UPDATE 2-Acura says pain drug to miss June 30 approval date

* Gets preliminary review letter from FDA

* Says pain drug will not be approved on June 30

* Acura shares fall as much as 36 pct (Recasts, adds analyst comments, updates share movement)

By Anand Basu

BANGALORE, June 23 (Reuters) - Acura Pharmaceuticals Inc (ACUR.O) said its experimental pain drug Acurox would miss its approval date of June 30 as it received a review letter from U.S. health regulators, sending its shares down as much as 36 percent.

The Food and Drug Administration's comments are preliminary and do not reflect a final decision on the information reviewed or a review of the entire new drug application, Acura said in a statement.

"It's a data and labelling issue. I don't think they have the data to have an appropriate label," Biologic Investment Research analyst Kevin McNamara told Reuters.

McNamara, who has a "sell" rating on Acura shares, expects a complete response letter from the FDA on June 30.

The FDA issues complete response letters to companies when it is not ready to approve a drug. It does not publicly disclose what steps are needed to win the approval.

McNamara, who sees a bleak possibility of the drug getting approval in the near-term, said: "I think they are going to be sitting on an approvable letter for quite a while."

Acurox, which is being co-developed by King Pharmaceuticals Inc KG.N, includes the powerful pain reliever oxycodone. It also contains components designed to thwart prescription drug abuse, which can be common with opioid pain drugs.

The FDA said in February it wanted manufacturers to take stronger measures to prevent misuse and abuse of long-acting and sustained-release opioids, a class of powerful, highly addictive narcotics prescribed to relieve chronic pain.

Shares of Acura were down 22 percent at $5.90 Tuesday on Nasdaq, while King shares were down 2 percent at $9.20 on the New York Stock Exchange. Acura shares touched a low of $4.85 earlier in the session.

For the alerts double-click [ID:nWNBB0275] (Editing by Aradhana Aravindan and Gopakumar Warrier)