Abuse trial win reanimates Remoxy

No one likes Remoxy – and for once that’s a good thing. Pain Therapeutics’ troubled opioid was significantly less appealing to recreational drug users than an immediate-release version in a clinical trial, and the company is to resubmit a US approval application at the beginning of next year. Its stock jumped 35% yesterday as a result.

Even so, the shares are still down 37% from October 24, a day before Pfizer handed back rights to the abuse-deterrent oxycodone formulation. These data are a good sign, but Pain has some way to go if it is to convince the FDA that Remoxy merits approval under the strict guidelines governing opioids.

The trial, conducted under Pfizer’s auspices as its last act before the licence was terminated, was geared towards proving that Remoxy deters abuse. The FDA has in the past said it will not approve new opioids unless they can prove they are resistant to being crushed or dissolved – or that, if they are, they do not produce a high. The study’s design was discussed with the FDA and conducted in accordance with the agency’s draft guidance to industry.

Nearly 60 healthy, non-dependent recreational opioid users completed the randomised, double-blind trial. They were instructed to chew 40mg Remoxy capsules, 40mg immediate-release oxycodone and placebo pills vigorously for up to five minutes.

Pain Therapeutics said that none was able to chew Remoxy for the specified time, thanks to its taste, texture or high viscosity.

No one likes us, we don’t care

The co-primary endpoints were drug liking and drug high for intact and chewed Remoxy compared with immediate-release oxycodone; both were met with statistical significance.

Secondary endpoints included good drug effects (significantly lower for Remoxy versus immediate-release oxycodone) and bad drug effects (significantly higher for Remoxy). On pupil constriction, nausea and feeling sick, scores were significantly lower for Remoxy compared with IR oxycodone.

The future of the project, and of Pain Therapeutics itself, depends on what the FDA makes of it. The regulator has already rejected it twice, in 2008 and 2011, and can be very strict when it comes to opioids.

And there is already a form of oxycodone on the US market that the FDA does consider abuse-deterrent – Purdue Pharma’s OxyContin. Even if the FDA is won over by Remoxy on the third try, it will be hard to forecast its market performance against a similar and more established product.

And first the company must at least get its lead asset re-submitted. The firm believes that no more clinical trials will be needed, but its chief executive, Remi Barbier, acknowledged on a conference call yesterday that “a little bit of in vitro work” remained to be done. Its finance chief, Peter Roddy, said the company’s roughly $40m cash would see it through to this point, and said about $12m would be spent this year.

The company is also working on other programmes, foremost of which is Fenrock, a transdermal patch formulation of fentanyl also designed to be abuse-resistant. Pain hopes to have preclinical proof of concept data on the project “sometime over the next few weeks”, Mr Barbier said.

It will also unveil an entirely new candidate later this year, perhaps in the third quarter. This targets a large, underserved, chronic non-pain CNS market, Mr Barbier said.

Pain will need more money for these projects. Its existing cash should take Fenrock to clinical proof of concept but not all the way to approval, and as for the undisclosed project the company is working on a new non-dilutive source of funding that should enable an IND filing. But all this is pretty vague and seems unlikely to have contributed to yesterday’s share ramp.

It is not surprising that the company is also very open to takeover offers, but with only one late-stage clinical prospect potential buyers are likely to wait for Remoxy’s approval – if, indeed, it comes.

To contact the writer of this story email Elizabeth Cairns in London at elizabethc@epvantage.com or follow @LizEPVantage on Twitter

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