(Refiles to fix typographical error in headline; Adds panel member, company comments)
GAITHERSBURG, Md. Nov 13 (Reuters) - An experimental painkiller from King Pharmaceuticals Inc KG.N and Pain Therapeutics Inc (PTIE.O) appears less susceptible to abuse than similar drugs, most members of a U.S. advisory panel said on Thursday.
A majority on the Food and Drug Administration panel said they felt the companies had shown Remoxy was less vulnerable to abuse than painkillers such as Purdue Pharma's Oxycontin. Eight members disagreed.
The FDA will make a final decision on whether to approve Remoxy. The panel's chairman said the members' views were not a formal vote as the agency had not requested one.
Some analysts forecast Remoxy sales to exceed $1 billion annually if the drug wins approval.
The FDA had asked for advice on whether Remoxy was different enough from other narcotic drugs to conclude it would be abused less and how much information about tamper-resistance should be included on prescribing instructions.
Agency officials said the panel appeared to struggle with where to set the threshold to call a drug abuse-resistant, one of the key questions the agency is grappling with internally.
"The message is that there are not a lot of answers to these very difficult questions," Dr. Bob Rappaport, director of the FDA division that reviews painkillers, said after the meeting.
Drug abusers often crush Oxycontin to snort or inject it and get a quick high.
The FDA, which wants to maintain painkiller access for patients who need it while minimizing misuse, has encouraged companies to develop abuse-resistant alternatives. That task "has proven to be more challenging than any of us would have imagined," Rappaport said.
The Remoxy capsules contain a thick gel and were designed to resist crushing, dissolving into a liquid or other forms of misuse.
The drug is not abuse-proof, Pain Therapeutics officials said. But various laboratory tests showed it was more difficult and took longer to extract a smaller amount of oxycodone, the active ingredient, when compared with Oxycontin.
"We believe we met our objective in showing Remoxy resists abuse by the oral route, snorting, injection and smoking," Michael Zamloot, a senior vice president for Pain Therapeutics, told the panel.
Some panel members called for more study to see how drug abusers would actually use it.
"We have no idea what this drug would do in all sorts of people," said Dr. Sidney Wolfe, head of Public Citizen's Health Research Group, a consumer group.
Pain Therapeutics, which has no FDA-approved products on the market now, would receive 15 percent royalties from Remoxy sales if it is cleared. King would handle marketing.
The drug is "a first step in developing an innovative medicine designed to strike a balance between the need for effective pain control and the need to minimize risks" with current options, James Green, a King executive vice president, said in a statement.
The FDA usually follows panel recommendations when deciding whether to approve new drugs. A decision is due by Dec. 10.
King is seeking to expand its pain management franchise by making a hostile bid to buy Alpharma Inc ALO.N for about $1.6 billion. On Friday, an FDA panel will consider Alpharma's experimental painkiller, Embeda, on Friday. (Editing by Andre Grenon)