CORRECTED-U.S. FDA declines to approve Avenue's painkiller again, shares drop

(Removes reference to tramadol as a non-opioid in headline, paragraph 1, 2)

June 14 (Reuters) - Avenue Therapeutics Inc said on Monday the U.S. Food and Drug Administration had once again declined to approve its painkiller tramadol, sending its shares about 5% lower in premarket trading.

The health regulator had previously declined to approve the painkiller in October, stating that it was not safe for the intended population.

The agency said the delayed and the unpredictable onset of analgesia - relief from pain - with intravenous (IV) tramadol does not support its benefit as a monotherapy to treat patients with acute pain.

There is also insufficient data to support that IV tramadol is safe and effective in combination with other drugs, FDA said in its decision that came more than two months after the scheduled target date of April 12.

The FDA did not mention any "Chemistry, Manufacturing and Controls (CMC)" issues in the complete response letter, Avenue said, adding that it disagreed with the health regulator's decision and would continue to seek regulatory approval for IV tramadol.

IV tramadol is being developed by the drugmaker as a potential alternative to conventional opioids for people with acute pain in the United States.

(Reporting by Trisha Roy in Bengaluru; Editing by Rashmi Aich)