BERLIN, June 2 (Reuters) - Morphosys on Wednesday said it will acquire U.S. cancer specialist Constellation Pharmaceuticals in a $1.7 billion deal that will enable the German biotech firm to add two final-stage cancer drugs to its portfolio. Morphosys will pay $34.00 per share in cash, representing a premium of about 68% on Tuesday's closing price. The transaction in expected to close in the third quarter, it said.

Shares in Morphosys dropped on the news and were down 9.7% at 1203 GMT. (Reporting by Riham Alkousaa, editing by Kirsti Knolle)