Opko Health Inc. (NYSE: OPK) is buying Israeli biopharmaceutical company Prolor Biotech Inc. (NYSE: PBTH) in an all-stock deal valued at $480 million.

Prolor aims to develop alternative-acting versions of already approved medications, including human growth hormone and clotting therapies for hemophilia.

Under the terms of the agreement, Prolor stockholders will receive 0.99 shares of Opko common stock for each share of Prolor common stock. Prolor’s shares closed at $5.83 on April 23, before the deal was announced. The deal values the shares at $7 per share.

The transaction is expected to close during the second half of 2013.

Phillip Frost, Opko Health’s chief executive and chairman, is also the chairman of both Prolor Biotech and Teva Pharmaceutical Industries Ltd. (TLV:TEVA).

Teva, also based in Israel, had originally been looking to buy Prolor, but those discussions reportedly ended in March.

Barrington Research Associates Inc. was Opko’s financial adviser, while Akerman Senterfitt acted as legal counsel. Jefferies LLC acted as Prolor’s financial adviser, and Greenberg Traurig PA provided legal advice. DLA Piper LLP provided legal counsel to Prolor’s strategic alternatives committee, and Oppenheimer & Co. provided a fairness opinion to the committee.

In April, Opko bought a 10 percent stake in Oao Pharmsynthez, a Russian pharmaceutical company. In August, the company purchased Farmadiet Group Holding SL, a company that develops and makes veterinary products.