Updated with statement from Pfizer and current stock prices. NEW YORK ( TheStreet) --U.S. regulators rejected Thursday a tamper-resistant painkiller from Pfizer ( PFE - Get Report) and Pain Therapeutics ( PTIE), said U.S. Food and Drug Administration spokesperson Shelly Burgess Thursday night. The Pfizer-Pain Therapeutics drug, Remoxy, is a long-acting opioid consisting of the narcotic oxycodone mixed with ingredients aimed at making it resistant to abuse and misuse. Pfizer confirmed Remoxy's rejection in a statement issued Friday morning but would not disclose the reasons for why FDA decided against approval. Durect Corp. ( DRRX - Get Report) is also responsible for some of the drug technology used in Remoxy and would have received royalties on sales had the drug been approved. Pain Therapeutics closed Thursday at $9.24 a share but was down 35% to $6 a share in early Friday trading. Durect shares closed Thursday at $3.09 but were off 32% to $2.10 early Friday. Pain Therapeutics has been seeking Remoxy's approval for more than three years and the drug was rejected by FDA once before, in 2008. Pfizer came on board the project when it acquired King Pharmaceuticals last year. King partnered with Pain Therapeutics in 2005 to help with Remoxy's development. Pfizer and Pain Therapeutics could not be reached for comment Thursday night so it's not known what steps need to be taken at this time for Remoxy to be resubmitted for approval again. Purdue Pharma already sells a tamper-resistant, long-acting form of oxycodone, so Remoxy's setback is a win for the privately held drug maker. Last Friday, FDA approved Oxecta, a short-acting, tamper-resistant painkiller from Pfizer and Acura Pharmaceuticals ( ACUR). --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: email@example.com.