UPDATE 1-Pfizer says pain drug as safe as rival pills in trial

(Adds details, background)

Oct 11 (Reuters) - Pfizer Inc said a late-stage trial of its experimental pain drug showed that the drug's long-term safety profile was comparable to those of similar formulations.

The trial tested the safety of the drug, called ALO-02, when administered for up to 12 months.

The study enrolled 395 patients. About 61 percent of them had chronic lower back pain and 18 percent had pain from osteoarthritis.

About 60 percent of the patients discontinued from the study over the one-year period, with 19 percent of patients reporting adverse events as the primary reason for discontinuation, Pfizer said in a statement.

The pill uses a technology that discourages common methods of drug abuse associated with prescription opioid use and consists of an extended-release oxycodone pellet that surrounds a core of naltrexone -- a drug used to treat alcohol and opioid addiction.

When used as directed, patients receive oxycodone in an extended release manner. But if the pills are crushed, the naltrexone is released and counteracts the effects of oxycodone.

Abuse of prescription opioid painkillers is a serious concern in the United States and doctors have even urged the U.S. health regulator to change prescription guidelines for opioids to prevent abuse.

(Reporting by Esha Dey in Bangalore; Editing by Sreejiraj Eluvangal)

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