Drug Development

Working to get its pain R&D strategy back on track, AcelRx steps closer to an FDA pitch

AcelRx has delivered another positive piece of the Phase III puzzle for ARX-04, its under-the-tongue application of a 30 mcg dose of the powerful opioid sufentanil designed to deliver a jolt of fast pain relief.

Expanding on an improvement in pain scores already recorded for the first cohort of 40 injured patients who turned up at the ER and received a single dose of ARX-04, the Redwood City, CA-based biotech says that it recorded a slightly better outcome for a small group of 36 more patients who were green-lighted for multiple applications.

The latest batch of data leaves this treatment on track to a near-term NDA, company execs tell me, as AcelRx works to stay on track with this program after being derailed on its lead effort last year.

The biotech $ACRX reported last February that ARX-04 cut baseline pain scores by an average of 2.7 on a 10-point scale. In the second cohort, the drop was 3.1 points from a baseline score of 8.1, hitting the primary endpoint. Most of the patients, 75%, got the pain relief they were looking for from a single dose under the tongue, while 7 required two doses and two got a third. Three were also dosed with morphine. Appropriately, the results were presented at the 7th World Congress of Mountain & Wilderness Medicine.

Pam Palmer, CMO and Co-Founder of AcelRx

Pam Palmer, CMO and Co-Founder of AcelRx

Those are small numbers, but company co-founder and Chief Medical Officer Pam Palmer says that the company has run 11 studies looking at different doses of sufentanil, including the 15 mcg dose. And all of that will be used to support its pitch to the agency.

“We wanted to go after a broader patient population than the post-operative setting,” she notes, noting that that is where you’ll find the bulk of the related painkillers used. According to the CDC, there are some 136 million visits to the emergency department each year, accounting for 44 visits for every 100 Americans. AcelRx says that close to 50 million of those visits require at least a couple of doses of opioids to control pain. And that’s the market the company hopes to tap in on, once it gets past the FDA.

It’s also no easy task to recruit emergency room patients for a clinical trial, she adds in explanation of the numbers used in the late-stage study, noting that most people rushing to the ER for help aren’t in the mood to be recruited for a trial.

The U.S. Army Medical Research and Materiel Command has helped fund the work on ARX-04, looking for a treatment that can be used in battlefield situations. And the treatment has also demonstrated its usefulness without severely afflicting cognition, notes the company – a useful feature for a drug that could be used in combat.

AcelRx’s stock, though, still hasn’t recovered from a nasty shock back in the spring of 2015, when the biotech had to suddenly and unexpectedly renege on its promise to investors than no new Phase III study would be required for its top opioid drug Zalviso.

Like ARX-04, Zalviso offers a twist on dosing the powerful opioid sufentanil. It is supposed to allow hospital patients to self-administer micro tablets of the drug under the tongue, replacing an IV, for lightning fast pain relief. But regulators, who have been on high alert wherever opioids are involved, want to see data from another study — the fourth from AcelRx -to better evaluate the risks of dispensing errors.

The setback forced the company to restructure and reconfigure its commercialization plans. Its CEO at the time left soon after.

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