Endo International said Thursday it was selling back rights to an opioid pain drug because the opioid-based pain market and Endo's strategies have "evolved."

The Ireland-based drugmaker, with U.S. headquarters in Malvern, said it would lay off its 375-member sales force for the drug, Belbuca, which it licensed in 2012 from BioDelivery Sciences International.

Financial terms were not disclosed. Shares of Endo closed up 56 cents, or 3.71 percent, to $15.65.

Endo said the agreement to return the licensing rights to Belbuca, an opioid buprenorphine for treating long-term chronic pain, becomes effective Jan. 6. Endo said it will focus resources on its specialty branded business, including the development of Xiaflex for cellulite. Endo said its older pain products, Opana ER and Percocet, will be managed as mature brands.

Endo will take a $40 million write-down and other costs of $22 million. The company expects cost savings of $90 million to $100 million annually that can be used to support other products.

"Since we entered into our licensing and development agreement with BioDelivery Sciences International (BDSI) in 2012, the opioid market and Endo's strategic priorities have evolved," said Endo president and CEO Paul Campanelli. "We believe that this path provides our U.S. branded business with its best opportunity for success going forward."

Fewer than 15 sales reps and home office staff will lose their jobs in Malvern and the Philadelphia area, an Endo spokeswoman said. Endo employs 350 in Malvern and 6,000 worldwide.

BioDelivery Sciences, based in Raleigh, N.C., said it expects annual Belbuca sales of more than $27 million.

"We are continuing our product-by-product portfolio assessment and the development of our full corporate strategy," said Campanelli, who took the helm at Endo in September. He succeeded Rajiv De Silva, who stepped down. Campanelli was formerly CEO of Par Pharmaceutical, which Endo bought last year. Endo sells branded and generic drugs as well as over-the-counter medications.