Shares of



jumped Friday morning after the company said the Food and Drug Administration had allowed it to resume clinical trials on a rare genetic disorder.

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Recently, the stock gained $2.42, or 22.2%, to $13.32, winning back much of the value lost May 25 when the FDA placed a 'clinical hold' on the company's research. The stock sank by 29% that day.

The FDA had asked Dyax to provide more information about some animal tests involving the experimental drug DX-88. The FDA's action, which didn't affect ongoing tests on humans, temporarily suspended the clinical trials on the drug being tested as a treatment for hereditary angioedema. This disease causes acute attacks of swelling over certain parts of the body.

At the time, Henry E. Blair, Dyax's chairman and CEO, said the matter would be resolved in a few weeks, and his prediction was correct. "I'm very pleased with how rapidly this matter has been resolved with the FDA," Blair said Friday.

The Cambridge, Mass.-based Dyax said Friday that it will "collaborate closely" with the FDA to design additional animals studies "in support of potential product approval." Dyax is working with


( GENZ) to develop the drug for the rare disease. The DX-88 research is now in phase II human testing, the second of three clinical trials on the path toward seeking FDA approval. The companies expect to announce results this month.

Independently, Dyax is in the early stages of trying to develop DX-88 as a treatment for patients undergoing coronary artery bypass surgery.