Dyax investors bid up shares on FDA's Kalbitor approval

Dyax shares rocketed up 38 percent yesterday evening after the developer announced that the FDA had approved its lead drug Kalbitor (also known as ecallantide or DX-88) for patients with hereditary angioedema, a rare and often lethal genetic disease characterized by pain and swelling in the face, lungs and upper airway.

As Xconomy notes, the approval marks a big win for Cambridge, MA-based Dyax, which has gone $335 million in the red as it pursued clinical development work. Kalbitor will be the 14-year-old biotech company's first marketed therapy. Dyax also licenses out its phage display technology to researchers.

Only some 6,000 to 30,000 Americans suffer from the condition. Dyax announced last week that it had inked a deal with AmerisourceBergen Corp. to distribute the drug and set up call centers for patients. It will be competing with Viropharma, which also sells a drug for HAE, and CSL Behring, which recently won approval for an HAE drug limited to patients suffering attacks in the face and abdomen.

"By specifically affecting a key mediator of the inflammation, pain and edema that are characteristic of HAE attacks, Kalbitor may be advantageous in offering physicians a targeted approach for treating acute attacks," said professor Jonathan Bernstein, MD, department of internal medicine, division of immunology/allergy, at the University of Cincinnati College of Medicine. "Additionally, the subcutaneous route of administration and efficacy in treating acute attacks in patients 16 years of age and older, regardless of anatomic location, make Kalbitor an important treatment option."

- here's the press release
- check out the Xconomy story