Biotech Lev Pharmaceuticals Inc, bought in July by rival ViroPharma Inc, has had its first drug on the market approved by the Food and Drug Administration (FDA): Cinryze, which had been granted orphan drug status due to its design for a genetic disorder that affects some 10,000 Americans, hereditary angioedema, which causes inflammation in the face, hands intestinal tract or airways, and can lead to death.

Lev´s Cinryze is the first genetically engineered C1 inhibitor to be approved in the U.S., a replacement protein derived from human plasma that helps regulate inflammation in the body. Lev has managed to move ahead of other companies developing HAE-fighting drugs, such as CSL Ltd., Pharming Group NV and Germany´s Jerini AG (Shire Plc), who´s Firazyr (icatibant) was rejected by the FDA last month.

Because Cinryze has orphan drug status, similar medicines may be prevented from entering the U.S. market for seven years. The drug had received unanimous approval by an FDA advisory committee in May.

Cinryze is administered intravenously and can be given every three or four days for routine prevention of HAE attacks, according to the FDA.

Cinryze´s approval was based on a Phase III trial called CHANGE, a double-blind study conducted in the U.S. with a total of 71 patients, randomized to either C1-INH (Cinryze) or placebo. The primary endpoint was met, with a median time to sustained symptom relief of 2.0 hours for patients receiving C1-INH compared to greater than four hours, the maximum evaluation period, for patients receiving placebo (p=0.026).

Additionally, 21 out of 21 laryngeal attacks were successfully treated with open-label C1-INH.

ViroPharma, based in Exton, Pennsylvania, agreed on July 15 to buy Lev for $ 442.9 million dollars, which analysts said at the time was too high a price to pay. According to another analyst, annual sales of Cinryze may reach $ 144 million dollars by 2010.

The FDA required Lev to do a study tracking the safety of Cinryze after it comes on the market, the company said in its statement. Lev also said it will submit a supplemental application seeking approval to use the drug for acute treatment of HAE attacks.