Dyax approaching its PDUFA Date (DYAX)

On 8 June 2009, Dyax Corp. (NASDAQ:DYAX), a clinical stage biopharmaceutical company that discovers, develops and commercializes biotherapeutics for inflammatory and oncology diseases, announced that it had obtained from the US Food and Drug Administration a new “Prescription Drug User Fee Act” (PDUFA) anticipated target action date of December 1, 2009 for its drug DX-88. The PDUFA would allow the FDA to collect fees from DYAX for reviewing its drug application.

The 8 June announcement came after Dyax submitted a “Risk Evaluation and Mitigation Strategy (REMS)” and supporting information concerning the “chemistry, manufacturing and controls (CMC)” section of the Biologic License Application (BLA) of DX-88. The REMS was mainly a modification of the company’s already proposed Safe Use program while the CMC questions focused on “analytical methodologies and specifications and validation activities in support of drug product filling and packaging”.

The initial PDUFA date was 23 March. However, on 26 March, Dyax acknowledged that the FDA asked the company to submit the REMS and other relevant information. The submission of the REMS was absolutely mandatory for the approval of DX-88 for treating “acute attacks” of hereditary angioedema (HAE).

“We are confident that our proposed REMS for assuring the safe use of DX-88 and our response to other FDA requests thoroughly address the matters raised in the agency’s letter,” said Gustav A. Christensen, President and Chief Executive Officer of Dyax.

Dyax Corp. submitted the BLA, which relied on data collected from two placebo-controlled Phase 3 clinical trials in which DX-88 showed “statistically significant improvements”, on 23 September 2008. The previous PDUFA date of 23 March 2009 was handed by the FDA after accepting the application. In February 2009, the FDA Pulmonary-Allergy Advisory Committee voted in favor of approving DX-88.

DX-88, also known as ecallantide, was discovered by Dyax’s drug discovery technology, otherwise known as phage display technology. DX-88 is a “potent and selective plasma kallikrein inhibitor” and prevents inflammation in angioedema. If approved by the FDA, it would be the only drug for treating acute attacks of HAE in the U.S. HAE is an inherited disease caused by low levels of the plasma protein C1 inhibitor (C1-INH). It causes painful swelling of the genitalia, gastrointestinal tract, and the larynx.

“With no treatment approved for acute attacks of HAE in the U.S., a new therapy for this debilitating and life-threatening disease remains a priority,” said Gustav A. Christensen. “DX-88 meets a number of criteria cited as important by both patients and physicians and was tested in a Phase 3 clinical program representing the largest placebo-controlled evaluation of any drug developed to treat this disease.”