(Reuters) - Acura Pharmaceuticals Inc's shares fell as much as 21 percent to a life low on Wednesday, a day after the U.S. health regulator said data on its experimental painkiller was insufficient to support its claim that the drug could not be abused by snorting.
Acura's tablet, which contains common painkillers hydrocodone bitartrate and acetaminophen, is designed to cause a burning sensation when snorted or form a gelatinous mixture when dissolved for injecting.
The U.S. Food and Drug Administration also questioned whether snorting was a relevant route of abuse of drugs containing hydrocodone bitartrate and acetaminophen, the company said on Tuesday.
Acura said in August that the painkiller did not show statistically significant results in reducing likeability among abusers in a mid-stage study.
In December, the FDA agreed to review the failed study on whether it could be included in the application for an approval to the drug.
The United States is battling a rapid rise in abuse of opioids, a class of drugs that includes prescription painkillers, pushing the FDA to tighten access to some commonly prescribed medicines such as those containing hydrocodone.
MLV & Co analyst Graig Suvannavejh cut his rating on Acura's stock to "hold" from "buy," saying that the specialty pharmaceutical company will not be able to file for approval of its version of the drug this year.
"Given this new uncertainty, we now push back the timing of an approval and potential 1st revenue a year to 2016," he wrote in a note on Wednesday.
Suvannavejh said the FDA's view on abuse by snorting was "odd and even a bit counterproductive."
"From our perspective, this unsolicited view comes out of nowhere, as according to Acura, snorting is the 2nd most prevalent method of abuse for immediate release hydrocodone-acetaminophen," he said.
Acura said it had earlier submitted a report to the FDA on the prevalence of abuse of hydrocodone drugs by snorting.
The company said on Tuesday that it would meet with the regulator to discuss the issue.
Acura's shares were down 17.5 percent at $1.04 in early trading on the Nasdaq, after hitting a life low of $1.00.
(Reporting by Vrinda Manocha in Bangalore; Editing by Kirti Pandey)