17-Mar-09 11:29 Viropharma's Cinryze regarded as reliable and safe, but IV delivery does not meet acute treatment challenges, physicians say
Story Viropharma's (NASDAQ:VPHM) Cinryze, currently approved for prophylaxis of hereditary angioedema (HAE), is effective and safe, but treatment through IV administration will be a challenge for acute attacks, physicians said.
Cinryze has a PDUFA date set for 3 June 2009.
Hereditary angioedema (HAE) is a rare disorder caused by deficient or improper function of the plasma protein C1 inhibitor (C1-INH). It causes swelling in various parts of the body, and can be fatal when swelling occurs in the larynx. The disease presentation varies widely; attacks may be weekly in severe cases while other individuals experience only one or two attacks a year.
Cinryze is a human-derived C1 esterase inhibitor that targets the underlying cause of HAE. C1 inhibitors are the standard of care in Europe, but are not currently approved in the US for acute attacks. There are no marketed treatments available for acute attacks of HAE in the US. Cinryze was approved for routine prophylaxis against angioedema in adolescent and adult patients with HAE in October 2008, with a December 2008 launch.
Dr Marc Riedl, an immunologist at the David Geffen School of Medicine at UCLA, said he believes that the efficacy data for all acute HAE agents is fairly compelling, but the positive factors are "somewhat offset by the logistics and complexity of arranging for quick and efficient IV administration." Two therapies in the pipeline for acute attacks of HAE, ecallantide (Dyax's DX-88) and icatibant (Shire's Firazyr), could be administered subcutaneously, and there is a clear advantage to those agents from their delivery, he added.
Viropharma CEO Van Milano said he believes that Cinryze is uniquely positioned for acute treatment as it represents one solution for all HAE patients, should the drug receive approval for acute treatment of HAE.
Dyax's (NASDAQ:DYAX) DX-88 has a PDUFA date set for 23 March 2009. Although an FDA advisory committee voted last month to recommend DX-88 for approval, members raised safety concerns, including anaphylaxis. Although the DX-88 decision remains to be seen, the history of safe use for Cinryze is a competitive advantage, Milano said.
C1 inhibitors have been widely used in Europe and work well for both prophylaxis and acute attacks, according to Dr Andreas Lehmann, an immunologist at the clinic for Anesthesiology and Operative Intensive Medicine, Germany. But all of the drugs currently being tested will be effective, he added.
Dr Hilary Longhurst, a consultant immunologist at Barts and the London NHS Trust, said C1 inhibitors are the gold standard in Europe for HAE. But the difficulty in treating acute episodes is that intermittent swellings can happen anytime and can be triggered by other health conditions, she said. And not everyone is set up for continuous treatment, especially those who get infrequent attacks and seek treatment only for acute care, she added. Even in a healthcare setting, the subcutaneous form would be easier to administer, especially for the family practitioner who may not be as inclined to administer IV therapy, she said.
Viropharma has a market cap of 323.56m.
by Janan Cargile
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