidate up to win approval by the end of 2017.

Slough, U.K.-based Indivior is developing the drug, RBP-6000, to free people with opioid use disorder from the need to take medication every day to control their conditions. RBP-6000 is a slow-release injection of the well-established opioid addiction treatment buprenorphine. Indivior has designed the depot formulation to be administered every month, a schedule that could be beneficial to those who struggle to comply with daily regimens.

Such benefits are all for naught, though, if the drug fails to control addiction. The Phase III data go a long way toward dismissing this concern. The trial enrolled 489 subjects with moderate to severe opioid disorder who, while not currently in treatment, wanted medication to help manage their conditions. After an induction phase in which subjects took Suboxone, a sublingual film containing buprenorphine and naloxone, they were randomized to receive either low or high doses of RBP-6000 or placebo.

Indivior tracked the efficacy of RBP-6000 by testing urine samples for opioids and asking participants about their illicit opioid use. After 24 weeks of testing, Indivior found both treatment arms outperformed placebo against this combined urine sample, self-reported endpoint.

As well as hitting that primary endpoint, RBP-6000 succeeded against a key secondary outcome measure. That endpoint looked at the number of people whose urine tested negative for opioids at least 80% of the time. This secondary outcome, which also incorporated self-reporting, was met by both treatment arms. Indivior is content with the safety data, too, although 4.6% of subjects in the RBP-6000 arm dropped out, compared to 2% for the placebo.

The release sent shares in Indivior up 15% in London, bringing the stock’s total gains since it listed at the end of 2014 up to 140% and its market cap to £2.45 billion ($3.2 billion). The latest gains are underpinned by a belief that Indivior is now closing in on approval of a drug that can make a dent on the opioid addiction crisis.

“We believe that RBP-6000 can potentially transform the treatment of opioid dependence, if approved, by possibly reducing patients’ treatment administration days from 365 a year to 12,” Indivior CEO Shaun Thaxter said in a statement. “RBP-6000 was designed to offer physicians the potential for increased certainty of treatment adherence, and developed with the desire to help mitigate abuse, misuse and diversion of medication.”

Indivior has FDA fast-track designation for the drug, a status that it thinks can enable it to wrap up the data analysis, file and win approval by the end of 2017. That would represent a big boost to Indivior’s chances of thriving as a standalone company. Currently, Indivior’s business is built upon daily oral formulations of buprenorphine. Now, with schizophrenia drug RBP-7000 also edging toward a regulatory decision, Indivior could be on the cusp of broadening its portfolio.

- read the release

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