(Adds details from statement)
July 7 (Reuters) - Endo International Plc and BioDelivery Sciences International Inc said their experimental pain drug was found effective in a second late-stage trial.
BioDelivery's shares jumped about 18 percent to $14.10 before the bell. Endo shares were untraded.
The painkiller, BEMA buprenorphine, was being tested against a placebo in 511 patients, who were on regular opioid therapy.
Data from the first late-stage trial in January showed that the drug significantly reduced chronic pain in patients who do not take opioids regularly.
Opioids are a class of drugs that includes not only powerful prescription painkillers like morphine, oxycodone and fentanyl but also heroin.
Biodelivery, which entered into an agreement with Endo to develop the drug for the treatment of chronic pain in January 2012, will receive a $10 million milestone payment from Endo as part of the deal.
Biodelivery's shares closed at $11.99, while Endo's stock closed at $69.26 on the Nasdaq on Thursday.
(Reporting by Natalie Grover in Bangalore; Editing by Saumyadeb Chakrabarty)