Biopharmaceutical company Nektar Therapeutics said it entered into a worldwide licensing deal with AstraZeneca Plc to develop two of its experimental drug candidates.

Under the agreement, AstraZeneca will develop Nektar's late-stage drug to treat opioid-induced constipation, NKTR-118, and NKTR-119, which is in its early-stage studies to treat pain without the side effects of constipation.

Nektar will receive an upfront payment of $125 million for both drugs and AstraZeneca will bear all costs related to their research and development, global manufacturing and commercialization.

Nektar is also eligible to receive up to $235 million in aggregate payments for NKTR-118 upon the achievement of certain regulatory milestones, and additional tiered sales milestone payments of up to $375 million.

Shares of Nektar Therapeutics closed at $8.46 Friday on Nasdaq. (Reporting by Anuradha Ramanathan in Bangalore; Editing by Aradhana Aravindan)