Abuse-deterrent specialty manufacturer Acura hit a wall in Phase II testing of what was supposed to be an abuse-resistant formula of a prescription pain medication pairing hydrocodone bitartrate with acetaminophen. The combination made use of the company’s Aversion technology, which is intended to trigger irritation if the drug is snorted and to make it harder to extract opioids for injection.

But crushing and snorting the drug didn’t elicit as negative a response as researchers perhaps expected among the recreational drug abusers who made up the test group. Snorting, which was a secondary endpoint in the study, pulled a mean “liking” score among subjects of 40.2, compared to the generic’s score of 50.4. A score of 50 or below indicates some dissatisfaction while using.

The study also assessed a pre/post perspective, and found differences based on when the drug was taken. While subjects were using the drugs, both the “Aversion” and generic versions exceeded the average mean of 50 in terms of likeability—known as the Overall Liking Score—at 52.7 and 71, respectively. There was a shift 12 hours later, known as the Take Drug Again assessment. In this instance, the mean Aversion likability factor dropped to 45.1, while the placebo stayed around the same with a mean “like” score of 71.0.

The desire for abuse-deterrent opioids is gaining strength for financial and social reasons. Drug makers can fend off generic versions of branded opiates, if they prove to the FDA that a new iteration is significantly harder to abuse, as Purdue Pharma was able to do recently.

The social incentive is also rising because painkiller-related deaths are trending upward for men and women. A Centers for Disease Control report in July found the spike is steeper among women, quadrupling between 1999 and 2010, compared to increasing by more than two-and-a-half times among men during that same period. Researchers found that women between the ages of 45 and 54 were the most at risk for prescription painkiller deaths, while women between 25 and 54 were more likely than those in other age groups to end up in the ER over painkiller abuse or misuse.

Acura said in a statement that it will discuss the data and next steps with the FDA.