* Dyax to get $2.5 mln upfront
* Eligible to get over $100 mln in milestone payments
* Sigma-Tau to buy Dyax shares worth $2.5 mln
June 21 (Reuters) - Dyax Corp DYAX.O and a unit of Italy-based Sigma-Tau SpA said they agreed to develop Dyax's DX-88 for hereditary angioedema and other indications, and market it in Europe, North Africa, the Middle East and Russia.
Under the terms of the deal, Sigma-Tau will make a $2.5 million upfront payment to Dyax and will also buy $2.5 million of Dyax's shares at a 50 percent premium to market value, the companies said.
Dyax will also be eligible to receive over $100 million in development and sales milestones and royalties equal to 41 percent of net sales of product, they said.
Dyax retains its rights to the drug DX-88, also known as ecallantide, in other territories, and also in the United States, where it is sold under the brand name Kalbitor, the companies said.
The drug has got U.S. Food and Drug Administration approval for the treatment of acute attacks of hereditary angioedema (HAE) in patients 16 years of age and older.
HAE is an inherited disorder that causes painful swelling of the skin, intestine, mouth and sometimes the throat. The throat swelling can be fatal.
Shares of Dyax closed at $2.68 Friday on Nasdaq. (Reporting by Shailesh Kuber in Bangalore; Editing by Vyas Mohan)